#include <Wire.h>
// PCF8575 的 I2C 位址，通常是 0x20（取決於 A0、A1、A2 的接線）
#define PCF8575_ADDRESS 0x20

// 用來儲存目前 GPIO 的狀態（16 位元，表示 16 個引腳）
unsigned int gpioState = 0x0000; // 初始化為全部 HIGH (未啟動)

const int segmentPins[8] = {4, 15, 19, 18, 5, 16, 17, 23};
const int digitPins[2] = {32, 33};
const int segmentCodes[10] = {0xC0, 0xF9, 0xA4, 0xB0, 0x99, 0x92, 0x82, 0xF8, 0x80, 0x90};
const int buttonPin1 = 35;  // 按鈕1接到的GPIO腳位
const int buttonPin2 = 34;  // 按鈕2接到的GPIO腳位
const int buttonPin3 = 39;  // 按鈕3接到的GPIO腳位
const int buttonPin4 = 36;  // 按鈕4接到的GPIO腳位

unsigned long previousMillis = 0;
const int interval[4] = {50, 70, 100, 150};
int intervalIndex = 0;
int ledIndex = 0;
int circleCount = 0;
int classSize = 35;  // 預設班級人數為35人
int randomNumber = classSize;
bool direction = true;  // 新增方向變數
bool buttonPressed = false;  // 新增按鈕觸發變數
bool settingMode = false;  // 新增設定模式變數

unsigned long pauseStart = 0;
bool isPausing = false;

// 防彈跳變數
unsigned long lastDebounceTime1 = 0;
unsigned long lastDebounceTime2 = 0;
unsigned long lastDebounceTime3 = 0;
unsigned long lastDebounceTime4 = 0;
int buttonState1 = HIGH;
int buttonState2 = HIGH;
int buttonState3 = HIGH;
int buttonState4 = HIGH;
int lastButtonState1 = HIGH;
int lastButtonState2 = HIGH;
int lastButtonState3 = HIGH;
int lastButtonState4 = HIGH;

void setup(void)
{
    Wire.begin(); // 啟動 I2C 通訊
    for (int i = 0; i < 8; i++) {
        pinMode(segmentPins[i], OUTPUT);
        digitalWrite(segmentPins[i], HIGH);
    }
    for (int i = 0; i < 2; i++) {
        pinMode(digitPins[i], OUTPUT);
        digitalWrite(digitPins[i], LOW);
    }
    pinMode(buttonPin1, INPUT_PULLUP);  // 設定按鈕1腳位為輸入模式，並啟用內部上拉電阻
    pinMode(buttonPin2, INPUT_PULLUP);  // 設定按鈕2腳位為輸入模式，並啟用內部上拉電阻
    pinMode(buttonPin3, INPUT_PULLUP);  // 設定按鈕3腳位為輸入模式，並啟用內部上拉電阻
    pinMode(buttonPin4, INPUT_PULLUP);  // 設定按鈕4腳位為輸入模式，並啟用內部上拉電阻
    Serial.begin(9600);
    randomSeed(analogRead(0));
}

void loop(void)
{
    int reading1 = digitalRead(buttonPin1);
    if (reading1 != lastButtonState1) {
        lastDebounceTime1 = millis();
    }
    if ((millis() - lastDebounceTime1) > 50) {
        if (reading1 != buttonState1) {
            buttonState1 = reading1;
            if (buttonState1 == LOW) {
                buttonPressed = true;
            }
        }
    }
    lastButtonState1 = reading1;

    int reading2 = digitalRead(buttonPin2);
    if (reading2 != lastButtonState2) {
        lastDebounceTime2 = millis();
    }
    if ((millis() - lastDebounceTime2) > 50) {
        if (reading2 != buttonState2) {
            buttonState2 = reading2;
            if (buttonState2 == LOW) {
                classSize++;  // 人數增加
            }
        }
    }
    lastButtonState2 = reading2;

    int reading3 = digitalRead(buttonPin3);
    if (reading3 != lastButtonState3) {
        lastDebounceTime3 = millis();
    }
    if ((millis() - lastDebounceTime3) > 50) {
        if (reading3 != buttonState3) {
            buttonState3 = reading3;
            if (buttonState3 == LOW) {
                classSize--;  // 人數減少
            }
        }
    }
    lastButtonState3 = reading3;

    int reading4 = digitalRead(buttonPin4);
    if (reading4 != lastButtonState4) {
        lastDebounceTime4 = millis();
    }
    if ((millis() - lastDebounceTime4) > 50) {
        if (reading4 != buttonState4) {
            buttonState4 = reading4;
            if (buttonState4 == LOW) {
                settingMode = !settingMode;  // 切換設定模式
            }
        }
    }
    lastButtonState4 = reading4;

    if (settingMode) {
        randomNumber = classSize;  // 更新顯示的數字
    } else {
        if (buttonPressed) {
            updateLEDandRandomNumber();
        }
    }
    displayNumber(randomNumber);  // 持續更新顯示器
}

#define BUZZER_PIN 12
void updateLEDandRandomNumber() {
    unsigned long currentMillis = millis();
    static int targetLedIndex = 0;
    if (!isPausing && currentMillis - previousMillis >= interval[intervalIndex]) {
        previousMillis = currentMillis;

        if (circleCount % 5 == 0) {
            intervalIndex = 3;  // 第五圈時，設定間隔索引為3
        } else if (circleCount % 5 == 4) {
            intervalIndex = 3;
        } else if (circleCount % 5 == 3) {
            intervalIndex = 2;
        } else if (circleCount % 5 >= 1) {
            intervalIndex = 1;
        } else {
            intervalIndex = 0;
        }

        PCF8575Write(ledIndex, 1); // 高態點亮
        noTone(BUZZER_PIN);
        if (direction) {
            ledIndex = (ledIndex + 1) % 16;
        } else {
            ledIndex = (ledIndex - 1 + 16) % 16;
        }
        if (ledIndex == 0) {
            circleCount++;
            if (circleCount % 5 == 0) {
                targetLedIndex = random(0, 15);
                if (targetLedIndex == 0) {
                    targetLedIndex = random(1, 15);
                }
            }
        }

        if (ledIndex == targetLedIndex && circleCount % 5 == 0) {
            isPausing = true;
            pauseStart = currentMillis;
            buttonPressed = false;  // 重置按鈕觸發變數
        }
        PCF8575Write(ledIndex, 0); // 高態點亮
        tone(BUZZER_PIN, 440, 50);

        randomNumber = random(1, classSize + 1);  // 產生的亂數最大值為班級人數
        Serial.println(randomNumber);
    } else if (isPausing && currentMillis - pauseStart >= 3000) {
        isPausing = false;
        if (circleCount % 5 == 0) {
            direction = !direction;  // 完成五圈時，切換方向
        }
    }
}

void displayNumber(int number) {
    int digits[2] = {number % 10, number / 10};
    for (int i = 0; i < 2; i++) {
        digitalWrite(digitPins[i], HIGH);
        for (int j = 0; j < 8; j++) {
            digitalWrite(segmentPins[j], bitRead(segmentCodes[digits[i]], j));
        }
        delay(5);
        for (int j = 0; j < 8; j++) {
            digitalWrite(segmentPins[j], HIGH);
        }
        digitalWrite(digitPins[i], LOW);
    }
}

void PCF8575Write(uint8_t pin, uint8_t state) {
    if (pin < 0 || pin > 15) return; // 引腳號碼超過範圍，直接返回

    if (state == HIGH) {
        gpioState &= ~(1 << pin); // 將對應引腳位置為 LOW
    } else {      
        gpioState |= (1 << pin); // 將對應引腳位置為 HIGH
    }

    // 將更新後的狀態寫入 PCF8575
    Wire.beginTransmission(PCF8575_ADDRESS);
    Wire.write(gpioState & 0xFF);       // 寫入低 8 位
    Wire.write((gpioState >> 8) & 0xFF); // 寫入高 8 位
    Wire.endTransmission();
}