-- YataiDON-HSS child override of PyTaikoGreen/Scripts/background/background.lua:
-- byte-copy of the parent plus the ArcadeGauge overlay (3 hooks, marked below).
local DonBG               = require("background/bg_objects/donbg")
local BGNormal            = require("background/bg_objects/bg_normal")
local BGFever             = require("background/bg_objects/bg_fever")
local Fever               = require("background/bg_objects/fever")
local Footer              = require("background/bg_objects/footer")
local Dancer              = require("background/bg_objects/dancer")
local RendaController     = require("background/bg_objects/renda")
local ChibiController     = require("background/bg_objects/chibi")
local ArcadeGauge         = require("background/bg_objects/arcade_gauge") -- child-only
local EnsoSkip            = require("background/bg_objects/enso_skip")     -- child-only

local PracticeBackground  = require("background/bg_collabs/practice")
local TutorialBackground  = require("background/bg_collabs/tutorial")
local A3Background        = require("background/bg_collabs/a3")
local AnimalBackground    = require("background/bg_collabs/animal")
local ButtoBackground     = require("background/bg_collabs/buttoburst")
local DanBackground       = require("background/bg_collabs/dan")
local FunassyiBackground  = require("background/bg_collabs/funassyi")
local ImasBackground      = require("background/bg_collabs/imas")
local ImasSidemBackground = require("background/bg_collabs/imas_sidem")
local OshiriBackground    = require("background/bg_collabs/oshiri")

local COLLABS             = {
    PRACTICE   = { PracticeBackground.new, nil, 1 },
    TUTORIAL   = { TutorialBackground.new, nil, 1 },
    A3         = { A3Background.new, "background/collab/a3", 4 },
    ANIMAL     = { AnimalBackground.new, "background/collab/animal", 5 },
    BUTTOBURST = { ButtoBackground.new, "background/collab/buttoburst", 4 },
    DAN        = { DanBackground.new, "background/collab/dan", 1 },
    FUNASSYI   = { FunassyiBackground.new, "background/collab/funassyi", 5 },
    IMAS       = { ImasBackground.new, "background/collab/imas", 5 },
    IMAS_CG    = { ImasBackground.new, "background/collab/imas_cg", 3 },
    IMAS_ML    = { ImasBackground.new, "background/collab/imas_ml", 3 },
    IMAS_SIDEM = { ImasSidemBackground.new, "background/collab/imas_sidem", 3 },
    OSHIRI     = { OshiriBackground.new, "background/collab/oshiri", 5 },
}

Background                = {}
Background.__index        = Background

function Background.new(player_num, bpm, scene_preset)
    local self        = setmetatable({}, Background)

    self.player_num   = player_num
    self.bpm          = bpm
    self.scene_preset = scene_preset
    self.is_2p        = (player_num == 3) -- PlayerNum::TWO_PLAYER

    tex.load_animations("background")

    -- child-only: arcade soul-gauge overlay, drawn in draw_fore (in front of the HUD)
    self.arcade_gauge = ArcadeGauge.new()

    -- child-only: 演奏スキップ countdown card / dim / banner.
    -- Fed by Background:handle_skip, which GameScreen::push_skip_state calls
    -- every frame once the feature is armed.
    --
    -- ROUND 19 (r19-skip2): the arcade own post-info draw list
    -- (datatable/enso_post.bin, target 0/2/3/4/5/6/7 -- every single-player
    -- enso target) places `skip.nulstb` (part 30) right after `song_info.nulstb`
    -- (part 16) and ahead of only `papamama.nulstb`, i.e. AFTER the title/genre
    -- plate and the soul gauge, not before them. So the skip panel (card,
    -- numeral, dim, banner -- one Lumen subtree, drawn as one unit at that one
    -- point in the list) has to sit on top of the whole HUD for the whole time
    -- it is alive, not just draw_fore. `allnet_indicator.lua`
    -- (global/allnet_indicator.lua) is the engine last Lua paint hook on GAME
    -- (game.cpp draw_overlay: it runs after song_info.draw(), draw_skip(), the
    -- transitions), so it is the only place this skin can put something that
    -- actually lands on top of song_info and the gauge. `self.enso_skip` is
    -- published on the shared Lua globals table for that hook to pick up and
    -- draw (all skin scripts run in one sol::state -- ScriptManager::init /
    -- LuaScript::load -- so a plain global is visible everywhere); it is
    -- cleared in Background:destroy so a stale reference cannot survive into
    -- the next screen.
    self.enso_skip = EnsoSkip.new()
    _G.g_active_enso_skip = self.enso_skip

    -- ROUND 52 (r52-lua-divergence-fixes, user bug report 「兩個人的狀態下，
    -- collab會出現graphic bug」): a SCENEPRESET song in 2P used to build the
    -- collab rig anyway, but every collab background is a 1P LAYOUT -- one
    -- full-height stage, dancers at 1P-stage y, a single top band -- with no
    -- knowledge of game_2p_offset or the dual donbg bands, so the idol sprite
    -- drew clipped behind the 2P lane and the collab's top band landed
    -- corrupted over the 2P chrome.  The skin's 2P background design is the
    -- dual-band donbg rig and nothing else (ROUND 18/49 audit: "2P branch: no
    -- bg objects by design"), so 2P now always routes there; a real 2P collab
    -- stage rig is future work (needs per-collab 2P geometry).
    local entry = (not self.is_2p) and scene_preset and COLLABS[scene_preset] or nil
    if entry then
        local ctor, path, max_dancers = entry[1], entry[2], entry[3]
        if path then
            self.collab = ctor(player_num, bpm, path, max_dancers)
        else
            self.collab = ctor(player_num, bpm)
        end
    else
        -- Standard (non-collab) case
        local max_dancers = 5
        self.max_dancers  = max_dancers

        if self.is_2p then
            local donbg_index = math.random(1, 6)
            self.donbg_1      = DonBG.create(1, "background", donbg_index)
            self.donbg_2      = DonBG.create(2, "background", donbg_index)
            local skin_cfg    = tex.get_skin_config("game_2p_offset")
            self.p2_y_offset  = skin_cfg and skin_cfg.y or 0
            self.is_clear_1   = false
            self.is_clear_2   = false
        else
            self.donbg     = DonBG.create(player_num, "background")
            self.bg_normal = BGNormal.create(math.random(0, 4), "background")
            self.bg_fever  = BGFever.create(math.random(0, 3), "background")
            self.fever     = Fever.create(math.random(0, 3), bpm, "background")
            self.dancer    = Dancer.create(math.random(0, 20), bpm, "background", max_dancers)
            self.footer    = Footer.new("background", math.random(0, 2))
        end

        -- ROUND 58 (r58-2p-background-polish): the cabinet's 2P enso_post set
        -- (the reference build target 1) carries TWO renda_effect instances of the SAME
        -- clip -- playerNo 0 at y=0 and playerNo 1 at y=804 (the 2P donbg
        -- band; = game_2p_offset in skin space). Each seat gets its own
        -- 25-slot pool, and a P2 roll rains into the P2 band.
        local renda_index   = math.random(0, 2)
        self.renda          = RendaController.new("background", renda_index)
        if self.is_2p then
            self.renda_2    = RendaController.new("background", renda_index, self.p2_y_offset)
        end
        self.chibi          = ChibiController.new(bpm, "background")
        self.is_clear       = false
        self.is_rainbow     = false
        -- ROUND 18 (r18-misc): the troupe size is an absolute function of the
        -- gauge (see handle_gauge), not a milestone counter, so there is no
        -- `last_milestone` to keep in step any more.
        self.clear_progress = nil
    end

    return self
end

function Background:update(current_ms, bpm)
    self.bpm = bpm
    self.enso_skip:update(current_ms)
    if self.collab then
        self.collab:update(current_ms, bpm)
    else
        if self.is_2p then
            self.donbg_1:update(current_ms)
            self.donbg_2:update(current_ms)
        else
            self.donbg:update(current_ms)
            self.bg_normal:update(current_ms)
            self.bg_fever:update(current_ms)
            self.fever:update(current_ms, bpm)
            self.dancer:update(current_ms, bpm)
        end
        self.renda:update(current_ms)
        if self.renda_2 then self.renda_2:update(current_ms) end
        self.chibi:update(current_ms, bpm)
    end
end

function Background:handle_good(player_num)
    if self.collab then
        self.collab:handle_good(player_num)
    else
        self.chibi:add_chibi(player_num, false)
    end
end

function Background:handle_ok(player_num)
    if self.collab then
        self.collab:handle_ok(player_num)
    else
        self.chibi:add_chibi(player_num, false)
    end
end

function Background:handle_bad(player_num)
    if self.collab then
        self.collab:handle_bad(player_num)
    else
        self.chibi:add_chibi(player_num, true)
    end
end

function Background:handle_drumroll(player_num)
    if self.collab then
        self.collab:handle_drumroll(player_num)
    else
        -- ROUND 58: seat-routed in 2P (arcade target 1 has one renda_effect
        -- instance per playerNo; P2's lives in the bottom band).
        if player_num == 2 and self.renda_2 then
            self.renda_2:add_renda()
        else
            self.renda:add_renda()
        end
    end
end

-- ROUND 52 (r52-lua-divergence-fixes): balloons and kusudama no longer spawn
-- renda effects.  the reference build `EnsoGraphicRendaEffect::Process` (0x14012BDA0) arms
-- its per-frame effect start ONLY while an active note of kind 6 or 9 is in
-- flight, and the the reference build note-kind table (tlb research enso_options.md:258) is
-- explicit: "6/9 drumroll, 0xA balloon, 0xC kusudama" -- so the effect family
-- belongs to DRUMROLLS alone.  The engine's handle_balloon covers both the
-- balloon and the kusudama (player.cpp check_balloon/check_kusudama), neither
-- of which the cabinet decorates.  Kept as a delegate for collabs that define
-- their own handler.
function Background:handle_balloon(player_num)
    if self.collab then
        self.collab:handle_balloon(player_num)
    end
end

-- ROUND 14 (r14-dan). `Background` is a WRAPPER that delegates to self.collab, and
-- the engine binds its hooks off THIS object (Background.cpp reads
-- lua_object["handle_dan"]). A handle_dan defined only on DanBackground is
-- therefore invisible to the engine -- `wants_dan()` returns false and the
-- binding never fires at all. This delegate is what makes it reachable; it is
-- additive and no-ops for every collab that does not define the method.
-- See ENGINE_BINDINGS.md "ROUND 14" and background/bg_objects/dan_info.lua.
function Background:handle_dan(player_num, state)
    if self.collab and self.collab.handle_dan then
        self.collab:handle_dan(player_num, state)
    end
end

-- `clear_progress` (ROUND 18) is the 5th argument: clear_start/gauge_max for this
-- chart's difficulty.  It is optional -- an engine that does not send it leaves it
-- nil and handle_dancer_count falls back (see there).
-- `flash` (ROUND 19, r19-gauge) is the 6th argument: the engine gauge-up
-- flash's current fade value (1 -> 0), 0 when none is active. Forwarded so
-- arcade_gauge.lua can redraw the flash on ITS OWN 21px segment grid instead
-- of the engine's 12px one -- see arcade_gauge.lua for why the stock flash
-- (still drawn by gauge.cpp, harmlessly hidden under this overlay's redraw)
-- cannot just be left alone.
function Background:handle_gauge(player_num, progress, is_clear, is_rainbow, clear_progress, flash)
    -- child-only
    -- ROUND 39 (r39-ghostgauge-secondsong): this forwarding call still only
    -- passed 5 args after ROUND 37 (r37-duplicate-gauge-clear) added the 6th
    -- formal parameter to arcade_gauge.lua's own handle_gauge -- so `flash`
    -- (the real 6th arg here) was landing in arcade_gauge's `clear_progress`
    -- slot, and arcade_gauge's own `flash` was silently nil every frame,
    -- permanently disabling the gauge-up flash redraw. Fixed to forward all
    -- six.
    self.arcade_gauge:handle_gauge(player_num, progress, is_clear, is_rainbow, clear_progress, flash)
    if self.collab then
        -- ROUND 52: forward clear_progress (5th arg) so the collab dancer
        -- model can divide by the CLEAR point like reference dance_b_* does
        -- (collabs that ignore it are unaffected).
        self.collab:handle_gauge(player_num, progress, is_clear, is_rainbow, clear_progress)
    elseif self.is_2p then
        -- Update each player's donbg clear state independently
        if player_num == 1 then
            self.donbg_1:set_clear(is_clear)
            self.is_clear_1 = is_clear
        elseif player_num == 2 then
            self.donbg_2:set_clear(is_clear)
            self.is_clear_2 = is_clear
        end
        self.is_clear = self.is_clear_1 or self.is_clear_2
        self.is_rainbow = is_rainbow
    else
        self.donbg:set_clear(is_clear)
        -- ROUND 52 (r52-lua-divergence-fixes): BOTH edges, matching the reference build
        -- BgFever/FeverEffect/DonBg::Process (each caches its flag and plays a
        -- clip on every change -- `normal_fever` rising, `fever_normal`
        -- falling, re-triggerable per gogo/clear excursion).
        if is_clear and not self.is_clear then self.bg_fever:start() end
        if not is_clear and self.is_clear then self.bg_fever:stop() end
        if is_rainbow and not self.is_rainbow then self.fever:start() end
        if not is_rainbow and self.is_rainbow then self.fever:stop() end
        self.is_clear   = is_clear
        self.is_rainbow = is_rainbow

        self:handle_dancer_count(progress, is_clear, clear_progress)
    end
end

-- ROUND 18 (r18-misc) -- the cabinet's dancer count.
--
-- `App::EnsoGraphicDancer::Process` (reference source `EnsoGraphicDancer.obj.c:2723-2752`)
-- is evaluated EVERY FRAME and is a pure function of the gauge:
--
--     r = current_gauge / CLEAR_POINT          -- +327256 / +327164
--     n = clamp(floor(2r + 3), 3, 5)           -- min3 troupes (all six normal ones)
--     CheckDancerNum(this, n)
--
-- so: **3 dancers from the first frame of the song** (r = 0), 4 from HALF the
-- clear point, 5 once the gauge reaches the clear point.  It is symmetric --
-- the count falls again when the gauge falls -- and 5 is a hard maximum
-- (`do {...} while (v3 < 5)`, `:2828-2895`).
--
-- What was wrong before: `math.floor(progress * 5)` starting from
-- `last_milestone = 1` gave ONE dancer at song start and reached three only at
-- 60 % of the whole bar.  That is the user's 「進歌曲其實預設是3隻」.
--
-- The divisor is the CLEAR point, not the full bar: `AiEnsoGameManager.obj.c:1513`
-- tests `gauge >= (float)*(int *)(v16 + 327164)` for the clear, which pins
-- +327164 as the norma line.  Our engine's equivalent is
-- `clear_start = {52, 60, 69, 69} / 87` (`src/objects/game/gauge.cpp:20`), passed
-- in as `clear_progress`.  FAIL-SOFT: on an engine that does not pass it (the
-- parent, or a pre-round-18 build) we fall back to the HARD/ONI line, and then
-- correct ourselves the moment `is_clear` flips -- the same "learn the
-- difficulty at the flip" trick `arcade_gauge.lua` already uses, because
-- difficulty itself is not bound to Lua.
local GAUGE_MAX     = 87.0
local CLEAR_STARTS  = { 52, 60, 69 }          -- easy / normal / hard+oni
local CLEAR_DEFAULT = 69 / GAUGE_MAX          -- 0.79310

function Background:handle_dancer_count(progress, is_clear, clear_progress)
    if not self.dancer or not self.dancer.set_dancer_count then return end

    if clear_progress and clear_progress > 0 then
        self.clear_progress = clear_progress
    elseif is_clear and not self.clear_progress then
        -- The engine flips is_clear at gauge_length > clear_start - 1, so the
        -- progress at the flip is just under clear_start/87; pick the first
        -- threshold at or above it.
        local p = progress or 0
        for _, cs in ipairs(CLEAR_STARTS) do
            if p < cs / GAUGE_MAX + 0.0005 then
                self.clear_progress = cs / GAUGE_MAX
                break
            end
        end
        self.clear_progress = self.clear_progress or CLEAR_DEFAULT
    end

    local cp = self.clear_progress or CLEAR_DEFAULT
    local r  = (progress or 0) / cp
    local n  = math.floor(2 * r + 3)
    if n < 3 then n = 3 elseif n > 5 then n = 5 end
    -- is_clear flips one gauge unit early; honour it so the fifth dancer and the
    -- クリア state arrive on the same frame.
    if is_clear then n = 5 end
    self.dancer:set_dancer_count(n)
end

function Background:draw_back()
    if self.collab then
        self.collab:draw_back()
    else
        if not self.is_2p then
            -- ROUND 52: draw the fever backdrop while it is entering, steady
            -- OR exiting (the falling-edge fade), with bg_normal beneath
            -- whenever it is not fully opaque.
            if self.bg_fever:is_visible() then
                if not self.bg_fever.transitioned then
                    self.bg_normal:draw()
                end
                self.bg_fever:draw()
            else
                self.bg_normal:draw()
            end
        end

        if self.is_2p then
            self.donbg_1:draw(0)
            self.donbg_2:draw(self.p2_y_offset)
        else
            self.donbg:draw()
        end

        self.renda:draw()
        if self.renda_2 then self.renda_2:draw() end
        if not self.is_2p then
            self.dancer:draw()
            -- ROUND 18 (r18-play): the 魂-max crowd goes UNDER the `dai` band.
            -- The cabinet's crowd (enso/fever/fever_effect1) is a 1920x540 stage
            -- whose art runs all the way to stage row 539 = screen 1079, i.e. it
            -- fully overlaps the dai band's screen rows 1014..1080; drawn on top
            -- it wipes the 紅白幕 out in both bottom corners, which is what the
            -- user reported. The crowd rises from BEHIND the stand, so `footer`
            -- (= bg_dai) is painted last. `dancer` was already behind it and stays
            -- there -- the dancers' feet stop at ~y 1010, above the band, so the
            -- band does not clip them.
            -- ROUND 52: gate on the object's own visibility (covers the exit
            -- ramp), not the raw is_rainbow flag.
            if self.fever:is_visible() then self.fever:draw() end
            self.footer:draw()
        end
        self.chibi:draw()
    end
end

-- child-only. The engine only calls this when the skin declares it
-- (Background::wants_skip), and it then suppresses its own skip_counter text.
function Background:handle_skip(player_num, state)
    self.enso_skip:handle(state)
end

-- ROUND 80 (r80-gauge-layering-recheck): child-only. The arcade gauge fill
-- USED TO be painted from draw_fore() below, i.e. after the whole GAME HUD --
-- which put the skin's half of the soul gauge on top of every element the
-- cabinet draws OVER the gauge. `datatable/enso_post.bin` target 0 (1P normal
-- enso) lists the graphics in the order EnsoGraphicFactory::CreateEnsoGraphics
-- appends them, and `tamashiigage/tamashii_gage` is row 12 of 33: above
-- donbg / bg_nomal / bg_fever / renda_effect / dancer / bg_dai / gogo_effect /
-- fever_effect / lane / lane_hit / onp_replace, and BELOW don_enso, lane_left,
-- taiko, onp_jump, hit_effect, course, option, score, combo_number,
-- action_result, branch_effect, don_fukidashi, renda_number, name_plate,
-- action_fusen, action_kusudama, song_info, skip and papamama.
--
-- The engine now calls this hook from Player::draw(), immediately after that
-- lane's own Gauge::draw(), so the gauge is ONE layer again. Measured defect
-- it fixes: the note arc / 魂 badge burst (the cabinet's `onp_jump`, row 17)
-- was being clipped dead at the gauge's left edge, screen x 738 -- see
-- MAPPING_hud ROUND 80.
--
-- `player_num` is the lane whose engine gauge just drew; only that record is
-- repainted, so in 2P each lane lands in its own slot.
function Background:draw_gauge(player_num)
    self.arcade_gauge:draw_one(player_num)
    -- ROUND 90 (r90-danplate-brown-and-place): the collab gets this slot too.
    -- GAME_DAN's 魂ゲージ condition plate is `gauge_border`, a CHILD of `gauge_mc`
    -- inside the cabinet's tamashii_gauge.nulm, so it belongs in the gauge's own
    -- layer, not at the end of the frame -- see bg_collabs/dan.lua:draw_gauge.
    if self.collab and self.collab.draw_gauge then
        self.collab:draw_gauge(player_num)
    end
end

function Background:draw_fore()
    if self.collab then
        self.collab:draw_fore()
    end
    -- ROUND 80: the arcade gauge fill moved OUT of here, into draw_gauge()
    -- above. Do NOT put it back: this hook runs after the whole GAME HUD.
    -- ROUND 19 (r19-skip2): the 演奏スキップ panel used to draw here too, but
    -- draw_fore runs BEFORE song_info.draw() and the gauge HUD (game.cpp
    -- draw() -> draw_players() -> background->draw_fore() -> draw_overlay()),
    -- so its full-screen dim could never reach the title/genre plate or the
    -- gauge -- exactly the defect the cabinet capture showed. It now draws
    -- from global/allnet_indicator.lua's GAME branch instead, the engine's
    -- last Lua paint hook on GAME, which lands after song_info AND the gauge,
    -- matching datatable/enso_post.bin's own draw order (skip.nulstb right
    -- after song_info.nulstb). See the comment at self.enso_skip's
    -- construction above for the full citation.
end

function Background:destroy()
    if _G.g_active_enso_skip == self.enso_skip then
        _G.g_active_enso_skip = nil
    end
    if self.collab then
        self.collab:destroy()
    else
        if self.is_2p then
            self.donbg_1:destroy()
            self.donbg_2:destroy()
        else
            self.donbg:destroy()
            self.bg_normal:destroy()
            self.bg_fever:destroy()
            self.fever:destroy()
            self.dancer:destroy()
            self.footer:destroy()
        end
        self.renda:destroy()
        -- renda_2 shares the same texture folder; unload_folder is dedup-keyed
        -- so the second destroy is a safe no-op.
        if self.renda_2 then self.renda_2:destroy() end
        self.chibi:destroy()
    end
end