// Copyright 2026 Google LLC
//
// 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 Foundation

protocol AppCheckCoreDebugProviderAPIServiceProtocol: NSObjectProtocol {
  func appCheckToken(debugToken: String, limitedUse: Bool) async throws -> AppCheckCoreToken
}

class AppCheckCoreDebugProviderAPIService: NSObject, AppCheckCoreDebugProviderAPIServiceProtocol {
  private let apiService: AppCheckCoreAPIServiceProtocol
  private let resourceName: String

  private static let contentTypeKey = "Content-Type"
  private static let jsonContentType = "application/json"
  private static let debugTokenField = "debug_token"
  private static let limitedUseField = "limited_use"

  init(apiService: AppCheckCoreAPIServiceProtocol, resourceName: String) {
    self.apiService = apiService
    self.resourceName = resourceName
    super.init()
  }

  func appCheckToken(debugToken: String, limitedUse: Bool) async throws -> AppCheckCoreToken {
    let urlString = "\(apiService.baseURL)/\(resourceName):exchangeDebugToken"
    guard let url = URL(string: urlString) else {
      throw AppCheckCoreErrorUtil.error(withFailureReason: "Invalid URL: \(urlString)")
    }

    let httpBody = try self.httpBody(debugToken: debugToken, limitedUse: limitedUse)

    let response = try await apiService.sendRequest(withURL: url,
                                                    httpMethod: "POST",
                                                    body: httpBody,
                                                    additionalHeaders: [Self.contentTypeKey: Self
                                                      .jsonContentType])

    return try apiService.appCheckToken(withAPIResponse: response)
  }

  private func httpBody(debugToken: String, limitedUse: Bool) throws -> Data {
    if debugToken.isEmpty {
      throw AppCheckCoreErrorUtil.error(withFailureReason: "Debug token must not be empty.")
    }

    let payload: [String: Any] = [
      Self.debugTokenField: debugToken,
      Self.limitedUseField: limitedUse,
    ]

    do {
      return try JSONSerialization.data(withJSONObject: payload, options: [])
    } catch {
      throw AppCheckCoreErrorUtil.jsonSerializationError(error)
    }
  }
}