feat: implemented a* algorithm

was actually dfs lol

.github/workflows/automatic-prerelease.yml

@@ -0,0 +1,33 @@
+---
+name: "pre-release"
+
+on:
+  push:
+    branches:
+      - "main"
+
+jobs:
+  pre-release:
+    name: "Pre Release"
+    runs-on: "ubuntu-latest"
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: "1.21"
+
+      - name: Build
+        run: go build -v ./...
+
+      - name: Test
+        run: go test -v ./...
+
+      - uses: "marvinpinto/action-automatic-releases@latest"
+        with:
+          repo_token: "${{ secrets.GITHUB_TOKEN }}"
+          automatic_release_tag: "latest"
+          prerelease: true
+          title: "Development Build"

.github/workflows/tagged-release.yml

@@ -0,0 +1,31 @@
+---
+name: "tagged-release"
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  tagged-release:
+    name: "Tagged Release"
+    runs-on: "ubuntu-latest"
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: "1.21"
+
+      - name: Build
+        run: go build -v ./...
+
+      - name: Test
+        run: go test -v ./...
+
+      - uses: "marvinpinto/action-automatic-releases@latest"
+        with:
+          repo_token: "${{ secrets.GITHUB_TOKEN }}"
+          prerelease: false

.gitignore

@@ -20,3 +20,5 @@
 # Go workspace file
 go.work
 /Session.vim
+/maze.png
+/maze_sol.png

assets/normal2.txt

@@ -0,0 +1,15 @@
+####### #######
+#   #       # #
+### # ##### # #
+#   #     #   #
+# ########### #
+#     #     # #
+### # # ##### #
+#   #   #   # #
+# ### ### # # #
+# #   #   #   #
+# ### # #######
+#   # # #     #
+# # ### ### # #
+# #         # #
+####### #######

assets/trivial-bigger-staggered.txt

@@ -0,0 +1,5 @@
+### ###
+### ###
+#     #
+#### ##
+#### ##

assets/trivial-bigger.txt

@@ -0,0 +1,5 @@
+### ###
+### ###
+#     #
+##### #
+##### #

go.mod

@@ -1,3 +1,15 @@
 module maze-solver
 
-go 1.20
+go 1.21
+
+require (
+	github.com/akamensky/argparse v1.4.0
+	github.com/mazznoer/colorgrad v0.9.1
+	golang.org/x/exp v0.0.0-20230801115018-d63ba01acd4b
+)
+
+require (
+	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/mazznoer/csscolorparser v0.1.2 // indirect
+	golang.org/x/image v0.11.0
+)

go.sum

@@ -0,0 +1,43 @@
+github.com/akamensky/argparse v1.4.0 h1:YGzvsTqCvbEZhL8zZu2AiA5nq805NZh75JNj4ajn1xc=
+github.com/akamensky/argparse v1.4.0/go.mod h1:S5kwC7IuDcEr5VeXtGPRVZ5o/FdhcMlQz4IZQuw64xA=
+github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
+github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
+github.com/mazznoer/colorgrad v0.9.1 h1:MB80JYVndKWSMEM1beNqnuOowWGhoQc3DXWXkFp6JlM=
+github.com/mazznoer/colorgrad v0.9.1/go.mod h1:WX2R9wt9B47+txJZVVpM9LY+LAGIdi4lTI5wIyreDH4=
+github.com/mazznoer/csscolorparser v0.1.2 h1:/UBHuQg792ePmGFzTQAC9u+XbFr7/HzP/Gj70Phyz2A=
+github.com/mazznoer/csscolorparser v0.1.2/go.mod h1:Aj22+L/rYN/Y6bj3bYqO3N6g1dtdHtGfQ32xZ5PJQic=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/exp v0.0.0-20230801115018-d63ba01acd4b h1:r+vk0EmXNmekl0S0BascoeeoHk/L7wmaW2QF90K+kYI=
+golang.org/x/exp v0.0.0-20230801115018-d63ba01acd4b/go.mod h1:FXUEEKJgO7OQYeo8N01OfiKP8RXMtf6e8aTskBGqWdc=
+golang.org/x/image v0.11.0 h1:ds2RoQvBvYTiJkwpSFDwCcDFNX7DqjL2WsUgTNk0Ooo=
+golang.org/x/image v0.11.0/go.mod h1:bglhjqbqVuEb9e9+eNR45Jfu7D+T4Qan+NhQk8Ck2P8=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/text v0.12.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

io/reader/image.go

@@ -1,9 +1,76 @@
 package reader
 
-import "maze-solver/maze"
+import (
+	"image"
+	"image/color"
+	"image/png"
+	"maze-solver/utils"
+	"os"
 
-type ImageReader struct{}
+	"golang.org/x/image/draw"
+)
 
-func (r *ImageReader) Read(filename string) (*maze.Maze, error) {
-	return nil, nil
+type ImageReader struct {
+	Filename              string
+	PathColor, WallColor  color.Color
+	CellWidth, CellHeight int
+}
+
+func (r *ImageReader) Read() (*RawMaze, error) {
+	defer utils.Timer("Image reader", 3)()
+	image, err := r.getShrunkImage()
+	if err != nil {
+		return nil, err
+	}
+
+	width, height := image.Bounds().Max.X, image.Bounds().Max.Y
+	ret := &RawMaze{
+		Width:  width,
+		Height: height,
+		Data:   make([][]byte, height),
+	}
+
+	n_chunks := width/CHUNK_SIZE + 1
+
+	for i := 0; i < height; i++ {
+		ret.Data[i] = make([]byte, n_chunks)
+	}
+
+	for y := 0; y < height; y++ {
+		for i := 0; i < n_chunks; i++ {
+			var chunk byte = 0 // all walls
+
+			end_index := min((i+1)*CHUNK_SIZE, width)
+
+			for x := i * CHUNK_SIZE; x < end_index; x++ {
+				c := image.At(x, y)
+				if c == r.PathColor {
+					chunk |= 1 << (CHUNK_SIZE - 1 - (x - i*CHUNK_SIZE))
+				}
+			}
+
+			ret.Data[y][i] = chunk
+		}
+	}
+
+	return ret, nil
+}
+
+func (r *ImageReader) getShrunkImage() (*image.RGBA, error) {
+	input, err := os.Open(r.Filename)
+	if err != nil {
+		return nil, err
+	}
+	defer input.Close()
+
+	// Decode the image (from PNG to image.Image):
+	src, _ := png.Decode(input)
+
+	// Set the expected size that you want:
+	dst := image.NewRGBA(image.Rect(0, 0, src.Bounds().Max.X/r.CellWidth, src.Bounds().Max.Y/r.CellHeight))
+
+	// Resize:
+	draw.NearestNeighbor.Scale(dst, dst.Rect, src, src.Bounds(), draw.Over, nil)
+
+	return dst, nil
 }

io/reader/image_test.go

@@ -0,0 +1,136 @@
+package reader
+
+import (
+	"image/color"
+	"maze-solver/utils"
+	"testing"
+)
+
+func TestImageReader(t *testing.T) {
+	white := color.RGBA{255, 255, 255, 255}
+	black := color.RGBA{0, 0, 0, 255}
+	tests := []struct {
+		name                  string
+		width, height         int
+		cellWidth, cellHeight int
+		pathColor, wallColor  color.Color
+		filename              string
+		expected              [][]byte
+	}{
+		{
+			"Trivial",
+			5, 3,
+			40, 40,
+			white, black,
+			"../../assets/trivial.png",
+			[][]byte{
+				{0b_00100_000},
+				{0b_01110_000},
+				{0b_00010_000},
+			},
+		},
+		{
+			"Trivial Bigger",
+			7, 5,
+			40, 40,
+			white, black,
+			"../../assets/trivial-bigger.png",
+			[][]byte{
+				{0b_0001000_0},
+				{0b_0001000_0},
+				{0b_0111110_0},
+				{0b_0000010_0},
+				{0b_0000010_0},
+			},
+		},
+		{
+			"Bigger Staggered",
+			7, 5,
+			40, 40,
+
+			white, black,
+			"../../assets/trivial-bigger-staggered.png",
+			[][]byte{
+				{0b_0001000_0},
+				{0b_0001000_0},
+				{0b_0111110_0},
+				{0b_0000100_0},
+				{0b_0000100_0},
+			},
+		},
+		{
+			"Normal",
+			11, 11,
+			40, 40,
+			white, black,
+			"../../assets/normal.png",
+			[][]byte{
+				{0b_00000100, 0b000_00000},
+				{0b_01111101, 0b110_00000},
+				{0b_00000100, 0b010_00000},
+				{0b_01110111, 0b110_00000},
+				{0b_01010000, 0b010_00000},
+				{0b_01011111, 0b110_00000},
+				{0b_00010001, 0b010_00000},
+				{0b_01110111, 0b010_00000},
+				{0b_01000000, 0b010_00000},
+				{0b_01111101, 0b110_00000},
+				{0b_00000100, 0b000_00000},
+			},
+		},
+		{
+			"Normal2",
+			15, 15,
+			20, 20,
+			white, black,
+			"../../assets/normal2.png",
+			[][]byte{
+				{0b00000001, 0b0000000_0},
+				{0b01110111, 0b1111010_0},
+				{0b00010100, 0b0001010_0},
+				{0b01110111, 0b1101110_0},
+				{0b01000000, 0b0000010_0},
+				{0b01111101, 0b1111010_0},
+				{0b00010101, 0b0000010_0},
+				{0b01110111, 0b0111010_0},
+				{0b01000100, 0b0101010_0},
+				{0b01011101, 0b1101110_0},
+				{0b01000101, 0b0000000_0},
+				{0b01110101, 0b0111110_0},
+				{0b01010001, 0b0001010_0},
+				{0b01011111, 0b1111010_0},
+				{0b00000001, 0b0000000_0},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		reader := ImageReader{
+			Filename:   test.filename,
+			PathColor:  test.pathColor,
+			WallColor:  test.wallColor,
+			CellWidth:  test.cellWidth,
+			CellHeight: test.cellHeight,
+		}
+		got, err := reader.Read()
+		if err != nil {
+			t.Fatalf("%s: got error while reading, got\n%v", test.filename, err)
+		}
+
+		utils.AssertEqual(t, got.Width, test.width, "%s: width of raw maze don't match", test.name)
+		utils.AssertEqual(t, got.Height, test.height, "%s: height of raw maze don't match", test.name)
+		utils.AssertEqual(t, len(got.Data), len(test.expected), "%s: don't have the same number of rows", test.name)
+
+		for y, line_exp := range test.expected {
+			line_got := got.Data[y]
+			utils.AssertEqual(t, len(line_got), len(line_exp), "%s (line %v): don't have same number of chunks", test.name, y)
+
+			for i, chunk_exp := range line_exp {
+				chunk_got := line_got[i]
+				if chunk_got != chunk_exp {
+					t.Fatalf("%s (line %v): chunk %v don't coincide, %08b, want %08b", test.name, y, i, chunk_got, chunk_exp)
+				}
+			}
+		}
+	}
+}

io/reader/raw_maze.go

@@ -0,0 +1,41 @@
+package reader
+
+import (
+	"strings"
+)
+
+const CHUNK_SIZE = 8 // size of a byte
+
+type RawMaze struct {
+	Width, Height int
+	Data          [][]byte
+}
+
+func (m *RawMaze) String() string {
+	var ret strings.Builder
+	ret.WriteString("{\n")
+	ret.WriteString("\tData: \n")
+	for _, line := range m.Data {
+		ret.WriteRune('\t')
+		ret.WriteRune('\t')
+		ret.Write(line) // TODO: prolly should fix this to make it readable
+		ret.WriteRune('\n')
+	}
+	ret.WriteString("}")
+
+	return ret.String()
+}
+
+func (m *RawMaze) IsPath(x int, y int) bool {
+	chunk_index := x / CHUNK_SIZE
+	chunk_rest := x % CHUNK_SIZE
+	chunk := m.Data[y][chunk_index]
+	return chunk&(1<<(CHUNK_SIZE-1-chunk_rest)) != 0
+}
+
+func (m *RawMaze) IsWall(x int, y int) bool {
+	chunk_index := x / CHUNK_SIZE
+	chunk_rest := x % CHUNK_SIZE
+	chunk := m.Data[y][chunk_index]
+	return chunk&(1<<(CHUNK_SIZE-1-chunk_rest)) == 0
+}

io/reader/raw_maze_test.go

@@ -0,0 +1,220 @@
+package reader
+
+import "testing"
+
+func TestRawMazeWall(t *testing.T) {
+	tests := []struct {
+		name               string
+		width, height      int
+		pathChar, wallChar byte
+		data               []string
+		expected           [][]bool
+	}{
+		{
+			"Trivial",
+			5, 3,
+			' ', '#',
+			[]string{
+				"## ##",
+				"#   #",
+				"### #",
+			},
+			[][]bool{
+				{true, true, false, true, true},
+				{true, false, false, false, true},
+				{true, true, true, false, true},
+			},
+		},
+		{
+			"Trivial Bigger",
+			7, 5,
+			' ', '#',
+			[]string{
+				"### ###",
+				"### ###",
+				"#     #",
+				"##### #",
+				"##### #",
+			},
+			[][]bool{
+				{true, true, true, false, true, true, true},
+				{true, true, true, false, true, true, true},
+				{true, false, false, false, false, false, true},
+				{true, true, true, true, true, false, true},
+				{true, true, true, true, true, false, true},
+			},
+		},
+		{
+			"Bigger Staggered",
+			7, 5,
+			' ', '#',
+			[]string{
+				"### ###",
+				"### ###",
+				"#     #",
+				"#### ##",
+				"#### ##",
+			},
+			[][]bool{
+				{true, true, true, false, true, true, true},
+				{true, true, true, false, true, true, true},
+				{true, false, false, false, false, false, true},
+				{true, true, true, true, false, true, true},
+				{true, true, true, true, false, true, true},
+			},
+		},
+		{
+			"Normal",
+			11, 11,
+			' ', '#',
+			[]string{
+				"##### #####",
+				"#     #   #",
+				"##### ### #",
+				"#   #     #",
+				"# # ##### #",
+				"# #       #",
+				"### ### # #",
+				"#   #   # #",
+				"# ####### #",
+				"#     #   #",
+				"##### #####",
+			},
+			[][]bool{
+				{true, true, true, true, true, false, true, true, true, true, true},
+				{true, false, false, false, false, false, true, false, false, false, true},
+				{true, true, true, true, true, false, true, true, true, false, true},
+				{true, false, false, false, true, false, false, false, false, false, true},
+				{true, false, true, false, true, true, true, true, true, false, true},
+				{true, false, true, false, false, false, false, false, false, false, true},
+				{true, true, true, false, true, true, true, false, true, false, true},
+				{true, false, false, false, true, false, false, false, true, false, true},
+				{true, false, true, true, true, true, true, true, true, false, true},
+				{true, false, false, false, false, false, true, false, false, false, true},
+				{true, true, true, true, true, false, true, true, true, true, true},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		reader := StringsReader{
+			PathChar: test.pathChar,
+			WallChar: test.wallChar,
+			Lines:    &test.data,
+		}
+		rawMaze, _ := reader.Read()
+		for y, row := range test.expected {
+			for x, expected := range row {
+				if rawMaze.IsWall(x, y) != expected {
+					t.Fatalf("%s: Wanted wall at (%v, %v), apparently it isn't", test.name, x, y)
+				}
+			}
+		}
+	}
+}
+
+func TestRawMazePath(t *testing.T) {
+	tests := []struct {
+		name          string
+		width, height int
+		data          [][]byte
+		expected      [][]bool
+	}{
+		{
+			"Trivial",
+			5, 3,
+			[][]byte{
+				{0b_00100_000},
+				{0b_01110_000},
+				{0b_00010_000},
+			},
+			[][]bool{
+				{false, false, true, false, false},
+				{false, true, true, true, false},
+				{false, false, false, true, false},
+			},
+		},
+		{
+			"Trivial Bigger",
+			7, 5,
+			[][]byte{
+				{0b_0001000_0},
+				{0b_0001000_0},
+				{0b_0111110_0},
+				{0b_0000010_0},
+				{0b_0000010_0},
+			},
+			[][]bool{
+				{false, false, false, true, false, false, false},
+				{false, false, false, true, false, false, false},
+				{false, true, true, true, true, true, false},
+				{false, false, false, false, false, true, false},
+				{false, false, false, false, false, true, false},
+			},
+		},
+		{
+			"Bigger Staggered",
+			7, 5,
+			[][]byte{
+				{0b_0001000_0},
+				{0b_0001000_0},
+				{0b_0111110_0},
+				{0b_0000100_0},
+				{0b_0000100_0},
+			},
+			[][]bool{
+				{false, false, false, true, false, false, false},
+				{false, false, false, true, false, false, false},
+				{false, true, true, true, true, true, false},
+				{false, false, false, false, true, false, false},
+				{false, false, false, false, true, false, false},
+			},
+		},
+		{
+			"Normal",
+			11, 11,
+			[][]byte{
+				{0b_00000100, 0b000_00000},
+				{0b_01111101, 0b110_00000},
+				{0b_00000100, 0b010_00000},
+				{0b_01110111, 0b110_00000},
+				{0b_01010000, 0b010_00000},
+				{0b_01011111, 0b110_00000},
+				{0b_00010001, 0b010_00000},
+				{0b_01110111, 0b010_00000},
+				{0b_01000000, 0b010_00000},
+				{0b_01111101, 0b110_00000},
+				{0b_00000100, 0b000_00000},
+			},
+			[][]bool{
+				{false, false, false, false, false, true, false, false, false, false, false},
+				{false, true, true, true, true, true, false, true, true, true, false},
+				{false, false, false, false, false, true, false, false, false, true, false},
+				{false, true, true, true, false, true, true, true, true, true, false},
+				{false, true, false, true, false, false, false, false, false, true, false},
+				{false, true, false, true, true, true, true, true, true, true, false},
+				{false, false, false, true, false, false, false, true, false, true, false},
+				{false, true, true, true, false, true, true, true, false, true, false},
+				{false, true, false, false, false, false, false, false, false, true, false},
+				{false, true, true, true, true, true, false, true, true, true, false},
+				{false, false, false, false, false, true, false, false, false, false, false},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		rawMaze := RawMaze{
+			Width:  test.width,
+			Height: test.height,
+			Data:   test.data,
+		}
+
+		for y, row := range test.expected {
+			for x, expected := range row {
+				if rawMaze.IsPath(x, y) != expected {
+					t.Fatalf("%s: Wanted path at (%v, %v), apparently it isn't", test.name, x, y)
+				}
+			}
+		}
+	}
+}

io/reader/reader.go

@@ -1,7 +1,48 @@
 package reader
 
-import "maze-solver/maze"
+import (
+	"fmt"
+	"image/color"
+)
 
 type Reader interface {
-	Read(filename string) (*maze.Maze, error)
+	Read() (*RawMaze, error)
+}
+
+type ReaderFactory struct {
+	Type                             string
+	Filename                         *string
+	PathChar, WallChar, SolutionChar *string
+	CellWidth, CellHeight            *int
+	WallColor, PathColor             color.Color
+}
+
+const (
+	_IMAGE = "image"
+	_TEXT  = "text"
+)
+
+var TYPES = map[string]string{
+	".png": _IMAGE,
+	".txt": _TEXT,
+}
+
+func (f *ReaderFactory) Get() Reader {
+	switch f.Type {
+	case _TEXT:
+		return &TextReader{
+			Filename: *f.Filename,
+			PathChar: byte((*f.PathChar)[0]),
+			WallChar: byte((*f.WallChar)[0]),
+		}
+	case _IMAGE:
+		return &ImageReader{
+			Filename:   *f.Filename,
+			CellWidth:  *f.CellWidth,
+			CellHeight: *f.CellHeight,
+			WallColor:  f.WallColor,
+			PathColor:  f.PathColor,
+		}
+	}
+	panic(fmt.Sprintf("Unrecognized reader type %q", f.Type))
 }

io/reader/strings.go

@@ -0,0 +1,53 @@
+package reader
+
+import (
+	"fmt"
+	"maze-solver/utils"
+)
+
+type StringsReader struct {
+	PathChar, WallChar byte
+	Lines              *[]string
+}
+
+func (r *StringsReader) Read() (*RawMaze, error) {
+	defer utils.Timer("Strings Reader", 3)()
+	width, height := len((*r.Lines)[0]), len(*r.Lines)
+	ret := &RawMaze{
+		Width:  width,
+		Height: height,
+		Data:   make([][]byte, height),
+	}
+
+	for i := 0; i < height; i++ {
+		ret.Data[i] = make([]byte, width/CHUNK_SIZE+1)
+	}
+
+	for y, line := range *r.Lines {
+		r.processLine(line, &ret.Data[y])
+	}
+
+	return ret, nil
+}
+
+func (r *StringsReader) processLine(line string, dest *[]byte) {
+	n_chunks := len(line)/CHUNK_SIZE + 1
+
+	if len(*dest) != n_chunks {
+		panic(fmt.Sprintf("The row that should receive the chunks does not have the correct length (%v, want %v)", len(*dest), n_chunks))
+	}
+
+	for i := 0; i < n_chunks; i++ {
+		var chunk byte = 0 // all walls
+
+		end_index := utils.Min((i+1)*CHUNK_SIZE, len(line))
+
+		for x, c := range line[i*CHUNK_SIZE : end_index] {
+			if c == rune(r.PathChar) {
+				chunk |= 1 << (CHUNK_SIZE - 1 - x)
+			}
+		}
+
+		(*dest)[i] = chunk
+	}
+}

io/reader/strings_test.go

@@ -0,0 +1,131 @@
+package reader
+
+import (
+	"maze-solver/utils"
+	"testing"
+)
+
+func TestStringsReader(t *testing.T) {
+	tests := []struct {
+		name          string
+		width, height int
+		pathChar      byte
+		wallChar      byte
+		lines         []string
+		expected      [][]byte
+	}{
+		{
+			"Trivial",
+			5, 3,
+			' ',
+			'#',
+			[]string{
+				"## ##",
+				"#   #",
+				"### #",
+			},
+			[][]byte{
+				{0b_00100_000},
+				{0b_01110_000},
+				{0b_00010_000},
+			},
+		},
+		{
+			"Trivial Bigger",
+			7, 5,
+			' ',
+			'#',
+			[]string{
+				"### ###",
+				"### ###",
+				"#     #",
+				"##### #",
+				"##### #",
+			},
+			[][]byte{
+				{0b_0001000_0},
+				{0b_0001000_0},
+				{0b_0111110_0},
+				{0b_0000010_0},
+				{0b_0000010_0},
+			},
+		},
+		{
+			"Bigger Staggered",
+			7, 5,
+			' ',
+			'#',
+			[]string{
+				"### ###",
+				"### ###",
+				"#     #",
+				"#### ##",
+				"#### ##",
+			},
+			[][]byte{
+				{0b_0001000_0},
+				{0b_0001000_0},
+				{0b_0111110_0},
+				{0b_0000100_0},
+				{0b_0000100_0},
+			},
+		},
+		{
+			"Normal",
+			11, 11,
+			' ',
+			'#',
+			[]string{
+				"##### #####",
+				"#     #   #",
+				"##### ### #",
+				"#   #     #",
+				"# # ##### #",
+				"# #       #",
+				"### ### # #",
+				"#   #   # #",
+				"# ####### #",
+				"#     #   #",
+				"##### #####",
+			},
+			[][]byte{
+				{0b_00000100, 0b000_00000},
+				{0b_01111101, 0b110_00000},
+				{0b_00000100, 0b010_00000},
+				{0b_01110111, 0b110_00000},
+				{0b_01010000, 0b010_00000},
+				{0b_01011111, 0b110_00000},
+				{0b_00010001, 0b010_00000},
+				{0b_01110111, 0b010_00000},
+				{0b_01000000, 0b010_00000},
+				{0b_01111101, 0b110_00000},
+				{0b_00000100, 0b000_00000},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		reader := StringsReader{
+			PathChar: test.pathChar,
+			WallChar: test.wallChar,
+			Lines:    &test.lines,
+		}
+		got, _ := reader.Read()
+
+		utils.AssertEqual(t, got.Width, test.width, "%s: width of raw maze don't match", test.name)
+		utils.AssertEqual(t, got.Height, test.height, "%s: height of raw maze don't match", test.name)
+		utils.AssertEqual(t, len(got.Data), len(test.expected), "%s: don't have the same number of rows", test.name)
+
+		for y, line_exp := range test.expected {
+			line_got := got.Data[y]
+			utils.AssertEqual(t, len(line_got), len(line_exp), "%s (line %v): don't have same number of chunks, %v, want %v", test.name, y)
+
+			for i, chunk_exp := range line_exp {
+				chunk_got := line_got[i]
+				if chunk_got != chunk_exp {
+					t.Fatalf("%s (line %v): chunk %v don't coincide, %08b, want %08b", test.name, y, i, chunk_got, chunk_exp)
+				}
+			}
+		}
+	}
+}

io/reader/text.go

@@ -2,21 +2,33 @@ package reader
 
 import (
 	"bufio"
-	"fmt"
-	"maze-solver/maze"
+	"maze-solver/utils"
 	"os"
 )
 
 type TextReader struct {
+	Filename           string
 	PathChar, WallChar byte
 }
 
-func (r *TextReader) Read(filename string) (*maze.Maze, error) {
-	nodesByCoord := make(map[maze.Coordinates]*maze.Node)
+func (r *TextReader) Read() (*RawMaze, error) {
+	defer utils.Timer("Text Reader", 3)()
+	lines, err := getLines(r.Filename)
+	if err != nil {
+		return nil, err
+	}
+
+	strings_reader := StringsReader{
+		PathChar: r.PathChar,
+		WallChar: r.WallChar,
+		Lines:    lines,
+	}
+
+	return strings_reader.Read()
+}
+
+func getLines(filename string) (*[]string, error) {
 	var lines []string
-
-	ret := &maze.Maze{}
-
 	if _, err := os.Stat(filename); err != nil {
 		return nil, err
 	}
@@ -25,101 +37,15 @@ func (r *TextReader) Read(filename string) (*maze.Maze, error) {
 	if err != nil {
 		return nil, err
 	}
+	defer file.Close()
 
 	scanner := bufio.NewScanner(file)
 	scanner.Split(bufio.ScanLines)
 
-	y := 0
-	var line string
 	for scanner.Scan() {
-		line = scanner.Text()
-
-		if len(lines) == 0 {
-			lines = make([]string, 0, len(line))
-		}
-
-		for x := 1; x < len(line)-1; x++ {
-			char := line[x]
-			var left_char, right_char, above_char byte
-
-			if y > 0 {
-				left_char = line[x-1]
-				right_char = line[x+1]
-				above_char = lines[y-1][x]
-			}
-
-			// Parse first line to get entrance
-			if y == 0 && char == r.PathChar {
-				coords := maze.Coordinates{X: x, Y: y}
-				node := maze.NewNode(coords)
-				ret.Nodes = append(ret.Nodes, node)
-				nodesByCoord[coords] = node
-				continue
-			}
-
-			// Parse middle of the maze
-			if y > 0 && char == r.PathChar &&
-				(left_char == r.WallChar && right_char == r.PathChar ||
-					left_char == r.PathChar && right_char == r.WallChar ||
-					above_char == r.PathChar && (left_char == r.PathChar || right_char == r.PathChar)) {
-				coords := maze.Coordinates{X: x, Y: y}
-				node := maze.NewNode(coords)
-				ret.Nodes = append(ret.Nodes, node)
-				nodesByCoord[coords] = node
-
-				r.lookupNeighbourAbove(&lines, node, &nodesByCoord)
-				if left_char == r.PathChar && right_char == r.WallChar ||
-					above_char == r.PathChar && (left_char == r.PathChar || right_char == r.PathChar) {
-					r.lookupNeighbourLeft(&line, node, &nodesByCoord)
-				}
-			}
-		}
+		line := scanner.Text()
 		lines = append(lines, line)
-		y++
-	}
-	y--
-	// Parse last line to get exit
-	for x, rune := range line {
-		char := byte(rune)
-		if char == r.PathChar {
-			fmt.Printf("last line number: %v\n", y)
-			coords := maze.Coordinates{X: x, Y: y}
-			node := maze.NewNode(coords)
-			r.lookupNeighbourAbove(&lines, node, &nodesByCoord)
-			ret.Nodes = append(ret.Nodes, node)
-			break
-		}
 	}
 
-	return ret, nil
-}
-
-func (r *TextReader) lookupNeighbourAbove(lines *[]string, node *maze.Node, nodesByCoord *map[maze.Coordinates]*maze.Node) {
-	for y := node.Coords.Y - 1; y >= 0; y-- {
-		if (*lines)[y][node.Coords.X] == r.WallChar {
-			break
-		}
-
-		neighbour, ok := (*nodesByCoord)[maze.Coordinates{X: node.Coords.X, Y: y}]
-		if ok {
-			node.Up = neighbour
-			neighbour.Down = node
-		}
-	}
-}
-
-func (r *TextReader) lookupNeighbourLeft(line *string, node *maze.Node, nodesByCoord *map[maze.Coordinates]*maze.Node) {
-	for x := node.Coords.X - 1; x > 0; x-- {
-		if (*line)[x] == r.WallChar {
-			panic(fmt.Sprintf("Found no node before wall while looking to the left at neighbours of node %v", node))
-		}
-
-		neighbour, ok := (*nodesByCoord)[maze.Coordinates{X: x, Y: node.Coords.Y}]
-		if ok {
-			node.Left = neighbour
-			fmt.Printf("Setting left of %v to %v\n", node.Coords, neighbour.Coords)
-			neighbour.Right = node
-			break
-		}
-	}
+	return &lines, nil
 }

io/reader/text_test.go

@@ -1,81 +1,105 @@
 package reader
 
 import (
-	"fmt"
-	"maze-solver/maze"
 	"maze-solver/utils"
+	"reflect"
 	"testing"
 )
 
-func TestTextRead(t *testing.T) {
-	/* trivial.txt
-	   ## ##
-	   #   #
-	   ### #
-
-	   Nodes are
-	   ##0##
-	   #123#
-	   ###4#
-	*/
-	nodes := make([]*maze.Node, 5)
-
-	nodes[0] = maze.NewNode(maze.Coordinates{X: 2, Y: 0})
-
-	nodes[1] = maze.NewNode(maze.Coordinates{X: 1, Y: 1})
-	nodes[2] = maze.NewNode(maze.Coordinates{X: 2, Y: 1})
-	nodes[3] = maze.NewNode(maze.Coordinates{X: 3, Y: 1})
-
-	nodes[4] = maze.NewNode(maze.Coordinates{X: 3, Y: 2})
-
-	nodes[0].Down = nodes[2]
-
-	nodes[1].Right = nodes[2]
-
-	nodes[2].Up = nodes[0]
-	nodes[2].Left = nodes[1]
-	nodes[2].Right = nodes[3]
-
-	nodes[3].Left = nodes[2]
-	nodes[3].Down = nodes[4]
-
-	nodes[4].Up = nodes[3]
+func TestTextReadTrivial(t *testing.T) {
+	tests := []struct {
+		name     string
+		filename string
+		pathChar byte
+		wallChar byte
+		expected *RawMaze
+	}{
+		{
+			"Trivial",
+			"../../assets/trivial.txt",
+			' ',
+			'#',
+			&RawMaze{
+				Width:  5,
+				Height: 3,
+				Data: [][]byte{
+					{0b_00100_000},
+					{0b_01110_000},
+					{0b_00010_000},
+				},
+			},
+		},
+		{
+			"Trivial Bigger",
+			"../../assets/trivial-bigger.txt",
+			' ',
+			'#',
+			&RawMaze{
+				Width:  7,
+				Height: 5,
+				Data: [][]byte{
+					{0b_0001000_0},
+					{0b_0001000_0},
+					{0b_0111110_0},
+					{0b_0000010_0},
+					{0b_0000010_0},
+				},
+			},
+		},
+		{
+			"Bigger Staggered",
+			"../../assets/trivial-bigger-staggered.txt",
+			' ',
+			'#',
+			&RawMaze{
+				Width:  7,
+				Height: 5,
+				Data: [][]byte{
+					{0b_0001000_0},
+					{0b_0001000_0},
+					{0b_0111110_0},
+					{0b_0000100_0},
+					{0b_0000100_0},
+				},
+			},
+		},
+		{
+			"Normal",
+			"../../assets/normal.txt",
+			' ',
+			'#',
+			&RawMaze{
+				Width:  11,
+				Height: 11,
+				Data: [][]byte{
+					{0b_00000100, 0b000_00000},
+					{0b_01111101, 0b110_00000},
+					{0b_00000100, 0b010_00000},
+					{0b_01110111, 0b110_00000},
+					{0b_01010000, 0b010_00000},
+					{0b_01011111, 0b110_00000},
+					{0b_00010001, 0b010_00000},
+					{0b_01110111, 0b010_00000},
+					{0b_01000000, 0b010_00000},
+					{0b_01111101, 0b110_00000},
+					{0b_00000100, 0b000_00000},
+				},
+			},
+		},
+	}
 
+	for _, test := range tests {
 		reader := TextReader{
-		PathChar: ' ',
-		WallChar: '#',
+			Filename: test.filename,
+			PathChar: test.pathChar,
+			WallChar: test.wallChar,
 		}
 
-	filename := "../../assets/trivial.txt"
-	got, err := reader.Read(filename)
-	utils.Check(err, "Couldn't create maze from %q", filename)
+		got, err := reader.Read()
+		utils.Check(err, "Couldn't read file %q", reader.Filename)
 
-	if len(nodes) != len(got.Nodes) {
-		t.Fatalf("Didn't get the same size of nodes: %v, want %v", len(got.Nodes), len(nodes))
-	}
-
-	for i, got := range got.Nodes {
-		fmt.Println(i)
-		expected := nodes[i]
-
-		checkNode(t, i, got, expected, "")
-		checkNode(t, i, got.Left, expected.Left, "left")
-		checkNode(t, i, got.Right, expected.Right, "Right")
-		checkNode(t, i, got.Up, expected.Up, "Up")
-		checkNode(t, i, got.Down, expected.Down, "Down")
+		if !reflect.DeepEqual(got, test.expected) {
+			t.Fatalf("%s: lexed mazes do not match\nGot: %v\nWant: %v", test.name, got, test.expected)
 		}
 	}
-
-func checkNode(t *testing.T, i int, got *maze.Node, expected *maze.Node, side string) {
-	if expected == nil {
-		return
-	}
-
-	if got == nil {
-		t.Fatalf("No %s node of %v, want %v", side, i, expected.Coords)
-	}
-
-	if got.Coords != expected.Coords {
-		t.Fatalf("Coords %s node of %v: %v, but want %v", side, i, got.Coords, expected.Coords)
-	}
 }

io/writer/image.go

@@ -1,11 +1,123 @@
 package writer
 
 import (
+	"errors"
+	"image"
+	"image/color"
+	"image/draw"
+	"image/png"
 	"maze-solver/maze"
+	"maze-solver/utils"
+	"os"
+
+	"github.com/mazznoer/colorgrad"
 )
 
-type ImageWriter struct{}
+type ImageWriter struct {
+	Filename              string
+	Maze                  *maze.SolvedMaze
+	CellWidth, CellHeight int
+	WallColor, PathColor  color.Color
+	SolutionGradient      colorgrad.Gradient
+	img                   *image.RGBA
+}
 
-func (w *ImageWriter) Write(filename string, maze *maze.SolvedMaze) error {
+func (w *ImageWriter) Write() error {
+	defer utils.Timer("Image writer", 3)()
+	if w.Filename[len(w.Filename)-4:] != ".png" {
+		return errors.New("Filename of ImageWriter doesn't have .png extension. The only suppported image type is png")
+	}
+
+	w.img = image.NewRGBA(image.Rect(0, 0, w.Maze.Width*w.CellWidth, w.Maze.Height*w.CellHeight))
+
+	// Fill the image with walls
+	draw.Draw(w.img, w.img.Bounds(), &image.Uniform{w.WallColor}, image.Pt(0, 0), draw.Src)
+
+	// Fill in the paths
+	var x0, y0, width, height int
+	for _, node := range w.Maze.Nodes {
+		x0 = node.Coords.X * w.CellWidth
+		y0 = node.Coords.Y * w.CellHeight
+		if node.Right != nil {
+			width = (node.Right.Coords.X - node.Coords.X + 1) * w.CellWidth
+			height = w.CellHeight
+			w.draw(x0, y0, width, height, w.PathColor)
+		}
+
+		if node.Down != nil {
+			width = w.CellWidth
+			height = (node.Down.Coords.Y - node.Coords.Y + 1) * w.CellHeight
+			w.draw(x0, y0, width, height, w.PathColor)
+		}
+	}
+
+	// Fill in the solution
+	total_len := w.getSolutionLength()
+	colors := w.SolutionGradient.Colors(uint(total_len + 1))
+	c := 0
+	width, height = w.CellWidth, w.CellHeight
+	for i, from := range w.Maze.Solution[:len(w.Maze.Solution)-1] {
+		to := w.Maze.Solution[i+1]
+
+		if from.Coords.X == to.Coords.X {
+			// Fill verticallly
+			x0 = from.Coords.X * w.CellWidth
+
+			if from.Coords.Y < to.Coords.Y {
+				for y := from.Coords.Y; y < to.Coords.Y; y++ {
+					y0 = y * w.CellHeight
+					w.draw(x0, y0, width, height, colors[c])
+					c++
+				}
+			} else {
+				for y := from.Coords.Y; y > to.Coords.Y; y-- {
+					y0 = y * w.CellHeight
+					w.draw(x0, y0, width, height, colors[c])
+					c++
+				}
+			}
+			y0 = to.Coords.Y * w.CellHeight
+			w.draw(x0, y0, width, height, colors[c])
+		} else {
+			// Fill horizontally
+			y0 = from.Coords.Y * w.CellHeight
+
+			if from.Coords.X < to.Coords.X {
+				for x := from.Coords.X; x < to.Coords.X; x++ {
+					x0 = x * w.CellWidth
+					w.draw(x0, y0, width, height, colors[c])
+					c++
+				}
+			} else {
+				for x := from.Coords.X; x > to.Coords.X; x-- {
+					x0 = x * w.CellWidth
+					w.draw(x0, y0, width, height, colors[c])
+					c++
+				}
+			}
+			x0 = to.Coords.X * w.CellWidth
+			w.draw(x0, y0, width, height, colors[c])
+		}
+	}
+
+	f, err := os.Create(w.Filename)
+	if err != nil {
+		return err
+	}
+	png.Encode(f, w.img)
+	f.Close()
 	return nil
 }
+
+func (w *ImageWriter) getSolutionLength() int {
+	ret := 0
+	for i, node := range w.Maze.Solution[:len(w.Maze.Solution)-1] {
+		next := w.Maze.Solution[i+1]
+		ret += int(node.Coords.Distance(next.Coords))
+	}
+	return ret
+}
+
+func (w *ImageWriter) draw(x0, y0, width, height int, color color.Color) {
+	draw.Draw(w.img, image.Rect(x0, y0, x0+width, y0+height), &image.Uniform{color}, image.Pt(0, 0), draw.Src)
+}

io/writer/image_test.go

@@ -0,0 +1,122 @@
+package writer
+
+import (
+	"bytes"
+	"image/color"
+	"io"
+	"maze-solver/maze"
+	"os"
+	"testing"
+
+	"github.com/mazznoer/colorgrad"
+)
+
+const (
+	OUT_DIR      = "./out"
+	EXPECTED_DIR = "../../assets/solved"
+)
+
+func TestImageWriter(t *testing.T) {
+	if _, err := os.Stat(OUT_DIR); os.IsNotExist(err) {
+		os.Mkdir(OUT_DIR, 0700)
+	}
+
+	tests := []struct {
+		name                  string
+		filename              string
+		m                     *maze.SolvedMaze
+		CellWidth, cellHeight int
+		pathColor, wallColor  color.Color
+		gradient              colorgrad.Gradient
+	}{
+		{
+			"Trivial",
+			"trivial.png",
+			trivial(),
+			20, 20,
+			color.White, color.Black,
+			colorgrad.Warm(),
+		},
+		{
+			"Trivial Bigger",
+			"trivial-bigger.png",
+			bigger(),
+			20, 20,
+			color.White, color.Black,
+			colorgrad.Warm(),
+		},
+		{
+			"Trivial Bigger Staggered",
+			"trivial-bigger-staggered.png",
+			bigger_staggered(),
+			20, 20,
+			color.White, color.Black,
+			colorgrad.Warm(),
+		},
+		{
+			"Normal",
+			"normal.png",
+			normal(),
+			20, 20,
+			color.White, color.Black,
+			colorgrad.Warm(),
+		},
+	}
+
+	for _, test := range tests {
+		writer := ImageWriter{
+			Filename:         OUT_DIR + "/" + test.filename,
+			Maze:             test.m,
+			CellWidth:        test.CellWidth,
+			CellHeight:       test.cellHeight,
+			WallColor:        test.wallColor,
+			PathColor:        test.pathColor,
+			SolutionGradient: test.gradient,
+		}
+
+		err := writer.Write()
+		if err != nil {
+			t.Fatalf("%s: couldn't write solution, got following error\n%v", test.name, err)
+		}
+
+		assertEqualFile(t, EXPECTED_DIR+"/"+test.filename, OUT_DIR+"/"+test.filename, test.name)
+		os.Remove(writer.Filename)
+	}
+	os.Remove(OUT_DIR)
+}
+
+const chunkSize = 64000
+
+func assertEqualFile(t *testing.T, file1, file2, name string) {
+	f1, err := os.Open(file1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f1.Close()
+
+	f2, err := os.Open(file2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f2.Close()
+
+	for {
+		b1 := make([]byte, chunkSize)
+		_, err1 := f1.Read(b1)
+
+		b2 := make([]byte, chunkSize)
+		_, err2 := f2.Read(b2)
+
+		if err1 != nil || err2 != nil {
+			if err1 == io.EOF && err2 == io.EOF {
+				return
+			} else if err1 == io.EOF || err2 == io.EOF {
+				t.Fatalf("%s: files are not equal. Got %q, wanted %q", name, file1, file2)
+			}
+		}
+
+		if !bytes.Equal(b1, b2) {
+			t.Fatalf("%s: files are not equal. Got %q, wanted %q", name, file1, file2)
+		}
+	}
+}

io/writer/strings.go

@@ -0,0 +1,77 @@
+package writer
+
+import (
+	"bytes"
+	"fmt"
+	"maze-solver/maze"
+	"maze-solver/utils"
+)
+
+type StringsWriter struct {
+	PathChar, WallChar byte
+	SolutionChar       byte
+	Maze               *maze.SolvedMaze
+	lines              [][]byte
+}
+
+func (w *StringsWriter) Write() error {
+	defer utils.Timer("Strings writer", 3)()
+	w.lines = make([][]byte, w.Maze.Height)
+
+	// Fill the lines with walls
+	for y := 0; y < w.Maze.Height; y++ {
+		w.lines[y] = bytes.Repeat([]byte{w.WallChar}, w.Maze.Width)
+	}
+
+	// Fill in the paths
+	for _, node := range w.Maze.Nodes {
+		if node.Right != nil {
+			w.fillHorizontally(node.Coords, node.Right.Coords, w.PathChar)
+		}
+		if node.Down != nil {
+			w.fillVertically(node.Coords, node.Down.Coords, w.PathChar)
+		}
+	}
+
+	// Fill in the solution
+	for i := 0; i < len(w.Maze.Solution)-1; i++ {
+		current := w.Maze.Solution[i].Coords
+		next := w.Maze.Solution[i+1].Coords
+
+		if current.X == next.X {
+			w.fillVertically(current, next, w.SolutionChar)
+		} else {
+			w.fillHorizontally(current, next, w.SolutionChar)
+		}
+	}
+
+	return nil
+}
+
+func (w *StringsWriter) fillHorizontally(from maze.Coordinates, to maze.Coordinates, char byte) {
+	y := from.Y
+	if from.X > to.X {
+		from, to = to, from
+	}
+	for x := from.X; x <= to.X; x++ {
+		w.lines[y][x] = char
+	}
+}
+
+func (w *StringsWriter) fillVertically(from maze.Coordinates, to maze.Coordinates, char byte) {
+	x := from.X
+	if from.Y > to.Y {
+		from, to = to, from
+	}
+	for y := from.Y; y <= to.Y; y++ {
+		w.lines[y][x] = char
+	}
+}
+
+func (w *StringsWriter) GetLines() []string {
+	ret := make([]string, len(w.lines))
+	for i, line := range w.lines {
+		ret[i] = fmt.Sprint(string(line))
+	}
+	return ret
+}

io/writer/strings_test.go

@@ -0,0 +1,86 @@
+package writer
+
+import (
+	"maze-solver/maze"
+	"maze-solver/utils"
+	"testing"
+)
+
+func TestStringsWriter(t *testing.T) {
+	tests := []struct {
+		name                             string
+		m                                *maze.SolvedMaze
+		pathChar, wallChar, solutionChar byte
+		expected                         []string
+	}{
+		{
+			"Trivial",
+			trivial(),
+			' ', '#', '.',
+			[]string{
+				"##.##",
+				"# ..#",
+				"###.#",
+			},
+		},
+		{
+			"Bigger",
+			bigger(),
+			'_', '~', '*',
+			[]string{
+				"~~~*~~~",
+				"~~~*~~~",
+				"~__***~",
+				"~~~~~*~",
+				"~~~~~*~",
+			},
+		},
+		{
+			"Bigger Staggered",
+			bigger_staggered(),
+			' ', '#', '.',
+			[]string{
+				"###.###",
+				"###.###",
+				"#  .. #",
+				"####.##",
+				"####.##",
+			},
+		},
+		{
+			"Normal",
+			normal(),
+			' ', '#', '.',
+			[]string{
+				"#####.#####",
+				"#    .#   #",
+				"#####.### #",
+				"#   #.....#",
+				"# # #####.#",
+				"# #.......#",
+				"###.### # #",
+				"#...#   # #",
+				"#.####### #",
+				"#.....#   #",
+				"#####.#####",
+			},
+		},
+	}
+
+	for _, test := range tests {
+		writer := StringsWriter{
+			PathChar:     test.pathChar,
+			WallChar:     test.wallChar,
+			SolutionChar: test.solutionChar,
+			Maze:         test.m,
+		}
+		writer.Write()
+		got := writer.GetLines()
+
+		utils.AssertEqual(t, len(got), len(test.expected), "%s: different amount of lines.", test.name)
+
+		for i, line := range test.expected {
+			utils.AssertEqual(t, got[i], line, "%s, line %v: not what we expected.", test.name, i)
+		}
+	}
+}

io/writer/utils.go

@@ -0,0 +1,291 @@
+package writer
+
+import "maze-solver/maze"
+
+func trivial() *maze.SolvedMaze {
+	/* trivial.txt
+	   ## ##
+	   #   #
+	   ### #
+
+	   Nodes are
+	   ##0##
+	   #123#
+	   ###4#
+	*/
+	nodes := make([]*maze.Node, 5)
+
+	nodes[0] = maze.NewNode(maze.Coordinates{X: 2, Y: 0})
+
+	nodes[1] = maze.NewNode(maze.Coordinates{X: 1, Y: 1})
+	nodes[2] = maze.NewNode(maze.Coordinates{X: 2, Y: 1})
+	nodes[3] = maze.NewNode(maze.Coordinates{X: 3, Y: 1})
+
+	nodes[4] = maze.NewNode(maze.Coordinates{X: 3, Y: 2})
+
+	nodes[0].Down = nodes[2]
+
+	nodes[1].Right = nodes[2]
+
+	nodes[2].Up = nodes[0]
+	nodes[2].Left = nodes[1]
+	nodes[2].Right = nodes[3]
+
+	nodes[3].Left = nodes[2]
+	nodes[3].Down = nodes[4]
+
+	nodes[4].Up = nodes[3]
+
+	ret := &maze.SolvedMaze{
+		Maze: &maze.Maze{
+			Width:  5,
+			Height: 3,
+			Nodes:  nodes,
+		},
+		Solution: []*maze.Node{
+			nodes[0], nodes[2], nodes[3], nodes[4],
+		},
+	}
+
+	return ret
+}
+
+func bigger() *maze.SolvedMaze {
+	/* trivial-bigger.txt
+	   ### ###
+	   ### ###
+	   #     #
+	   ##### #
+	   ##### #
+
+	   Nodes are
+	   ###0###
+	   ### ###
+	   #1 2 3#
+	   ##### #
+	   #####4#
+	*/
+	nodes := make([]*maze.Node, 5)
+
+	nodes[0] = maze.NewNode(maze.Coordinates{X: 3, Y: 0})
+
+	nodes[1] = maze.NewNode(maze.Coordinates{X: 1, Y: 2})
+	nodes[2] = maze.NewNode(maze.Coordinates{X: 3, Y: 2})
+	nodes[3] = maze.NewNode(maze.Coordinates{X: 5, Y: 2})
+
+	nodes[4] = maze.NewNode(maze.Coordinates{X: 5, Y: 4})
+
+	nodes[0].Down = nodes[2]
+
+	nodes[1].Right = nodes[2]
+
+	nodes[2].Up = nodes[0]
+	nodes[2].Left = nodes[1]
+	nodes[2].Right = nodes[3]
+
+	nodes[3].Left = nodes[2]
+	nodes[3].Down = nodes[4]
+
+	nodes[4].Up = nodes[3]
+
+	ret := &maze.SolvedMaze{
+		Maze: &maze.Maze{
+			Width:  7,
+			Height: 5,
+			Nodes:  nodes,
+		},
+		Solution: []*maze.Node{
+			nodes[0], nodes[2], nodes[3], nodes[4],
+		},
+	}
+
+	return ret
+}
+
+func bigger_staggered() *maze.SolvedMaze {
+	/* trivial-bigger-staggered.txt
+	   ### ###
+	   ### ###
+	   #     #
+	   #### ##
+	   #### ##
+
+	   Nodes are
+	   ###0###
+	   ### ###
+	   #1 243#
+	   #### ##
+	   ####5##
+	*/
+	nodes := make([]*maze.Node, 6)
+
+	nodes[0] = maze.NewNode(maze.Coordinates{X: 3, Y: 0})
+
+	nodes[1] = maze.NewNode(maze.Coordinates{X: 1, Y: 2})
+	nodes[2] = maze.NewNode(maze.Coordinates{X: 3, Y: 2})
+	nodes[3] = maze.NewNode(maze.Coordinates{X: 5, Y: 2})
+
+	nodes[4] = maze.NewNode(maze.Coordinates{X: 4, Y: 2})
+
+	nodes[5] = maze.NewNode(maze.Coordinates{X: 4, Y: 4})
+
+	nodes[0].Down = nodes[2]
+
+	nodes[1].Right = nodes[2]
+
+	nodes[2].Up = nodes[0]
+	nodes[2].Left = nodes[1]
+	nodes[2].Right = nodes[4]
+
+	nodes[3].Left = nodes[4]
+
+	nodes[4].Left = nodes[2]
+	nodes[4].Right = nodes[3]
+	nodes[4].Down = nodes[5]
+
+	nodes[5].Up = nodes[4]
+
+	ret := &maze.SolvedMaze{
+		Maze: &maze.Maze{
+			Width:  7,
+			Height: 5,
+			Nodes:  nodes,
+		},
+		Solution: []*maze.Node{
+			nodes[0], nodes[2], nodes[4], nodes[5],
+		},
+	}
+
+	return ret
+}
+
+func normal() *maze.SolvedMaze {
+	/* normal.txt
+		##### #####
+		#     #   #
+		##### ### #
+		#   #     #
+		# # ##### #
+		# #       #
+		### ### # #
+		#   #   # #
+		# ####### #
+		#     #   #
+		##### #####
+
+	    Nodes are
+		#####0#####
+		#1   2#3 4#
+		##### ### #
+		#5 6#7   8#
+		# # ##### #
+		#9#A   F B#
+		### ### # #
+		#C D#E G# #
+		# ####### #
+		#H   I#J K#
+		#####L#####
+	*/
+	nodes := make([]*maze.Node, 22)
+
+	// ---- Node creation ----
+	coords := []struct{ x, y int }{
+		{5, 0}, // 0
+
+		{1, 1}, // 1
+		{5, 1}, // 2
+		{7, 1}, // 3
+		{9, 1}, // 4
+
+		{1, 3}, // 5
+		{3, 3}, // 6
+		{5, 3}, // 7
+		{9, 3}, // 8
+
+		{1, 5}, // 9
+		{3, 5}, // A (10)
+		{9, 5}, // B (11)
+
+		{1, 7}, // C (12)
+		{3, 7}, // D (13)
+		{5, 7}, // E (14)
+		{7, 5}, // F (15)
+		{7, 7}, // G (16)
+
+		{1, 9}, // H (17)
+		{5, 9}, // I (18)
+		{7, 9}, // J (19)
+		{9, 9}, // K (20)
+
+		{5, 10}, // L (21)
+	}
+
+	for i, coord := range coords {
+		nodes[i] = maze.NewNode(maze.Coordinates{X: coord.x, Y: coord.y})
+	}
+
+	// ---- Node linking ----
+	// Vertical
+	links := []struct {
+		from, to int
+	}{
+		{0, 2},
+		{2, 7},
+		{4, 8},
+		{5, 9},
+		{6, 10},
+		{8, 11},
+		{10, 13},
+		{15, 16},
+		{11, 20},
+		{12, 17},
+		{18, 21},
+	}
+	for _, link := range links {
+		nodes[link.from].Down = nodes[link.to]
+		nodes[link.to].Up = nodes[link.from]
+	}
+
+	links = []struct {
+		from, to int
+	}{
+		{1, 2},
+		{3, 4},
+		{5, 6},
+		{7, 8},
+		{10, 15},
+		{15, 11},
+		{12, 13},
+		{14, 16},
+		{17, 18},
+		{19, 20},
+	}
+	for _, link := range links {
+		nodes[link.from].Right = nodes[link.to]
+		nodes[link.to].Left = nodes[link.from]
+	}
+
+	ret := &maze.SolvedMaze{
+		Maze: &maze.Maze{
+			Width:  11,
+			Height: 11,
+			Nodes:  nodes,
+		},
+		Solution: []*maze.Node{
+			nodes[0],
+			nodes[2],
+			nodes[7],
+			nodes[8],
+			nodes[11],
+			nodes[15],
+			nodes[10],
+			nodes[13],
+			nodes[12],
+			nodes[17],
+			nodes[18],
+			nodes[21],
+		},
+	}
+
+	return ret
+}

io/writer/writer.go

@@ -1,7 +1,46 @@
 package writer
 
-import "maze-solver/maze"
+import (
+	"fmt"
+	"image/color"
+	"maze-solver/maze"
+
+	"github.com/mazznoer/colorgrad"
+)
 
 type Writer interface {
-	Write(filename string, maze *maze.SolvedMaze) error
+	Write() error
+}
+
+type WriterFactory struct {
+	Type                             string
+	Filename                         *string
+	PathChar, WallChar, SolutionChar *string
+	CellWidth, CellHeight            *int
+	WallColor, PathColor             color.Color
+	SolutionGradient                 colorgrad.Gradient
+}
+
+const (
+	_IMAGE = "image"
+)
+
+var TYPES = map[string]string{
+	".png": _IMAGE,
+}
+
+func (f *WriterFactory) Get(m *maze.SolvedMaze) Writer {
+	switch f.Type {
+	case _IMAGE:
+		return &ImageWriter{
+			Filename:         *f.Filename,
+			Maze:             m,
+			CellWidth:        *f.CellWidth,
+			CellHeight:       *f.CellHeight,
+			WallColor:        f.WallColor,
+			PathColor:        f.PathColor,
+			SolutionGradient: f.SolutionGradient,
+		}
+	}
+	panic(fmt.Sprintf("Unrecognized writer type %q", f.Type))
 }

main.go

@@ -1,25 +1,163 @@
 package main
 
 import (
+	"errors"
+	"fmt"
+	"image/color"
 	"maze-solver/io/reader"
 	"maze-solver/io/writer"
+	"maze-solver/maze/parser"
 	"maze-solver/solver"
 	"maze-solver/utils"
+	"os"
+	"strings"
+
+	"github.com/akamensky/argparse"
+	"github.com/mazznoer/colorgrad"
 )
 
 func main() {
-	input := "filename"
-	output := "filename"
+	readerFactory, writerFactory, solverFactory, ok := parse_arguments()
 
-	reader := &reader.TextReader{PathChar: ' ', WallChar: '#'}
-	writer := &writer.ImageWriter{}
-
-	solver := &solver.Bfs{}
-
-	maze, err := reader.Read(input)
-	utils.Check(err, "Couldn't read maze from %q", input)
-
-	solved := solver.Solve(maze)
-	err = writer.Write(output, solved)
-	utils.Check(err, "Couldn't write solved maze to %q", output)
+	if !ok {
+		return
+	}
+
+	defer utils.Timer("TOTAL", 1)()
+	reader := readerFactory.Get()
+
+	maze, err := parser.Parse(reader)
+	utils.Check(err, "Couldn't read maze")
+
+	solver := solverFactory.Get()
+	solved := solver.Solve(maze)
+
+	writer := writerFactory.Get(solved)
+
+	err = writer.Write()
+	utils.Check(err, "Couldn't write solved maze")
+}
+
+func parse_arguments() (*reader.ReaderFactory, *writer.WriterFactory, *solver.SolverFactory, bool) {
+	argparser := argparse.NewParser("maze-solver", "Solves the given maze (insane, right? who would've guessed?)")
+
+	var verboseLevel *int = argparser.FlagCounter("v", "verbose", &argparse.Options{
+		Help: `Verbose level of the solver
+        0: nothing printed to stdout
+        1: print the total time taken by the solver (time of the main() function)
+        2: prints the time the solving algorithm took to run
+        3: prints the time taken by each section (reader, solving algorithm, writer)`,
+	})
+
+	readerFactory := reader.ReaderFactory{}
+	writerFactory := writer.WriterFactory{}
+	solverFactory := solver.SolverFactory{}
+
+	readerFactory.Type = reader.TYPES[".png"]
+	readerFactory.Filename = argparser.String("i", "input", &argparse.Options{
+		Help:    "Input file",
+		Default: "maze.png",
+		Validate: func(args []string) error {
+			var ok bool
+			extension := args[0][len(args[0])-4:]
+			readerFactory.Type, ok = reader.TYPES[extension]
+			if ok {
+				return nil
+			} else {
+				return errors.New(fmt.Sprintf("Filetype not recognized %q", extension))
+			}
+		},
+	})
+
+	writerFactory.Type = writer.TYPES[".png"]
+	writerFactory.Filename = argparser.String("o", "output", &argparse.Options{
+		Help:    "Input file",
+		Default: "maze_sol.png",
+		Validate: func(args []string) error {
+			var ok bool
+			extension := args[0][len(args[0])-4:]
+			writerFactory.Type, ok = writer.TYPES[extension]
+			if ok {
+				return nil
+			} else {
+				return errors.New(fmt.Sprintf("Filetype not recognized %q", extension))
+			}
+		},
+	})
+
+	readerFactory.PathChar = argparser.String("", "path-char-in", &argparse.Options{
+		Help:    "Character to represent the path in a input text file",
+		Default: " ",
+		Validate: func(args []string) error {
+			if len(args[0]) > 1 {
+				return errors.New("Character must a string of length 1")
+			}
+			return nil
+		},
+	})
+
+	readerFactory.WallChar = argparser.String("", "wall-char-in", &argparse.Options{
+		Help:    "Character to represent the wall in a input text file",
+		Default: "#",
+		Validate: func(args []string) error {
+			if len(args[0]) > 1 {
+				return errors.New("Character must a string of length 1")
+			}
+			return nil
+		},
+	})
+
+	writerFactory.PathChar = argparser.String("", "path-char-out", &argparse.Options{
+		Help:    "Character to represent the path in a output text file",
+		Default: " ",
+		Validate: func(args []string) error {
+			if len(args[0]) > 1 {
+				return errors.New("Character must a string of length 1")
+			}
+			return nil
+		},
+	})
+
+	writerFactory.WallChar = argparser.String("", "wall-char-out", &argparse.Options{
+		Help:    "Character to represent the wall in a output text file",
+		Default: "#",
+		Validate: func(args []string) error {
+			if len(args[0]) > 1 {
+				return errors.New("Character must a string of length 1")
+			}
+			return nil
+		},
+	})
+
+	cellSizeIn := argparser.Int("", "cell-size-in", &argparse.Options{
+		Help:    "Size of a cell (in pixels) for input file of image type",
+		Default: 3,
+	})
+
+	cellSizeOut := argparser.Int("", "cell-size-out", &argparse.Options{
+		Help:    "Size of a cell (in pixels) for output file of image type",
+		Default: 3,
+	})
+
+	solverFactory.Type = argparser.Selector("a", "algo", solver.TYPES, &argparse.Options{
+		Help:    fmt.Sprintf("Algorithm to solve the maze, avaiable options: %s", strings.Join(solver.TYPES, ", ")),
+		Default: solver.TYPES[0],
+	})
+
+	if err := argparser.Parse(os.Args); err != nil {
+		fmt.Println(argparser.Usage(err))
+		return nil, nil, nil, false
+	}
+	utils.VERBOSE_LEVEL = *verboseLevel
+
+	readerFactory.CellHeight, readerFactory.CellWidth = cellSizeIn, cellSizeIn
+	readerFactory.WallColor = color.RGBA{0, 0, 0, 255}
+	readerFactory.PathColor = color.RGBA{255, 255, 255, 255}
+
+	writerFactory.CellHeight, writerFactory.CellWidth = cellSizeOut, cellSizeOut
+	writerFactory.WallColor = color.RGBA{0, 0, 0, 255}
+	writerFactory.PathColor = color.RGBA{255, 255, 255, 255}
+	writerFactory.SolutionGradient = colorgrad.Warm()
+
+	return &readerFactory, &writerFactory, &solverFactory, true
 }

maze/maze.go

@@ -1,12 +1,36 @@
 package maze
 
+import "math"
+
 type Coordinates struct {
 	X, Y int
 }
+
+func (c Coordinates) Distance(o Coordinates) float64 {
+	x, y := float64(o.X-c.X), float64(o.Y-c.Y)
+
+	if y == 0 {
+		if x < 0 {
+			return -x
+		}
+		return x
+	}
+
+	if x == 0 {
+		if y < 0 {
+			return -y
+		}
+		return y
+	}
+
+	return math.Sqrt(x*x + y*y)
+}
+
 type Node struct {
 	Coords      Coordinates
 	Up, Down    *Node
 	Left, Right *Node
+	Visited     bool `default:"false"`
 }
 
 func NewNode(coords Coordinates) *Node {
@@ -20,11 +44,11 @@ func NewNode(coords Coordinates) *Node {
 }
 
 type Maze struct {
-	Width, Height uint
+	Width, Height int
 	Nodes         []*Node
 }
 
 type SolvedMaze struct {
-	Maze
+	*Maze
 	Solution []*Node
 }

maze/parser/parser.go

@@ -0,0 +1,144 @@
+package parser
+
+import (
+	"fmt"
+	"maze-solver/io/reader"
+	"maze-solver/maze"
+)
+
+func Parse(reader reader.Reader) (*maze.Maze, error) {
+	nodesByCoord := make(map[maze.Coordinates]*maze.Node)
+
+	raw_maze, err := reader.Read()
+	if err != nil {
+		return nil, err
+	}
+
+	ret := &maze.Maze{
+		Width:  raw_maze.Width,
+		Height: raw_maze.Height,
+		Nodes:  []*maze.Node{},
+	}
+
+	y := 0
+	// Parse first line to get entrance
+	for x := 0; x < raw_maze.Width-1; x++ {
+		if raw_maze.IsPath(x, y) {
+			coords := maze.Coordinates{X: x, Y: y}
+			node := maze.NewNode(coords)
+			ret.Nodes = append(ret.Nodes, node)
+			nodesByCoord[coords] = node
+			break
+		}
+	}
+
+	for y = 1; y < raw_maze.Height-1; y++ {
+		for x := 1; x < raw_maze.Width-1; x++ {
+			// Parse middle of the maze
+			if isCoordEligibleForNode(x, y, raw_maze) {
+				coords := maze.Coordinates{X: x, Y: y}
+				node := maze.NewNode(coords)
+
+				lookupNeighbourAbove(raw_maze, node, &nodesByCoord, ret)
+
+				ret.Nodes = append(ret.Nodes, node)
+				nodesByCoord[coords] = node
+
+				if raw_maze.IsPath(x-1, y) && raw_maze.IsWall(x+1, y) ||
+					raw_maze.IsPath(x, y-1) &&
+						(raw_maze.IsPath(x-1, y) || raw_maze.IsPath(x+1, y)) {
+					lookupNeighbourLeft(raw_maze, node, &nodesByCoord)
+				}
+			}
+		}
+	}
+
+	// Parse last line to get exit
+	for x := 0; x < raw_maze.Width-1; x++ {
+		if raw_maze.IsPath(x, y) {
+			coords := maze.Coordinates{X: x, Y: y}
+			node := maze.NewNode(coords)
+			lookupNeighbourAbove(raw_maze, node, &nodesByCoord, ret)
+			ret.Nodes = append(ret.Nodes, node)
+			break
+		}
+	}
+
+	return ret, nil
+}
+
+func isCoordEligibleForNode(x int, y int, raw_maze *reader.RawMaze) bool {
+	return raw_maze.IsPath(x, y) &&
+		(raw_maze.IsWall(x-1, y) && raw_maze.IsPath(x+1, y) || // wall left, path right
+			raw_maze.IsPath(x-1, y) && raw_maze.IsWall(x+1, y) || // path left, wall right
+			raw_maze.IsPath(x, y-1) && (raw_maze.IsPath(x-1, y) || raw_maze.IsPath(x+1, y)) || // path above and not in vertical corridor
+			raw_maze.IsWall(x-1, y) && raw_maze.IsWall(x+1, y) && raw_maze.IsPath(x, y-1) && raw_maze.IsWall(x, y+1)) // wall to left, below, above and path above
+}
+
+func lookupNeighbourAbove(raw_maze *reader.RawMaze, node *maze.Node, nodesByCoord *map[maze.Coordinates]*maze.Node, m *maze.Maze) {
+	for y := node.Coords.Y - 1; y >= 0; y-- {
+		neighbour, ok := (*nodesByCoord)[maze.Coordinates{X: node.Coords.X, Y: y}]
+
+		if ok {
+			node.Up = neighbour
+			neighbour.Down = node
+			break
+		}
+
+		if y >= 0 && raw_maze.IsWall(node.Coords.X, y) {
+			y++
+			if y == node.Coords.Y {
+				break
+			}
+			coords := maze.Coordinates{X: node.Coords.X, Y: y}
+			new_node := maze.NewNode(coords)
+			lookupNeighbourLeft(raw_maze, new_node, nodesByCoord)
+			lookupNeighbourRight(raw_maze, new_node, nodesByCoord)
+			(*nodesByCoord)[coords] = new_node
+			m.Nodes = append(m.Nodes, new_node)
+
+			node.Up = new_node
+			new_node.Down = node
+			break
+		}
+
+	}
+}
+
+func lookupNeighbourLeft(raw_maze *reader.RawMaze, node *maze.Node, nodesByCoord *map[maze.Coordinates]*maze.Node) {
+	for x := node.Coords.X - 1; x > 0; x-- {
+		if raw_maze.IsWall(x, node.Coords.Y) && x == node.Coords.X-1 {
+			return
+		}
+
+		if raw_maze.IsWall(x, node.Coords.Y) && x < node.Coords.X-1 {
+			panic(fmt.Sprintf("Found no node before wall while looking to the left at neighbours of node %v (arrived at x=%v before hitting a wall)", node, x))
+		}
+
+		neighbour, ok := (*nodesByCoord)[maze.Coordinates{X: x, Y: node.Coords.Y}]
+		if ok {
+			node.Left = neighbour
+			neighbour.Right = node
+			break
+		}
+	}
+}
+
+func lookupNeighbourRight(raw_maze *reader.RawMaze, node *maze.Node, nodesByCoord *map[maze.Coordinates]*maze.Node) {
+	for x := node.Coords.X + 1; x < raw_maze.Width; x++ {
+		if raw_maze.IsWall(x, node.Coords.Y) && x == node.Coords.X+1 {
+			return
+		}
+
+		if raw_maze.IsWall(x, node.Coords.Y) && x > node.Coords.X+1 {
+			panic(fmt.Sprintf("Found no node before wall while looking to the right at neighbours of node %v", node))
+		}
+
+		neighbour, ok := (*nodesByCoord)[maze.Coordinates{X: x, Y: node.Coords.Y}]
+		if ok {
+			node.Right = neighbour
+			neighbour.Left = node
+			break
+		}
+	}
+}

maze/parser/parser_test.go

@@ -0,0 +1,550 @@
+package parser
+
+import (
+	"fmt"
+	"maze-solver/io/reader"
+	"maze-solver/maze"
+	"maze-solver/utils"
+	"testing"
+)
+
+func TestTextReadTrivial(t *testing.T) {
+	/* trivial.txt
+	   ## ##
+	   #   #
+	   ### #
+
+	   Nodes are
+	   ##0##
+	   #123#
+	   ###4#
+	*/
+	nodes := make([]*maze.Node, 5)
+
+	nodes[0] = maze.NewNode(maze.Coordinates{X: 2, Y: 0})
+
+	nodes[1] = maze.NewNode(maze.Coordinates{X: 1, Y: 1})
+	nodes[2] = maze.NewNode(maze.Coordinates{X: 2, Y: 1})
+	nodes[3] = maze.NewNode(maze.Coordinates{X: 3, Y: 1})
+
+	nodes[4] = maze.NewNode(maze.Coordinates{X: 3, Y: 2})
+
+	nodes[0].Down = nodes[2]
+
+	nodes[1].Right = nodes[2]
+
+	nodes[2].Up = nodes[0]
+	nodes[2].Left = nodes[1]
+	nodes[2].Right = nodes[3]
+
+	nodes[3].Left = nodes[2]
+	nodes[3].Down = nodes[4]
+
+	nodes[4].Up = nodes[3]
+
+	reader := &reader.TextReader{
+		Filename: "../../assets/trivial.txt",
+		PathChar: ' ',
+		WallChar: '#',
+	}
+
+	got, err := Parse(reader)
+	utils.Check(err, "Couldn't create maze from %q", reader.Filename)
+
+	utils.AssertEqual(t, got.Width, 5, "Normal: width differ")
+	utils.AssertEqual(t, got.Height, 3, "Normal: height differ")
+
+	if len(nodes) != len(got.Nodes) {
+		t.Fatalf("Didn't get the same size of nodes: %v, want %v", len(got.Nodes), len(nodes))
+	}
+
+	for i, got := range got.Nodes {
+		expected := nodes[i]
+
+		checkNode(t, i, got, expected, "")
+		checkNode(t, i, got.Left, expected.Left, "left")
+		checkNode(t, i, got.Right, expected.Right, "Right")
+		checkNode(t, i, got.Up, expected.Up, "Up")
+		checkNode(t, i, got.Down, expected.Down, "Down")
+	}
+}
+
+func TestTextReadTrivialBigger(t *testing.T) {
+	/* trivial-bigger.txt
+	   ### ###
+	   ### ###
+	   #     #
+	   ##### #
+	   ##### #
+
+	   Nodes are
+	   ###0###
+	   ### ###
+	   #1 2 3#
+	   ##### #
+	   #####4#
+	*/
+	nodes := make([]*maze.Node, 5)
+
+	nodes[0] = maze.NewNode(maze.Coordinates{X: 3, Y: 0})
+
+	nodes[1] = maze.NewNode(maze.Coordinates{X: 1, Y: 2})
+	nodes[2] = maze.NewNode(maze.Coordinates{X: 3, Y: 2})
+	nodes[3] = maze.NewNode(maze.Coordinates{X: 5, Y: 2})
+
+	nodes[4] = maze.NewNode(maze.Coordinates{X: 5, Y: 4})
+
+	nodes[0].Down = nodes[2]
+
+	nodes[1].Right = nodes[2]
+
+	nodes[2].Up = nodes[0]
+	nodes[2].Left = nodes[1]
+	nodes[2].Right = nodes[3]
+
+	nodes[3].Left = nodes[2]
+	nodes[3].Down = nodes[4]
+
+	nodes[4].Up = nodes[3]
+
+	reader := &reader.TextReader{
+		Filename: "../../assets/trivial-bigger.txt",
+		PathChar: ' ',
+		WallChar: '#',
+	}
+
+	got, err := Parse(reader)
+	utils.Check(err, "Couldn't create maze from %q", reader.Filename)
+
+	utils.AssertEqual(t, got.Width, 7, "Normal: width differ")
+	utils.AssertEqual(t, got.Height, 5, "Normal: height differ")
+
+	if len(nodes) != len(got.Nodes) {
+		t.Fatalf("Didn't get the same size of nodes: %v, want %v", len(got.Nodes), len(nodes))
+	}
+
+	for i, got := range got.Nodes {
+		expected := nodes[i]
+
+		checkNode(t, i, got, expected, "")
+		checkNode(t, i, got.Left, expected.Left, "left")
+		checkNode(t, i, got.Right, expected.Right, "Right")
+		checkNode(t, i, got.Up, expected.Up, "Up")
+		checkNode(t, i, got.Down, expected.Down, "Down")
+	}
+}
+
+func TestTextReadTrivialBiggerStaggered(t *testing.T) {
+	/* trivial-bigger-staggered.txt
+	   ### ###
+	   ### ###
+	   #     #
+	   #### ##
+	   #### ##
+
+	   Nodes are
+	   ###0###
+	   ### ###
+	   #1 243#
+	   #### ##
+	   ####5##
+	*/
+	nodes := make([]*maze.Node, 6)
+
+	nodes[0] = maze.NewNode(maze.Coordinates{X: 3, Y: 0})
+
+	nodes[1] = maze.NewNode(maze.Coordinates{X: 1, Y: 2})
+	nodes[2] = maze.NewNode(maze.Coordinates{X: 3, Y: 2})
+	nodes[3] = maze.NewNode(maze.Coordinates{X: 5, Y: 2})
+
+	nodes[4] = maze.NewNode(maze.Coordinates{X: 4, Y: 2})
+
+	nodes[5] = maze.NewNode(maze.Coordinates{X: 4, Y: 4})
+
+	nodes[0].Down = nodes[2]
+
+	nodes[1].Right = nodes[2]
+
+	nodes[2].Up = nodes[0]
+	nodes[2].Left = nodes[1]
+	nodes[2].Right = nodes[4]
+
+	nodes[3].Left = nodes[4]
+
+	nodes[4].Down = nodes[5]
+	nodes[4].Left = nodes[2]
+	nodes[4].Right = nodes[3]
+
+	nodes[5].Up = nodes[4]
+
+	reader := &reader.TextReader{
+		Filename: "../../assets/trivial-bigger-staggered.txt",
+		PathChar: ' ',
+		WallChar: '#',
+	}
+
+	got, err := Parse(reader)
+	utils.Check(err, "Couldn't create maze from %q", reader.Filename)
+
+	utils.AssertEqual(t, got.Width, 7, "Normal: width differ")
+	utils.AssertEqual(t, got.Height, 5, "Normal: height differ")
+
+	if len(nodes) != len(got.Nodes) {
+		t.Fatalf("Didn't get the same size of nodes: %v, want %v", len(got.Nodes), len(nodes))
+	}
+
+	for i, got := range got.Nodes {
+		expected := nodes[i]
+
+		checkNode(t, i, got, expected, "")
+		checkNode(t, i, got.Left, expected.Left, "left")
+		checkNode(t, i, got.Right, expected.Right, "Right")
+		checkNode(t, i, got.Up, expected.Up, "Up")
+		checkNode(t, i, got.Down, expected.Down, "Down")
+	}
+}
+
+func TestTextReadNormal(t *testing.T) {
+	/* normal.txt
+		##### #####
+		#     #   #
+		##### ### #
+		#   #     #
+		# # ##### #
+		# #       #
+		### ### # #
+		#   #   # #
+		# ####### #
+		#     #   #
+		##### #####
+
+	    Nodes are
+		#####0#####
+		#1   2#3 4#
+		##### ### #
+		#5 6#7   8#
+		# # ##### #
+		#9#A   F B#
+		### ### # #
+		#C D#E G# #
+		# ####### #
+		#H   I#J K#
+		#####L#####
+	*/
+	nodes := make([]*maze.Node, 22)
+
+	// ---- Node creation ----
+	coords := []struct{ x, y int }{
+		{5, 0}, // 0
+
+		{1, 1}, // 1
+		{5, 1}, // 2
+		{7, 1}, // 3
+		{9, 1}, // 4
+
+		{1, 3}, // 5
+		{3, 3}, // 6
+		{5, 3}, // 7
+		{9, 3}, // 8
+
+		{1, 5}, // 9
+		{3, 5}, // A (10)
+		{9, 5}, // B (11)
+
+		{1, 7}, // C (12)
+		{3, 7}, // D (13)
+		{5, 7}, // E (14)
+		{7, 5}, // F (15)
+		{7, 7}, // G (16)
+
+		{1, 9}, // H (17)
+		{5, 9}, // I (18)
+		{7, 9}, // J (19)
+		{9, 9}, // K (20)
+
+		{5, 10}, // L (21)
+	}
+
+	for i, coord := range coords {
+		nodes[i] = maze.NewNode(maze.Coordinates{X: coord.x, Y: coord.y})
+	}
+
+	// ---- Node linking ----
+	// Vertical
+	links := []struct {
+		from, to int
+	}{
+		{0, 2},
+		{2, 7},
+		{4, 8},
+		{5, 9},
+		{6, 10},
+		{8, 11},
+		{10, 13},
+		{15, 16},
+		{11, 20},
+		{12, 17},
+		{18, 21},
+	}
+	for _, link := range links {
+		nodes[link.from].Down = nodes[link.to]
+		nodes[link.to].Up = nodes[link.from]
+	}
+
+	links = []struct {
+		from, to int
+	}{
+		{1, 2},
+		{3, 4},
+		{5, 6},
+		{7, 8},
+		{10, 15},
+		{15, 11},
+		{12, 13},
+		{14, 16},
+		{17, 18},
+		{19, 20},
+	}
+	for _, link := range links {
+		nodes[link.from].Right = nodes[link.to]
+		nodes[link.to].Left = nodes[link.from]
+	}
+
+	reader := &reader.TextReader{
+		Filename: "../../assets/normal.txt",
+		PathChar: ' ',
+		WallChar: '#',
+	}
+
+	got, err := Parse(reader)
+	utils.Check(err, "Couldn't create maze from %q", reader.Filename)
+
+	utils.AssertEqual(t, got.Width, 11, "Normal: width differ")
+	utils.AssertEqual(t, got.Height, 11, "Normal: height differ")
+
+	if len(nodes) != len(got.Nodes) {
+		for i, node := range got.Nodes {
+			fmt.Printf("%v: %v\n", i, node)
+		}
+		t.Fatalf("Didn't get the same size of nodes: %v, want %v", len(got.Nodes), len(nodes))
+	}
+
+	for i, got := range got.Nodes {
+		expected := nodes[i]
+
+		checkNode(t, i, got, expected, "")
+		checkNode(t, i, got.Left, expected.Left, "left")
+		checkNode(t, i, got.Right, expected.Right, "Right")
+		checkNode(t, i, got.Up, expected.Up, "Up")
+		checkNode(t, i, got.Down, expected.Down, "Down")
+	}
+}
+
+func TestTextReadNormal2(t *testing.T) {
+	/* normal2.txt
+	   ####### #######
+	   #   #       # #
+	   ### # ##### # #
+	   #   #     #   #
+	   # ########### #
+	   #     #     # #
+	   ### # # ##### #
+	   #   #   #   # #
+	   # ### ### # # #
+	   # #   #   #   #
+	   # ### # #######
+	   #   # # #     #
+	   # # ### ### # #
+	   # #         # #
+	   ####### #######
+
+	   Nodes are
+	   #######0#######
+	   #1 2#3 4   5#B#
+	   ### # ##### # #
+	   #6 7#8   9#A C#
+	   # ########### #
+	   #D I E#F   G# #
+	   ### # # ##### #
+	   #H J#K L#M N# #
+	   # ### ### # # #
+	   # #O P#Q R#S T#
+	   # ### # #######
+	   #U V#W# #X C Y#
+	   # # ### ### # #
+	   #Z#A   B   D#E#
+	   #######F#######
+	*/
+	nodes := make([]*maze.Node, 42)
+
+	// ---- Node creation ----
+	coords := []struct{ x, y int }{
+		{7, 0}, // 0
+
+		{1, 1},  // 1
+		{3, 1},  // 2
+		{5, 1},  // 3
+		{7, 1},  // 4
+		{11, 1}, // 5
+
+		{1, 3},  // 6
+		{3, 3},  // 7
+		{5, 3},  // 8
+		{9, 3},  // 9
+		{11, 3}, // 10 (A)
+		{13, 1}, // 11 (B)
+		{13, 3}, // 12 (C)
+
+		{1, 5},  // 13 (D)
+		{5, 5},  // 14 (E)
+		{7, 5},  // 15 (F)
+		{11, 5}, // 16 (G)
+
+		{1, 7},  // 17 (H)
+		{3, 5},  // 18 (I)
+		{3, 7},  // 19 (J)
+		{5, 7},  // 20 (K)
+		{7, 7},  // 21 (L)
+		{9, 7},  // 22 (M)
+		{11, 7}, // 23 (N)
+
+		{3, 9},  // 24 (O)
+		{5, 9},  // 25 (P)
+		{7, 9},  // 26 (Q)
+		{9, 9},  // 27 (R)
+		{11, 9}, // 28 (S)
+		{13, 9}, // 29 (T)
+
+		{1, 11},  // 30 (U)
+		{3, 11},  // 31 (V)
+		{5, 11},  // 32 (W)
+		{9, 11},  // 33 (X)
+		{13, 11}, // 34 (Y)
+
+		{1, 13},  // 35 (Z)
+		{3, 13},  // 36 (AA)
+		{7, 13},  // 37 (AB)
+		{11, 11}, // 38 (AC)
+		{11, 13}, // 39 (AD)
+		{13, 13}, // 40 (AE)
+
+		{7, 14}, // 42 (AF)
+	}
+
+	for i, coord := range coords {
+		nodes[i] = maze.NewNode(maze.Coordinates{X: coord.x, Y: coord.y})
+	}
+
+	// ---- Node linking ----
+	// Vertical
+	links := []struct {
+		from, to int
+	}{
+		{0, 4},
+		{2, 7},
+		{3, 8},
+		{5, 10},
+		{11, 12},
+		{6, 13},
+		{12, 29},
+		{18, 19},
+		{14, 20},
+		{15, 21},
+		{17, 30},
+		{20, 25},
+		{22, 27},
+		{23, 28},
+		{25, 32},
+		{26, 37},
+		{30, 35},
+		{31, 36},
+		{38, 39},
+		{34, 40},
+		{37, 41},
+	}
+	for _, link := range links {
+		nodes[link.from].Down = nodes[link.to]
+		nodes[link.to].Up = nodes[link.from]
+	}
+
+	links = []struct {
+		from, to int
+	}{
+		{1, 2},
+		{3, 4},
+		{4, 5},
+
+		{6, 7},
+		{8, 9},
+		{10, 12},
+
+		{13, 18},
+		{18, 14},
+		{15, 16},
+
+		{17, 19},
+		{20, 21},
+		{22, 23},
+
+		{24, 25},
+		{26, 27},
+		{28, 29},
+
+		{30, 31},
+		{33, 38},
+		{38, 34},
+		{36, 37},
+		{37, 39},
+	}
+	for _, link := range links {
+		nodes[link.from].Right = nodes[link.to]
+		nodes[link.to].Left = nodes[link.from]
+	}
+
+	reader := &reader.TextReader{
+		Filename: "../../assets/normal2.txt",
+		PathChar: ' ',
+		WallChar: '#',
+	}
+
+	got, err := Parse(reader)
+	utils.Check(err, "Couldn't create maze from %q", reader.Filename)
+
+	utils.AssertEqual(t, got.Width, 15, "Normal 2: width differ")
+	utils.AssertEqual(t, got.Height, 15, "Normal 2: height differ")
+
+	if len(nodes) != len(got.Nodes) {
+		for i, node := range got.Nodes {
+			fmt.Printf("%v: %v\n", i, node)
+		}
+		t.Fatalf("Didn't get the same size of nodes: %v, want %v", len(got.Nodes), len(nodes))
+	}
+
+	for i, got := range got.Nodes {
+		expected := nodes[i]
+
+		checkNode(t, i, got, expected, "")
+		checkNode(t, i, got.Left, expected.Left, "left")
+		checkNode(t, i, got.Right, expected.Right, "Right")
+		checkNode(t, i, got.Up, expected.Up, "Up")
+		checkNode(t, i, got.Down, expected.Down, "Down")
+	}
+}
+
+func checkNode(t *testing.T, i int, got *maze.Node, expected *maze.Node, side string) {
+	if expected == nil && got != nil {
+		t.Fatalf("Somehow there is a node %s of %v, didn't want any", side, i)
+	}
+
+	if expected == nil && got == nil {
+		return
+	}
+
+	if expected != nil && got == nil {
+		t.Fatalf("No %s node of %v, want %v", side, i, expected.Coords)
+	}
+
+	if got.Coords != expected.Coords {
+		t.Fatalf("Coords %s node of %v: %v, but want %v", side, i, got.Coords, expected.Coords)
+	}
+}

solver/a-star.go

@@ -0,0 +1,66 @@
+package solver
+
+import (
+	"maze-solver/maze"
+	"maze-solver/utils"
+	"sort"
+)
+
+type AStarSolver struct {
+	dist_from_start map[*maze.Node]int
+	dist_from_end   map[*maze.Node]int
+	parent          map[*maze.Node]*maze.Node
+	stack           sorted_stack
+}
+
+func (s *AStarSolver) Solve(m *maze.Maze) *maze.SolvedMaze {
+	defer utils.Timer("A* algorithm", 2)()
+	s.dist_from_start = make(map[*maze.Node]int, len(m.Nodes))
+	s.dist_from_end = make(map[*maze.Node]int, len(m.Nodes))
+	s.parent = make(map[*maze.Node]*maze.Node, len(m.Nodes))
+
+	current, end := m.Nodes[0], m.Nodes[len(m.Nodes)-1]
+
+	for _, node := range m.Nodes {
+		s.dist_from_start[node] = 0
+		s.dist_from_end[node] = int(node.Coords.Distance(end.Coords))
+	}
+
+	for current != end {
+		current.Visited = true
+
+		for _, child := range []*maze.Node{current.Left, current.Right, current.Up, current.Down} {
+			if child != nil {
+				dist := s.dist_from_start[current] + int(current.Coords.Distance(child.Coords))
+				if !child.Visited {
+					s.parent[child] = current
+					s.dist_from_start[child] = dist
+					s.stack.insert(child, &s.dist_from_end)
+				} else if s.dist_from_start[child] > dist {
+					s.parent[child] = current
+					s.dist_from_start[child] = dist
+					sort.Slice(s.stack, func(i, j int) bool {
+						return s.dist_from_end[s.stack[i]] < s.dist_from_end[s.stack[j]]
+					})
+				}
+			}
+		}
+		current = s.stack.pop()
+	}
+
+	solution := make([]*maze.Node, 0, len(m.Nodes))
+	for current != m.Nodes[0] {
+		solution = append(solution, current)
+		current = s.parent[current]
+	}
+	solution = append(solution, m.Nodes[0])
+
+	for i, j := 0, len(solution)-1; i < j; i, j = i+1, j-1 {
+		solution[i], solution[j] = solution[j], solution[i]
+	}
+
+	return &maze.SolvedMaze{
+		Maze:     m,
+		Solution: solution,
+	}
+}

solver/bfs.go

@@ -1,9 +1,117 @@
 package solver
 
-import "maze-solver/maze"
+import (
+	"errors"
+	"fmt"
+	"maze-solver/maze"
+	"maze-solver/utils"
+	"strings"
+)
 
-type Bfs struct{}
-
-func (*Bfs) Solve(maze *maze.Maze) *maze.SolvedMaze {
-	return nil
+type BFSSolver struct {
+	queue *Queue
+}
+
+type Queue struct {
+	head, tail *Element
+}
+
+type Element struct {
+	prev, next *Element
+	value      []*maze.Node
+}
+
+func (q *Queue) enqueue(v []*maze.Node) {
+	prev_last := q.tail
+	new_elem := &Element{
+		prev:  prev_last,
+		next:  nil,
+		value: v,
+	}
+	if prev_last != nil {
+		prev_last.next = new_elem
+	}
+
+	q.tail = new_elem
+
+	if q.head == nil {
+		q.head = new_elem
+	}
+}
+
+func (q *Queue) dequeue() ([]*maze.Node, error) {
+	if q.head == nil {
+		return nil, errors.New("Can't dequeue and empty queue")
+	}
+	ret := q.head.value
+	q.head = q.head.next
+	if q.head != nil {
+		q.head.prev = nil
+	} else {
+		q.tail = nil
+	}
+
+	return ret, nil
+}
+
+func (q Queue) String() string {
+	var ret strings.Builder
+	i := 0
+	for history := q.head; history != nil; history = history.next {
+		ret.WriteString(fmt.Sprintf("%v: %v\n", i, history_str(history.value)))
+		i++
+	}
+	return ret.String()
+}
+
+func history_str(history []*maze.Node) string {
+	var ret strings.Builder
+	for _, node := range history {
+		ret.WriteString(fmt.Sprintf("%v ", node.Coords))
+	}
+	return ret.String()
+}
+
+func (s *BFSSolver) Solve(m *maze.Maze) *maze.SolvedMaze {
+	defer utils.Timer("BFS algorithm", 2)()
+
+	current, end := m.Nodes[0], m.Nodes[len(m.Nodes)-1]
+	s.queue = &Queue{
+		head: nil,
+		tail: nil,
+	}
+
+	current_history := make([]*maze.Node, 0, len(m.Nodes))
+	current_history = append(current_history, current)
+
+	var err error
+	for current != end {
+		current.Visited = true
+
+		s.addIfNotVisited(current.Down, current_history)
+		s.addIfNotVisited(current.Left, current_history)
+		s.addIfNotVisited(current.Right, current_history)
+		s.addIfNotVisited(current.Up, current_history)
+
+		current_history, err = s.queue.dequeue()
+		if err != nil {
+			panic(err)
+		}
+		current = current_history[len(current_history)-1]
+	}
+
+	return &maze.SolvedMaze{
+		Maze:     m,
+		Solution: current_history,
+	}
+}
+
+func (s *BFSSolver) addIfNotVisited(node *maze.Node, current_history []*maze.Node) {
+	if !visited(node) {
+		new_history := make([]*maze.Node, len(current_history)+1)
+		copy(new_history, current_history)
+		new_history[len(current_history)] = node
+
+		s.queue.enqueue(new_history)
+	}
 }

solver/dfs.go

@@ -0,0 +1,48 @@
+package solver
+
+import (
+	"maze-solver/maze"
+	"maze-solver/utils"
+)
+
+type DFSSolver struct{}
+
+func (s *DFSSolver) Solve(m *maze.Maze) *maze.SolvedMaze {
+	defer utils.Timer("DFS algorithm", 2)()
+
+	current, end := m.Nodes[0], m.Nodes[len(m.Nodes)-1]
+
+	stack := make([]*maze.Node, 0, len(m.Nodes))
+	stack = append(stack, current)
+
+	for current != end {
+		current.Visited = true
+
+		left_visited, right_visited, up_visited, down_visited := visited(current.Left), visited(current.Right), visited(current.Up), visited(current.Down)
+
+		if left_visited && right_visited && up_visited && down_visited {
+			// dead end or no more visited nodes
+			stack = stack[:len(stack)-1]
+			current = stack[len(stack)-1]
+		} else {
+
+			if !left_visited {
+				current = current.Left
+			} else if !down_visited {
+				current = current.Down
+			} else if !right_visited {
+				current = current.Right
+			} else if !up_visited {
+				current = current.Up
+			}
+
+			stack = append(stack, current)
+		}
+	}
+
+	ret := &maze.SolvedMaze{
+		Maze:     m,
+		Solution: stack,
+	}
+	return ret
+}

solver/dijkstra.go

@@ -0,0 +1,63 @@
+package solver
+
+import (
+	"maze-solver/maze"
+	"maze-solver/utils"
+	"sort"
+)
+
+type DijkstraSolver struct {
+	dist_from_start map[*maze.Node]int
+	parent          map[*maze.Node]*maze.Node
+	stack           sorted_stack
+}
+
+func (s *DijkstraSolver) Solve(m *maze.Maze) *maze.SolvedMaze {
+	defer utils.Timer("Dijkstra algorithm", 2)()
+	s.dist_from_start = make(map[*maze.Node]int, len(m.Nodes))
+	s.parent = make(map[*maze.Node]*maze.Node, len(m.Nodes))
+
+	for _, node := range m.Nodes {
+		s.dist_from_start[node] = 0
+	}
+
+	current, end := m.Nodes[0], m.Nodes[len(m.Nodes)-1]
+
+	for current != end {
+		current.Visited = true
+
+		for _, child := range []*maze.Node{current.Left, current.Right, current.Up, current.Down} {
+			if child != nil {
+				dist := s.dist_from_start[current] + int(current.Coords.Distance(child.Coords))
+				if !child.Visited {
+					s.parent[child] = current
+					s.dist_from_start[child] = dist
+					s.stack.insert(child, &s.dist_from_start)
+				} else if s.dist_from_start[child] > dist {
+					s.parent[child] = current
+					s.dist_from_start[child] = dist
+					sort.Slice(s.stack, func(i, j int) bool {
+						return s.dist_from_start[s.stack[i]] < s.dist_from_start[s.stack[j]]
+					})
+				}
+			}
+		}
+		current = s.stack.pop()
+	}
+
+	solution := make([]*maze.Node, 0, len(m.Nodes))
+	for current != m.Nodes[0] {
+		solution = append(solution, current)
+		current = s.parent[current]
+	}
+	solution = append(solution, m.Nodes[0])
+
+	for i, j := 0, len(solution)-1; i < j; i, j = i+1, j-1 {
+		solution[i], solution[j] = solution[j], solution[i]
+	}
+
+	return &maze.SolvedMaze{
+		Maze:     m,
+		Solution: solution,
+	}
+}

solver/solver.go

@@ -1,7 +1,46 @@
 package solver
 
-import "maze-solver/maze"
+import (
+	"fmt"
+	"maze-solver/maze"
+)
 
 type Solver interface {
 	Solve(*maze.Maze) *maze.SolvedMaze
 }
+
+type SolverFactory struct {
+	Type *string
+}
+
+const (
+	_DFS      = "dfs"
+	_BFS      = "bfs"
+	_Dijkstra = "dijkstra"
+	_AStar    = "a-star"
+)
+
+var TYPES = []string{
+	_DFS,
+	_BFS,
+	_Dijkstra,
+	_AStar,
+}
+
+func (f *SolverFactory) Get() Solver {
+	switch *f.Type {
+	case _DFS:
+		return &DFSSolver{}
+	case _BFS:
+		return &BFSSolver{}
+	case _AStar:
+		return &AStarSolver{}
+	case _Dijkstra:
+		return &DijkstraSolver{}
+	}
+	panic(fmt.Sprintf("Unrecognized solver type %q", *f.Type))
+}
+
+func visited(node *maze.Node) bool {
+	return node == nil || node.Visited
+}

solver/utils.go

@@ -0,0 +1,27 @@
+package solver
+
+import (
+	"maze-solver/maze"
+	"slices"
+)
+
+type sorted_stack []*maze.Node
+
+func (s *sorted_stack) insert(node *maze.Node, weights *map[*maze.Node]int) {
+	var dummy *maze.Node
+	*s = append(*s, dummy) // extend the slice
+
+	i, _ := slices.BinarySearchFunc(*s, node, func(e, t *maze.Node) int {
+		return (*weights)[t] - (*weights)[e]
+	})
+
+	copy((*s)[i+1:], (*s)[i:]) // make room
+	(*s)[i] = node
+}
+
+func (s *sorted_stack) pop() *maze.Node {
+	last_i := len(*s) - 1
+	ret := (*s)[last_i]
+	*s = (*s)[:last_i]
+	return ret
+}

utils/utils.go

@@ -1,6 +1,13 @@
 package utils
 
-import "log"
+import (
+	"fmt"
+	"log"
+	"testing"
+	"time"
+
+	"golang.org/x/exp/constraints"
+)
 
 func Check(err error, msg string, args ...any) {
 	if err != nil {
@@ -8,3 +15,28 @@ func Check(err error, msg string, args ...any) {
 		panic(err)
 	}
 }
+
+func Min[T constraints.Ordered](a, b T) T {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func AssertEqual[T comparable](t *testing.T, got T, want T, msg string, args ...any) {
+	args = append(args, got, want)
+	if got != want {
+		t.Fatalf(msg+"\nGot: %v, Want: %v", args...)
+	}
+}
+
+var VERBOSE_LEVEL int
+
+func Timer(msg string, level int) func() {
+	start := time.Now()
+	return func() {
+		if level <= VERBOSE_LEVEL {
+			fmt.Printf("%-19s %12v\n", msg, time.Since(start))
+		}
+	}
+}