import struct
import socket
import time
import random
import math

class Ship:
    def __init__(self, mmsi, lat, lon, heading, speed=280.24):
        self.mmsi = mmsi
        self.lat = lat
        self.lon = lon
        self.heading = heading
        self.speed = speed  # 加速100倍用于演示
        
    def update_position(self):
        """更新船只位置"""
        # 速度转换
        speed_kmh = self.speed * 1.852
        speed_kmps = speed_kmh / 3600
        distance_km = speed_kmps * 1
        
        # 航向转弧度
        heading_rad = math.radians(self.heading)
        
        # 计算经纬度变化
        delta_lat = distance_km / 111.0 * math.cos(heading_rad)
        delta_lon = distance_km / (111.0 * math.cos(math.radians(self.lat))) * math.sin(heading_rad)
        
        # 更新位置
        self.lat += delta_lat
        self.lon += delta_lon
        
        return self.lon, self.lat

class OwnShip(Ship):
    def __init__(self, lat, lon, heading, speed=280.24):
        super().__init__(336295999, lat, lon, heading, speed)  # 使用固定MMSI作为本船
    
    def get_position(self):
        """获取本船位置并更新"""
        return self.update_position()

class VDESPacketCreator:
    @staticmethod
    def create_tcp_packet(packet_type, content):
        """创建符合VDES TCP协议的报文"""
        header = b'####'
        type_field = struct.pack('>I', packet_type)
        length_field = struct.pack('>I', len(content))
        return header + type_field + length_field + content
    
    @classmethod
    def create_gps_packet(cls, own_ship):
        """创建GPS解析数据报文(类型7)的内容"""
        lon, lat = own_ship.get_position()
        
        # 打包GPS数据
        return struct.pack(
            '>QiiiHHHBBIII',
            1680000000,         # UTC时间
            int(lon * 10000000),  # 经度
            int(lat * 10000000),  # 纬度
            50,                 # 海拔高度
            10,                 # 定位使用的卫星数
            8,                  # GPS卫星数
            7,                  # 北斗卫星数
            1,                  # GPS状态
            3,                  # 定位模式
            2550,               # 水平精度因子
            1024,               # 运动速度
            own_ship.heading    # 运动方向
        )
    
    @classmethod
    def create_ais_info_packet(cls, ship):
        """创建解调信息报文(类型12)的内容"""
        demod_content = cls.encode_demod_fields(ship)
        
        # 打包解调信息
        message_type = 12
        satellite_id = 1
        demodulator_id = 0
        demod_slot = 1234
        receive_delay = 5678
        snr = 25.75
        
        # 处理信噪比
        snr_int = int(snr)
        snr_frac = int((snr - snr_int) * 100)
        snr_packed = (snr_int & 0xFF) << 8 | (snr_frac & 0xFF)
        
        header = struct.pack(
            '>BBBHHH',
            message_type,
            satellite_id,
            demodulator_id,
            demod_slot,
            receive_delay,
            snr_packed
        )
        return header + demod_content
    
    @staticmethod
    def encode_demod_fields(ship):
        """编码解调信息字段"""
        lon, lat = ship.update_position()
        
        # 准备数据
        message_id = 1
        repeat_indicator = 0
        user_id = ship.mmsi
        navigation_status = 8
        rot = -128
        sog = 102
        position_accuracy = 1
        cog = ship.heading
        true_heading = ship.heading
        timestamp = 30
        special_maneuver = 0
        spare = 0
        raim_flag = 0
        comm_state = 0
        
        # 转换为协议要求的格式
        longitude_min = int(lon * 60 * 10000)
        latitude_min = int(lat * 60 * 10000)
        
        # 构建二进制位
        bits = [
            format(message_id, '06b'),
            format(repeat_indicator, '02b'),
            format(user_id, '030b'),
            format(navigation_status, '04b'),
            format(rot & 0xFF, '08b'),
            format(min(sog, 1023), '010b'),
            str(position_accuracy),
            format(longitude_min & 0x0FFFFFFF, '028b'),
            format(latitude_min & 0x07FFFFFF, '027b'),
            format(min(cog, 3600), '012b'),
            format(min(true_heading, 511), '09b'),
            format(min(timestamp, 63), '06b'),
            format(special_maneuver, '02b'),
            format(spare, '03b'),
            str(raim_flag),
            format(comm_state, '019b')
        ]
        
        # 合并所有位并转换为字节
        bit_string = ''.join(bits)
        binary_int = int(bit_string, 2)
        byte_length = (len(bit_string) + 7) // 8
        return binary_int.to_bytes(byte_length, 'big')

class VDEServer:
    def __init__(self, host='127.0.0.1', port=10):
        self.host = host
        self.port = port
        self.own_ship = OwnShip(31.23, 123.87, 90)
        self.ships = self.create_ships(30)
    
    @staticmethod
    def create_ships(count):
        """创建指定数量的船只"""
        return [
            Ship(
                mmsi=336295939 + i,
                lat=round(random.uniform(30.0, 34.0), 6),
                lon=round(random.uniform(123.5, 126.0), 6),
                heading=random.randint(0, 359)
            ) for i in range(count)
        ]
    
    def send_data_continuously(self):
        """启动Socket服务端并持续发送数据"""
        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
            s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
            s.bind((self.host, self.port))
            s.listen(1)
            print(f"Socket服务端已启动，监听 {self.host}:{self.port}")
            
            while True:
                try:
                    conn, addr = s.accept()
                    print(f"客户端连接来自: {addr}")
                    
                    while True:
                        try:
                            # 随机选择一艘船发送AIS报文
                            selected_ship = random.choice(self.ships)
                            ais_data = VDESPacketCreator.create_ais_info_packet(selected_ship)
                            ais_packet = VDESPacketCreator.create_tcp_packet(12, ais_data)
                            conn.sendall(ais_packet)
                            
                            # 发送本船GPS报文
                            gps_content = VDESPacketCreator.create_gps_packet(self.own_ship)
                            gps_packet = VDESPacketCreator.create_tcp_packet(7, gps_content)
                            conn.sendall(gps_packet)
                            
                            time.sleep(0.5)
                            
                        except (ConnectionResetError, BrokenPipeError):
                            print("客户端断开连接")
                            break
                            
                except KeyboardInterrupt:
                    print("\n服务端已停止")
                    break
                except Exception as e:
                    print(f"服务端错误: {e}")
                    break

if __name__ == "__main__":
    server = VDEServer()
    server.send_data_continuously()