local DonBG           = require("background/bg_objects/donbg")
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 ChibiWave       = require("background/bg_objects/chibi/wave")
local Timing          = require("background/bg_objects/timing")

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

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

-- Clear background: the stage flashes white over a beat, cuts to the clear savanna under
-- the flash, and the flash fades over 0.8 beat. Losing clear fades the savanna out over a
-- beat to the normal one, which stays underneath. Timed in beats.
local BG_FEVER_FLASH = { { 0.975, 1000 }, { 0.8, -1000 } }
local BG_FEVER_CUT   = { { 0.975, 0 }, { 0, 1000 } }
local BG_FEVER_OUT   = 1

local AnimalBGFever   = {}
AnimalBGFever.__index = AnimalBGFever

function AnimalBGFever.new(bpm)
    local self = setmetatable({}, AnimalBGFever)
    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_flash = id("flash")
    self.beat      = 60000 / bpm
    self.offset    = 0
    self.fade      = {}
    self.flash     = {}
    return self
end

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

function AnimalBGFever:start()
    self.offset = 0
    self.fade   = chain_moves(BG_FEVER_CUT, self.beat, 1)
    self.flash  = chain_moves(BG_FEVER_FLASH, self.beat, 1)
end

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

function AnimalBGFever: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
    for _, m in ipairs(self.flash) do m:update(current_time_ms) end
end

function AnimalBGFever:draw()
    local opacity = self:opacity() / 1000
    if opacity > 0 then tex.draw_texture(self._id_bg, { fade = opacity }) end
    local flash = sum(self.flash) / 1000
    if flash > 0 then tex.draw_texture(self._id_flash, { fade = flash }) end
end

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

-- Fever: the animals' line-up (one image) jumps up from below, bounces once a beat and
-- hops off when the rainbow gauge is lost
local ANIMAL_FEVER = { rise = 330, peak = 109, bounce = 70, drop = 400 }

-- Dancers
-- Timed in beats; poses are offsets from where each dancer stands, pivoting about its feet
-- (the bottom-left of its images). Each jumps up from below on its first entry frame, lands
-- through five more, loops an 8-beat routine, and leaving, rises and drops off the bottom.

-- the routine's frames: big frames hold most of a beat, with two quick in-betweens
local SMALL_DANCE = {
    { 0, 0.125 }, { 1, 0.125 }, { 2, 0.125 }, { 3, 0.6 }, { 4, 0.125 }, { 5, 0.125 }, { 6, 0.75 },
    { 7, 0.125 }, { 8, 0.125 }, { 9, 0.75 }, { 10, 0.125 }, { 11, 0.125 }, { 12, 0.75 },
    { 0, 0.125 }, { 1, 0.125 }, { 2, 0.125 }, { 3, 0.625 }, { 4, 0.125 }, { 5, 0.125 }, { 6, 0.75 },
    { 7, 0.125 }, { 8, 0.125 }, { 9, 0.75 }, { 10, 0.125 }, { 11, 0.125 }, { 12, 0.775 },
}
local BIG_DANCE = {
    { 0, 0.125 }, { 1, 0.125 }, { 2, 0.125 }, { 3, 0.6 }, { 4, 0.125 }, { 5, 0.125 }, { 6, 0.1 },
    { 7, 0.775 }, { 8, 0.125 }, { 9, 0.125 }, { 10, 0.625 }, { 11, 0.125 }, { 12, 0.25 }, { 13, 0.1 },
    { 0, 0.65 }, { 1, 0.125 }, { 2, 0.125 }, { 3, 0.625 }, { 4, 0.125 }, { 5, 0.125 }, { 6, 0.1 },
    { 7, 0.775 }, { 8, 0.125 }, { 9, 0.125 }, { 10, 0.625 }, { 11, 0.125 }, { 12, 0.25 }, { 13, 0.1 },
    { 0, 0.55 },
}

local ENTER = {
    beats = 2,
    { 0,     0, 0, 396, to = { 0, -100, "out" } },    -- shoots up from below
    { 0.975, 0, 0, -100, to = { 0, -34, "in" } },
    { 1.4,   0, 0, -34 },
    { 1.425, 1, 0, -4 }, { 1.475, 2, 0, 19 }, { 1.525, 3, 0, 34 }, -- lands, sinking in
    { 1.6, 4, 0, 0 }, { 1.7, 5 }, { 1.8, 0, key = "loop" },
}
-- leaving: hops up, then drops off the bottom (the small ones from their last routine frame)
local function exit(first)
    local leave = { beats = 1.725 }
    if first then table.insert(leave, { 0, first, 0, 0, key = "loop" }) else table.insert(leave, { 0, 0, 0, 0 }) end
    for _, p in ipairs({
        { 0.125, first and 0 or 1 },
        { 0.25,  1, 0, -36, to = { 0, -64 } }, { 0.5, 1, 0, -64 }, { 0.6, 2 },
        { 0.725, 3, 0, -64, to = { 0, 333 } },
        { 1.7, hide = true },
    }) do table.insert(leave, p) end
    return leave
end

-- h: image height, so the dancer pivots about its feet
local function animal_dancer(h, dance, first_out)
    return { origin = { 0, h }, enter = ENTER, dance = Timing.steps(dance), leave = exit(first_out) }
end
local ANIMAL_DANCERS = Dancer.define({
    [0] = animal_dancer(432, BIG_DANCE),
    [1] = animal_dancer(432, SMALL_DANCE, 12),
    default = animal_dancer(376, SMALL_DANCE, 12),
})

-- Fixed dancer slots, left to right. Each slot always gets the same dancer: the group
-- fills slots centre, left, right, far-left, far-right, so dancers join in index order 4..0.
local DANCER_CENTERS    = { 172, 426, 640, 874, 1108 }
local DANCER_DRAW_ORDER = { 5, 1, 4, 2, 3 }
local DANCER_JOIN_ORDER = { 4, 3, 2, 1, 0 }

-- Chibi for good hits: the bird hops in growing from 70% size, then bobs across the band
local ANIMAL_CHIBI = {
    key  = "1",
    run  = { y = -2 },
    wave = { first = 18, height = 38, beats = 0.85 },
}

-- Background

local AnimalBackground = {}
AnimalBackground.__index = AnimalBackground

function AnimalBackground.new(player_num, bpm)
    local self          = setmetatable({}, AnimalBackground)
    self.donbg          = DonBG.create(player_num, "background", 5)
    self.bg_normal      = BGNormal.Base.new(0, COLLAB_PATH)
    self.bg_fever       = AnimalBGFever.new(bpm)
    self.footer         = Footer.new(COLLAB_PATH, 0)
    self.fever          = Fever.new(bpm, COLLAB_PATH, ANIMAL_FEVER)
    self.dancer         = Dancer.BaseDancerGroup.new(0, bpm, MAX_DANCERS, COLLAB_PATH, ANIMAL_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(COLLAB_PATH, 0, { ms = { 2000 } })
    self.chibi          = ChibiController.new(bpm, COLLAB_PATH, 1)
    self.is_clear       = false
    self.is_rainbow     = false
    self.last_milestone = 1
    return self
end

function AnimalBackground: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 AnimalBackground:handle_good(player_num) BaseChibi.add(self.chibi, ANIMAL_CHIBI, COLLAB_PATH, player_num, ChibiWave) end

function AnimalBackground:handle_ok(player_num) BaseChibi.add(self.chibi, ANIMAL_CHIBI, COLLAB_PATH, player_num, ChibiWave) end

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

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

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

function AnimalBackground: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 AnimalBackground: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 AnimalBackground:draw_fore() end

function AnimalBackground: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 AnimalBackground