#import <CoreFoundation/CoreFoundation.h>
#import <CoreServices/CoreServices.h>
#import <QuickLook/QuickLook.h>
#import <Cocoa/Cocoa.h>

@interface FakeClass : NSObject

@end

@implementation FakeClass

@end

OSStatus GeneratePreviewForURL(void *thisInterface, QLPreviewRequestRef preview, CFURLRef url, CFStringRef contentTypeUTI, CFDictionaryRef options);
void CancelPreviewGeneration(void *thisInterface, QLPreviewRequestRef preview);

struct Kara {
    CGFloat x;
    CGFloat y;
    CGFloat direction;
};
typedef struct Kara Kara;

/* -----------------------------------------------------------------------------
   Generate a preview for file

   This function's job is to create preview for designated file
   ----------------------------------------------------------------------------- */

void HandleError(NSError *error)
{

}

NSPoint ConvertXMLElelementToPoint(NSXMLElement *element)
{
    NSPoint point;
    point.x = [[[element attributeForName:@"x"] stringValue] integerValue];
    point.y = [[[element attributeForName:@"y"] stringValue] integerValue];
    return point;
}

int fieldBorderLength = 10;

NSPoint ConvertPointToFlipped(NSPoint point, NSSize world)
{
    NSPoint flippedPoint;
    flippedPoint.x = point.x;
    flippedPoint.y = world.height-point.y-1;
    return flippedPoint;
}

void DrawBackground(NSSize world) {
    NSColor *greenBackground = [NSColor colorWithCalibratedRed:180/255.0 green:230/255.0 blue:180/255.0 alpha:1];
    [greenBackground set];
    NSRectFill(NSMakeRect(0, 0, world.width*fieldBorderLength, world.height*fieldBorderLength));
}

void DrawField(NSSize world)
{
    for (int y = 0; y<world.height; y++) {
        for (int x = 0; x<world.width; x++) {
            NSRect field = NSMakeRect(x*fieldBorderLength, y*fieldBorderLength, fieldBorderLength, fieldBorderLength);
            [[NSColor lightGrayColor] set];
            NSFrameRectWithWidth(field, 0.25);
        }
    }
}

void DrawKara(Kara kara, NSSize world)
{
    NSString *filename = [NSString stringWithFormat:@"%@%i", @"Kara", ((int)kara.direction)];
    NSString *imagePath = [[NSBundle bundleForClass:[FakeClass class]] pathForResource:filename ofType:@"tiff"];
    NSImage *image = [[NSImage alloc] initWithContentsOfFile:imagePath];

    NSPoint flippedOrigin = ConvertPointToFlipped(NSMakePoint(kara.x, kara.y), world);
    NSPoint origin = NSMakePoint(flippedOrigin.x*fieldBorderLength, flippedOrigin.y*fieldBorderLength);

    NSSize size = {fieldBorderLength, fieldBorderLength};

    NSRect destRect;
    destRect.origin = origin;
    destRect.size = size;

    [image drawInRect:destRect fromRect:NSZeroRect operation:NSCompositeSourceOver fraction:1.0];
}

void DrawObjects(NSArray *objects, NSString *imageName, NSSize world)
{
    NSString *imagePath = [[NSBundle bundleForClass:[FakeClass class]] pathForResource:imageName ofType:@"tiff"];
    NSImage *image = [[NSImage alloc] initWithContentsOfFile:imagePath];

    NSSize imageSize = {fieldBorderLength, fieldBorderLength};


    for (NSXMLElement *element in objects) {
        [[NSGraphicsContext currentContext] setImageInterpolation: NSImageInterpolationHigh];

        NSPoint originInWorld = ConvertXMLElelementToPoint(element);
        NSPoint flippedOriginInWorld = ConvertPointToFlipped(originInWorld, world);

        NSPoint origin;
        origin.x = flippedOriginInWorld.x * fieldBorderLength;
        origin.y = flippedOriginInWorld.y * fieldBorderLength;
        
        NSRect destRect;
        destRect.origin = origin;
        destRect.size = imageSize;

        [image drawInRect: destRect fromRect: NSZeroRect operation: NSCompositeSourceOver fraction: 1.0];
    }
}

OSStatus GenerateWorldPreview(QLPreviewRequestRef preview, NSXMLElement *root)
{
    NSArray *children = [root children];
    NSMutableArray *trees = [NSMutableArray new];
    NSMutableArray *leafs = [NSMutableArray new];
    NSMutableArray *mushrooms = [NSMutableArray new];
    Kara kara;
    BOOL karaExists = NO;

    int worldWidth = [[[root attributeForName:@"sizex"] stringValue] intValue];
    int worldHeight = [[[root attributeForName:@"sizey"] stringValue] intValue];

    for (NSXMLNode *node in children) {
        if ([node.name isEqualToString:@"XmlWallPoints"]) {
            for (NSXMLNode *object in node.children) {
                [trees addObject:object];
            }
        } else if ([node.name isEqualToString:@"XmlObstaclePoints"]) {
            for (NSXMLNode *object in node.children) {
                [mushrooms addObject:object];
            }
        } else if ([node.name isEqualToString:@"XmlPaintedfieldPoints"]) {
            for (NSXMLNode *object in node.children) {
                [leafs addObject:object];
            }
        } else if ([node.name isEqualToString:@"XmlKaraList"]) {
            if (node.children.count > 0) {
                NSXMLElement *karaElement = [node.children objectAtIndex:0];
                kara.x = [[[karaElement attributeForName:@"x"] stringValue] integerValue];
                kara.y = [[[karaElement attributeForName:@"y"] stringValue] integerValue];
                kara.direction = [[[karaElement attributeForName:@"direction"] stringValue] integerValue];
                karaExists = YES;
            }
        }
    }

    NSSize world = NSMakeSize(worldWidth, worldHeight);
    NSSize field = NSMakeSize(worldWidth*fieldBorderLength, worldHeight*fieldBorderLength);

    CGContextRef cgContext = QLPreviewRequestCreateContext(preview, *(CGSize *)&field, false, NULL);
    NSGraphicsContext* context = [NSGraphicsContext graphicsContextWithGraphicsPort:(void *)cgContext flipped:YES];

    if (context) {
        [NSGraphicsContext setCurrentContext:context];

        DrawBackground(world);
        DrawField(world);
        DrawObjects(trees, @"Tree", world);
        DrawObjects(leafs, @"Shamrock", world);
        DrawObjects(mushrooms, @"Mushroom", world);
        if (karaExists) {
            DrawKara(kara, world);
        }

        QLPreviewRequestFlushContext(preview, cgContext);
        CFRelease(cgContext);
    }
    
    return noErr;

}

OSStatus GenerateProgramPreview(QLPreviewRequestRef preview, NSXMLElement *root)
{
    return noErr;
}

OSStatus GeneratePreviewForURL(void *thisInterface, QLPreviewRequestRef preview, CFURLRef url, CFStringRef contentTypeUTI, CFDictionaryRef options)
{
    NSXMLDocument *xmlDoc;
    NSError *err=nil;
    NSURL *furl = (__bridge NSURL *)url;
    if (!furl) {
        NSLog(@"Can't create an URL from file %@.", furl.path);
        return noErr;
    }
    xmlDoc = [[NSXMLDocument alloc] initWithContentsOfURL:furl options:(NSXMLNodePreserveWhitespace|NSXMLNodePreserveCDATA) error:&err];
    if (xmlDoc == nil) {
        xmlDoc = [[NSXMLDocument alloc] initWithContentsOfURL:furl options:NSXMLDocumentTidyXML error:&err];
    }
    if (xmlDoc == nil)  {
        if (err) {
            HandleError(err);
        }
        return noErr;
    }

    if (err) {
        HandleError(err);
        return noErr;
    }

    NSXMLElement *root = xmlDoc.rootElement;

    if ([furl.pathExtension compare:@"world" options:NSCaseInsensitiveSearch] == NSOrderedSame) {
        return GenerateWorldPreview(preview, root);
    } else if ([furl.pathExtension compare:@"kara" options:NSCaseInsensitiveSearch] == NSOrderedSame) {
        return GenerateProgramPreview(preview, root);
    }
    return noErr;
}

void CancelPreviewGeneration(void *thisInterface, QLPreviewRequestRef preview)
{
    // Implement only if supported
}