local ExpMoveMissileSystem = {}
local private = {}
local Vector3_New=Vector3.New
local _tempV3 = Vector3_New(0,0,0)
local _forwardV3 = Vector3_New(0,0,0)
local tonumberV2=FP.tonumberV2
local tonumberV1=FP.tonumberV1
local Const_Zero=FP.Const.Zero
local Vector3_up=Vector3.up
local Vector3_left=Vector3.left

local LuaConst_MissileMoveType_Bind=LuaConst.MissileMoveType.Bind
local LuaConst_MissileMoveType_Parabola=LuaConst.MissileMoveType.Parabola
local LuaConst_MissileMoveType_BindWithOutRotate=LuaConst.MissileMoveType.BindWithOutRotate
local LuaConst_MissileMoveType_BindAndAroundRotate=LuaConst.MissileMoveType.BindAndAroundRotate

function ExpMoveMissileSystem.OnFire(expMissile,paramData,isForOptimize)
    
end

function ExpMoveMissileSystem.UpdateExpressionPosAndDir(expMissile,deltaTime)
    local missile = expMissile.Missile

    local missileData = missile.MissileData
    if missile.IsTracker then
        if missile.InFreeFly then   --自由飞行阶段
            if missile.IsBinding then--跟随角色位移
                local x,y,z = missile.Attacker.ExpEntity:GetPosition()
                local attackerMoveComponent = missile.Attacker.components.move
                local dirX,dirZ = FP.tonumberV2(attackerMoveComponent.LogicRotateDir)                
                
                local dir = Vector3_New(dirX, 0, dirZ)

                local right = Vector3_New(dir.z, 0 , -dir.x)
                local offset = dir * expMissile.PosOffset.z + right * expMissile.PosOffset.x
                expMissile.Pos = Vector3_New(x + offset.x, y + expMissile.PosOffset.y, z + offset.z)
                expMissile.Trans:SetPosition(expMissile.Pos.x,expMissile.Pos.y,expMissile.Pos.z)                
                
                if missile.FireRotate then
                    local forward = dir
                    local right = Vector3_New(dirZ, 0, -dirX)

                    local rx, rz = tonumberV2(missile.FireRotate)
                    dir = Quaternion.AngleAxis(rx, right) * forward
                    dir = Quaternion.AngleAxis(rz, Vector3_up) * dir
                end
                
                expMissile.MoveVec = dir                
                expMissile.Trans.forward = expMissile.MoveVec
                
            elseif missile.MissileData.FreeFlyType == 1 then    --直线
                private.TrackerExpressionPosAndDir(expMissile, missileData, deltaTime, true)
            end
        else    --追击阶段
            if missile.MissileData.TrackFlyType == 1 then   --直线
                private.TrackerExpressionPosAndDir(expMissile, missileData, deltaTime,  true)
            else
                private.TrackerExpressionPosAndDir(expMissile, missileData, deltaTime, false)
            end
        end
    elseif missile.MoveType == LuaConst_MissileMoveType_Parabola then
        private.ParabolaExpressionPosAndDir(expMissile,missileData,deltaTime)
    elseif missile.MoveType == LuaConst_MissileMoveType_Bind then
        private.BindingExpressionPosAndDir(expMissile,missileData,deltaTime)
    elseif missile.MoveType == LuaConst_MissileMoveType_BindWithOutRotate then
        private.BindingNoRotateExpressionPosAndDir(expMissile,missileData,deltaTime)
    elseif missile.MoveType == LuaConst_MissileMoveType_BindAndAroundRotate then
        private.BindingAroundRotateExpressionPosAndDir(expMissile,missileData,deltaTime)
    else
        private.LineExpressionPosAndDir(expMissile,missileData,deltaTime)
    end
end

--追踪弹
function private.TrackerExpressionPosAndDir(expMissile, missileData, deltaTime, isLine)
    local missile = expMissile.Missile
    local timeScale = tonumberV1(missile.Attacker.components.timeScale:GetCurMissileTimeScale())

    if missile.InFreeFly and missileData.FreeFlySpd <= 0 then
        return
    end

    local speedX = expMissile.Missile.InFreeFly and missileData.FreeFlySpd or tonumberV1(missile.TrackSpeed)

    if missile.InFreeFly then --自由飞行阶段
        _tempV3:Set(expMissile.MoveVec.x,expMissile.MoveVec.y,expMissile.MoveVec.z)
        expMissile.Trans.forward = _tempV3
        expMissile.Pos:Add(_tempV3:Mul(speedX * deltaTime * timeScale))
        expMissile.Trans:SetPosition(expMissile.Pos.x,expMissile.Pos.y,expMissile.Pos.z)
    else   --追击阶段
        local targetY = 0
        if missile.TrackerTarget then
            local tx,tz = tonumberV2(missile.TrackerTarget.components.move.LogicPos)
            local offsetx,offsetz = tonumberV2(missile.TrackerOffset)
            _tempV3:Set(tx+offsetx, 0, tz+offsetz)
            
            --TODO 临时加判空逻辑，后面希望将TrackerTarget的引用从missile中移除
            if missile.TrackerTarget.ExpEntity:GetRenderEntity() then
                local slotInt = LuaConst.HumanEquipSlot[missileData.AimNode]
                local y = missile.TrackerTarget.ExpEntity:GetEquipSlotHeight(slotInt ,expMissile.Pos.y)
                targetY = y + expMissile.TrackerOffset.y
            else
                targetY = AuxUtil.GetHigh(_tempV3.x, targetY, _tempV3.z) + expMissile.TrackerOffset.y
            end
        else
            -- 虚拟目标，子弹高度不变
            if not missile.TrackerVirtualPos then
                return
            end
            local x,z = tonumberV2(missile.TrackerVirtualPos)
            _tempV3:Set(x, 0, z)
            targetY = expMissile.TrackerForceY or expMissile.Pos.y
        end
        
        local mx,mz = expMissile.Pos.x, expMissile.Pos.z
        local dx,dz = _tempV3.x - mx, _tempV3.z -mz
        local disY = targetY - expMissile.Pos.y

        --- 速度为0 ，不追踪了 ，但是朝向实时变化
        if speedX == 0 then 
            _forwardV3:Set(dx ,disY,dz)
            expMissile.Trans.forward = _forwardV3
            return
        end
        
        local dis = math.sqrt(dx*dx + dz*dz)
        
        local time = math.abs( dis / speedX)        
        local speedY = 0
        local setForward = true

        if isLine then
            if time <= 0.052 then-- 最后一帧的时间不要在变向了
                setForward = false
            end 
            if dis < math.epsilon then
                speedY = 0
            else
                speedY = disY / time
                dx, dz = dx/dis, dz/dis
            end
        else
            if time <= 0.052 then -- 最后一帧的时间不要在变向了
                setForward = false
            end
            if dis < math.epsilon then
                speedY = 0
            else
                if math.abs(disY) > 0.1 then
                    local accelerate = 2 * speedX * (speedX * disY - expMissile.TrackerSpeedY * dis) / (dis * dis) -- a = (h-Vy*t)*2/(t*t)  t = s/Vx
                    expMissile.TrackerSpeedY = expMissile.TrackerSpeedY + accelerate * deltaTime * timeScale
                    speedY = expMissile.TrackerSpeedY
                    if math.abs(speedY) > 100 then -- gws: Y速度不可能这么快的，如果这么快一定是加速度值计算有问题了
                        speedY = 0
                    end
                else
                    speedY = 0
                end
                dx, dz = dx/dis, dz/dis
            end
        end

        _tempV3:Set(dx * speedX, speedY, dz * speedX) --final Direction
        if setForward and dis > 0.0005 then
            expMissile.Trans.forward = _tempV3
        end
        expMissile.Pos:Add(_tempV3:Mul(deltaTime * timeScale))
        expMissile.Trans:SetPosition(expMissile.Pos.x,expMissile.Pos.y,expMissile.Pos.z)
    end
end

--直线 + 角速度转身 的位移
function private.LineExpressionPosAndDir(expMissile,missileData,deltaTime)
    local realSpeed = tonumberV1(missileData.MoveSpeed)
    local realAngleSpeed = tonumberV1(missileData.AngleSpeed)
    if realSpeed <= 0 and realAngleSpeed == 0 then -- realAngleSpeed 有正负区分
        return
    end
    local timer = expMissile.ExpressionTimer * 1000 - tonumberV1(missileData.DelayMoveFrame)
    if timer > 0 then

        local timeScale = tonumberV1(expMissile.Missile.Attacker.components.timeScale:GetCurMissileTimeScale())

        if realAngleSpeed ~= 0 then
            --[[ 这种算法会产生 table 比较多
            local quaternion = Quaternion.AngleAxis(realAngleSpeed * deltaTime * timeScale, Vector3.up)
            expMissile.MoveVec = quaternion * expMissile.MoveVec
            expMissile.MoveVec = expMissile.MoveVec.normalized
            expMissile.Trans.forward = expMissile.MoveVec
            --]]
            UIUtils.RotateByUp(expMissile.Trans,realAngleSpeed * deltaTime * timeScale) -- 如果是螺旋向上升 ，还需要判断是否以世界Y轴旋转，目前暂时不考虑了
        end
        
        -- 水平移动
        _tempV3:Set(expMissile.Trans.forward.x ,0 ,expMissile.Trans.forward.z ) -- 现在认为子弹的表现朝向和子弹的飞行方向一致，如果以后有需求，子弹横着飘，需要改这句代码。
        expMissile.Pos:Add(_tempV3:Mul(realSpeed * deltaTime * timeScale))
        
        -- 要贴合地面
        if missileData.FollowTerrainHeight then
            expMissile.Pos.y = AuxUtil.GetHigh(expMissile.Pos.x, expMissile.Pos.y, expMissile.Pos.z)
        elseif expMissile.Missile.SpeedY ~= Const_Zero then-- 垂直移动
            expMissile.Pos.y = expMissile.Pos.y + expMissile.SpeedY * deltaTime * timeScale
        end
        
        expMissile.Trans:SetPosition(expMissile.Pos.x,expMissile.Pos.y,expMissile.Pos.z)
    end
end


--抛物线位移
function private.ParabolaExpressionPosAndDir(expMissile,missileData,deltaTime)
    local time = expMissile.ExpressionTimer
    if time <= 0 then
        return
    end
    local realSpeed = tonumberV1(missileData.MoveSpeed)
    local x = realSpeed * time ---水平位移
    local y = expMissile.ParabolaParam_a * x * x + expMissile.ParabolaParam_b * x;
    
    expMissile.Pos:Set(expMissile.MoveVec.x * x, y, expMissile.MoveVec.z * x)
    expMissile.Pos:Add(expMissile.InitPos)

    --旋转
    if missileData.CanRotate then
        local timeScale = tonumberV1(expMissile.Missile.Attacker.components.timeScale:GetCurMissileTimeScale())
        local angle = expMissile.FireAngleSpeed * deltaTime * timeScale
        UIUtils.SetPositionAndRotateByLeft(expMissile.Trans,expMissile.Pos.x,expMissile.Pos.y,expMissile.Pos.z,angle)
    else
        expMissile.Trans:SetPosition(expMissile.Pos.x,expMissile.Pos.y,expMissile.Pos.z)
    end
    
end

--绑定在发射至身上的子弹更新位置（类似绑定在某个骨骼上）
function private.BindingExpressionPosAndDir(expMissile,missileData,deltaTime)
    local missile = expMissile.Missile

    local x,y,z = missile.Attacker.ExpEntity:GetPosition()
    local attackerMoveComponent = missile.Attacker.components.move
    local dirX,dirZ = FP.tonumberV2(attackerMoveComponent.LogicRotateDir)

    local dir = Vector3_New(dirX, 0, dirZ)

    local right = Vector3_New(dir.z, 0 , -dir.x)
    local offset = dir * expMissile.PosOffset.z + right * expMissile.PosOffset.x
    expMissile.Pos = Vector3_New(x + offset.x, y + expMissile.PosOffset.y, z + offset.z)
    expMissile.Trans:SetPosition(expMissile.Pos.x,expMissile.Pos.y,expMissile.Pos.z)

    local data = missile.CallData
    if data.BornForwardType == 0 then
        expMissile.MoveVec = dir
    elseif data.BornForwardType == 1 then -- 背离
        expMissile.MoveVec = Vector3_New(expMissile.Pos.x - x, 0 , expMissile.Pos.z - z)
        expMissile.MoveVec:SetNormalize()
    elseif data.BornForwardType == 2 then -- 面向
        expMissile.MoveVec = Vector3_New(x - expMissile.Pos.x , 0 , z - expMissile.Pos.z)
        expMissile.MoveVec:SetNormalize()
    end
    
    expMissile.Trans.forward = expMissile.MoveVec
    
end

--绑定在发射至身上的子弹更新位置（不带转向，绝对的位移偏差）
function private.BindingNoRotateExpressionPosAndDir(expMissile,missileData,deltaTime)
    local missile = expMissile.Missile
    local x,y,z = missile.Attacker.ExpEntity:GetPosition()    
    expMissile.Pos = Vector3_New(x + expMissile.PosOffset.x, y + expMissile.PosOffset.y, z + expMissile.PosOffset.z)
    expMissile.Trans:SetPosition(expMissile.Pos.x,expMissile.Pos.y,expMissile.Pos.z)
end

--围绕在发射者的子弹 更新位置（子弹的朝向始终远离发射者）
function private.BindingAroundRotateExpressionPosAndDir(expMissile,missileData,deltaTime)
    local missile = expMissile.Missile
    local x,y,z = missile.Attacker.ExpEntity:GetPosition()

    local angleSpeed = missile.overrideAngleSpeed or missileData.AngleSpeed
    local realAngleSpeed = tonumberV1(angleSpeed)
    local toAttackerDistance = tonumberV1(missile.PosOffsetDistance)

    local timer = expMissile.ExpressionTimer * 1000 - tonumberV1(missileData.DelayMoveFrame)
    if timer > 0 then
        local timeScale = tonumberV1(expMissile.Missile.Attacker.components.timeScale:GetCurMissileTimeScale())

        if realAngleSpeed ~= 0 then
            UIUtils.RotateByUp(expMissile.Trans,realAngleSpeed * deltaTime * timeScale) -- 计算角度
        end
        
        -- 位置
        expMissile.Pos = Vector3_New(x + expMissile.Trans.forward.x * toAttackerDistance, y + expMissile.PosOffset.y, z + expMissile.Trans.forward.z * toAttackerDistance)

        expMissile.Trans:SetPosition(expMissile.Pos.x,expMissile.Pos.y,expMissile.Pos.z)
    end
    
end


return ExpMoveMissileSystem