#import "MTLTexturePool.h"

#import "Trace.h"

@implementation MTLTexturePoolItem

@synthesize texture;

@synthesize isBusy;

- (id) initWithTexture:(id<MTLTexture>)tex {

    self = [super init];

    if (self == nil) return self;

    self.texture = tex;

    isBusy = NO;

    return self;

}

@end

@implementation MTLTexturePool

@synthesize device;

@synthesize pool;

- (id) initWithDevice:(id<MTLDevice>)dev {

    self = [super init];

    if (self == nil) return self;

    self.device = dev;

    self.pool = [NSMutableArray arrayWithCapacity:10];

    return self;

}

// NOTE: called from RQ-thread (on blit operations)

- (id<MTLTexture>) getTexture:(int)width height:(int)height format:(MTLPixelFormat)format {

    @synchronized (self) {

        // 1. find free item

        // TODO: optimize search, use Map<(w,h,pf), TexPoolItem>

        const int count = [self.pool count];

        for (int c = 0; c < count; ++c) {

            MTLTexturePoolItem *tpi = [self.pool objectAtIndex:c];

            if (tpi == nil)

                continue;

            // TODO: use checks tpi.texture.width <= width && tpi.texture.height <= height

            if (tpi.texture.width == width && tpi.texture.height == height && tpi.texture.pixelFormat == format &&

                !tpi.isBusy) {

                tpi.isBusy = YES;

                return tpi.texture;

            }

        }

        // 2. create

        MTLTextureDescriptor *textureDescriptor = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat:format width:width height:height mipmapped:NO];

        id <MTLTexture> tex = [self.device newTextureWithDescriptor:textureDescriptor];

        MTLTexturePoolItem *tpi = [[MTLTexturePoolItem alloc] initWithTexture:tex];

        [self.pool addObject:tpi];

        J2dTraceLn4(J2D_TRACE_VERBOSE, "MTLTexturePool: created pool item: tex=%p, w=%d h=%d, pf=%d", tex, width, height, format);

        return tpi.texture;

    }

};

// NOTE: called from completion-handler (pooled thread)

- (void) markTextureFree:(id<MTLTexture>)texture {

    // TODO: optimize search, use Map<(w,h,pf), TexPoolItem>

    @synchronized (self) {

        const int count = [self.pool count];

        for (int c = 0; c < count; ++c) {

            MTLTexturePoolItem * tpi = [self.pool objectAtIndex:c];

            if (tpi == nil)

                continue;

            if (tpi.texture == texture) {

                tpi.isBusy = NO;

                return;

            }

        }

        J2dTraceLn1(J2D_TRACE_ERROR, "MTLTexturePool: can't find item with texture %p", texture);

    }

}

// NOTE: called from completion-handler (pooled thread)

- (void) markAllTexturesFree {

    @synchronized (self) {

        const int count = [self.pool count];

        for (int c = 0; c < count; ++c) {

            MTLTexturePoolItem *tpi = [self.pool objectAtIndex:c];

            if (tpi == nil)

                continue;

            tpi.isBusy = NO;

        }

    }

}

@end