汲取：从它血条里抽一口，化作你的护体

 fx-vitaldrain

-- @file VitalDrain.lua
-- 汲取 —— 从它血条里抽一口，化作你的护体

local VitalDrain = {}

local CONST = {
    DRAW_PCT      = 0.15,
    DRAW_MIN      = 20,
    SHIELD_DECAY  = 6,
    DRAIN_CD      = 6.0,

    COLOR_DRAIN   = "#c05868",
    COLOR_DEEP    = "#4e1220",
    COLOR_GHOST   = "#f0b0c0",

    ZORDER_SHIELD = 131,
    ZORDER_FX     = 135,
    AUTOINC_BASE  = 1007000,
}

local _shield    = 0
local _cdLeft    = 0
local _shieldFx  = nil
local _scheduler = nil
local _autoInc   = 0

local function GenID(prefix)
    _autoInc = _autoInc + 1
    return string.format("%s_%d", prefix or "VTD",
        CONST.AUTOINC_BASE + _autoInc)
end

local function GetActorPos(id)
    if not id then return nil end
    local x = SL:GetValue("ACTOR_POSITION_X", id)
    local y = SL:GetValue("ACTOR_POSITION_Y", id)
    if not x or not y then return nil end
    return { x = x, y = y }
end

local function SafeRemove(node)
    if node and not GUI:Widget_IsNull(node) then
        GUI:removeFromParent(node)
    end
end

local function ShowTip(msg)
    if msg and msg ~= "" then SL:ShowSystemTips(msg) end
end

local function RefreshShieldRing()
    SafeRemove(_shieldFx)
    if _shield <= 0 then return end
    local myID = SL:GetValue("USER_ID")
    local mp = GetActorPos(myID)
    if not mp then return end
    _shieldFx = GUI:Layout_Create(GUI:Attach_SceneF(),
        GenID("Shield"), mp.x, mp.y - 52, 0, 0, false)
    GUI:setLocalZOrder(_shieldFx, CONST.ZORDER_SHIELD)
    GUI:DrawCircle_Create(_shieldFx, "ring", 0, 0, 34,
        CONST.COLOR_DRAIN, 2, 200)
end

function VitalDrain.Cast()
    if _cdLeft > 0 then
        ShowTip("口在吸——" .. string.format("%.1f", _cdLeft) .. "秒")
        return
    end
    local tid = SL:GetValue("MARK_TARGET_ID")
    local hp = SL:GetValue("ACTOR_HP", tid)
    if not tid or not hp then return end
    local draw = math.floor(hp * CONST.DRAW_PCT)
    if draw < CONST.DRAW_MIN then
        ShowTip("它血太薄——抽不出像样的一口")
        return
    end
    _cdLeft = CONST.DRAIN_CD
    SL:ActorHurt(tid, draw)
    _shield = draw
    SL:PlayDrainFx(tid, SL:GetValue("USER_ID"))
    SL:TipAbove(tid, "汲-" .. draw)
    SL:TipAboveMe("盾+" .. draw)
    RefreshShieldRing()
    ShowTip("抽了" .. draw .. "点现血——化作护体，先扛再打")
end

-- 护体出口：盾先吃刀
SL:RegisterLUAEvent(LUA_EVENT_BEFORE_HURT, "VTD_Shield", function(tid, dmg)
    if _shield > 0 and tid == SL:GetValue("USER_ID") then
        local ate = math.min(_shield, dmg)
        _shield = _shield - ate
        local left = dmg - ate
        RefreshShieldRing()
        if left > 0 then return left end
        ShowTip("盾挡了" .. ate .. "点——护体见底了")
        return 0
    end
    return dmg
end)

-- 定时器：盾的缓消与环的跟脚
if not _scheduler then
    _scheduler = SL:Schedule(function(dt)
        _cdLeft = math.max(0, _cdLeft - dt)
        if _shield > 0 then
            _shield = math.max(0, _shield - CONST.SHIELD_DECAY * dt)
            if _shield <= 0 then
                SafeRemove(_shieldFx)
            end
        end
    end, 0.02)
end

SL:ScheduleOnce(function()
    SL:BindDebugButton("汲取", function()
        VitalDrain.Cast()
    end)
    ShowTip("技能已加载: 汲取 (调试按钮触发)")
end, 1.0)

function VitalDrain.Unload()
    if _scheduler then SL:Unschedule(_scheduler) end
    SL:UnregisterLUAEvent(LUA_EVENT_BEFORE_HURT, "VTD_Shield")
    SafeRemove(_shieldFx)
    _shield = 0
end

return VitalDrain