/*

 Copyright (C) 2016 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 The CollectionViewController for the CollectionView of the shaders.

 */

#import "AAPLShaderCollectionViewController.h"

#import "AAPLView.h"

#import "AAPLViewController.h"

#import "AAPLRenderer.h"

#import "AAPLTeapotMesh.h"

#import "AAPLCubeMesh.h"

#import "AAPLParticleSystemRenderer.h"

@interface AAPLShaderCollectionViewController ()

{

    NSArray *shaderImages;

    AAPLRenderer *_renderer;

    AAPLViewController *_controller;

    AAPLTeapotMesh *_teapotMesh;

    AAPLCubeMesh *_cubeMesh;

    AAPLTexture *_sphereMapTexture;

    AAPLTexture *_normalMapTexture;

}

@end

@implementation AAPLShaderCollectionViewController

static NSString * const reuseIdentifier = @"Cell";

- (void)viewDidLoad {

    [super viewDidLoad];

    shaderImages = [NSArray arrayWithObjects:@"PhongShader", @"WoodShader", @"FogShader", @"CelShader", @"SphereMapShader", @"NormalMapShader", @"ParticleShader", nil];

}

- (void) viewWillAppear:(BOOL)animated

{

    [super viewWillAppear:animated];

    CGFloat currentWidthOfCollectionView = self.collectionView.frame.size.width;

    // the width of the collectionView is about to become the height

    CGFloat newDimension = (currentWidthOfCollectionView - 2.0f) / 2.0f;

    UICollectionViewFlowLayout *flow = (UICollectionViewFlowLayout *)self.collectionView.collectionViewLayout;

    flow.itemSize = CGSizeMake(newDimension, newDimension);

    [flow invalidateLayout];

    // Remove the references so we don't have a cycle

    _renderer = nil;

    if (_controller) {

        _controller.view = nil;

    }

    _controller = nil;

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

#pragma mark - Navigation

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender

{

    if ([segue.identifier isEqualToString:@"showShader"])

    {

        NSArray *indexPaths = [self.collectionView indexPathsForSelectedItems];

        NSIndexPath *indexPath = [indexPaths objectAtIndex:0];

        NSInteger index = indexPath.row;

        _controller = (AAPLViewController *)[segue destinationViewController];

        _device = MTLCreateSystemDefaultDevice();

        _teapotMesh = [AAPLTeapotMesh sharedInstance];

        _cubeMesh = [AAPLCubeMesh sharedInstance];

        if(!_controller)

        {

            NSLog(@">> ERROR: Failed creating a view controller!");

        }

        _sphereMapTexture = [[AAPLTexture alloc] initWithResourceName:@"SphereMap" extension:@"jpg"];

        BOOL isAcquired = [_sphereMapTexture finalize:_device];

        if(!isAcquired)

        {

            NSLog(@">> ERROR: Failed creating an input 2d texture!");

            assert(0);

        }

        _normalMapTexture = [[AAPLTexture alloc] initWithResourceName:@"NormalMap" extension:@"png"];

        isAcquired = [_normalMapTexture finalize:_device];

        if(!isAcquired)

        {

            NSLog(@">> ERROR: Failed creating an input 2d texture!");

            assert(0);

        }

        // Create a renderer based on the index of the shader the user picks

        switch (index) {

            case Phong:

                _renderer = [[AAPLRenderer alloc] initWithName:@"Phong Shader" vertexShader:@"phong_vertex" fragmentShader:@"phong_fragment" mesh:_teapotMesh];

                break;

            case Wood:

                _renderer = [[AAPLRenderer alloc] initWithName:@"Wood Shader" vertexShader:@"wood_vertex" fragmentShader:@"wood_fragment" mesh:_teapotMesh];

                break;

            case Fog:

                _renderer = [[AAPLRenderer alloc] initWithName:@"Fog Shader" vertexShader:@"fog_vertex" fragmentShader:@"fog_fragment" mesh:_teapotMesh];

                break;

            case CelShading:

                _renderer = [[AAPLRenderer alloc] initWithName:@"Cel Shader" vertexShader:@"cel_shading_vertex" fragmentShader:@"cel_shading_fragment" mesh:_teapotMesh];

                break;

            case SphereMap:

                _renderer = [[AAPLRenderer alloc] initWithName:@"Sphere Map" vertexShader:@"sphere_map_vertex" fragmentShader:@"sphere_map_fragment" mesh:_teapotMesh texture:_sphereMapTexture];

                break;

            case NormalMap:

                _renderer = [[AAPLRenderer alloc] initWithName:@"Normal Map" vertexShader:@"normal_map_vertex" fragmentShader:@"normal_map_fragment" mesh:_cubeMesh texture:_normalMapTexture];

                break;

            case ParticleSystem:

                _renderer = [[AAPLParticleSystemRenderer alloc] initWithName:@"Particle System" vertexShader:@"particle_vertex" fragmentShader:@"particle_fragment" mesh:nil];

                break;

            default:

                _renderer = [[AAPLRenderer alloc] initWithName:@"Default Shader" vertexShader:@"phong_vertex" fragmentShader:@"phong_fragment" mesh:_teapotMesh];

                break;

        }

        if(!_renderer)

        {

            NSLog(@">> ERROR: Failed creating a renderer!");

        }

        _controller.navigationItem.title = _renderer.name;

        _controller.delegate = _renderer;

        AAPLView *renderView = (AAPLView *)_controller.view;

        if(!renderView)

        {

            NSLog(@">> ERROR: Failed creating a renderer view!");

        }

        renderView.delegate = _renderer;

        // load all renderer assets before starting game loop

        [_renderer configure:renderView];

        [self.collectionView deselectItemAtIndexPath:indexPath animated:NO];

    }

}

#pragma mark <UICollectionViewDataSource>

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView

{

    return 1;

}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section

{

    return shaderImages.count;

}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath

{

    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:indexPath];

    UIImageView *shaderImageView = (UIImageView *)[cell viewWithTag:100];

    shaderImageView.image = [UIImage imageNamed:[shaderImages objectAtIndex:indexPath.row]];

    UILabel *shaderLabel = (UILabel *)[cell viewWithTag:200];

    // Set the text for the label 

    NSInteger index = indexPath.row;

    switch (index) {

        case Phong:

            shaderLabel.text = @"Phong";

            break;

        case Wood:

            shaderLabel.text = @"Wood";

            break;

        case Fog:

            shaderLabel.text = @"Fog";

            break;

        case CelShading:

            shaderLabel.text = @"Cel Shading";

            break;

        case SphereMap:

            shaderLabel.text = @"Sphere Map";

            break;

        case NormalMap:

            shaderLabel.text = @"Normal Map";

            break;

        case ParticleSystem:

            shaderLabel.text = @"Particle System";

            break;

        default:

            shaderLabel.text = @"Default";

            break;

    }

    return cell;

}

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)orientation

                                duration:(NSTimeInterval)duration

{

    CGFloat currentWidthOfCollectionHeight = self.collectionView.frame.size.height;

    // the height of the collectionView is about to become the width

    CGFloat newDimension = (currentWidthOfCollectionHeight - 2.0f) / 2.0f;

    UICollectionViewFlowLayout *flow = (UICollectionViewFlowLayout *)self.collectionView.collectionViewLayout;

    flow.itemSize = CGSizeMake(newDimension, newDimension);

    [flow invalidateLayout];

    [super willRotateToInterfaceOrientation:orientation duration:duration];

}

@end