-- Lesson 16:  Branching.  The finished script, exactly as the lesson ends.
-- Run it with:  Singe -R -v Singe/menuBackground.mkv 16-branching.singe
local FPS = 30

local scenes = {
    arrive = {
        first  = 0,
        last   = 119,
        ask    = 30,
        prompt = "The dragon lands.  Left or Right?",
        left   = "sunset",
        right  = "pit",
        goesTo = "pit"
    },
    sunset = {
        first  = 120,
        last   = 259,
        ask    = 170,
        prompt = "It breathes fire.  Duck Left or run Right?",
        left   = "escape",
        right  = "pit",
        goesTo = "pit"
    },
    pit = {
        first  = 260,
        last   = 339,
        death  = true,
        goesTo = "arrive"
    },
    escape = {
        first  = 340,
        last   = 410
    }
}

local answer = nil
local ending = "You got out alive."
local lives  = 3


local function drawScene(scene, frame, asking)
    overlayClear()
    overlayPrint(2, 2, "Lives: " .. lives)
    if scene.death then
        overlayPrint(2, 4, "That did not go well.")
    elseif asking then
        overlayPrint(2, 4, scene.prompt)
        overlayPrint(2, 6, math.ceil((scene.last - frame) / FPS) .. " seconds left.")
    end
end


local function waitForGo(text)
    answer = nil
    while answer ~= "go" do
        overlayClear()
        overlayPrint(2, 2, "Lives: " .. lives)
        overlayPrint(2, 4, text)
        singeYield()
    end
end


local function playScene(name)
    local scene = scenes[name]

    discSkipToFrame(scene.first)
    while discGetFrame() < scene.last do
        local frame  = discGetFrame()
        local asking = scene.ask ~= nil and frame >= scene.ask

        if not asking then
            answer = nil
        elseif answer == "left" or answer == "right" then
            return scene[answer]
        end
        drawScene(scene, frame, asking)
        singeYield()
    end
    discPause()

    if scene.death then
        lives = lives - 1
        if lives == 0 then
            ending = "The dragon wins.  Game over."
            return nil
        end
        waitForGo("Press the space bar to try again.")
    end

    return scene.goesTo
end


function onInputPressed(what)
    if what == SWITCH_LEFT then
        answer = "left"
    elseif what == SWITCH_RIGHT then
        answer = "right"
    elseif what == SWITCH_BUTTON1 then
        answer = "go"
    end
end


function singeMain()
    local scene = "arrive"

    while scene ~= nil do
        scene = playScene(scene)
    end
    waitForGo(ending .. "  Space to quit.")
end


dofile("Singe/Framework.singe")