逆时步：三秒前站在哪，一步回到哪

 fx-rewindpos

-- @file RewindPos.lua
-- 逆时步 —— 三秒前站在哪，一步回到哪

local RewindPos = {}

local CONST = {
    REWIND_CD     = 6.0,
    BACK_TIME     = 3.0,
    TRAIL_GAP     = 0.1,
    TRAIL_KEEP    = 3.2,
    MISS_WINDOW   = 1.0,

    COLOR_TIME    = "#58b8d8",
    COLOR_DEEP    = "#1a4a5e",
    COLOR_GHOST   = "#c0ecf8",

    ZORDER_TRAIL  = 129,
    ZORDER_FX     = 135,
    AUTOINC_BASE  = 991000,
}

local _trail     = {}
local _trailTick = 0
local _cdLeft    = 0
local _missT     = 0
local _scheduler = nil
local _autoInc   = 0

local function GenID(prefix)
    _autoInc = _autoInc + 1
    return string.format("%s_%d", prefix or "RWP",
        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 FindStamp(want)
    local best = nil
    for i = 1, #_trail do
        local s = _trail[i]
        if s.t <= want and (not best or s.t > best.t) then
            best = s
        end
    end
    return best
end

local function LeaveGhosts(from, to)
    local myID = SL:GetValue("USER_ID")
    for k = 1, 5 do
        SL:DropGhostAt(myID, from + (to - from) * k / 5)
    end
end

-- 回溯入口
function RewindPos.Cast()
    if _cdLeft > 0 then
        ShowTip("步在冷却——"
            .. string.format("%.1f", _cdLeft) .. "秒")
        return
    end
    local myID = SL:GetValue("USER_ID")
    local mp = GetActorPos(myID)
    if not mp then return end
    local stamp = FindStamp(SL:GetTime() - CONST.BACK_TIME)
    if not stamp then
        ShowTip("还没走出三秒——再撑一撑")
        return
    end
    _cdLeft = CONST.REWIND_CD
    _missT = CONST.MISS_WINDOW
    LeaveGhosts(mp.x, stamp.x)
    SL:SetActorPos(myID, stamp.x, stamp.y)
    SL:PlayRippleFx(mp.x, mp.y)
    SL:PlayRippleFx(stamp.x, stamp.y)
    ShowTip("回来了——三秒前的位置，它的刀扑个空")
end

-- 扑空判定：回溯窗口里落在原地的攻击记扑空
SL:RegisterLUAEvent(LUA_EVENT_MONSTER_ATTACK_MISS,
    "RWP_Miss", function(tid)
    if _missT > 0 then
        SL:TipAbove(tid, "扑空")
        ShowTip("它这一刀砍在空气上——再拉一轮")
    end
end)

-- 定时器：脚印压环与冷却推进
if not _scheduler then
    _scheduler = SL:Schedule(function(dt)
        _cdLeft = math.max(0, _cdLeft - dt)
        _missT = math.max(0, _missT - dt)
        _trailTick = _trailTick + dt
        if _trailTick >= CONST.TRAIL_GAP then
            _trailTick = 0
            local myID = SL:GetValue("USER_ID")
            local mp = GetActorPos(myID)
            if mp then
                table.insert(_trail, {
                    x = mp.x, y = mp.y,
                    t = SL:GetTime() })
            end
            while #_trail > 0 and _trail[1].t
                < SL:GetTime() - CONST.TRAIL_KEEP do
                table.remove(_trail, 1)
            end
        end
    end, 0.02)
end

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

function RewindPos.Unload()
    if _scheduler then SL:Unschedule(_scheduler) end
    SL:UnregisterLUAEvent(LUA_EVENT_MONSTER_ATTACK_MISS, "RWP_Miss")
    _trail = {}
end

return RewindPos