#import <Foundation/NSJSONSerialization.h>
#import <Foundation/NSURLResponse.h>
#import <CoreFoundation/CFString.h>
#import "NSURLSession+AnyPromise.h"
#import <Foundation/NSOperation.h>
#import <Foundation/NSURLError.h>
#import <PromiseKit/PromiseKit.h>
#import <CoreFoundation/CFURL.h>
#import <Foundation/NSThread.h>
#import <Foundation/NSArray.h>
#import <Foundation/NSError.h>
#import <Foundation/NSURL.h>

@implementation NSURLSession (PromiseKit)

- (AnyPromise *)promiseDataTaskWithRequest:(NSURLRequest *)rq {
    return [AnyPromise promiseWithResolverBlock:^(PMKResolver resolve) {
        [[self dataTaskWithRequest:rq completionHandler:^(NSData *data, id rsp, NSError *urlError){
            assert(![NSThread isMainThread]);

            PMKResolver fulfiller = ^(id responseObject){
                resolve(PMKManifold(responseObject, rsp, data));
            };
            PMKResolver rejecter = ^(NSError *error){
                id userInfo = error.userInfo.mutableCopy ?: [NSMutableDictionary new];
                if (data) userInfo[PMKURLErrorFailingDataKey] = data;
                if (rsp) userInfo[PMKURLErrorFailingURLResponseKey] = rsp;
                error = [NSError errorWithDomain:error.domain code:error.code userInfo:userInfo];
                resolve(error);
            };

            NSStringEncoding (^stringEncoding)(void) = ^NSStringEncoding{
                id encodingName = [rsp textEncodingName];
                if (encodingName) {
                    CFStringEncoding encoding = CFStringConvertIANACharSetNameToEncoding((CFStringRef)encodingName);
                    if (encoding != kCFStringEncodingInvalidId)
                        return CFStringConvertEncodingToNSStringEncoding(encoding);
                }
                return NSUTF8StringEncoding;
            };

            if (urlError) {
                rejecter(urlError);
            } else if (![rsp isKindOfClass:[NSHTTPURLResponse class]]) {
                fulfiller(data);
            } else if ([rsp statusCode] < 200 || [rsp statusCode] >= 300) {
                id info = @{
                            NSLocalizedDescriptionKey: @"The server returned a bad HTTP response code",
                            NSURLErrorFailingURLStringErrorKey: rq.URL.absoluteString,
                            NSURLErrorFailingURLErrorKey: rq.URL
                            };
                id err = [NSError errorWithDomain:NSURLErrorDomain code:NSURLErrorBadServerResponse userInfo:info];
                rejecter(err);
            } else if (PMKHTTPURLResponseIsJSON(rsp)) {
                // work around ever-so-common Rails workaround: https://github.com/rails/rails/issues/1742
                if ([rsp expectedContentLength] == 1 && [data isEqualToData:[NSData dataWithBytes:" " length:1]])
                    return fulfiller(nil);

                NSError *err = nil;
                id json = [NSJSONSerialization JSONObjectWithData:data options:PMKJSONDeserializationOptions error:&err];
                if (!err) {
                    fulfiller(json);
                } else {
                    id userInfo = err.userInfo.mutableCopy;
                    if (data) {
                        NSString *string = [[NSString alloc] initWithData:data encoding:stringEncoding()];
                        if (string)
                            userInfo[PMKURLErrorFailingStringKey] = string;
                    }
                    long long length = [rsp expectedContentLength];
                    id bytes = length <= 0 ? @"" : [NSString stringWithFormat:@"%lld bytes", length];
                    id fmt = @"The server claimed a %@ JSON response, but decoding failed with: %@";
                    userInfo[NSLocalizedDescriptionKey] = [NSString stringWithFormat:fmt, bytes, userInfo[NSLocalizedDescriptionKey]];
                    err = [NSError errorWithDomain:err.domain code:err.code userInfo:userInfo];
                    rejecter(err);
                }
    #ifdef UIKIT_EXTERN
            } else if (PMKHTTPURLResponseIsImage(rsp)) {
                UIImage *image = [[UIImage alloc] initWithData:data];
                image = [[UIImage alloc] initWithCGImage:[image CGImage] scale:image.scale orientation:image.imageOrientation];
                if (image)
                    fulfiller(image);
                else {
                    id info = @{
                                NSLocalizedDescriptionKey: @"The server returned invalid image data",
                                NSURLErrorFailingURLStringErrorKey: rq.URL.absoluteString,
                                NSURLErrorFailingURLErrorKey: rq.URL
                                };
                    id err = [NSError errorWithDomain:NSURLErrorDomain code:NSURLErrorCannotDecodeContentData userInfo:info];
                    rejecter(err);
                }
    #endif
            } else if (PMKHTTPURLResponseIsText(rsp)) {
                id str = [[NSString alloc] initWithData:data encoding:stringEncoding()];
                if (str)
                    fulfiller(str);
                else {
                    id info = @{
                        NSLocalizedDescriptionKey: @"The server returned invalid string data",
                        NSURLErrorFailingURLStringErrorKey: rq.URL.absoluteString,
                        NSURLErrorFailingURLErrorKey: rq.URL
                    };
                    id err = [NSError errorWithDomain:NSURLErrorDomain code:NSURLErrorCannotDecodeContentData userInfo:info];
                    rejecter(err);
                }
            } else {
                fulfiller(data);
            }
        }] resume];
    }];
}

@end