local Common = require("common.util")
local Dim = require("common.dimensions")

local splashSample = "titlescreen/splash/splash1.wav"

game.LoadSkinSample(splashSample)
local splash1SfxPlayed = false

require "common.globals"
require "common.class"
local Page = require "api.page.page"
local KShootManiaPage = require "titlescreen.pages.splash.kshootmaniapage"
local USCPage = require "titlescreen.pages.splash.uscpage"
local TeamExceedPage = require "titlescreen.pages.splash.teamexceedpage"
local CreditsPage = require "titlescreen.pages.splash.creditspage"

---@class SplashPage : Page
---@field pages Page[]
---@field currentPage integer
---@field _isTransitioning boolean # actively fading between pages
local SplashPage = {
    __name = "SplashScreen",
    BACKGROUND_COLOR = {255, 255, 255},
    FADE_DURATION = 0.5
}

---Create a new SplashScreen instance
---@param params? SplashPage
---@return SplashPage
function SplashPage.new(params)
    local self = CreateInstance(SplashPage, params, Page)

    self.currentPage = 1
    self.content = {
        KShootManiaPage.new(),
        USCPage.new(),
        TeamExceedPage.new(),
        CreditsPage.new()
    }

    self._isTransitioning = false

    -- set callbacks
    for index, page in ipairs(self.content) do
        if index < #self.content then
            page.onInvalidation = function (page_inst)
                self._isTransitioning = true
                self.currentPage = index + 1
            end
        else -- last index
            page.onInvalidation = function (page_inst)
                self:onInvalidation()
            end
        end
    end
    return self
end

function SplashPage:init()
    self.currentPage = 1
    self._isTransitioning = false
    Page.init(self)
end

function SplashPage:handleButtonInput(button)
    if button == game.BUTTON_STA then
        game.StopSample(splashSample)
        self:onInvalidation()
    end
end

---Fade between pages
---@param fadeDuration? number
---@param fadeColor? integer[]
function SplashPage:fadeTransition(deltaTime, fadeDuration, fadeColor)
    fadeDuration = fadeDuration or 0.5
    fadeColor = fadeColor or {255, 255, 255}

    local fadeAlpha = 0.0

    -- reset variables on first call
    if not self["__fadeStarted"] then
        self.__fadeTimer = 0.0
        self.__fadeStarted = true
    end

    local halfDuration = fadeDuration / 2
    if self.__fadeTimer < halfDuration then
        fadeAlpha = Common.lerp(self.__fadeTimer, 0, 0, halfDuration, 255) -- fade out
    elseif self.__fadeTimer < fadeDuration then
        fadeAlpha = Common.lerp(self.__fadeTimer, halfDuration, 255, fadeDuration, 0) -- fade in
    else
        self.__fadeStarted = false -- fade done, reset variable
        self._isTransitioning = false
    end

    local fillColor = {table.unpack(fadeColor, 1, 3)} -- copy color table
    table.insert(fillColor, fadeAlpha) -- add alpha

    gfx.BeginPath()
    gfx.FillColor(table.unpack(fillColor))
    gfx.Rect(0, 0, Dim.design.width, Dim.design.height)
    gfx.Fill()

    self.__fadeTimer = self.__fadeTimer + deltaTime
end

function SplashPage:drawBackground(deltaTime)
    gfx.BeginPath()
    gfx.FillColor(table.unpack(self.BACKGROUND_COLOR))
    gfx.Rect(0, 0, Dim.design.width, Dim.design.height)
    gfx.Fill()
end

function SplashPage:drawContent(deltaTime)
    self.content[self.currentPage]:render(deltaTime)
end

function SplashPage:drawForeground(deltaTime)
    local fadeColor = {255, 255, 255}
    if self._isTransitioning then
        self:fadeTransition(deltaTime, self.FADE_DURATION, fadeColor)
    end
end

return SplashPage