local DonBGBase        = require("background/bg_objects/donbg/base")
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 COLLAB_PATH -- set per-variant in create()
local MAX_DANCERS -- set per-variant in create()

-- Spotlight colors: {r,g,b,a}
local SPOTLIGHT_COLORS = {
    { 0,   255, 255, 255 }, -- cyan
    { 255, 255, 0,   255 }, -- yellow
    { 255, 0,   255, 255 }, -- magenta
    { 0,   255, 255, 255 }, -- cyan
    { 255, 255, 0,   255 }, -- yellow
}

-- BGNormal: flicker fade + 5 alternating spotlights
local ImasBGNormal     = {}
ImasBGNormal.__index   = ImasBGNormal

function ImasBGNormal.new(path)
    local self = setmetatable({}, ImasBGNormal)
    self.name = "bg_0"
    self.path = path
    tex.load_folder(path, "bg_normal/" .. self.name)
    self.overlay_fade = anim.fade(1000, {
        initial_opacity = 0.0,
        final_opacity = 1.0,
        reverse_delay = 500,
        delay = 500,
        loop = true
    })
    self._id_bg         = tex.get_texture(self.path .. "/" .. self.name .. "/" .. "background") or 0
    self._id_overlay    = tex.get_texture(self.path .. "/" .. self.name .. "/" .. "overlay") or 0
    self._id_spotlight  = tex.get_texture(self.path .. "/" .. self.name .. "/" .. "spotlight") or 0
    return self
end

function ImasBGNormal:update(current_time_ms)
    self.overlay_fade:update(current_time_ms)
end

function ImasBGNormal:draw()
    local ov = self.overlay_fade.attribute
    tex.draw_texture(self._id_bg)
    tex.draw_texture(self._id_overlay, { fade = ov })
    for i = 0, 4 do
        local fade = (i % 2 == 0) and math.min(0.5, ov) or math.min(0.5, 1 - ov)
        tex.draw_texture(self._id_spotlight, {
            index = i, color = SPOTLIGHT_COLORS[i + 1], fade = fade
        })
    end
end

function ImasBGNormal:destroy()
    tex.unload_folder(self.path, "bg_normal/" .. self.name)
end

-- BGFever: same flicker fade + spotlights + orange/green lights
local ImasBGFever = {}
ImasBGFever.__index = ImasBGFever

function ImasBGFever.new(path)
    local self = setmetatable({}, ImasBGFever)
    self.name = "bg_fever_0"
    self.path = path
    tex.load_folder(path, "bg_fever/" .. self.name)
    self.transitioned = false
    self.overlay_fade = anim.fade(1000, {
        initial_opacity = 0.0,
        final_opacity = 1.0,
        reverse_delay = 500,
        delay = 500,
        loop = true
    })
    self._id_bg           = tex.get_texture(self.path .. "/" .. self.name .. "/" .. "background") or 0
    self._id_overlay      = tex.get_texture(self.path .. "/" .. self.name .. "/" .. "overlay") or 0
    self._id_light_orange = tex.get_texture(self.path .. "/" .. self.name .. "/" .. "light_orange") or 0
    self._id_light_green  = tex.get_texture(self.path .. "/" .. self.name .. "/" .. "light_green") or 0
    self._id_spotlight    = tex.get_texture(self.path .. "/" .. self.name .. "/" .. "spotlight") or 0
    return self
end

function ImasBGFever:start()
    self.transitioned = true
end

function ImasBGFever:update(current_time_ms)
    self.overlay_fade:update(current_time_ms)
end

function ImasBGFever:draw()
    local ov = self.overlay_fade.attribute
    tex.draw_texture(self._id_bg)
    tex.draw_texture(self._id_overlay,      { fade = ov })
    tex.draw_texture(self._id_light_orange, { fade = ov })
    tex.draw_texture(self._id_light_green,  { fade = 1 - ov })
    for i = 0, 4 do
        local fade = (i % 2 == 0) and math.min(0.5, ov) or math.min(0.5, 1 - ov)
        tex.draw_texture(self._id_spotlight, {
            index = i, color = SPOTLIGHT_COLORS[i + 1], fade = fade
        })
    end
end

function ImasBGFever:destroy()
    tex.unload_folder(self.path, "bg_fever/" .. self.name)
end

-- Fever: BaseFever + 2-frame texture_change overlay (2-beat cycle)
local ImasFever = {}
ImasFever.__index = ImasFever

function ImasFever.new(bpm, path)
    local self = setmetatable({}, ImasFever)
    local base = Fever.Base.new(0, bpm, path)
    for k, v in pairs(base) do self[k] = v end
    local total = 120000 / bpm
    self.texture_change = anim.texture_change(total, {
        { 0,         total / 2, 0 },
        { total / 2, total,     1 }
    }, { loop = true })
    return self
end

function ImasFever:start()
    Fever.Base.start(self)
end

function ImasFever:update(current_time_ms, bpm)
    Fever.Base.update(self, current_time_ms, bpm)
    self.texture_change:update(current_time_ms)
end

function ImasFever:draw()
    local y = self.bounce_down.attribute - self.bounce_up.attribute
    tex.draw_texture(self._id_overlay, { y = y, frame = self.texture_change.attribute })
end

-- Background factory (used for IMAS, IMAS_CG, IMAS_ML)

local ImasBackground = {}
ImasBackground.__index = ImasBackground

function ImasBackground.new(player_num, bpm, path, max_dancers)
    local self          = setmetatable({}, ImasBackground)
    self.donbg          = DonBGBase.new(1, player_num, path)
    self.bg_normal      = ImasBGNormal.new(path)
    self.bg_fever       = ImasBGFever.new(path)
    self.footer         = Footer.new(path, 0)
    self.fever          = ImasFever.new(bpm, path)
    self.dancer         = Dancer.BaseDancerGroup.new(0, bpm, max_dancers, path)
    self.renda          = RendaController.new(path, 0)
    self.chibi          = ChibiController.new(bpm, path, 0)
    self.max_dancers    = max_dancers
    self.is_clear       = false
    self.is_rainbow     = false
    self.last_milestone = 1
    return self
end

function ImasBackground:update(current_ms, bpm)
    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)
    self.renda:update(current_ms)
    self.chibi:update(current_ms, bpm)
end

function ImasBackground:handle_good(player_num) self.chibi:add_chibi(player_num, false) end

function ImasBackground:handle_ok(player_num) self.chibi:add_chibi(player_num, false) end

function ImasBackground:handle_bad(player_num) self.chibi:add_chibi(player_num, true) end

function ImasBackground:handle_drumroll(player_num) self.renda:add_renda() end

function ImasBackground:handle_balloon(player_num) self.renda:add_renda() end

function ImasBackground:handle_gauge(player_num, progress, is_clear, is_rainbow)
    self.donbg:set_clear(is_clear)
    if is_clear and not self.is_clear then self.bg_fever:start() end
    if is_rainbow and not self.is_rainbow then self.fever:start() end
    self.is_clear   = is_clear
    self.is_rainbow = is_rainbow

    local md        = self.max_dancers
    local current_milestone
    if is_clear then
        current_milestone = md
    else
        current_milestone = math.min(md - 1, math.floor(progress * md))
    end
    if current_milestone > self.last_milestone then
        for _ = 1, current_milestone - self.last_milestone do self.dancer:add_dancer() end
        self.last_milestone = current_milestone
    elseif current_milestone < self.last_milestone then
        for _ = 1, self.last_milestone - current_milestone do self.dancer:remove_dancer() end
        self.last_milestone = current_milestone
    end
end

function ImasBackground:draw_back()
    if self.is_clear then
        if not self.bg_fever.transitioned then
            self.bg_normal:draw()
            self.bg_fever:draw()
        else
            self.bg_fever:draw()
        end
    else
        self.bg_normal:draw()
    end
    self.donbg:draw()
    self.renda:draw()
    self.dancer:draw()
    self.footer:draw()
    if self.is_rainbow then self.fever:draw() end
    self.chibi:draw()
end

function ImasBackground:draw_fore() end

function ImasBackground:destroy()
    self.donbg:destroy()
    self.bg_normal:destroy()
    self.bg_fever:destroy()
    self.fever:destroy()
    self.dancer:destroy()
    self.footer:destroy()
    self.renda:destroy()
    self.chibi:destroy()
end

-- Export the factory and the ImasFever class (reused by imas_sidem)
local Imas     = {}
Imas.new       = ImasBackground.new
Imas.ImasFever = ImasFever

-- Callable as a collab constructor: Imas.new(player_num, bpm, path, max_dancers)
setmetatable(Imas, {
    __call = function(_, player_num, bpm, path, max_dancers)
        return ImasBackground.new(player_num, bpm, path, max_dancers)
    end
})

return Imas