Pacman.kt

/*
 * Copyright 2025 Kyriakos Georgiopoulos
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import android.annotation.SuppressLint
import androidx.compose.animation.core.LinearEasing
import androidx.compose.animation.core.RepeatMode
import androidx.compose.animation.core.animateFloat
import androidx.compose.animation.core.infiniteRepeatable
import androidx.compose.animation.core.rememberInfiniteTransition
import androidx.compose.animation.core.tween
import androidx.compose.foundation.Canvas
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.BoxWithConstraints
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableIntStateOf
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.runtime.toMutableStateList
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.geometry.CornerRadius
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Rect
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.Path
import androidx.compose.ui.platform.LocalDensity
import androidx.compose.ui.unit.Dp
import kotlinx.coroutines.delay

val ClassicMazeLayout = listOf(
    "############################",
    "#..P.........##............#",
    "#.####.#####.##.#####.####.#",
    "#o####.#####.##.#####.####.#",
    "#.####.#####.##.#####.####.#",
    "#..........................#",
    "#.####.##.########.##.####.#",
    "#.####.##.########.##.####.#",
    "#......##....##....##......#",
    "######.#####.##.#####.######",
    "######.#####.##.#####.######",
    "######.##..........##.######",
    "######.##.########.##.######",
    "######.##.########.##.######",
    "#............##............#",
    "######.##.########.##.######",
    "######.##.########.##.######",
    "######.##....O.....##.######",
    "######.##.########.##.######",
    "######.##.########.##.######",
    "#............##............#",
    "#.####.#####.##.#####.####.#",
    "#o####.#####.##.#####.####.#",
    "#...##................##...#",
    "###.##.##.########.##.##.###",
    "#......##....##....##......#",
    "#.##########.##.##########.#",
    "#............A.....P....G..#",
    "############################"
)

@SuppressLint("UnusedBoxWithConstraintsScope")
@Composable
fun PacmanMaze(modifier: Modifier = Modifier) {
    val mazeState = remember {
        ClassicMazeLayout.map { it.toMutableList().toMutableStateList() }.toMutableStateList()
    }

    val pacmanPosition = remember { mutableStateOf(Pair(23, 13)) }
    val pacmanDirection = remember { mutableStateOf(Pair(0, -1)) }
    val lastMoveDirection = remember { mutableStateOf(Pair(0, -1)) }

    val ghostInitialPosition = remember {
        ClassicMazeLayout.withIndex()
            .flatMap { (rowIndex, row) ->
                row.mapIndexedNotNull { colIndex, char ->
                    if (char == 'G') Pair(rowIndex, colIndex) else null
                }
            }
            .firstOrNull() ?: Pair(1, 1)
    }
    val monsterInitialPosition = remember {
        ClassicMazeLayout.withIndex()
            .flatMap { (rowIndex, row) ->
                row.mapIndexedNotNull { colIndex, char ->
                    if (char == 'M') Pair(rowIndex, colIndex) else null
                }
            }
            .firstOrNull() ?: Pair(1, 1)
    }
    val ghostPosition = remember { mutableStateOf(ghostInitialPosition) }
    var ghostDirection by remember { mutableIntStateOf(1) }

    mazeState[ghostInitialPosition.first][ghostInitialPosition.second] = ' '

    val mouthOffset by rememberInfiniteTransition(label = "mouth").animateFloat(
        initialValue = 0f,
        targetValue = 25f,
        animationSpec = infiniteRepeatable(
            animation = tween(durationMillis = 200, easing = LinearEasing),
            repeatMode = RepeatMode.Reverse
        ),
        label = "mouthOffset"
    )

    LaunchedEffect(Unit) {
        while (true) {
            delay(150L)

            val (row, col) = pacmanPosition.value
            findNextDirectionToDot(mazeState.map { it.toList() }, pacmanPosition.value)?.let {
                pacmanDirection.value = it
            }

            val (dy, dx) = pacmanDirection.value
            val nextTile = mazeState.getOrNull(row + dy)?.getOrNull(col + dx)
            if (nextTile != null && nextTile != '#') {
                pacmanPosition.value = row + dy to col + dx
                lastMoveDirection.value = pacmanDirection.value
                if (nextTile in listOf('.', 'O', 'A', 'P')) {
                    mazeState[row + dy][col + dx] = ' '
                }
            }
        }
    }

    LaunchedEffect(Unit) {
        while (true) {
            delay(400L)
            val (r, c) = ghostPosition.value
            val nextCol = c + ghostDirection
            if (mazeState.getOrNull(r)?.getOrNull(nextCol) == '#') {
                ghostDirection *= -1
            } else {
                ghostPosition.value = r to nextCol
            }
        }
    }

    BoxWithConstraints(
        modifier = modifier
            .fillMaxSize()
            .background(Color.Black)
    ) {
        val cols = mazeState.maxOf { it.size }
        val rows = mazeState.size
        val tileSizePx = minOf(maxWidth.toPx() / cols, maxHeight.toPx() / rows)
        val offsetX = (maxWidth.toPx() - cols * tileSizePx) / 2f
        val offsetY = (maxHeight.toPx() - rows * tileSizePx) / 2f

        Canvas(modifier = Modifier.fillMaxSize()) {
            mazeState.forEachIndexed { row, tiles ->
                tiles.forEachIndexed { col, tile ->
                    val x = col * tileSizePx + offsetX
                    val y = row * tileSizePx + offsetY

                    when (tile) {
                        '.' -> drawCircle(
                            Color(0xFFFFE0B2),
                            tileSizePx / 10,
                            Offset(x + tileSizePx / 2, y + tileSizePx / 2)
                        )

                        '#' -> {
                            val stroke = tileSizePx / 5
                            if (mazeState.getOrNull(row - 1)
                                    ?.getOrNull(col) != '#'
                            ) drawLine(Color.Blue, Offset(x, y), Offset(x + tileSizePx, y), stroke)
                            if (mazeState.getOrNull(row + 1)?.getOrNull(col) != '#') drawLine(
                                Color.Blue,
                                Offset(x, y + tileSizePx),
                                Offset(x + tileSizePx, y + tileSizePx),
                                stroke
                            )
                            if (mazeState.getOrNull(row)
                                    ?.getOrNull(col - 1) != '#'
                            ) drawLine(Color.Blue, Offset(x, y), Offset(x, y + tileSizePx), stroke)
                            if (mazeState.getOrNull(row)?.getOrNull(col + 1) != '#') drawLine(
                                Color.Blue,
                                Offset(x + tileSizePx, y),
                                Offset(x + tileSizePx, y + tileSizePx),
                                stroke
                            )
                        }

                        'O' -> drawCircle(
                            Color(0xFFFFA500),
                            tileSizePx / 3,
                            Offset(x + tileSizePx / 2, y + tileSizePx / 2)
                        )

                        'A' -> {
                            drawCircle(
                                Color.Red,
                                tileSizePx / 3,
                                Offset(x + tileSizePx / 2, y + tileSizePx / 2)
                            )
                            drawLine(
                                Color.Green,
                                Offset(x + tileSizePx / 2, y + tileSizePx / 4),
                                Offset(x + tileSizePx / 2, y + tileSizePx / 8),
                                tileSizePx / 12
                            )
                        }

                        'P' -> {
                            drawRoundRect(
                                color = Color(0xFFFFC107),
                                topLeft = Offset(x + tileSizePx * 0.25f, y + tileSizePx * 0.2f),
                                size = Size(tileSizePx * 0.5f, tileSizePx * 0.6f),
                                cornerRadius = CornerRadius(tileSizePx * 0.15f)
                            )
                            val leafWidth = tileSizePx * 0.1f
                            for (i in -1..1) {
                                drawLine(
                                    color = Color(0xFF2E7D32),
                                    start = Offset(x + tileSizePx / 2, y + tileSizePx * 0.2f),
                                    end = Offset(x + tileSizePx / 2 + i * tileSizePx * 0.15f, y),
                                    strokeWidth = leafWidth
                                )
                            }
                        }
                    }
                }
            }

            val (prow, pcol) = pacmanPosition.value
            val (pdy, pdx) = lastMoveDirection.value
            val pcenterX = pcol * tileSizePx + offsetX + tileSizePx / 2
            val pcenterY = prow * tileSizePx + offsetY + tileSizePx / 2
            val angleOffset = when (pdx to pdy) {
                1 to 0 -> 0f
                0 to -1 -> 270f
                -1 to 0 -> 180f
                0 to 1 -> 90f
                else -> 0f
            }
            drawArc(
                color = Color.Yellow,
                startAngle = angleOffset + mouthOffset,
                sweepAngle = 360f - 2 * mouthOffset,
                useCenter = true,
                topLeft = Offset(pcenterX - tileSizePx / 2, pcenterY - tileSizePx / 2),
                size = Size(tileSizePx, tileSizePx)
            )

            val (gRow, gCol) = ghostPosition.value
            val gx = gCol * tileSizePx + offsetX
            val gy = gRow * tileSizePx + offsetY

            val ghostPath = Path().apply {
                moveTo(x = gx, y = gy + tileSizePx / 2)
                arcTo(
                    rect = Rect(Offset(gx, gy), Size(tileSizePx, tileSizePx)),
                    startAngleDegrees = 180f,
                    sweepAngleDegrees = 180f,
                    forceMoveTo = false
                )
                lineTo(gx + tileSizePx, gy + tileSizePx)
                val waveCount = 4
                val waveWidth = tileSizePx / waveCount
                for (i in waveCount - 1 downTo 0) {
                    val cx = gx + i * waveWidth + waveWidth / 2
                    val cy = gy + tileSizePx
                    quadraticBezierTo(
                        gx + i * waveWidth + waveWidth / 4,
                        cy - tileSizePx / 6,
                        cx,
                        cy
                    )
                }
                lineTo(gx, gy + tileSizePx)
                close()
            }
            drawPath(ghostPath, Color.Cyan)
            listOf(-1, 1).forEach { dir ->
                drawCircle(
                    Color.White,
                    tileSizePx / 6,
                    Offset(gx + tileSizePx / 2 + dir * tileSizePx / 4, gy + tileSizePx / 3)
                )
                drawCircle(
                    Color.Blue,
                    tileSizePx / 10,
                    Offset(gx + tileSizePx / 2 + dir * tileSizePx / 4, gy + tileSizePx / 3)
                )
            }
        }
    }
}


fun findNextDirectionToDot(
    maze: List<List<Char>>,
    start: Pair<Int, Int>
): Pair<Int, Int>? {
    val directions = listOf(0 to -1, -1 to 0, 1 to 0, 0 to 1)
    val visited = mutableSetOf<Pair<Int, Int>>()
    val queue = ArrayDeque<List<Pair<Int, Int>>>()
    queue.add(listOf(start))

    while (queue.isNotEmpty()) {
        val path = queue.removeFirst()
        val current = path.last()

        if (current != start &&
            (maze.getOrNull(current.first)?.getOrNull(current.second) == '.' ||
                    maze.getOrNull(current.first)?.getOrNull(current.second) == 'F' ||
                    maze.getOrNull(current.first)?.getOrNull(current.second) == 'A' ||
                    maze.getOrNull(current.first)?.getOrNull(current.second) == 'G' ||
                    maze.getOrNull(current.first)?.getOrNull(current.second) == 'B')
        ) {
            val nextStep = path[1]
            return nextStep.first - start.first to nextStep.second - start.second
        }

        for ((dy, dx) in directions) {
            val next = current.first + dy to current.second + dx
            if (
                next !in visited &&
                maze.getOrNull(next.first)?.getOrNull(next.second) != null &&
                maze[next.first][next.second] != '#'
            ) {
                visited.add(next)
                queue.add(path + next)
            }
        }
    }

    return null
}

@Composable
fun Dp.toPx(): Float {
    return with(LocalDensity.current) { [email protected]() }
}

@SuppressLint("UnusedBoxWithConstraintsScope")
@Composable
fun PacmanMazeDemo() {
    Column(
        modifier = Modifier
            .fillMaxSize()
            .background(Color.Black),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center
    ) {
        PacmanMaze()
    }
}