/*
*
* Copyright 2015 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/

#import "GRPCRequestHeaders.h"

#import <Foundation/Foundation.h>

#import "NSDictionary+GRPC.h"

static void CheckIsNilOrString(NSString *name, id value) {
if (value && ![value isKindOfClass:[NSString class]]) {
[NSException raise:NSInvalidArgumentException format:@"%@ must be an NSString", name];
}
}

// Used by the setter.
static void CheckIsNonNilASCIIString(NSString *name, id value) {
if (!value) {
[NSException raise:NSInvalidArgumentException format:@"%@ cannot be nil", name];
}
CheckIsNilOrString(name, value);
if (![value canBeConvertedToEncoding:NSASCIIStringEncoding]) {
[NSException raise:NSInvalidArgumentException
format:@"%@ %@ contains non-ASCII characters", name, value];
}
}

// Precondition: key isn't nil.
static void CheckKeyValuePairIsValid(NSString *key, id value) {
if ([key hasSuffix:@"-bin"]) {
if (![value isKindOfClass:[NSData class]]) {
[NSException raise:NSInvalidArgumentException
format:@"Expected NSData value for header %@ ending in \"-bin\", "
@"instead got %@",
key, value];
}
} else {
if (![value isKindOfClass:[NSString class]]) {
[NSException raise:NSInvalidArgumentException
format:@"Expected NSString value for header %@ not ending in \"-bin\", "
@"instead got %@",
key, value];
}
CheckIsNonNilASCIIString(@"Text header value", value);
}
}

@implementation GRPCRequestHeaders {
__weak GRPCCall *_call;
// The NSMutableDictionary superclass doesn't hold any storage (so that people can implement their
// own in subclasses). As that's not the reason we're subclassing, we just delegate storage to the
// default NSMutableDictionary subclass returned by the cluster (e.g. __NSDictionaryM on iOS 9).
NSMutableDictionary *_delegate;
}

- (instancetype)init {
return [self initWithCall:nil];
}

- (instancetype)initWithCapacity:(NSUInteger)numItems {
return [self init];
}

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
return [self init];
}

- (instancetype)initWithCall:(GRPCCall *)call {
return [self initWithCall:call storage:[NSMutableDictionary dictionary]];
}

// Designated initializer
- (instancetype)initWithCall:(GRPCCall *)call storage:(NSMutableDictionary *)storage {
// TODO(jcanizales): Throw if call or storage are nil.
if ((self = [super init])) {
_call = call;
_delegate = storage;
}
return self;
}

- (instancetype)initWithObjects:(const id _Nonnull __unsafe_unretained *)objects
forKeys:(const id<NSCopying> _Nonnull __unsafe_unretained *)keys
count:(NSUInteger)cnt {
return [self init];
}

- (void)checkCallIsNotStarted {
if (_call.state != GRXWriterStateNotStarted) {
[NSException raise:@"Invalid modification"
format:@"Cannot modify request headers after call is started"];
}
}

- (id)objectForKey:(id)key {
CheckIsNilOrString(@"Header name", key);
NSString *stringKey = [(NSString *)key lowercaseString];
return _delegate[stringKey];
}

- (void)setObject:(id)obj forKey:(id<NSCopying>)key {
CheckIsNonNilASCIIString(@"Header name", key);
NSString *stringKey = [(NSString *)key lowercaseString];
CheckKeyValuePairIsValid(stringKey, obj);
_delegate[stringKey] = obj;
}

- (void)removeObjectForKey:(id)key {
CheckIsNilOrString(@"Header name", key);
NSString *stringKey = [(NSString *)key lowercaseString];
[self checkCallIsNotStarted];
[_delegate removeObjectForKey:stringKey];
}

- (NSUInteger)count {
return _delegate.count;
}

- (NSEnumerator *_Nonnull)keyEnumerator {
return [_delegate keyEnumerator];
}

@end