local BaseFever = {}
BaseFever.__index = BaseFever

function BaseFever.new(index, bpm, path)
    local self = setmetatable({}, BaseFever)
    self.name = "fever_" .. index
    self.path = path or "background"
    tex.load_folder(self.path, "fever/" .. self.name)
    local half_beat = (60000 / bpm) / 2
    self.bounce_up = anim.move(half_beat, {total_distance = 50, ease_out = "quadratic"})
    self.bounce_down = anim.move(half_beat, {total_distance = 50, ease_in = "quadratic", delay = half_beat})
    return self
end

function BaseFever:start()
    self.bounce_up:start()
    self.bounce_down:start()
end

function BaseFever:update(current_time_ms, bpm)
    self.bounce_up:update(current_time_ms)
    self.bounce_down:update(current_time_ms)
    if self.bounce_down.is_finished then
        local half_beat = (60000 / bpm) / 2
        self.bounce_up = anim.move(half_beat, {total_distance = 50, ease_out = "quadratic"})
        self.bounce_down = anim.move(half_beat, {total_distance = 50, ease_in = "quadratic", delay = half_beat})
        self.bounce_up:start()
        self.bounce_down:start()
    end
end

function BaseFever:destroy()
    tex.unload_folder(self.path, "fever/" .. self.name)
end

local Fever0 = setmetatable({}, {__index = BaseFever})
Fever0.__index = Fever0

function Fever0.new(index, bpm, path)
    local self = setmetatable({}, Fever0)
    local base = BaseFever.new(index, bpm, path)
    for k, v in pairs(base) do self[k] = v end
    return self
end

function Fever0:draw()
    local y = self.bounce_down.attribute - self.bounce_up.attribute
    tex.draw_texture(self.name, "overlay_l", {y = y})
    tex.draw_texture(self.name, "overlay_r", {y = y})
end

-- Fever1 and Fever2 share the same draw as Fever0
local Fever1 = setmetatable({}, {__index = Fever0})
Fever1.__index = Fever1
function Fever1.new(index, bpm, path)
    local self = setmetatable({}, Fever1)
    local base = BaseFever.new(index, bpm, path)
    for k, v in pairs(base) do self[k] = v end
    return self
end
function Fever1:draw() Fever0.draw(self) end

local Fever2 = setmetatable({}, {__index = Fever0})
Fever2.__index = Fever2
function Fever2.new(index, bpm, path)
    local self = setmetatable({}, Fever2)
    local base = BaseFever.new(index, bpm, path)
    for k, v in pairs(base) do self[k] = v end
    return self
end
function Fever2:draw() Fever0.draw(self) end

local Fever3 = setmetatable({}, {__index = BaseFever})
Fever3.__index = Fever3

function Fever3.new(index, bpm, path)
    local self = setmetatable({}, Fever3)
    local base = BaseFever.new(index, bpm, path)
    for k, v in pairs(base) do self[k] = v end
    return self
end

function Fever3:draw()
    local y = self.bounce_down.attribute - self.bounce_up.attribute
    tex.draw_texture(self.name, "overlay", {y = y})
end

local Fever = {}
Fever.Base = BaseFever
Fever.Fever0 = Fever0
Fever.Fever1 = Fever1
Fever.Fever2 = Fever2
Fever.Fever3 = Fever3

function Fever.create(index, bpm, path)
    local map = {Fever0, Fever1, Fever2, Fever3}
    return map[index + 1].new(index, bpm, path)
end

return Fever