from machine import Pin
from picozero import Speaker
import time

# --- 1. 硬件配置 (Pins) ---
# 車用燈: 紅(10), 黃(11), 綠(12)
v_red = Pin(10, Pin.OUT)
v_yellow = Pin(11, Pin.OUT)
v_green = Pin(12, Pin.OUT)

# 行用燈: 紅(18), 綠(19), 請求燈(22)
p_red = Pin(18, Pin.OUT)
p_green = Pin(19, Pin.OUT)
req_led = Pin(22, Pin.OUT)

# 輸入裝置: 按鈕(20), 蜂鳴器(21)
button = Pin(20, Pin.IN, Pin.PULL_DOWN)
buzzer = Speaker(21)

# --- 2. 參數設定 (Variables) ---
MODE = 1               # 1: 下一個紅燈前限按一次; 2: 隨時可按
V_GREEN_TIME = 30      # 車輛綠燈時長
P_TOTAL_GREEN = 20     # 行人綠燈總時長 (含閃爍)
V_PRE_RED = 5          # 車輛準備轉紅 (綠+黃)
V_PRE_GREEN = 3        # 車輛準備轉綠 (紅+黃)

# 計算行人閃爍時間 (最低 8 秒)
P_FLASH_TIME = max(int(P_TOTAL_GREEN / 3), 8)
P_STEADY_GREEN = P_TOTAL_GREEN - P_FLASH_TIME

# --- 3. 系統狀態變量 ---
state = "VEHICLE_PASS" # 初始狀態: 車輛通行
start_time = time.ticks_ms()
request_active = False # 是否有過馬路請求
has_processed_request = False # 模式1專用：本輪是否已處理過請求

def all_off():
    """關閉所有燈號"""
    for pin in [v_red, v_yellow, v_green, p_red, p_green, req_led]:
        pin.value(0)

def handle_buzzer(pattern_type, current_ms):
    """處理蜂鳴器節奏 (非阻塞)"""
    # pattern_type: "slow", "fast", "flash"
    cycle_ms = current_ms % 1000
    
    if pattern_type == "slow":
        # 慢速: 每秒響 0.1 秒
        if cycle_ms < 100: buzzer.on()
        else: buzzer.off()
        
    elif pattern_type == "fast":
        # 快速: 每 0.2 秒一個週期 (0.1響, 0.1停)
        if (cycle_ms % 200) < 100: buzzer.on()
        else: buzzer.off()
        
    elif pattern_type == "flash":
        # 閃爍 pattern: [XXXX ] 前0.8秒快速, 後0.2秒停
        if cycle_ms < 800:
            if (cycle_ms % 200) < 100: buzzer.on()
            else: buzzer.off()
        else:
            buzzer.off()

# --- 4. 主循環 ---
print("系統啟動: 當前模式", MODE)

while True:
    current_ms = time.ticks_ms()
    elapsed = (current_ms - start_time) / 1000
    
    # --- A. 按鈕偵測邏輯 ---
    if button.value() == 1:
        if not request_active:
            if MODE == 1 and not has_processed_request:
                request_active = True
                req_led.value(1)
                print("收到請求 (模式1)")
            elif MODE == 2:
                request_active = True
                req_led.value(1)
                print("收到請求 (模式2)")

    # --- B. 狀態機邏輯 ---
    if state == "VEHICLE_PASS":
        # 車綠(12) ON, 行紅(18) ON
        all_off()
        v_green.value(1)
        p_red.value(1)
        if request_active: req_led.value(1)
        handle_buzzer("slow", current_ms)
        
        # 檢查是否縮短時間
        current_limit = V_GREEN_TIME - V_PRE_RED
        if request_active and (current_limit - elapsed > 8):
            # 剩餘時間大於8秒，縮短至8秒
            start_time = current_ms - (current_limit - 8) * 1000
            
        if elapsed >= current_limit:
            state = "VEHICLE_PRE_RED"
            start_time = current_ms

    elif state == "VEHICLE_PRE_RED":
        # 車綠+黃(11,12) ON, 行紅(18) ON
        all_off()
        v_green.value(1)
        v_yellow.value(1)
        p_red.value(1)
        if request_active: req_led.value(1)
        handle_buzzer("slow", current_ms)
        
        if elapsed >= V_PRE_RED:
            state = "PEDESTRIAN_PASS"
            start_time = current_ms
            request_active = False # 重置請求
            req_led.value(0)
            if MODE == 1: has_processed_request = True

    elif state == "PEDESTRIAN_PASS":
        # 車紅(10) ON, 行綠(19) ON
        all_off()
        v_red.value(1)
        p_green.value(1)
        handle_buzzer("fast", current_ms)
        
        if elapsed >= P_STEADY_GREEN:
            state = "PEDESTRIAN_FLASH"
            start_time = current_ms

    elif state == "PEDESTRIAN_FLASH":
        # 車紅(10) ON, 行綠(19) 閃爍
        all_off()
        v_red.value(1)
        # 行人綠燈閃爍 (0.5s 切換)
        p_green.value(1 if (current_ms // 500) % 2 == 0 else 0)
        
        # 車輛準備轉綠 (最後3秒加入黃燈)
        if (P_FLASH_TIME - elapsed) <= V_PRE_GREEN:
            v_yellow.value(1)
            
        handle_buzzer("flash", current_ms)
        
        if elapsed >= P_FLASH_TIME:
            state = "VEHICLE_PASS"
            start_time = current_ms
            has_processed_request = False # 開啟新的一輪

    time.sleep(0.01) # 稍微減輕 CPU 負擔