// Copyright 2024 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 os.log

@_implementationOnly import FirebaseCoreExtension

enum VertexLog {
  /// Log message codes for the Vertex AI SDK
  ///
  /// These codes should ideally not be re-used in order to facilitate matching error codes in
  /// support requests to lines in the SDK. These codes should range between 0 and 999999 to avoid
  /// being truncated in log messages.
  enum MessageCode: Int {
    // Logging Configuration
    case verboseLoggingDisabled = 100
    case verboseLoggingEnabled = 101

    // API Enablement Errors
    case vertexAIInFirebaseAPIDisabled = 200

    // Model Configuration
    case generativeModelInitialized = 1000

    // Network Errors
    case generativeAIServiceNonHTTPResponse = 2000
    case loadRequestResponseError = 2001
    case loadRequestResponseErrorPayload = 2002
    case loadRequestStreamResponseError = 2003
    case loadRequestStreamResponseErrorPayload = 2004

    // Parsing Errors
    case loadRequestParseResponseFailedJSON = 3000
    case loadRequestParseResponseFailedJSONError = 3001
    case generateContentResponseUnrecognizedFinishReason = 3002
    case generateContentResponseUnrecognizedBlockReason = 3003
    case generateContentResponseUnrecognizedBlockThreshold = 3004
    case generateContentResponseUnrecognizedHarmProbability = 3005
    case generateContentResponseUnrecognizedHarmCategory = 3006

    // SDK State Errors
    case generateContentResponseNoCandidates = 4000
    case generateContentResponseNoText = 4001
    case appCheckTokenFetchFailed = 4002

    // SDK Debugging
    case loadRequestStreamResponseLine = 5000
  }

  /// Subsystem that should be used for all Loggers.
  static let subsystem = "com.google.firebase"

  /// Log identifier for the Vertex AI SDK.
  ///
  /// > Note: This corresponds to the `category` in `OSLog`.
  static let service = "[FirebaseVertexAI]"

  /// The raw `OSLog` log object.
  ///
  /// > Important: This is only needed for direct `os_log` usage.
  static let logObject = OSLog(subsystem: subsystem, category: service)

  /// The argument required to enable additional logging.
  static let enableArgumentKey = "-FIRDebugEnabled"

  static func log(level: FirebaseLoggerLevel, code: MessageCode, _ message: String) {
    let messageCode = String(format: "I-VTX%06d", code.rawValue)
    FirebaseLogger.log(
      level: level,
      service: VertexLog.service,
      code: messageCode,
      message: message
    )
  }

  static func error(code: MessageCode, _ message: String) {
    log(level: .error, code: code, message)
  }

  static func warning(code: MessageCode, _ message: String) {
    log(level: .warning, code: code, message)
  }

  static func notice(code: MessageCode, _ message: String) {
    log(level: .notice, code: code, message)
  }

  static func info(code: MessageCode, _ message: String) {
    log(level: .info, code: code, message)
  }

  static func debug(code: MessageCode, _ message: String) {
    log(level: .debug, code: code, message)
  }

  /// Returns `true` if additional logging has been enabled via a launch argument.
  static func additionalLoggingEnabled() -> Bool {
    return ProcessInfo.processInfo.arguments.contains(enableArgumentKey)
  }
}