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

/********* OLED *********/
#define SCREEN_WIDTH    128
#define SCREEN_HEIGHT   64
#define SCREEN_ADDRESS  0x3C
// 保持你已验证可用的构造参数
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1, 1700000UL, 1700000UL);

/********* Touch pins (official pinout) *********/
// CH0..CH5 → P03,P04,P02,P27,P01,P26  (3,4,2,27,1,26)
#define N_TOUCH 6
int touch_pins[N_TOUCH] = {3, 4, 2, 27, 1, 26};

/********* Touch timing *********/
const uint32_t SAFE_WINDOW_MS   = 2000;
volatile uint16_t T_MAX_US      = 500;     // 足够你的板子
const uint16_t DISCHARGE_US     = 25;

/********* Game timing *********/
const uint32_t FRAME_MS         = 50;      // 20 FPS

/********* Physics tuning *********/
const float GRAVITY        = 1.00f;   // 更快下落
const float JUMP_IMPULSE   = -7.8f;   // 更有力起跳
const float MAX_FALL_SPEED = 10.0f;   // 终端速度
const float AIR_DOWN_BOOST = 0.6f;    // 空中按下加速落地

/********* Input mapping *********/
// CH2,3,4,5 = down,left,right,up ; CH0,1 = func right/left
#define CH_DOWN   2
#define CH_LEFT   3
#define CH_RIGHT  4
#define CH_UP     5
#define CH_FUNC_R 0   // start/pause/resume
#define CH_FUNC_L 1   // reset/restart

/********* Touch state *********/
uint16_t touch_us[N_TOUCH] = {0};
bool     pressed[N_TOUCH]  = {0};     // 非0即按下

/********* Utils *********/
static inline void usb_friendly_yield() { yield(); }
static inline uint16_t measure_touch_us(int pin) {
  pinMode(pin, OUTPUT);
  digitalWriteFast(pin, LOW);
  delayMicroseconds(DISCHARGE_US);
  pinMode(pin, INPUT_PULLUP);
  unsigned long t0 = micros();
  while (!digitalReadFast(pin)) {
    if ((uint16_t)(micros() - t0) >= T_MAX_US) break;
    usb_friendly_yield();
  }
  return (uint16_t)(micros() - t0);
}
void poll_touch() {
  for (int i=0;i<N_TOUCH;i++) {
    touch_us[i] = measure_touch_us(touch_pins[i]);
    pressed[i]  = (touch_us[i] != 0);
  }
}

/********* Game state *********/
enum GameState { GS_MENU, GS_PLAY, GS_PAUSE, GS_GAMEOVER };
GameState gstate = GS_MENU;

struct Dino {
  int   x = 12;
  int   y = 48;          // 物理层保证不穿地
  float vy = 0;
  bool  crouch = false;
} dino;

const int groundY = 56;        // 地面线
const int dinoW = 16;          // 像素恐龙尺寸（含头尾）
const int dinoH = 12;
const int dinoH_crouch = 8;
uint8_t   runPhase = 0;        // 跑步两帧动画相位

struct Rock {
  int x = 140;
  int y = groundY - 6;
  int w = 6;
  int h = 6;
  bool active = false;
};
const int MAX_ROCKS = 3;
Rock rocks[MAX_ROCKS];

int      scrollSpeed = 2;      // 水平卷动速度
uint32_t frameTimer  = 0;
uint32_t spawnTimer  = 0;
uint32_t score = 0, best = 0;

/********* Spawn / difficulty tuning *********/
int      activeRocksLimit = 2;          // 同屏最大障碍数量
uint32_t spawnInterval    = 1400;       // 生成基础间隔(ms)
uint32_t spawnJitter      = 900;        // 间隔抖动
uint16_t minGapPx         = 70;         // 新障碍与屏右边最小像素间距

int rightmostRockX() {
  int rx = -1000;
  for (int i=0;i<MAX_ROCKS;i++) if (rocks[i].active) rx = max(rx, rocks[i].x);
  return rx;
}
int activeRockCount() {
  int c=0; for (int i=0;i<MAX_ROCKS;i++) if (rocks[i].active) c++; return c;
}
void retune_spawn_from_score() {
  if (score >= 150) scrollSpeed = 3;
  if (score >= 300) scrollSpeed = 4;

  uint32_t base = 1400;
  if (score >= 100) base = 1200;
  if (score >= 250) base = 1000;
  spawnInterval = base;
  spawnJitter   = 700;

  minGapPx = 70;
  if (score >= 150) minGapPx = 60;
  if (score >= 300) minGapPx = 52;
}
void spawn_rock() {
  if (activeRockCount() >= activeRocksLimit) return;
  if (rightmostRockX() > SCREEN_WIDTH - (int)minGapPx) return;

  for (int i=0;i<MAX_ROCKS;i++) if (!rocks[i].active) {
    rocks[i].active = true;
    rocks[i].x = SCREEN_WIDTH + random(0, 24);
    int type = random(0,3);
    if (type == 0) { rocks[i].w = 6;  rocks[i].h = 6;  }
    if (type == 1) { rocks[i].w = 8;  rocks[i].h = 10; }
    if (type == 2) { rocks[i].w = 4;  rocks[i].h = 4;  }
    rocks[i].y = groundY - rocks[i].h;
    break;
  }
  retune_spawn_from_score();
  spawnTimer    = 0;
  uint32_t jitter = random(0, spawnJitter);
  spawnInterval  = max<uint32_t>(spawnInterval + jitter, 700);
}

/********* collision *********/
bool collideRect(int x1,int y1,int w1,int h1, int x2,int y2,int w2,int h2) {
  return !(x2 > x1+w1-1 || x2+w2-1 < x1 || y2 > y1+h1-1 || y2+h2-1 < y1);
}

/********* drawing *********/
void draw_dino() {
  int x = dino.x;
  int h = dino.crouch ? dinoH_crouch : dinoH;
  int y = dino.y;
  // 身体
  display.fillRect(x, y+2, 10, h-2, SSD1306_WHITE);
  // 尾巴
  display.fillTriangle(x-5, y+h-3,  x, y+h-3,  x, y+h-7, SSD1306_WHITE);
  // 头
  display.fillRect(x+9, y, 7, 6, SSD1306_WHITE);
  // 嘴开口与眼睛
  display.drawPixel(x+14, y+5, SSD1306_BLACK);
  display.drawPixel(x+14, y+2, SSD1306_BLACK);
  // 背脊
  display.drawPixel(x+3, y+1, SSD1306_WHITE);
  display.drawPixel(x+5, y,   SSD1306_WHITE);

  // 腿 / 脚
  int footY = y + h - 1; if (footY > groundY) footY = groundY;
  if (dino.crouch) {
    display.fillRect(x+2,  footY-1, 3, 2, SSD1306_WHITE);
    display.fillRect(x+7,  footY-1, 3, 2, SSD1306_WHITE);
  } else {
    bool onGround = (dino.y >= groundY - h);
    if (onGround) {
      if (runPhase == 0) {
        display.fillRect(x+2,  footY-2, 3, 3, SSD1306_WHITE); // 左弯
        display.fillRect(x+8,  footY-1, 3, 2, SSD1306_WHITE); // 右伸
      } else {
        display.fillRect(x+2,  footY-1, 3, 2, SSD1306_WHITE); // 左伸
        display.fillRect(x+8,  footY-2, 3, 3, SSD1306_WHITE); // 右弯
      }
    } else {
      display.fillRect(x+3,  footY-2, 3, 3, SSD1306_WHITE);
      display.fillRect(x+9,  footY-2, 3, 3, SSD1306_WHITE);
    }
  }
}
void draw_ground() {
  display.drawLine(0, groundY+1, SCREEN_WIDTH-1, groundY+1, SSD1306_WHITE);
}
void draw_rocks() {
  for (int i=0;i<MAX_ROCKS;i++) if (rocks[i].active) {
    display.fillRect(rocks[i].x, rocks[i].y, rocks[i].w, rocks[i].h, SSD1306_WHITE);
  }
}
void draw_hud() {
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0,0);
  display.print("S:"); display.print(score);
  display.setCursor(64,0);
  display.print("B:"); display.print(best);
  display.setCursor(0,56);
  if (gstate==GS_MENU)           display.print("CH0:Start  CH1:Reset");
  else if (gstate==GS_PAUSE)     display.print("PAUSE  CH0:Resume");
  else if (gstate==GS_PLAY)      display.print("UP Jump  L/R Move  CH0 Pause");
  else if (gstate==GS_GAMEOVER)  display.print("GameOver  CH1 Restart");
}
void draw_scene() {
  display.clearDisplay();
  draw_ground();
  draw_rocks();
  draw_dino();
  draw_hud();

  if (gstate == GS_MENU) {
    display.setCursor(20, 24); display.println("Tiny Dino");
    display.setCursor(10, 36); display.println("CH0 Start  CH1 Reset");
  } else if (gstate == GS_PAUSE) {
    display.setCursor(44, 24); display.println("PAUSED");
  } else if (gstate == GS_GAMEOVER) {
    display.setCursor(28, 24); display.println("GAME OVER");
    display.setCursor(10, 36); display.println("CH1: Restart");
  }
  display.display();
}

/********* game helpers *********/
void reset_game(bool keep_best) {
  dino.x = 12;
  dino.y = groundY - dinoH;
  dino.vy = 0;
  dino.crouch = false;
  runPhase = 0;

  for (int i=0;i<MAX_ROCKS;i++) { rocks[i].active=false; rocks[i].x=140; rocks[i].y=groundY-6; rocks[i].w=6; rocks[i].h=6; }
  scrollSpeed = 2;
  if (!keep_best) best = 0;
  score = 0;
  spawnTimer = 0;
  spawnInterval = 1400;
}

/********* loop parts *********/
void do_menu() {
  if (pressed[CH_FUNC_R]) gstate = GS_PLAY;
  if (pressed[CH_FUNC_L]) { reset_game(false); }
}
void do_pause() {
  if (pressed[CH_FUNC_R]) gstate = GS_PLAY;
  if (pressed[CH_FUNC_L]) { reset_game(true); gstate = GS_MENU; }
}
void do_gameover() {
  if (pressed[CH_FUNC_L]) { reset_game(true); gstate = GS_MENU; }
}
void do_play() {
  bool jump  = pressed[CH_UP];
  bool left  = pressed[CH_LEFT];
  bool right = pressed[CH_RIGHT];
  bool down  = pressed[CH_DOWN];

  if (pressed[CH_FUNC_R]) { gstate = GS_PAUSE; return; }

  // crouch
  dino.crouch = down;

  // on ground?
  int curH = dino.crouch ? dinoH_crouch : dinoH;
  bool onGround = (dino.y >= groundY - curH);
  if (onGround) { dino.y = groundY - curH; dino.vy = 0; }
  if (jump && onGround) dino.vy = JUMP_IMPULSE;

  // horizontal
  if (left)  dino.x -= 2;
  if (right) dino.x += 2;
  dino.x = constrain(dino.x, 2, 50);

  // gravity & vertical
  dino.vy += GRAVITY;
  if (!onGround && down) dino.vy += AIR_DOWN_BOOST;
  if (dino.vy >  MAX_FALL_SPEED) dino.vy =  MAX_FALL_SPEED;
  if (dino.vy < -MAX_FALL_SPEED) dino.vy = -MAX_FALL_SPEED;
  dino.y  += (int)dino.vy;
  curH = dino.crouch ? dinoH_crouch : dinoH;
  if (dino.y > groundY - curH) { dino.y = groundY - curH; dino.vy = 0; }

  // 跑步动画：落地且非蹲下时，每帧切一相位
  if (dino.y >= groundY - curH && !dino.crouch) runPhase ^= 1;

  // spawn
  spawnTimer += FRAME_MS;
  if (spawnTimer >= spawnInterval) {
    spawn_rock();
  }

  // move rocks & scoring/collision
  for (int i=0;i<MAX_ROCKS;i++) if (rocks[i].active) {
    rocks[i].x -= scrollSpeed;
    if (rocks[i].x + rocks[i].w < 0) {
      rocks[i].active = false;
      score += 10;
      if (score > best) best = score;
      if (score % 80 == 0 && scrollSpeed < 4) scrollSpeed++;
      retune_spawn_from_score();
    } else {
      int dH = dino.crouch ? dinoH_crouch : dinoH;
      if (collideRect(dino.x, dino.y, dinoW, dH,
                      rocks[i].x, rocks[i].y, rocks[i].w, rocks[i].h)) {
        gstate = GS_GAMEOVER;
      }
    }
  }
}

/********* setup/loop *********/
unsigned long t_boot = 0;

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(115200);
  t_boot = millis();

  // OLED
  Wire.begin();
  Wire.setClock(400000);
  delay(30);
  display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(8, 26); display.println("Tiny Dino!");
  display.setCursor(8, 38); display.println("CH0 Start / CH1 Reset");
  display.display();

  randomSeed(micros());
  reset_game(true);
  gstate = GS_MENU;
}

void loop() {
  // Safe window
  if (millis() - t_boot < SAFE_WINDOW_MS) {
    digitalWrite(LED_BUILTIN, (millis()/250)%2);
    delay(50);
    return;
  }

  // frame pacing
  static uint32_t last = 0;
  uint32_t now = millis();
  if (now - last < FRAME_MS) return;
  last = now;

  // input
  poll_touch();

  // state machine
  switch (gstate) {
    case GS_MENU:     do_menu();     break;
    case GS_PLAY:     do_play();     break;
    case GS_PAUSE:    do_pause();    break;
    case GS_GAMEOVER: do_gameover(); break;
  }

  // render
  draw_scene();
}