// Copyright 2021 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
import XCTest
import FirebaseCoreInternal

@objc(FIRHeartbeatLoggingTestUtils)
@objcMembers
public class HeartbeatLoggingTestUtils: NSObject {
  /// This should mirror the `Constants` enum in the `HeartbeatLogging` module.
  /// See `HeartbeatLogging/Sources/StorageFactory.swift`.
  public enum Constants {
    /// The name of the file system directory where heartbeat data is stored.
    public static let heartbeatFileStorageDirectoryPath = "google-heartbeat-storage"
    /// The name of the user defaults suite where heartbeat data is stored.
    public static let heartbeatUserDefaultsSuiteName = "com.google.heartbeat.storage"
  }

  public static var dateFormatter: DateFormatter {
    HeartbeatsPayload.dateFormatter
  }

  public static var emptyHeartbeatsPayload: _ObjC_HeartbeatsPayload {
    let literalData = """
       {
         "version": 2,
         "heartbeats": []
       }
    """
    .data(using: .utf8)!

    let decoder = JSONDecoder()
    decoder.dateDecodingStrategy = .formatted(HeartbeatsPayload.dateFormatter)

    let heartbeatsPayload = try! decoder.decode(HeartbeatsPayload.self, from: literalData)
    return _ObjC_HeartbeatsPayload(heartbeatsPayload)
  }

  public static var nonEmptyHeartbeatsPayload: _ObjC_HeartbeatsPayload {
    let literalData = """
       {
         "version": 2,
         "heartbeats": [
           {
             "agent": "dummy_agent_1",
             "dates": ["2021-11-01", "2021-11-02"]
           },
           {
             "agent": "dummy_agent_2",
             "dates": ["2021-11-03"]
           }
         ]
       }
    """
    .data(using: .utf8)!

    let decoder = JSONDecoder()
    decoder.dateDecodingStrategy = .formatted(HeartbeatsPayload.dateFormatter)

    let heartbeatsPayload = try! decoder.decode(HeartbeatsPayload.self, from: literalData)
    return _ObjC_HeartbeatsPayload(heartbeatsPayload)
  }

  @objc(assertEncodedPayloadString:isEqualToLiteralString:withError:)
  public static func assertEqualPayloadStrings(_ encoded: String, _ literal: String) throws {
    var encodedData = try XCTUnwrap(Data(base64URLEncoded: encoded))
    if encodedData.count > 0 {
      encodedData = try! encodedData.unzipped()
    }

    let literalData = try XCTUnwrap(literal.data(using: .utf8))

    let decoder = JSONDecoder()
    decoder.dateDecodingStrategy = .formatted(HeartbeatsPayload.dateFormatter)

    let payloadFromEncoded = try? decoder.decode(HeartbeatsPayload.self, from: encodedData)

    let payloadFromLiteral = try? decoder.decode(HeartbeatsPayload.self, from: literalData)

    let encoder = JSONEncoder()
    encoder.dateEncodingStrategy = .formatted(HeartbeatsPayload.dateFormatter)
    encoder.outputFormatting = .prettyPrinted

    let payloadDataFromEncoded = try XCTUnwrap(encoder.encode(payloadFromEncoded))
    let payloadDataFromLiteral = try XCTUnwrap(encoder.encode(payloadFromLiteral))

    XCTAssertEqual(
      payloadFromEncoded,
      payloadFromLiteral,
      """
      Mismatched payloads!

      Payload 1:
      \(String(data: payloadDataFromEncoded, encoding: .utf8) ?? "")

      Payload 2:
      \(String(data: payloadDataFromLiteral, encoding: .utf8) ?? "")

      """
    )
  }

  /// Removes all underlying storage containers used by the module.
  /// - Throws: An error if the storage container could not be removed.
  public static func removeUnderlyingHeartbeatStorageContainers() throws {
    #if os(tvOS)
      UserDefaults().removePersistentDomain(forName: Constants.heartbeatUserDefaultsSuiteName)
    #else

      let applicationSupportDirectory = try XCTUnwrap(
        FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask).first
      )

      let heartbeatsDirectoryURL = applicationSupportDirectory
        .appendingPathComponent(
          Constants.heartbeatFileStorageDirectoryPath, isDirectory: true
        )
      do {
        try FileManager.default.removeItem(at: heartbeatsDirectoryURL)
      } catch CocoaError.fileNoSuchFile {
        // Do nothing.
      } catch {
        throw error
      }
    #endif // os(tvOS)
  }
}