using System;
using System.Collections.Generic;
using System.Text;
using UnityEngine;

namespace ET
{
    public static class MoveHelper
    {
        public const float AtkDis = 2.7f * 2.7f;
        private const float TeamDistanceBetweenUnits = 0.8f;
        
        public static void MoveTo(Unit unit, Vector2 target){
            UnitScene unitScene = unit.GetComponent<UnitScene>();
            Vector2 pos = unitScene.Position;
            int yAngle = pos.x<=target.x?0:180;
            MoveTo(unit,target,yAngle).Coroutine();
        }
        public static async ETVoid MoveTo(Unit unit, Vector2 target, int yAngle)
        {
            try
            {
                Team team = TeamComponent.Instance.Get(unit.TeamLeaderId);
                if (team == null)
                {
                    Log.Error($"team id = {unit.TeamLeaderId} is null when MoveTo({target})");
                    return;
                }
                int index = 0;
                foreach (var u in team.GetUnits())
                {
                    if (u.IsTransfer) continue;
                    if (u.IsTeamLeader)
                    {
                        FindPathMoveToAsync(u, target).Coroutine();
                        u.GetComponent<UnitScene>().YAngle = yAngle;
                    }
                    else
                    {
                        await TimerComponent.Instance.WaitAsync(300);
                        UnitScene unitScene = u.GetComponent<UnitScene>();
                        Vector2 delta = CalucateDistanceXandY(unitScene.Position, target);
                        Vector2 targetPos = new Vector2(target.x - delta.x * ++index, target.y - delta.y * index);
                        FindPathMoveToAsync(u, targetPos).Coroutine();
                        unitScene.YAngle = yAngle;
                    }
                }
            }
            catch (Exception e)
            {
                Log.Error(e);
            }
        }
        private static Vector2 CalucateDistanceXandY(Vector2 posA, Vector2 posB)
        {
            float dx = posB.x - posA.x;
            int positive = dx >= 0 ? 1 : -1;
            float gradient = (posB.y - posA.y) / dx;
            return new Vector2(positive * TeamDistanceBetweenUnits / Mathf.Sqrt(1 + gradient * gradient)
                , positive * gradient * TeamDistanceBetweenUnits / Mathf.Sqrt(1 + gradient * gradient));
        }
        // 可以多次调用，多次调用的话会取消上一次的协程
        public static async ETTask FindPathMoveToAsync(this Unit unit, Vector3 target, ETCancellationToken cancellationToken = null)
        {
            float speed = ConstDefine.MoveSpeed;
            if (speed < 0.001)
            {
                SendStop(unit,-1);
                return;
            }

            using var list = ListComponent<Vector3>.Create();
            UnitScene unitScene = unit.GetComponent<UnitScene>();
            list.List.Add(unitScene.Position);
            list.List.Add(target);

            // 广播寻路路径
            M2C_PathfindingResult m2CPathfindingResult = new M2C_PathfindingResult
            {
                Id = unit.Id,

                X = unitScene.X,
                Y = unitScene.Y,


                TX = target.x,
                TY = target.y,
                MoveSpeed = ConstDefine.MoveSpeed
            };
            var brocast = unit.GetComponent<BrocastComponent>();
            brocast.Brocast(m2CPathfindingResult);


            bool ret = await unit.GetComponent<MoveComponent>().MoveToAsync(list.List, speed, cancellationToken);
            if (ret) // 如果返回false，说明被其它移动取消了，这时候不需要通知客户端stop
            {
                SendStop(unit,0);
            }
        }

        public static void Stop(this Unit unit)
        {
            unit.GetComponent<MoveComponent>().Stop();
            SendStop(unit, 0);
        }
        private static void SendStop(Unit unit, int error)
        {
            if (!unit.IsTeamLeader) return;
            UnitScene unitScene = unit.GetComponent<UnitScene>();
            var brocast = unit.GetComponent<BrocastComponent>();
            brocast.Brocast(new M2C_Stop()
            {
                Error = error,
                Id = unit.Id,
                X = unitScene.X,
                Y = unitScene.Y,

                YAngle = unitScene.YAngle
            });
        }
    }
}