import time
import json
import urllib.request
import urllib.error
import logging
import os
import sys

# --- 配置 --- 
CPP_SERVER_URL = "http://localhost:8082/trafficlight" # C++ TrafficLightHttpServer 的地址和端口
SEND_INTERVAL = 1.0  # 发送间隔（秒）

# 红绿灯循环周期 (North/South State, East/West State, Duration in seconds)
TRAFFIC_LIGHT_CYCLE = [
    ("GREEN", "RED", 10), 
    ("YELLOW", "RED", 2),
    ("RED", "GREEN", 10),
    ("RED", "YELLOW", 2),
]

# --- 日志设置 --- 
LOG_DIR = 'logs'
if not os.path.exists(LOG_DIR):
    try:
        os.makedirs(LOG_DIR)
    except OSError as e:
        print(f"Error creating log directory {LOG_DIR}: {e}", file=sys.stderr)
        LOG_DIR = '.' # Fallback to current directory

logging.basicConfig(
    level=logging.DEBUG,
    format='%(asctime)s - %(levelname)s - %(message)s',
    handlers=[
        logging.FileHandler(os.path.join(LOG_DIR, 'mock_traffic_light_client.log')),
        logging.StreamHandler() # 同时输出到控制台
    ]
)

# --- 全局状态 --- 
current_cycle_index = 0
last_cycle_switch_time = time.time()

# --- 辅助函数 --- 
def generate_di_payload(ns_state, ew_state):
    """根据南北和东西状态生成 DI 信号 Payload。"""
    # 初始化所有 DI 信号为 0
    payload = {f"DI-{i:02d}": 0 for i in range(1, 19)}
    # 设置南北向状态 (DI-11: 北红, DI-12: 北黄, DI-13: 北绿)
    if ns_state == "RED": payload["DI-11"] = 1
    elif ns_state == "YELLOW": payload["DI-12"] = 1
    elif ns_state == "GREEN": payload["DI-13"] = 1
    # 设置东西向状态 (DI-14: 东红, DI-15: 东黄, DI-16: 东绿)
    if ew_state == "RED": payload["DI-14"] = 1
    elif ew_state == "YELLOW": payload["DI-15"] = 1
    elif ew_state == "GREEN": payload["DI-16"] = 1
    return payload

def send_traffic_light_update(url, payload):
    """使用 urllib 发送 POST 请求。"""
    try:
        data = json.dumps(payload).encode('utf-8')
        req = urllib.request.Request(url, data=data, headers={'Content-Type': 'application/json'}, method='POST')
        # 设置一个较短的超时时间，避免长时间阻塞
        with urllib.request.urlopen(req, timeout=0.8) as response:
            logging.debug(f"Sent: {payload}, Status: {response.status}")
            # 可以选择性地读取响应内容
            # response.read()
    except (urllib.error.URLError, TimeoutError, ConnectionRefusedError) as e:
        logging.error(f"Failed to send to {url}: {e}")
    except Exception as e:
        logging.error(f"Unexpected error during send: {e}")

# --- 主循环 --- 
def traffic_light_sender_loop():
    """主循环，管理状态切换并发送数据。"""
    global current_cycle_index, last_cycle_switch_time
    logging.info(f"Starting traffic light client, sending to {CPP_SERVER_URL}")
    while True:
        try:
            now = time.time()
            
            # 检查是否需要切换循环阶段
            current_ns_state, current_ew_state, duration = TRAFFIC_LIGHT_CYCLE[current_cycle_index]
            if now - last_cycle_switch_time >= duration:
                current_cycle_index = (current_cycle_index + 1) % len(TRAFFIC_LIGHT_CYCLE)
                last_cycle_switch_time = now
                next_ns_state, next_ew_state, _ = TRAFFIC_LIGHT_CYCLE[current_cycle_index]
                logging.info(f"Switching phase: {current_ns_state}/{current_ew_state} -> {next_ns_state}/{next_ew_state}")
                # 更新当前状态以供本次发送
                current_ns_state, current_ew_state, _ = TRAFFIC_LIGHT_CYCLE[current_cycle_index]
            
            # 生成 Payload 并发送
            payload = generate_di_payload(current_ns_state, current_ew_state)
            send_traffic_light_update(CPP_SERVER_URL, payload)
            
            # 等待指定间隔
            time.sleep(SEND_INTERVAL)
            
        except KeyboardInterrupt:
            logging.info("Traffic light client stopped by user.")
            break
        except Exception as e:
            logging.error(f"Error in main loop: {e}", exc_info=True)
            # 等待一段时间再重试，避免快速失败循环
            time.sleep(5) 

# --- 启动入口 --- 
if __name__ == '__main__':
    traffic_light_sender_loop()