local APP = {}
-- Name that appears on the home screen
APP.PrintName = "Half Bit"
-- Path to the icon, relative to materials directory
APP.Icon = "vgui/gphone/app_image.png"
APP.FPS = 30

local isInGame = false
local mat_player = Material( "vgui/gphone/apps/player.png" )
 --416 w 234 h
-- Called when your App opens
function APP.Run( objects, screen )
	--local objects = gApp["_children_"]
	--local screen = gPhone.phoneScreen
	gPhone.HideStatusBar()

	gPhone.RotateToLandscape()
	--gPhone.RotateToPortrait()

	isInGame = true

	APP.SetUpGame()
end

-- Holds the zombies for in game messing
local zombies = {}

local zombieCount = 1
local function spawnZombie()
	local objects = gApp["_children_"]
	local screen = gPhone.phoneScreen
	local y = math.random(1,204)
	local x = math.random(1,276)
	objects[zombieCount] = vgui.Create("DPanel", screen)
	objects[zombieCount]:SetSize( 20, 20 )
	objects[zombieCount]:SetPos( x, y )
	--objects.zombie.Rotation = 0
	objects[zombieCount].Paint = function( self, w, h )
			--surface.SetDrawColor( color_white )
			--surface.SetMaterial( mat_player )
			--surface.DrawTexturedRectRotated( w/2, h/2, w, h, objects.Player.Rotation )
			draw.RoundedBox(0, 0, 0, w, h, Color(0, 255, 0) )
	end

	table.insert(zombies, objects[zombieCount])
	zombieCount = zombieCount + 1
 end

function APP.SetUpGame()
	local objects = gApp["_children_"]
	local screen = gPhone.phoneScreen
	objects.GameTitle = vgui.Create( "DLabel", screen)
	objects.GameTitle:SetText( "Half Bit Alpha" )
	objects.GameTitle:SetTextColor( color_white )
	objects.GameTitle:SetFont("gPhone_22")
	objects.GameTitle:SizeToContents()
	objects.GameTitle:SetPos( screen:GetWide()/2 - objects.GameTitle:GetWide()/2, 10 )

	objects.Player = vgui.Create("DPanel", screen)
	objects.Player:SetSize( 20, 20 )
	objects.Player:SetPos( screen:GetWide()/2, screen:GetTall()/2 )
	objects.Player.Rotation = 0
	objects.Player.Paint = function( self, w, h )
			surface.SetDrawColor( color_white )
			surface.SetMaterial( mat_player )
			surface.DrawTexturedRectRotated( w/2, h/2, w, h, objects.Player.Rotation )
	end
	timer.Create("zambiespawn", 1, 5, spawnZombie)
	--objects.Zombie

	-- Detect shooting
	screen.OnMousePressed = function( self, code )
		if code == MOUSE_LEFT then
			objects.Player.ShouldFire = true
		end
	end

	objects.Bullets = {}
end

local shotCount = 0
local img_bullet = Material( "vgui/gphone/apps/2d_bullet.png" )
local function createBullet( x, y )
	local objects = gApp["_children_"]
	local screen = gPhone.phoneScreen

	local projectile = vgui.Create("DPanel", screen)
	projectile:SetSize( 8, 4 )
	projectile:SetPos( x, y )
	projectile.Rotation = 0
	projectile.Paint = function( self, w, h )
		draw.RoundedBox(0, 0, 0, w, h, color_white )

		surface.SetDrawColor( color_white )
		surface.SetMaterial( img_bullet )

		surface.DrawTexturedRectRotated( w/2, h/2, w, w, self.Rotation )
	end
	projectile.VelocityX = 0
	projectile.VelocityY = 0

	objects.Bullets[shotCount] = projectile
	shotCount = shotCount + 1

	return projectile
end

local function shootBullet()
	local objects = gApp["_children_"]

	if objects.Player.ShouldFire == true then
		local x, y = objects.Player:GetPos()
		local ang = objects.Player.Rotation

		local bullet = createBullet( x + objects.Player:GetWide(), y )

		local mX, mY = gPhone.phoneScreen:ScreenToLocal( gui.MouseX(), gui.MouseY() )
		local shootAngle = math.atan2((mY - y), (mX - x))
		shootAngle = -( math.Clamp(shootAngle, -90, 90) )

		-- The bullet needs proper velocity for its trajectory
		bullet.VelocityX = math.cos(shootAngle) * 5
		bullet.VelocityY = math.sin(-shootAngle) * 5
		bullet.Rotation = shootAngle

		objects.Player.ShouldFire = false
	end
end

local function movePlayer( direction )
	local objects = gApp["_children_"]
	local screen = gPhone.phoneScreen

	local x, y = objects.Player:GetPos()
	local newX, newY = x, y

	if direction == "UP" then
		newY = newY - 2
	elseif direction == "DOWN" then
		newY = newY + 2
	end

	if direction == "LEFT" then
		newX = newX - 2
	elseif direction == "RIGHT" then
		newX = newX + 2
	end

	newX = math.Clamp( newX, 0, screen:GetWide() - objects.Player:GetWide() )
	newY = math.Clamp( newY, 0, screen:GetTall() - objects.Player:GetTall() )

	objects.Player:SetPos( newX, newY )
end

local function updatePlayerRotation()
	local objects = gApp["_children_"]
	local screen = gPhone.phoneScreen

	local mX, mY = screen:ScreenToLocal(gui.MouseX(), gui.MouseY())
	local x, y = objects.Player:GetPos()

	local yDis = mY - y
	local xDis = mX - x

	local ang = math.deg( math.atan2( yDis, xDis ) )

	objects.Player.Rotation = -ang
end


local function handleKeys()
	if input.IsKeyDown( KEY_W ) then
			movePlayer( "UP" )
	elseif input.IsKeyDown( KEY_S ) then
			movePlayer( "DOWN" )
	end

	if input.IsKeyDown( KEY_A ) then
			movePlayer( "LEFT" )
	elseif input.IsKeyDown( KEY_D ) then
			movePlayer( "RIGHT" )
	end

end

-- Called when the phone screen's Think function is called
function APP.Think( screen )
	local objects = gApp["_children_"]
	local screen = gPhone.phoneScreen

	if isInGame then
		handleKeys()
		updatePlayerRotation()

		shootBullet()

		for num, pnl in pairs(objects.Bullets) do
			if IsValid(pnl) then
				local x, y = pnl:GetPos()
				pnl:SetPos(x + pnl.VelocityX, y + pnl.VelocityY)
			else
				objects.Bullets[num] = nil
			end
		end
	end
end

-- Called when the phone screen's Paint function is called
function APP.Paint( screen )
	if isInGame then
			-- Draw the game board
			draw.RoundedBox(2, 0, 0, screen:GetWide(), screen:GetTall(), Color(100, 200, 100))

	else
			-- Not in game
			draw.RoundedBox(2, 0, 0, screen:GetWide(), screen:GetTall(), Color(0, 0, 0))
	end
end

-- You MUST uncomment this line for the app to work. This adds it to the phone
gPhone.AddApp(APP)