#!/usr/bin/env python3
"""
指令發送模組
負責將目標位置轉成具體的通訊指令發送到飛控

目前使用 Ros2CommandSender，經 fc_network_adapter 的
/fc_network/vehicle/pos_global_int service 發送。

MavlinkSender 保留作為直連 SITL 的 fallback 工具，但已不是預設路徑。
"""
import asyncio
import traceback
from abc import ABC, abstractmethod

from PyQt6.QtCore import QObject, pyqtSignal
from pymavlink import mavutil


def _log(level, message):
    print(f"[{level}] {message}")


class CommandSender(ABC):
    """指令發送抽象介面"""

    @abstractmethod
    def send_position_global(self, drone_id, sysid, lat, lon, alt):
        """
        發送全球座標位置指令

        Args:
            drone_id: GUI 用的 drone 識別字串 (如 's0_11')
            sysid: 目標無人機的 MAVLink system ID
            lat: 緯度 (度)
            lon: 經度 (度)
            alt: 高度 (公尺)
        """
        pass

    @abstractmethod
    def close(self):
        """關閉連線"""
        pass


class MavlinkSender(CommandSender):
    """
    MAVLink 直接發送 (驗證階段用)
    透過 SET_POSITION_TARGET_GLOBAL_INT 發送目標位置

    使用方式:
        sender = MavlinkSender("udpout:127.0.0.1:14550")
        sender.send_position_global(sysid=1, lat=24.123, lon=120.567, alt=10.0)
    """

    # type_mask: 只使用位置 (lat, lon, alt)
    # 忽略速度 (bit 3,4,5)、加速度 (bit 6,7,8)、yaw (bit 10)、yaw_rate (bit 11)
    TYPE_MASK_POSITION_ONLY = (
        0b0000_1101_1111_1000  # = 0x0DF8
    )

    def __init__(self, connection_string="udpout:127.0.0.1:14550"):
        """
        Args:
            connection_string: MAVLink 連線字串
                SITL 範例: "udpout:127.0.0.1:14550"
        """
        self.connection_string = connection_string
        self.mav = mavutil.mavlink_connection(connection_string)
        _log("INFO", f"MavlinkSender 已建立連線: {connection_string}")

    def send_position_global(self, drone_id, sysid, lat, lon, alt):
        """發送 SET_POSITION_TARGET_GLOBAL_INT。drone_id 未使用，保留為介面相容。"""
        self.mav.mav.set_position_target_global_int_send(
            0,                          # time_boot_ms (不使用)
            sysid,                      # target_system
            1,                          # target_component (autopilot)
            mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT_INT,
            self.TYPE_MASK_POSITION_ONLY,
            int(lat * 1e7),             # lat_int
            int(lon * 1e7),             # lon_int
            float(alt),                 # alt
            0, 0, 0,                    # vx, vy, vz (忽略)
            0, 0, 0,                    # afx, afy, afz (忽略)
            0, 0                        # yaw, yaw_rate (忽略)
        )

    def close(self):
        """關閉 MAVLink 連線"""
        if self.mav:
            self.mav.close()
            self.mav = None
            _log("INFO", "MavlinkSender 已關閉")


class Ros2CommandSender(QObject):
    """
    透過 fc_network_apps.PositionTargetGlobalIntClient 送 goto 指令。

    設計重點:
        - send_position_global 是同步介面，立刻回傳。結果透過 send_result signal 回報
        - 每台 drone 維護自己的 asyncio.Task pipeline，新的目標會 cancel 掉舊的 in-flight
        - client 由 DroneMonitor.get_or_create_position_client 管理，per-drone 獨立節點
    """

    # (drone_id, sysid, success, message)
    send_result = pyqtSignal(str, int, bool, str)

    DEFAULT_TIMEOUT_SEC = 2.0

    def __init__(self, monitor, timeout_sec: float = DEFAULT_TIMEOUT_SEC):
        super().__init__()
        self._monitor = monitor
        self._timeout_sec = timeout_sec
        self._pending = {}  # drone_id -> asyncio.Task

    def send_position_global(self, drone_id, sysid, lat, lon, alt):
        """同步介面。立刻回，結果透過 send_result signal 回報。"""
        # 取消該機上一個未完成的 task，避免舊指令覆蓋新指令
        old = self._pending.get(drone_id)
        if old is not None and not old.done():
            old.cancel()

        try:
            loop = asyncio.get_event_loop()
        except RuntimeError:
            loop = asyncio.new_event_loop()
            asyncio.set_event_loop(loop)

        task = loop.create_task(
            self._do_send(drone_id, int(sysid), float(lat), float(lon), float(alt))
        )
        self._pending[drone_id] = task

    async def _do_send(self, drone_id, sysid, lat, lon, alt):
        try:
            client = self._monitor.get_or_create_position_client(drone_id)
            if client is None:
                self.send_result.emit(
                    drone_id, sysid, False,
                    "PositionTargetGlobalIntClient 無法建立"
                )
                return

            result = await client.goto_position_only_async(
                target_sysid=sysid,
                target_compid=0,
                latitude_deg=lat,
                longitude_deg=lon,
                alt=alt,
                timeout_sec=self._timeout_sec,
            )
            self.send_result.emit(
                drone_id, sysid, bool(result.success), str(result.message or "")
            )
        except asyncio.CancelledError:
            # 被新的目標取代，正常狀況，不用回報
            pass
        except Exception as e:
            traceback.print_exc()
            self.send_result.emit(drone_id, sysid, False, f"exception: {e}")

    def close(self):
        """取消所有未完成的 task。PositionTargetGlobalIntClient 由 DroneMonitor 負責 destroy。"""
        for task in self._pending.values():
            if not task.done():
                task.cancel()
        self._pending.clear()
        _log("INFO", "Ros2CommandSender 已關閉")