module Main where

import Graphics.Rendering.OpenGL.GL

import qualified GameShell

data TestEventHandler = TestEventHandler {
    elapsed :: Float,
    frames  :: Int
}

initializeTest handler = do
    putStrLn "initializing"
    return handler

openGLContextCreatedTest handler = do
    putStrLn "OpenGL context created"
    return handler

openGLContextWillBeDestroyedTest handler = do
    putStrLn "OpenGL context will be destroyed"
    return handler

openGLContextStateInvalidatedTest handler = do
    putStrLn "OpenGL context state invalidated"
    clearColor $= Color4 0.0 0.5 0.0 0.0
    return handler

openGLContextResizedTest w h handler = do
    putStrLn ("OpenGL context resized to " ++ (show w) ++ "x" ++ (show h))
    viewport $= (Position 0 0, Size (fromIntegral w) (fromIntegral h))
    return handler

fps (oldElapsed, oldFrames) dt =
    let newElapsed = oldElapsed + dt
        newFrames = oldFrames + 1
    in
        if newElapsed > 1.0
        then do
            let framesPerSecond = (fromIntegral newFrames) / newElapsed
            putStrLn $ (show framesPerSecond) ++ " fps"
            return (0.0, 0)
        else return (newElapsed, newFrames)

displayTest dt handler = do
    clear [ColorBuffer]
    (newElapsed, newFrames) <- fps (elapsed handler, frames handler) dt
    return TestEventHandler { elapsed = newElapsed, frames = newFrames }

mousePressedTest button handler = do
    putStrLn ("Mouse button " ++ (show button) ++ " pressed")
    return handler

mouseReleasedTest button handler = do
    putStrLn ("Mouse button " ++ (show button) ++ " released")
    return handler

mouseMovedByTest dx dy handler = do
    putStrLn ("Mouse moved by (" ++ (show dx) ++ ", " ++ (show dy) ++ ")")
    return handler

mouseMovedToTest x y handler = do
    putStrLn ("Mouse moved to (" ++ (show x) ++ ", " ++ (show y) ++ ")")
    return handler

keyPressedTest k handler = do
    putStrLn ("Key " ++ (show k) ++ " pressed")
    return handler

keyReleasedTest k handler = do
    putStrLn ("Key " ++ (show k) ++ " released")
    return handler

textInputTest s handler = do
    putStrLn ("Text input: " ++ s)
    return handler

instance GameShell.EventHandlerObject TestEventHandler where
    initialize                    = initializeTest
    openGLContextCreated          = openGLContextCreatedTest
    openGLContextWillBeDestroyed  = openGLContextWillBeDestroyedTest
    openGLContextStateInvalidated = openGLContextStateInvalidatedTest
    openGLContextResized          = openGLContextResizedTest
    display                       = displayTest
    mousePressed                  = mousePressedTest
    mouseReleased                 = mouseReleasedTest
    mouseMovedBy                  = mouseMovedByTest
    mouseMovedTo                  = mouseMovedToTest
    keyPressed                    = keyPressedTest
    keyReleased                   = keyReleasedTest
    textInput                     = textInputTest

main = do
    GameShell.start TestEventHandler { elapsed = 0.0, frames = 0 }