#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET    -1
#define OLED_ADDRESS  0x3C
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// 定義按鍵引腳
#define LEFT_BUTTON_PIN 2
#define RIGHT_BUTTON_PIN 3
#define UP_BUTTON_PIN 4
#define DOWN_BUTTON_PIN 5

const int mazeWidth = 16;
const int mazeHeight = 8;
int maze[mazeWidth][mazeHeight];
int playerX = 1;
int playerY = 1;
int exitX, exitY;

void setup() {
  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }
  display.clearDisplay();
  display.display();
  
  // 設置隨機種子
  randomSeed(analogRead(0));
  
  generateMaze();
  placeExit();
  drawMaze();

  // 設置按鍵引腳為輸入
  pinMode(LEFT_BUTTON_PIN, INPUT_PULLUP);
  pinMode(RIGHT_BUTTON_PIN, INPUT_PULLUP);
  pinMode(UP_BUTTON_PIN, INPUT_PULLUP);
  pinMode(DOWN_BUTTON_PIN, INPUT_PULLUP);
}

void loop() {
  bool moved = false;

  // 偵測按鍵按下，控制角色移動
  if (digitalRead(LEFT_BUTTON_PIN) == LOW && maze[playerX - 1][playerY] != 1) {
    playerX--;
    moved = true;
  } else if (digitalRead(RIGHT_BUTTON_PIN) == LOW && maze[playerX + 1][playerY] != 1) {
    playerX++;
    moved = true;
  } else if (digitalRead(UP_BUTTON_PIN) == LOW && maze[playerX][playerY - 1] != 1) {
    playerY--;
    moved = true;
  } else if (digitalRead(DOWN_BUTTON_PIN) == LOW && maze[playerX][playerY + 1] != 1) {
    playerY++;
    moved = true;
  }

  // 檢查勝利條件
  if (playerX == exitX && playerY == exitY) {
    display.clearDisplay();
    display.setTextSize(2);
    display.setTextColor(SSD1306_WHITE);
    display.setCursor(0, 0);
    display.print(F("You Win!"));
    display.display();
    while (1); // 停止遊戲
  }

  if (moved) {
    drawMaze();
    delay(100); // 減少延遲
  }
}

void generateMaze() {
  // 初始化迷宮
  for (int x = 0; x < mazeWidth; x++) {
    for (int y = 0; y < mazeHeight; y++) {
      maze[x][y] = 1; // 填充所有牆壁
    }
  }

  // 設置起點
  playerX = 1;
  playerY = 1;
  maze[playerX][playerY] = 0; // 起點

  // 開始深度優先搜索生成迷宮
  carvePassagesFrom(1, 1);
}

void carvePassagesFrom(int x, int y) {
  int directions[] = {0, 1, 2, 3};
  // 打亂方向
  for (int i = 0; i < 4; i++) {
    int r = random(4);
    int temp = directions[i];
    directions[i] = directions[r];
    directions[r] = temp;
  }

  for (int i = 0; i < 4; i++) {
    int nx = x, ny = y;
    switch (directions[i]) {
      case 0: nx = x + 2; break; // 右
      case 1: ny = y + 2; break; // 下
      case 2: nx = x - 2; break; // 左
      case 3: ny = y - 2; break; // 上
    }

    if (nx > 0 && nx < mazeWidth - 1 && ny > 0 && ny < mazeHeight - 1 && maze[nx][ny] == 1) {
      maze[nx][ny] = 0;
      maze[nx - (nx - x) / 2][ny - (ny - y) / 2] = 0;
      carvePassagesFrom(nx, ny);
    }
  }
}

void placeExit() {
  while (true) {
    exitX = random(1, mazeWidth - 1);
    exitY = random(1, mazeHeight - 1);
    if (maze[exitX][exitY] == 0) {
      maze[exitX][exitY] = 3;
      break;
    }
  }
}

void drawMaze() {
  display.clearDisplay();
  for (int y = 0; y < mazeHeight; y++) {
    for (int x = 0; x < mazeWidth; x++) {
      if (maze[x][y] == 1) {
        display.drawRect(x * 8, y * 8, 8, 8, SSD1306_WHITE); // 畫牆壁
      } else if (x == exitX && y == exitY) {
        display.fillRect(x * 8, y * 8, 8, 8, SSD1306_WHITE); // 畫出出口
      } else if (x == playerX && y == playerY) {
        display.fillRect(x * 8, y * 8, 8, 8, SSD1306_WHITE); // 畫出角色
      }
    }
  }
  display.display();
}