local DonBGBase         = require("background/bg_objects/donbg/base")
local BGNormal          = require("background/bg_objects/bg_normal")
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 BaseChibi         = require("background/bg_objects/chibi/base")
local Timing            = require("background/bg_objects/timing")

local COLLAB_PATH       = "background/collab/funassyi"
local MAX_DANCERS       = 5

local chain_moves, sum  = Timing.chain_moves, Timing.sum

-- Don band: the fruit-pattern tiles scroll one tile left every 10.7 s; the clear set swaps
-- in the bright tiles and a strip of pears running twice as fast. Ambient, in ms.
local DONBG_SCROLL_MS = 10667
local DONBG_SPEC = { layers = {
    { key = "background", ms = DONBG_SCROLL_MS, x = -81 },
    { key = "overlay", ms = DONBG_SCROLL_MS, dx = -704, x = -81, clear_only = true },
} }

-- Clear background: the sunburst and the shouting strip fade in over the stage (which
-- stays underneath) in 1.75 beats and back out in 0.85 beat. The burst swaps between its
-- two panels every 0.75 beat; the strip (three copies, 1216 px apart) scrolls 1212 px left
-- every 14 beats. Timed in beats.
local BG_FEVER_IN    = 1.75
local BG_FEVER_OUT   = 0.85
local BG_FEVER_SWAP  = 0.75
local BG_FEVER_TEXT  = { beats = 14, distance = -1212, tile = 1216 }

local FunassyiBGFever   = {}
FunassyiBGFever.__index = FunassyiBGFever

function FunassyiBGFever.new(bpm)
    local self = setmetatable({}, FunassyiBGFever)
    self.name = "bg_fever_0"
    tex.load_folder(COLLAB_PATH, "bg_fever/" .. self.name)
    local function id(key) return tex.get_texture(COLLAB_PATH .. "/" .. self.name .. "/" .. key) or 0 end
    self._id_bg   = id("background")
    self._id_text = id("overlay")
    self.beat     = 60000 / bpm
    self.offset   = 0
    self.fade     = {}
    return self
end

function FunassyiBGFever:opacity() return self.offset + sum(self.fade) end

-- fades in from wherever it is; the burst and strip start over
function FunassyiBGFever:start()
    local scale  = tex.get_screen_scale()
    local swap   = BG_FEVER_SWAP * self.beat
    self.offset  = self:opacity()
    self.fade    = chain_moves({ { BG_FEVER_IN, 1000 - self.offset } }, self.beat, 1)
    self.panels  = anim.texture_change(2 * swap, { { 0, swap, 0 }, { swap, 2 * swap, 1 } }, { loop = true })
    self.scroll  = anim.move(BG_FEVER_TEXT.beats * self.beat,
        { total_distance = math.floor(BG_FEVER_TEXT.distance * scale), loop = true })
    self.panels:start()
    self.scroll:start()
end

-- fades out from wherever it is
function FunassyiBGFever:stop()
    self.offset = self:opacity()
    self.fade   = chain_moves({ { BG_FEVER_OUT, -self.offset } }, self.beat, 1)
end

function FunassyiBGFever:update(current_time_ms, bpm)
    if bpm then self.beat = 60000 / bpm end
    for _, m in ipairs(self.fade) do m:update(current_time_ms) end
    if self.panels then
        self.panels:update(current_time_ms)
        self.scroll:update(current_time_ms)
    end
end

function FunassyiBGFever:draw()
    local fade = self:opacity() / 1000
    if fade <= 0 then return end
    tex.draw_texture(self._id_bg, { frame = self.panels.attribute, fade = fade })
    local tile = math.floor(BG_FEVER_TEXT.tile * tex.get_screen_scale())
    for k = 0, 2 do
        tex.draw_texture(self._id_text, { x = self.scroll.attribute + k * tile, fade = fade })
    end
end

function FunassyiBGFever:destroy() tex.unload_folder(COLLAB_PATH, "bg_fever/" .. self.name) end

-- Dancers
-- Timed in beats; poses are offsets from Lumen's dancer origin (texture.json y 670), which
-- sits in the middle of each image. Squashes move the origin down by half the height lost,
-- so the feet stay planted.
-- The four small dancers jump in from below and land with a squash, then loop an 8-beat
-- routine: two pose pairs swapped every half beat, a step back through their entry frames,
-- a hop and a squash. Leaving, they squash, spring up and drop off the bottom.
local SMALL_Y = -72

local SMALL_ENTER = Timing.steps({
    { 0, 0.625, x = 0, y = 267, to = { 0, -128, "out" } }, -- shoots up from below
    { 0, 0.275, to = { 0, SMALL_Y, "in" } },
    { 0, 0.225, to = { 0, SMALL_Y + 6, "out", sy = 0.94 } }, -- lands
    { 0, 0.25,  sy = 0.94, to = { 0, SMALL_Y, "in", sy = 1 } },
    { 0, 0.35 },
    { 1, 0.275 },
})
SMALL_ENTER.beats = 2

local SMALL_DANCE = Timing.steps({
    { 0, 0.5, x = 0, y = SMALL_Y }, { 1, 0.5 }, { 0, 0.5 }, { 1, 0.5 },
    { 2, 0.5 }, { 3, 0.5 }, { 2, 0.5 }, { 3, 0.5 },
    { 1, 0.5, key = "start" }, { 0, 0.5, key = "start" }, { 1, 0.5, key = "start" }, { 0, 0.625, key = "start" },
    { 4, 0.475, to = { 0, SMALL_Y - 68, "out" } }, -- hop
    { 4, 0.425, to = { 0, SMALL_Y, "in" } },
    { 5, 0.25,  to = { 0, SMALL_Y + 4, nil, sy = 0.96 } }, -- squash
    { 5, 0.225, sy = 0.96, to = { 0, SMALL_Y, nil, sy = 1 } },
    { 5, 0.5 },
})

local SMALL_LEAVE = Timing.steps({
    { 0, 0.15,  x = 0, y = SMALL_Y, to = { 0, SMALL_Y + 7, "out", sy = 0.93 } },
    { 0, 0.125, sy = 0.93, to = { 0, SMALL_Y, "in", sy = 1 } },
    { 0, 0.225, to = { 0, -128, "out" } }, -- springs up
    { 0, 0.85,  to = { 0, 267, "in" } },   -- and drops off
})
SMALL_LEAVE.beats = 1.35

-- Funassyi in the middle drops in through its own entry frames, loops three pose pairs a
-- quarter beat each, then the same hop and squash; it never leaves.
local BIG_Y = -162

local BIG_ENTER = Timing.steps({
    { 0, 0.5,   x = 0, y = 194, to = { 0, -170, "out" } }, -- drops in from below
    { 1, 0.35,  to = { 0, -174, "out" } },
    { 2, 0.45,  to = { 0, -143, "in" } },
    { 3, 0.225, y = BIG_Y, to = { 0, BIG_Y + 20, "out", sy = 0.9 } }, -- lands
    { 4, 0.25,  sy = 0.9, to = { 0, BIG_Y, "in", sy = 1 } },
    { 4, 0.225 },
})
BIG_ENTER.beats = 2

local function swap(a, b)
    local out = {}
    for _ = 1, 4 do
        table.insert(out, { a, 0.25 })
        table.insert(out, { b, 0.25 })
    end
    return out
end
local BIG_DANCE = Timing.steps({ { 0, 0, x = 0, y = BIG_Y } }, swap(0, 1), swap(2, 3), swap(4, 5), {
    { 6, 0.125 },
    { 7, 0.475, to = { 0, BIG_Y - 40, "out" } }, -- hop
    { 7, 0.425, to = { 0, BIG_Y + 10, "in" } },
    { 3, 0.225, key = "start", y = BIG_Y, to = { 0, BIG_Y + 20, "out", sy = 0.9 } },
    { 4, 0.25,  key = "start", sy = 0.9, to = { 0, BIG_Y, "in", sy = 1 } },
    { 4, 0.5,   key = "start" },
})

local SMALL = { origin = { 136, 100 }, enter = SMALL_ENTER, dance = SMALL_DANCE, leave = SMALL_LEAVE }
local FUNASSYI_DANCERS = Dancer.define({
    [0] = { origin = { 148, 196 }, enter = BIG_ENTER, dance = BIG_DANCE },
    default = SMALL,
})

-- Lumen's slots, left to right; the group fills centre, left, right, far-left, far-right,
-- which is Lumen's dancer1..5 (skin dancers 0, 4, 3, 2, 1)
local DANCER_CENTERS    = { 183, 417, 640, 863, 1097 }
local DANCER_DRAW_ORDER = { 5, 1, 4, 2, 3 }
local DANCER_JOIN_ORDER = { 0, 4, 3, 2, 1 }

-- Chibi for good hits: Funassyi hops in growing from 70% size, then every beat as it runs
-- it crouches and slides back, springs up and lands
local FUNASSYI_CHIBI = {
    key    = "0",
    run    = { y = 0 },
    period = 1,
    poses  = {
        { 0,     1, 0,   0,   sy = { 1, 0.9 }, to = { -18, 7 } }, -- crouches, sliding back
        { 0.1,   1, -23, 7,   sy = 0.9, to = { -64, 7 } },
        { 0.275, 1, -64, 5,   sy = { 0.93, 1 }, to = { -76, 0 } },
        { 0.35,  0, -76, 8,   to = { -76, -16, "out" } },         -- springs up
        { 0.55,  2, -76, -12, to = { -76, -6, "in" } },
        { 0.775, 3, -68, -14, to = { -68, 1 } },                  -- lands
    },
}

-- Background

local FunassyiBackground = {}
FunassyiBackground.__index = FunassyiBackground

function FunassyiBackground.new(player_num, bpm)
    local self          = setmetatable({}, FunassyiBackground)
    self.donbg          = DonBGBase.new(1, player_num, COLLAB_PATH, DONBG_SPEC)
    self.bg_normal      = BGNormal.Base.new(0, COLLAB_PATH)
    self.bg_fever       = FunassyiBGFever.new(bpm)
    self.footer         = Footer.new("background", 2)
    self.fever          = Fever.create(0, bpm, "background")
    self.dancer         = Dancer.BaseDancerGroup.new(0, bpm, MAX_DANCERS, COLLAB_PATH, FUNASSYI_DANCERS)
    local by_index = {}
    for _, d in ipairs(self.dancer.dancers) do by_index[d.index] = d end
    for i, index in ipairs(DANCER_JOIN_ORDER) do self.dancer.dancers[i] = by_index[index] end
    self.renda          = RendaController.new("background", 0)
    self.chibi          = ChibiController.new(bpm, COLLAB_PATH, 1)
    self.is_clear       = false
    self.is_rainbow     = false
    self.last_milestone = 1
    return self
end

function FunassyiBackground:update(current_ms, bpm)
    self.donbg:update(current_ms, bpm)
    self.bg_fever:update(current_ms, bpm)
    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 FunassyiBackground:handle_good(player_num) BaseChibi.add(self.chibi, FUNASSYI_CHIBI, COLLAB_PATH, player_num) end

function FunassyiBackground:handle_ok(player_num) BaseChibi.add(self.chibi, FUNASSYI_CHIBI, COLLAB_PATH, player_num) end

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

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

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

function FunassyiBackground: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 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

    local current_milestone
    if is_clear then
        current_milestone = MAX_DANCERS
    else
        current_milestone = math.min(MAX_DANCERS - 1, math.floor(progress * MAX_DANCERS))
    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:leave_dancer() end
        self.last_milestone = current_milestone
    end
end

function FunassyiBackground:draw_back()
    self.bg_normal:draw()
    self.bg_fever:draw()
    self.footer:draw()
    self.donbg:draw()
    self.renda:draw()
    self.dancer:draw_slots(DANCER_CENTERS, DANCER_DRAW_ORDER)
    self.fever:draw()
    self.chibi:draw()
end

function FunassyiBackground:draw_fore() end

function FunassyiBackground: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

return FunassyiBackground