#import "Constraints.h"
#import "FunctionalUtil.h"

@implementation NSArray (FunctionalUtil)
- (bool)any:(int (^)(id item))predicate {
    ows_require(predicate != nil);
    for (id e in self) {
        if (predicate(e)) {
            return true;
        }
    }
    return false;
}
- (bool)all:(int (^)(id item))predicate {
     ows_require(predicate != nil);
    for (id e in self) {
        if (!predicate(e)) {
            return false;
        }
    }
    return true;
}
- (id)firstMatchingElseNil:(int (^)(id item))predicate {
     ows_require(predicate != nil);
    for (id e in self) {
        if (predicate(e)) {
            return e;
        }
    }
    return nil;
}
- (NSArray *)map:(id (^)(id item))projection {
     ows_require(projection != nil);

    NSMutableArray *r = [NSMutableArray arrayWithCapacity:self.count];
    for (id e in self) {
        [r addObject:projection(e)];
    }
    return r;
}
- (NSArray *)filter:(int (^)(id item))predicate {
     ows_require(predicate != nil);

    NSMutableArray *r = [NSMutableArray array];
    for (id e in self) {
        if (predicate(e)) {
            [r addObject:e];
        }
    }
    return r;
}
- (double)sumDouble {
    double s = 0.0;
    for (NSNumber *e in self) {
        s += [e doubleValue];
    }
    return s;
}
- (NSUInteger)sumNSUInteger {
    NSUInteger s = 0;
    for (NSNumber *e in self) {
        s += [e unsignedIntegerValue];
    }
    return s;
}
- (NSInteger)sumNSInteger {
    NSInteger s = 0;
    for (NSNumber *e in self) {
        s += [e integerValue];
    }
    return s;
}
- (NSDictionary *)keyedBy:(id (^)(id value))keySelector {
     ows_require(keySelector != nil);

    NSMutableDictionary *result = [NSMutableDictionary dictionary];

    for (id value in self) {
        result[keySelector(value)] = value;
    }
     ows_require(result.count == self.count);

    return result;
}
- (NSDictionary *)groupBy:(id (^)(id value))keySelector {
     ows_require(keySelector != nil);

    NSMutableDictionary *result = [NSMutableDictionary dictionary];

    for (id item in self) {
        id key = keySelector(item);

        NSMutableArray *group = result[key];
        if (group == nil) {
            group       = [NSMutableArray array];
            result[key] = group;
        }
        [group addObject:item];
    }

    return result;
}
@end