/*
 * Copyright 2017 Google
 *
 * 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 "FIRSecureTokenRequest.h"
#import "FIRAuthRequestConfiguration.h"

NS_ASSUME_NONNULL_BEGIN

/** @var kFIRSecureTokenServiceGetTokenURLFormat
    @brief The format of the secure token service URLs. Requires string format substitution with
        the client's API Key.
 */
static NSString *const kFIRSecureTokenServiceGetTokenURLFormat = @"https://%@/v1/token?key=%@";

/** @var kFIRSecureTokenServiceGrantTypeRefreshToken
    @brief The string value of the @c FIRSecureTokenRequestGrantTypeRefreshToken request type.
 */
static NSString *const kFIRSecureTokenServiceGrantTypeRefreshToken = @"refresh_token";

/** @var kFIRSecureTokenServiceGrantTypeAuthorizationCode
    @brief The string value of the @c FIRSecureTokenRequestGrantTypeAuthorizationCode request type.
 */
static NSString *const kFIRSecureTokenServiceGrantTypeAuthorizationCode = @"authorization_code";

/** @var kGrantTypeKey
    @brief The key for the "grantType" parameter in the request.
 */
static NSString *const kGrantTypeKey = @"grantType";

/** @var kScopeKey
    @brief The key for the "scope" parameter in the request.
 */
static NSString *const kScopeKey = @"scope";

/** @var kRefreshTokenKey
    @brief The key for the "refreshToken" parameter in the request.
 */
static NSString *const kRefreshTokenKey = @"refreshToken";

/** @var kCodeKey
    @brief The key for the "code" parameter in the request.
 */
static NSString *const kCodeKey = @"code";

/** @var gAPIHost
 @brief Host for server API calls.
 */
static NSString *gAPIHost = @"securetoken.googleapis.com";

@implementation FIRSecureTokenRequest {
  /** @var _requestConfiguration
      @brief Contains configuration relevant to the request.
   */
  FIRAuthRequestConfiguration *_requestConfiguration;
}

+ (FIRSecureTokenRequest *)authCodeRequestWithCode:(NSString *)code
                                     requestConfiguration:(FIRAuthRequestConfiguration *)
                                         requestConfiguration {
  return [[self alloc] initWithGrantType:FIRSecureTokenRequestGrantTypeAuthorizationCode
                                   scope:nil
                            refreshToken:nil
                                    code:code
                    requestConfiguration:requestConfiguration];
}

+ (FIRSecureTokenRequest *)refreshRequestWithRefreshToken:(NSString *)refreshToken
                                     requestConfiguration:(FIRAuthRequestConfiguration *)
                                         requestConfiguration {
  return [[self alloc] initWithGrantType:FIRSecureTokenRequestGrantTypeRefreshToken
                                   scope:nil
                            refreshToken:refreshToken
                                    code:nil
                    requestConfiguration:requestConfiguration];
}

/** @fn grantTypeStringWithGrantType:
    @brief Converts a @c FIRSecureTokenRequestGrantType to it's @c NSString equivilent.
 */
+ (NSString *)grantTypeStringWithGrantType:(FIRSecureTokenRequestGrantType)grantType {
  switch (grantType) {
    case FIRSecureTokenRequestGrantTypeAuthorizationCode:
      return kFIRSecureTokenServiceGrantTypeAuthorizationCode;
    case FIRSecureTokenRequestGrantTypeRefreshToken:
      return kFIRSecureTokenServiceGrantTypeRefreshToken;
    // No Default case so we will notice if new grant types are added to the enum.
  }
}

- (nullable instancetype)initWithGrantType:(FIRSecureTokenRequestGrantType)grantType
                                     scope:(nullable NSString *)scope
                              refreshToken:(nullable NSString *)refreshToken
                                      code:(nullable NSString *)code
                      requestConfiguration:(FIRAuthRequestConfiguration *)requestConfiguration {
  self = [super init];
  if (self) {
    _grantType = grantType;
    _scope = [scope copy];
    _refreshToken = [refreshToken copy];
    _code = [code copy];
    _APIKey = [requestConfiguration.APIKey copy];
    _requestConfiguration = requestConfiguration;
  }
  return self;
}

- (FIRAuthRequestConfiguration *)requestConfiguration {
  return _requestConfiguration;
}

- (NSURL *)requestURL {
  NSString *URLString =
      [NSString stringWithFormat:kFIRSecureTokenServiceGetTokenURLFormat, gAPIHost, _APIKey];
  NSURL *URL = [NSURL URLWithString:URLString];
  return URL;
}

- (BOOL)containsPostBody {
  return YES;
}

- (nullable id)unencodedHTTPRequestBodyWithError:(NSError *_Nullable *_Nullable)error {
  NSMutableDictionary *postBody = [@{
    kGrantTypeKey : [[self class] grantTypeStringWithGrantType:_grantType]
  } mutableCopy];
  if (_scope) {
    postBody[kScopeKey] = _scope;
  }
  if (_refreshToken) {
    postBody[kRefreshTokenKey] = _refreshToken;
  }
  if (_code) {
    postBody[kCodeKey] = _code;
  }
  return postBody;
}

#pragma mark - Internal API for development

+ (NSString *)host {
  return gAPIHost;
}

+ (void)setHost:(NSString *)host {
  gAPIHost = host;
}

@end

NS_ASSUME_NONNULL_END