import (
	"c"
	"c/raylib"
)

const (
	BOARD_WIDTH  = 10
	BOARD_HEIGHT = 20
	BLOCK_SIZE   = 30

	SCREENWIDTH  = 300
	SCREENHEIGHT = 600
)

const MAX_BLOCKS = 4

type Shape struct {
	Blocks [MAX_BLOCKS]raylib.Vector2
	Color  raylib.Color
}

var SHAPES = []Shape{
	{Blocks: [MAX_BLOCKS]raylib.Vector2{{X: 0, Y: 0}, {X: 1, Y: 0}, {X: 2, Y: 0}, {X: 3, Y: 0}}, Color: raylib.SKYBLUE},
	{Blocks: [MAX_BLOCKS]raylib.Vector2{{X: 0, Y: 0}, {X: 1, Y: 0}, {X: 0, Y: 1}, {X: 1, Y: 1}}, Color: raylib.YELLOW},
	{Blocks: [MAX_BLOCKS]raylib.Vector2{{X: 1, Y: 0}, {X: 0, Y: 1}, {X: 1, Y: 1}, {X: 2, Y: 1}}, Color: raylib.PURPLE},
	{Blocks: [MAX_BLOCKS]raylib.Vector2{{X: 1, Y: 0}, {X: 2, Y: 0}, {X: 0, Y: 1}, {X: 1, Y: 1}}, Color: raylib.GREEN},
	{Blocks: [MAX_BLOCKS]raylib.Vector2{{X: 0, Y: 0}, {X: 1, Y: 0}, {X: 1, Y: 1}, {X: 2, Y: 1}}, Color: raylib.RED},
	{Blocks: [MAX_BLOCKS]raylib.Vector2{{X: 0, Y: 0}, {X: 0, Y: 1}, {X: 1, Y: 1}, {X: 2, Y: 1}}, Color: raylib.BLUE},
	{Blocks: [MAX_BLOCKS]raylib.Vector2{{X: 2, Y: 0}, {X: 0, Y: 1}, {X: 1, Y: 1}, {X: 2, Y: 1}}, Color: raylib.ORANGE},
}

var board [BOARD_HEIGHT][BOARD_WIDTH]raylib.Color

var curShape Shape
var curPos raylib.Vector2

var fallTime = c.Float(0)
var fallSpeed = c.Float(0.2)
var score = 0
var scoreText = (*c.Char)(c.malloc(20))
var gameOver = false

func genShape() {
	curShape = SHAPES[raylib.getRandomValue(0, 6)]
	curPos = raylib.Vector2{BOARD_WIDTH/2 - 1, 0}
}

func checkCollision() bool {
	for i := 0; i < MAX_BLOCKS; i++ {
		x := int(curPos.X + curShape.Blocks[i].X)
		y := int(curPos.Y + curShape.Blocks[i].Y)
		if x < 0 || x >= BOARD_WIDTH || y >= BOARD_HEIGHT || (y >= 0 && board[y][x] != raylib.BLANK) {
			return true
		}
	}
	return false
}

func lockShape() {
	for i := 0; i < MAX_BLOCKS; i++ {
		x := int(curPos.X + curShape.Blocks[i].X)
		y := int(curPos.Y + curShape.Blocks[i].Y)
		if y >= 0 {
			board[y][x] = curShape.Color
		}
	}
}

func rotateShape() {
	rotated := curShape
	for i := 0; i < MAX_BLOCKS; i++ {
		x := rotated.Blocks[i].X
		rotated.Blocks[i].X = -rotated.Blocks[i].Y
		rotated.Blocks[i].Y = x
	}

	temp := curShape
	curShape = rotated
	if checkCollision() {
		curShape = temp
	}
}

func clearLines() int {
	linesCleared := 0
	for y := BOARD_HEIGHT - 1; y >= 0; y-- {
		lineFull := true
		for x := 0; x < BOARD_WIDTH; x++ {
			if board[y][x] == raylib.BLANK {
				lineFull = false
				break
			}
		}
		if lineFull {
			for yy := y; yy > 0; yy-- {
				for x := 0; x < BOARD_WIDTH; x++ {
					board[yy][x] = board[yy-1][x]
				}
			}
			for x := 0; x < BOARD_WIDTH; x++ {
				board[0][x] = raylib.BLANK
			}
			y += 1
			linesCleared += 1
		}
	}
	return linesCleared
}

func keyPressed(key c.Int) bool {
	return raylib.isKeyPressed(key) || raylib.isKeyPressedRepeat(key)
}

raylib.initWindow SCREENWIDTH, SCREENHEIGHT, c"tetris (powered by raylib and Go+)"
raylib.setTargetFPS 60
genShape

for !raylib.windowShouldClose && !gameOver {
	fallTime += raylib.getFrameTime
	if fallTime >= fallSpeed {
		fallTime = 0
		curPos.Y += 1
		if checkCollision() {
			curPos.Y -= 1
			lockShape
			linesCleared := clearLines()
			score += linesCleared * 100
			genShape
			if checkCollision() {
				gameOver = true
			}
		}
	}

	if keyPressed(raylib.KEY_LEFT) {
		curPos.X--
		if checkCollision() {
			curPos.X++
		}
	}
	if keyPressed(raylib.KEY_RIGHT) {
		curPos.X++
		if checkCollision() {
			curPos.X--
		}
	}
	if keyPressed(raylib.KEY_SPACE) || keyPressed(raylib.KEY_UP) || keyPressed(raylib.KEY_DOWN) {
		rotateShape
	}

	raylib.beginDrawing
	raylib.clearBackground raylib.RAYWHITE
	for y := 0; y < BOARD_HEIGHT; y++ {
		for x := 0; x < BOARD_WIDTH; x++ {
			raylib.drawRectangle c.Int(x*BLOCK_SIZE), c.Int(y*BLOCK_SIZE), c.Int(BLOCK_SIZE-1), c.Int(BLOCK_SIZE-1), board[y][x]
		}
	}

	for i := 0; i < MAX_BLOCKS; i++ {
		raylib.drawRectangle c.Int((curPos.X+curShape.Blocks[i].X)*BLOCK_SIZE), c.Int((curPos.Y+curShape.Blocks[i].Y)*BLOCK_SIZE),
			BLOCK_SIZE-1, BLOCK_SIZE-1, curShape.Color
	}

	c.sprintf scoreText, c"Score:%d", score
	raylib.drawText scoreText, 10, 10, 20, raylib.BLACK
	raylib.endDrawing
}

for !raylib.windowShouldClose {
	raylib.beginDrawing
	raylib.clearBackground raylib.RAYWHITE
	raylib.drawText c"Game Over", SCREENWIDTH/2-50, SCREENHEIGHT/2-10, 20, raylib.RED
	raylib.drawText scoreText, SCREENWIDTH/2-50, SCREENHEIGHT/2+10, 20, raylib.BLACK
	raylib.endDrawing
}