From 41e665c169def8d47fa808cf67756c35f4530e3e Mon Sep 17 00:00:00 2001
From: Karma Riuk <riukkarma@gmail.com>
Date: Wed, 9 Aug 2023 17:44:59 +0200
Subject: [PATCH] Written the ImageWriter

---
 go.mod             |  12 +++++-
 go.sum             |   6 +++
 io/writer/image.go | 103 ++++++++++++++++++++++++++++++++++++++++++++-
 maze/maze.go       |  23 ++++++++++
 4 files changed, 140 insertions(+), 4 deletions(-)

diff --git a/go.mod b/go.mod
index 5033a7e..b060f9c 100644
--- a/go.mod
+++ b/go.mod
@@ -1,5 +1,13 @@
 module maze-solver
 
-go 1.20
+go 1.21
 
-require golang.org/x/exp v0.0.0-20230801115018-d63ba01acd4b
+require (
+	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
+)
diff --git a/go.sum b/go.sum
index 9cf7e1c..247b345 100644
--- a/go.sum
+++ b/go.sum
@@ -1,2 +1,8 @@
+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=
 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=
diff --git a/io/writer/image.go b/io/writer/image.go
index e3727e2..5731a83 100644
--- a/io/writer/image.go
+++ b/io/writer/image.go
@@ -1,11 +1,110 @@
 package writer
 
 import (
+	"errors"
+	"image"
+	"image/color"
+	"image/draw"
+	"image/png"
 	"maze-solver/maze"
+	"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 {
+	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 {
+			x0 = from.Coords.X * w.CellWidth
+
+			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 {
+			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)
+}
diff --git a/maze/maze.go b/maze/maze.go
index 997597c..a603628 100644
--- a/maze/maze.go
+++ b/maze/maze.go
@@ -1,8 +1,31 @@
 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