-- Lesson 25:  Particles.  The finished script, exactly as the lesson ends.
dofile("Singe/Framework.singe")

local SHIP_WIDTH  = 32
local SHIP_HEIGHT = 24
local SHIP_SPEED  = 120
local RESPAWN_MS  = 1400

local shipSprite  = spriteLoad(DIR .. "art/ship.png")
local sparkSprite = spriteLoad(DIR .. "art/star.png")
local boomSound   = soundLoad(DIR .. "art/boom.wav")

local ground = overlayGetHeight() - 20
local shipX  = (overlayGetWidth() - SHIP_WIDTH) / 2
local shipY  = overlayGetHeight() - 56

local flying      = true
local movingLeft  = false
local movingRight = false
local lastTicks   = singeGetTicks()

local exhaust = emitterNew()
emitterSetBlend(exhaust, PARTICLE_ADD)
emitterSetRate(exhaust, 90)
emitterSetLife(exhaust, 0.15, 0.40)
emitterSetDirection(exhaust, 0, 1)
emitterSetSpread(exhaust, 12)
emitterSetSpeed(exhaust, 40, 90)
emitterSetSize(exhaust, 7, 1)
emitterSetColor(exhaust, 255, 240, 180, 255, 255, 60, 0, 0)
emitterSetMax(exhaust, 120)
emitterStart(exhaust)

local boom = emitterNew()
emitterSetTexture(boom, sparkSprite)
emitterSetBlend(boom, PARTICLE_ADD)
emitterSetLife(boom, 0.4, 1.1)
emitterSetSpeed(boom, 40, 220)
emitterSetSpread(boom, 180)
emitterSetGravity(boom, 0, 160)
emitterSetDrag(boom, 0.9)
emitterSetSize(boom, 10, 2, 0.4)
emitterSetSpin(boom, -240, 240)
emitterSetColor(boom, 255, 255, 220, 255, 255, 70, 20, 0)
emitterSetCollide(boom, COLLIDE_FLOOR, 0.35, 0.3, ground)
emitterSetTrail(boom, 4, 2)
emitterSetMax(boom, 400)


function explode()
    if not flying then
        return
    end
    flying = false
    emitterStop(exhaust)
    emitterSetPosition(boom, shipX + SHIP_WIDTH / 2, shipY + SHIP_HEIGHT / 2)
    emitterBurst(boom, 140)
    soundPlay(boomSound)
    timerAfter(RESPAWN_MS, function()
        flying = true
        emitterStart(exhaust)
    end)
end


function onInputPressed(what)
    if what == SWITCH_LEFT then
        movingLeft = true
    elseif what == SWITCH_RIGHT then
        movingRight = true
    elseif what == SWITCH_BUTTON1 then
        explode()
    end
end


function onInputReleased(what)
    if what == SWITCH_LEFT then
        movingLeft = false
    elseif what == SWITCH_RIGHT then
        movingRight = false
    end
end


function onOverlayUpdate()
    local now     = singeGetTicks()
    local seconds = (now - lastTicks) / 1000
    lastTicks     = now

    if flying then
        if movingLeft then
            shipX = shipX - SHIP_SPEED * seconds
        end
        if movingRight then
            shipX = shipX + SHIP_SPEED * seconds
        end
        if shipX < 0 then
            shipX = 0
        end
        if shipX > overlayGetWidth() - SHIP_WIDTH then
            shipX = overlayGetWidth() - SHIP_WIDTH
        end
        emitterSetPosition(exhaust, shipX + SHIP_WIDTH / 2, shipY + SHIP_HEIGHT - 2)
    end

    overlayClear()
    if flying then
        spriteDraw(shipSprite, shipX, shipY)
    end
    emitterDraw(exhaust)
    emitterDraw(boom)
    overlayPrint(2, 2, "Left and right to fly.  Button 1 to blow up.")
    overlayPrint(2, 4, "Particles alive: " .. (emitterGetCount(exhaust) + emitterGetCount(boom)))
    return OVERLAY_UPDATED
end