ENT_PLAYER = 0
ENT_BULLET = 1
ENT_ENEMY = 2

function initPlayer()

    playerX = 0
    playerY = 0

    playerTopSpeed = 30
    playerSpeedX = 0
    playerSpeedY = 0
    playerAccelRate = 3000
    playerFriction = 6
    playerNextShot = 0

    player = spawnPlayer()

end

function init()

    playing = false
    limitX = 175


    print("BULLET TYPE: " .. ENT_BULLET)

end

function drawScrollBG(x,y,w,h,s,tex)

    _r.quad(0,0,x,y,
        w,0,s+x,0+y,
        w,h,s+x,s+y,
        0,h,0+x,s+y,
        tex)

end

function drawBG(w,h)

    _r.color(0,0,0,1)
    _r.rect(0,0,w,h)

    _r.color(1,1,1,1,1)
    drawScrollBG(0,time*-.01,w,h,.5,_t.clouds)

    _r.color(.2,.2,.2,1,1)
    drawScrollBG(0,time*-.2,w,h,.6,_t.stars)

    _r.color(.4,.4,.4,1,1)
    drawScrollBG(0,time*-.04,w,h,.7,_t.stars)

end

function toCoords(x,y)

    return x + _width/2, y + _height-32

end

function playerCoords()

    return toCoords(playerX, playerY)

end

function draw()

    _width, _height = _r.size()
    local w,h = _r.size()

    local sx = 0
    local sy = 0

    _r.layer(0)
    drawBG(w,h)

    _r.layer(1)
    _r.color(1,1,1,1,0)

    if not playing then
        return
    end

    local x,y = playerCoords()
    drawEdicts()

end

function think(time, dt)
    game.time = time

    if not playing then return end

    tickEdicts(time, dt)
end

function startGame()

    if playing then return end

    edicts = {}

    ch_music = sound.play(_s.music)
    sound.setLooping(ch_music, true)
    sound.setVolume(ch_music, .2)

    playing = true

    initPlayer()

end

function stopGame()

    if not playing then return false end

    sound.stop(ch_music)

    playing = false
    return true

end

function onMousePressed(x,y,b,focus)

end

function onMouseReleased(x,y,b,focus)

end

function onMouseMoved(x,y,dx,dy,focus)

end

function onFocusGained(e)

end

function onFocusLost(e)
    stopGame()
end

function onKeyPressed(k)

    print(_keynames[k] .. " is down")

    if k == _keys.Z then
        if not startGame() then
            k_shoot = true
        end
    end

    if k == _keys.LEFT then k_left = true end
    if k == _keys.RIGHT then k_right = true end
    if k == _keys.UP then k_up = true end
    if k == _keys.DOWN then k_down = true end

end

function onKeyReleased(k)
    print(_keynames[k] .. " is up")

    if k == _keys.LEFT then k_left = false end
    if k == _keys.RIGHT then k_right = false end
    if k == _keys.UP then k_up = false end
    if k == _keys.DOWN then k_down = false end

    if k == _keys.Z then
        k_shoot = false
    end

end

function edict(type)
    local e = { type = type }
    table.insert(edicts, e)
    return e
end

function drawEdicts()
    for _,e in pairs( edicts ) do
        if e.draw then e:draw() end
    end
end

function tickEdicts(time, dt)
    for i=#edicts, 1, -1 do
        if edicts[i].think then edicts[i]:think(dt) end
        if edicts[i].dead then table.remove(edicts, i) end
    end
end

function edictsByType(t)
    local out = {}
    for _,e in pairs( edicts ) do
        if e.type == t then table.insert(out, e) end
    end
    return out
end

function spawnBullet(x,y,vx,vy,life)
    local e = edict(ENT_BULLET)
    e.x = x
    e.y = y
    e.vx = vx
    e.vy = vy
    e.life = life or 3
    e.think = function(e,dt)
        e.x = e.x + e.vx * dt
        e.y = e.y + e.vy * dt
        e.life = e.life - dt
        if e.life <= 0 then e.dead = true end
    end
    e.draw = function(e)
        _r.color(1,1,1,1,2)
        _r.sprite(e.x, e.y, 24, 24, 0, e.tex)
    end

    local ch_bullet = sound.play(_s.shoot)
    sound.setVolume(ch_bullet, .3)

    local result = host.bulletSpawned(x,y)
    print( tostring(result) )

    return e
end

function spawnPlayer(x,y)
    local e = edict(ENT_PLAYER)
    e.x = x or 0
    e.y = y or 0
    e.vx = 0
    e.vy = 0
    e.ax = 0
    e.ay = 0
    e.nextshoot = 0
    e.altshoot = false
    e.think = function(e,dt)

        local move_horiz = 0
        if k_left then move_horiz = -1
        elseif k_right then move_horiz = 1 end

        local move_vert = 0
        if k_up then move_vert = -1
        elseif k_down then move_vert = 1 end

        e.vx = e.vx + playerAccelRate * move_horiz * dt
        e.vx = e.vx * math.exp(dt * -playerFriction)

        e.vy = e.vy + playerAccelRate * move_vert * dt
        e.vy = e.vy * math.exp(dt * -playerFriction)

        e.x = e.x + dt * e.vx
        e.y = e.y + dt * e.vy

        if e.x > limitX then
            e.x = limitX
            e.vx = e.vx * -.5
        end

        if e.x < -limitX then
            e.x = -limitX
            e.vx = e.vx * -.5
        end

        if e.y > 0 then
            e.y = 0
            e.vy = e.vy * -.5
        end

        if k_shoot and e.nextshoot < time then
            local x,y = toCoords( e.x, e.y )
            local width = 12

            if e.altshoot then
                x = x - width
                e.altshoot = false
            else
                x = x + width
                e.altshoot = true
            end

            local b = spawnBullet(x,y,0,-800)
            b.tex = _t.shoot

            e.nextshoot = time + .1
        end

    end
    e.draw = function(e)
        local r = -e.vx / 1200
        local x,y = toCoords(e.x, e.y)
        _r.sprite(x,y,64,64,r,math.fmod(time, .1) > .05 and _t.ship0 or _t.ship1)
    end

    return e
end