From b6dff509f9341c0acb2f722b844cd7380a702b5d Mon Sep 17 00:00:00 2001
From: Karma Riuk <riukkarma@gmail.com>
Date: Mon, 7 Aug 2023 17:43:35 +0200
Subject: [PATCH] Fixed parser

---
 maze/parser/parser.go      | 18 ++++++++++++------
 maze/parser/parser_test.go | 30 +++++++++++++++---------------
 2 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/maze/parser/parser.go b/maze/parser/parser.go
index 5da9046..b0cd915 100644
--- a/maze/parser/parser.go
+++ b/maze/parser/parser.go
@@ -30,10 +30,7 @@ func Parse(reader reader.Reader) (*maze.Maze, error) {
 	for y = 1; y < raw_maze.Height-1; y++ {
 		for x := 1; x < raw_maze.Width-1; x++ {
 			// Parse middle of the maze
-			if raw_maze.IsPath(x, y) &&
-				(raw_maze.IsWall(x-1, y) && raw_maze.IsPath(x+1, y) ||
-					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))) {
+			if isCoordEligibleForNode(x, y, raw_maze) {
 				coords := maze.Coordinates{X: x, Y: y}
 				node := maze.NewNode(coords)
 
@@ -43,7 +40,8 @@ func Parse(reader reader.Reader) (*maze.Maze, error) {
 				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)) {
+					raw_maze.IsPath(x, y-1) &&
+						(raw_maze.IsPath(x-1, y) || raw_maze.IsPath(x+1, y)) {
 					lookupNeighbourLeft(raw_maze, node, &nodesByCoord)
 				}
 			}
@@ -64,6 +62,14 @@ func Parse(reader reader.Reader) (*maze.Maze, error) {
 	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}]
@@ -97,7 +103,7 @@ func lookupNeighbourAbove(raw_maze *reader.RawMaze, node *maze.Node, nodesByCoor
 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 {
-			panic(fmt.Sprintf("Found no node before wall while looking to the left at neighbours of node %v", node))
+			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}]
diff --git a/maze/parser/parser_test.go b/maze/parser/parser_test.go
index 024d3c1..61560c9 100644
--- a/maze/parser/parser_test.go
+++ b/maze/parser/parser_test.go
@@ -215,9 +215,9 @@ func TestTextReadNormal(t *testing.T) {
 		##### ### #
 		#5 6#7   8#
 		# # ##### #
-		#9#A   G B#
+		#9#A   F B#
 		### ### # #
-		#C D#E F# #
+		#C D#E G# #
 		# ####### #
 		#H   I#J K#
 		#####L#####
@@ -241,13 +241,13 @@ func TestTextReadNormal(t *testing.T) {
 
 		{1, 5}, // 9
 		{3, 5}, // A (10)
-		{7, 5}, // G (16)
 		{9, 5}, // B (11)
 
 		{1, 7}, // C (12)
 		{3, 7}, // D (13)
 		{5, 7}, // E (14)
-		{7, 7}, // F (15)
+		{7, 5}, // F (15)
+		{7, 7}, // G (16)
 
 		{1, 9}, // H (17)
 		{5, 9}, // I (18)
@@ -290,27 +290,27 @@ func TestTextReadNormal(t *testing.T) {
 	nodes[9].Up = nodes[5]
 
 	nodes[10].Up = nodes[6]
-	nodes[10].Right = nodes[16]
+	nodes[10].Right = nodes[15]
 	nodes[10].Down = nodes[13]
 
-	nodes[11].Up = nodes[6]
-	nodes[11].Right = nodes[16]
+	nodes[11].Up = nodes[8]
+	nodes[11].Left = nodes[15]
 	nodes[11].Down = nodes[20]
 
 	nodes[12].Right = nodes[13]
 	nodes[12].Down = nodes[17]
 
 	nodes[13].Up = nodes[10]
-	nodes[13].Left = nodes[16]
+	nodes[13].Left = nodes[12]
 
-	nodes[14].Right = nodes[15]
+	nodes[14].Right = nodes[16]
 
-	nodes[15].Up = nodes[16]
-	nodes[15].Left = nodes[14]
+	nodes[15].Left = nodes[10]
+	nodes[15].Right = nodes[11]
+	nodes[15].Down = nodes[16]
 
-	nodes[16].Left = nodes[10]
-	nodes[16].Right = nodes[11]
-	nodes[16].Down = nodes[15]
+	nodes[16].Up = nodes[15]
+	nodes[16].Left = nodes[14]
 
 	nodes[17].Up = nodes[12]
 	nodes[17].Right = nodes[18]
@@ -323,7 +323,7 @@ func TestTextReadNormal(t *testing.T) {
 	nodes[20].Up = nodes[11]
 	nodes[20].Left = nodes[19]
 
-	nodes[21].Up = nodes[20]
+	nodes[21].Up = nodes[18]
 
 	reader := reader.TextReader{
 		Filename: "../../assets/normal.txt",