SongTransition = {}
SongTransition.__index = SongTransition

function SongTransition.new(title, subtitle, is_second)
    local self = setmetatable({}, SongTransition)
    self.is_second = is_second and true or false

    self.t_rainbow_bg_bottom = tex.get_texture("global/rainbow_transition/rainbow_bg_bottom")
    self.t_rainbow_bg_top    = tex.get_texture("global/rainbow_transition/rainbow_bg_top")
    self.t_rainbow_bg        = tex.get_texture("global/rainbow_transition/rainbow_bg")
    self.t_chara_left        = tex.get_texture("global/rainbow_transition/chara_left")
    self.t_chara_right       = tex.get_texture("global/rainbow_transition/chara_right")
    self.t_chara_center      = tex.get_texture("global/rainbow_transition/chara_center")

    return self
end

function SongTransition:draw_bg(total_offset, rainbow_up, mini_up, chara_down)
    tex.draw_texture(self.t_rainbow_bg_bottom, { y = -rainbow_up - total_offset })
    tex.draw_texture(self.t_rainbow_bg_top,    { y = -rainbow_up - total_offset })
    tex.draw_texture(self.t_rainbow_bg,        { y = -rainbow_up - total_offset })

    local offset = chara_down
    local chara_offset = 0
    if self.is_second then
        offset = chara_down - mini_up / 3
        local cfg = tex.get_skin_config("transition_chara_offset")
        chara_offset = (cfg and cfg.y) or 0
    end

    tex.draw_texture(self.t_chara_left,   { x = -mini_up / 2 - chara_offset, y = -mini_up + offset - total_offset })
    tex.draw_texture(self.t_chara_right,  { x =  mini_up / 2 + chara_offset, y = -mini_up + offset - total_offset })
    tex.draw_texture(self.t_chara_center, { y = -rainbow_up + offset - total_offset })
end