#import "NSExpression+MGLAdditions.h"

#import "MGLTypes.h"
#if TARGET_OS_IPHONE
    #import "UIColor+MGLAdditions.h"
#else
    #import "NSColor+MGLAdditions.h"
#endif

@implementation NSExpression (MGLAdditions)

- (std::vector<mbgl::Value>)mgl_aggregateMBGLValue {
    if ([self.constantValue isKindOfClass:[NSArray class]] || [self.constantValue isKindOfClass:[NSSet class]]) {
        std::vector<mbgl::Value> convertedValues;
        for (id value in self.constantValue) {
            NSExpression *expression = value;
            if (![expression isKindOfClass:[NSExpression class]]) {
                expression = [NSExpression expressionForConstantValue:expression];
            }
            convertedValues.push_back(expression.mgl_constantMBGLValue);
        }
        return convertedValues;
    }
    [NSException raise:NSInvalidArgumentException
                format:@"Constant value expression must contain an array or set."];
    return {};
}

- (mbgl::Value)mgl_constantMBGLValue {
    id value = self.constantValue;
    if ([value isKindOfClass:NSString.class]) {
        return { std::string([(NSString *)value UTF8String]) };
    } else if ([value isKindOfClass:NSNumber.class]) {
        NSNumber *number = (NSNumber *)value;
        if ((strcmp([number objCType], @encode(char)) == 0) ||
            (strcmp([number objCType], @encode(BOOL)) == 0)) {
            // char: 32-bit boolean
            // BOOL: 64-bit boolean
            return { (bool)number.boolValue };
        } else if (strcmp([number objCType], @encode(double)) == 0) {
            // Double values on all platforms are interpreted precisely.
            return { (double)number.doubleValue };
        } else if (strcmp([number objCType], @encode(float)) == 0) {
            // Float values when taken as double introduce precision problems,
            // so warn the user to avoid them. This would require them to
            // explicitly use -[NSNumber numberWithFloat:] arguments anyway.
            // We still do this conversion in order to provide a valid value.
            static dispatch_once_t onceToken;
            dispatch_once(&onceToken, ^{
                NSLog(@"Float value in expression will be converted to a double; some imprecision may result. "
                      @"Use double values explicitly when specifying constant expression values and "
                      @"when specifying arguments to predicate and expression format strings. "
                      @"This will be logged only once.");
            });
            return { (double)number.doubleValue };
        } else if ([number compare:@(0)] == NSOrderedDescending ||
                   [number compare:@(0)] == NSOrderedSame) {
            // Positive integer or zero; use uint64_t per mbgl::Value definition.
            // We use unsigned long long here to avoid any truncation.
            return { (uint64_t)number.unsignedLongLongValue };
        } else if ([number compare:@(0)] == NSOrderedAscending) {
            // Negative integer; use int64_t per mbgl::Value definition.
            // We use long long here to avoid any truncation.
            return { (int64_t)number.longLongValue };
        }
    } else if ([value isKindOfClass:[MGLColor class]]) {
        auto hexString = [(MGLColor *)value mgl_color].stringify();
        return { hexString };
    } else if (value && value != [NSNull null]) {
        [NSException raise:NSInvalidArgumentException
                    format:@"Can’t convert %s:%@ to mbgl::Value", [value objCType], value];
    }
    return {};
}

- (std::vector<mbgl::FeatureType>)mgl_aggregateFeatureType {
    if ([self.constantValue isKindOfClass:[NSArray class]] || [self.constantValue isKindOfClass:[NSSet class]]) {
        std::vector<mbgl::FeatureType> convertedValues;
        for (id value in self.constantValue) {
            NSExpression *expression = value;
            if (![expression isKindOfClass:[NSExpression class]]) {
                expression = [NSExpression expressionForConstantValue:expression];
            }
            convertedValues.push_back(expression.mgl_featureType);
        }
        return convertedValues;
    }
    [NSException raise:NSInvalidArgumentException
                format:@"Constant value expression must contain an array or set."];
    return {};
}

- (mbgl::FeatureType)mgl_featureType {
    id value = self.constantValue;
    if ([value isKindOfClass:NSString.class]) {
        if ([value isEqualToString:@"Point"]) {
            return mbgl::FeatureType::Point;
        }
        if ([value isEqualToString:@"LineString"]) {
            return mbgl::FeatureType::LineString;
        }
        if ([value isEqualToString:@"Polygon"]) {
            return mbgl::FeatureType::Polygon;
        }
    } else if ([value isKindOfClass:NSNumber.class]) {
        switch ([value integerValue]) {
            case 1:
                return mbgl::FeatureType::Point;
            case 2:
                return mbgl::FeatureType::LineString;
            case 3:
                return mbgl::FeatureType::Polygon;
            default:
                break;
        }
    }
    return mbgl::FeatureType::Unknown;
}

- (std::vector<mbgl::FeatureIdentifier>)mgl_aggregateFeatureIdentifier {
    if ([self.constantValue isKindOfClass:[NSArray class]] || [self.constantValue isKindOfClass:[NSSet class]]) {
        std::vector<mbgl::FeatureIdentifier> convertedValues;
        for (id value in self.constantValue) {
            NSExpression *expression = value;
            if (![expression isKindOfClass:[NSExpression class]]) {
                expression = [NSExpression expressionForConstantValue:expression];
            }
            convertedValues.push_back(expression.mgl_featureIdentifier);
        }
        return convertedValues;
    }
    [NSException raise:NSInvalidArgumentException
                format:@"Constant value expression must contain an array or set."];
    return {};
}

- (mbgl::FeatureIdentifier)mgl_featureIdentifier {
    mbgl::Value mbglValue = self.mgl_constantMBGLValue;

    if (mbglValue.is<std::string>()) {
        return mbglValue.get<std::string>();
    }
    if (mbglValue.is<double>()) {
        return mbglValue.get<double>();
    }
    if (mbglValue.is<uint64_t>()) {
        return mbglValue.get<uint64_t>();
    }
    if (mbglValue.is<int64_t>()) {
        return mbglValue.get<int64_t>();
    }

    return {};
}

@end