import socket
from rest_framework.exceptions import ParseError
import json
import time
from django.core.cache import cache
from apps.utils.thread import MyThread
import struct

def get_checksum(body_msg):
    return sum(body_msg) & 0xFF

def handle_bytes(arr):
    if len(arr) < 8:
        return "返回数据长度错误"
    
    if arr[0] != 0xEB or arr[1] != 0x90:
        return "数据头不正确"


    # 读取长度信息
    length_arr = arr[2:4][::-1]  # 反转字节
    length = struct.unpack('<H', bytes(length_arr))[0]  # 小端格式
    
    # 提取内容
    body = arr[4:4 + length - 3]

    # 校验和检查
    check_sum = get_checksum(body)
    if check_sum != arr[length + 1]:
        return "校验错误"
        

    # 尾部标识检查
    if arr[length + 2] != 0xFF or arr[length + 3] != 0xFE:
        return "尾错误"

    content = body.decode('utf-8')

    res = json.loads(content)
    
    return res[0]

def get_tyy_data_t(host, port):
    cd_thread_key = f"cd_thread_{host}_{port}"
    sc = None
    def connect_and_send(retry=1):
        nonlocal sc
        try:
            if sc is None:
                sc = socket.socket()
                sc.connect((host, int(port)))
            sc.sendall(b"R")
        except BrokenPipeError:
            sc = None
            if retry > 0:
                connect_and_send(retry-1)
        except OSError as e:
            sc = None
            cache.set(cd_thread_key, {"err_msg": f"采集器连接失败-{str(e)}"})
        except ConnectionResetError:
            sc = None
            cache.set(cd_thread_key, {"err_msg": "采集器重置了连接"})
        except socket.timeout:
            sc = None
            cache.set(cd_thread_key, {"err_msg": "采集器连接超时"})
        except Exception as e:
            sc = None
            cache.set(cd_thread_key, {"err_msg": f"采集器连接失败-{str(e)}"})

    while True:
        cd_thread_val = cache.get(cd_thread_key, default=None)
        if cd_thread_val is None:
            if sc:
                try:
                    sc.close()
                except Exception:
                    pass
            break
        elif cd_thread_val == "get":
            cache.set(cd_thread_key, "working")
            connect_and_send()
            if sc is None:
                continue
            resp = sc.recv(1024)
            res = handle_bytes(resp)
            if isinstance(res, str):
                cache.set(cd_thread_key, {"err_msg": f'采集器返回数据错误-{res}'})
            else:
                cache.set(cd_thread_key, res)
        time.sleep(0.3)

def get_tyy_data(*args, sleep=0):
    if sleep > 0:
        time.sleep(sleep)
    host, port = args[0], int(args[1])
    cd_thread_key = f"cd_thread_{host}_{port}"
    cd_thread_val = cache.get(cd_thread_key, default=None)
    if cd_thread_val is None:
        cache.set(cd_thread_key, "start")
        cd_thread = MyThread(target=get_tyy_data_t, args=(host, port), daemon=True)
        cd_thread.start()
    cache.set(cd_thread_key, "get")
    num = 0
    get_val = False

    while True:
        num += 1
        if num > 8:
            break
        val = cache.get(cd_thread_key)
        if isinstance(val, dict):
            get_val = True
            if "err_msg" in val:
                raise ParseError(val["err_msg"])
            return val
        time.sleep(0.3)

    if not get_val:
        cache.set(cd_thread_key, None)
        get_tyy_data(*args, sleep=2)


if __name__ == '__main__':
    print(get_tyy_data())