# Copyright 2017 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
#
#     https://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.


require "monitor"
require "google-cloud-error_reporting"
require "google/cloud/error_reporting/async_error_reporter"
require "google/cloud/error_reporting/project"
require "google/cloud/error_reporting/middleware"
require "google/cloud/config"
require "google/cloud/env"
require "stackdriver/core"

module Google
  module Cloud
    ##
    # # Error Reporting
    #
    # Stackdriver Error Reporting counts, analyzes and aggregates the crashes in
    # your running cloud services.
    #
    # See {file:OVERVIEW.md Error Reporting Overview}.
    #
    module ErrorReporting
      ##
      # @private The default Google::Cloud::ErrorReporting::Project client used
      # for the Google::Cloud::ErrorReporting.report API.
      @default_reporter = nil
      @default_reporter_mutex = Monitor.new

      ##
      # Creates a new object for connecting to the Stackdriver Error Reporting
      # service. Each call creates a new connection.
      #
      # For more information on connecting to Google Cloud see the
      # {file:AUTHENTICATION.md Authentication Guide}.
      #
      # @param [String] project_id Google Cloud Platform project identifier for
      #   the Stackdriver Error Reporting service you are connecting to. If not
      #   present, the default project for the credentials is used.
      # @param [String, Hash, Google::Auth::Credentials] credentials The path to
      #   the keyfile as a String, the contents of the keyfile as a Hash, or a
      #   Google::Auth::Credentials object. (See {ErrorReporting::Credentials})
      # @param [String, Array<String>] scope The OAuth 2.0 scopes controlling
      #   the set of resources and operations that the connection can access.
      #   See [Using OAuth 2.0 to Access Google
      #   APIs](https://developers.google.com/identity/protocols/OAuth2).
      #
      #   The default scope is:
      #
      #   * `https://www.googleapis.com/auth/cloud-platform`
      #
      # @param [Integer] timeout Default timeout to use in requests. Optional.
      # @param [String] endpoint Override of the endpoint host name. Optional.
      #   If the param is nil, uses the default endpoint.
      # @param [String] project Alias for the `project_id` argument. Deprecated.
      # @param [String] keyfile Alias for the `credentials` argument.
      #   Deprecated.
      #
      # @return [Google::Cloud::ErrorReporting::Project]
      #
      # @example
      #   require "google/cloud/error_reporting"
      #
      #   error_reporting = Google::Cloud::ErrorReporting.new
      #   # ...
      #
      def self.new project_id: nil,
                   credentials: nil,
                   scope: nil,
                   timeout: nil,
                   endpoint: nil,
                   project: nil,
                   keyfile: nil
        project_id    ||= project
        project_id    ||= ErrorReporting::Project.default_project_id
        scope         ||= configure.scope
        timeout       ||= configure.timeout
        endpoint      ||= configure.endpoint
        credentials   ||= (keyfile || default_credentials(scope: scope))

        credentials = resolve_credentials credentials, scope
        project_id = resolve_project_id project_id, credentials

        service = ErrorReporting::Service.new project_id, credentials, host: endpoint, timeout: timeout
        ErrorReporting::Project.new service
      end

      ##
      # Configure the default {Google::Cloud::ErrorReporting::Project}
      # client, allows the {.report} public method to reuse these
      # configured parameters.
      #
      # The following Stackdriver ErrorReporting configuration parameters are
      # supported:
      #
      # * `project_id` - (String)  Google Cloud Platform project identifier for
      #   the Stackdriver Error Reporting service you are connecting to. (The
      #   parameter `project` is considered deprecated, but may also be used.)
      # * `credentials` - (String, Hash, Google::Auth::Credentials) The path to
      #   the keyfile as a String, the contents of the keyfile as a Hash, or a
      #   Google::Auth::Credentials object. (See {ErrorReporting::Credentials})
      #   (The parameter `keyfile` is considered deprecated, but may also be
      #   used.)
      # * `scope` - (String, Array<String>) The OAuth 2.0 scopes controlling
      #   the set of resources and operations that the connection can access.
      # * `timeout` - (Integer) Default timeout to use in requests.
      # * `endpoint` - (String) Override of the endpoint host name, or `nil`
      #   to use the default endpoint.
      # * `service_name` - (String) Name for the application.
      # * `service_version` - (String) Version identifier for the application.
      # * `ignore_classes` - (Array<Exception>) Array of exception types that
      #   should not be reported.
      # * `on_error` - (Proc) A Proc to be run when an error is encountered
      #   on a background thread, such as {ErrorReporting.report} or
      #   {Middleware}. The Proc must take the error object as the single
      #   argument. If ErrorReporting is being used to report errors using
      #   `Google::Cloud::cofigure.on_error`, then this `on_error` should be
      #   configured to report errors raised when reporting through
      #   ErrorReporting.
      #
      # See the [Configuration
      # Guide](https://googleapis.dev/ruby/stackdriver/latest/file.INSTRUMENTATION_CONFIGURATION.html)
      # for full configuration parameters.
      #
      # @example
      #   # in app.rb
      #   require "google/cloud/error_reporting"
      #
      #   Google::Cloud::ErrorReporting.configure do |config|
      #     config.project_id = "my-project"
      #     config.credentials = "/path/to/keyfile.json"
      #     config.service_name = "my-service"
      #     config.service_version = "v8"
      #   end
      #
      #   begin
      #     fail "boom"
      #   rescue => exception
      #     # Report exception using configuration parameters provided above
      #     Google::Cloud::ErrorReporting.report exception
      #   end
      #
      # @return [Google::Cloud::Config] The configuration object
      #   the Google::Cloud::ErrorReporting module uses.
      #
      def self.configure
        yield Google::Cloud.configure.error_reporting if block_given?

        Google::Cloud.configure.error_reporting
      end

      ##
      # Provides an easy-to-use interface to Report a Ruby exception object to
      # Stackdriver ErrorReporting service. This method helps users to
      # transform the Ruby exception into an Stackdriver ErrorReporting
      # ErrorEvent gRPC structure, so users don't need to. This should be the
      # prefered method to use when users wish to report captured exception in
      # applications.
      #
      # This public method creates a default Stackdriver ErrorReporting client
      # and reuse that between calls. The default client is initialized with
      # parameters defined in {.configure}.
      #
      # The error event can be customized before reporting. See the example
      # below and {Google::Cloud::ErrorReporting::ErrorEvent} class for avaiable
      # error event fields.
      #
      # @example Basic usage
      #   # in app.rb
      #   require "google/cloud/error_reporting"
      #
      #   begin
      #     fail "boom"
      #   rescue => exception
      #     # Report exception using configuration parameters provided above
      #     Google::Cloud::ErrorReporting.report exception
      #   end
      #
      # @example The error event can be customized if needed
      #   require "google/cloud/error_reporting"
      #
      #   begin
      #     fail "boom"
      #   rescue => exception
      #     Google::Cloud::ErrorReporting.report exception do |error_event|
      #       error_event.user = "johndoh@example.com"
      #       error_event.http_status = "502"
      #     end
      #   end
      #
      # @param [Exception] exception The captured Ruby Exception object
      # @param [String] service_name An identifier for running service.
      #   Optional.
      # @param [String] service_version A version identifier for running
      #   service.
      #
      def self.report exception, service_name: nil, service_version: nil
        return if Google::Cloud.configure.use_error_reporting == false

        service_name ||= Project.default_service_name
        service_version ||= Project.default_service_version

        # Ensure the reported exception has a backtrace
        exception.set_backtrace caller if exception.backtrace.nil?

        error_event = ErrorEvent.from_exception(exception).tap do |event|
          event.service_name = service_name
          event.service_version = service_version
        end

        yield error_event if block_given?

        default_reporter.report error_event
      end

      ##
      # @private Resolve credentials
      def self.resolve_credentials credentials, scope
        unless credentials.is_a? Google::Auth::Credentials
          credentials = ErrorReporting::Credentials.new credentials,
                                                        scope: scope
        end
        credentials
      end

      private_class_method :resolve_credentials

      ##
      # @private Resolve project.
      def self.resolve_project_id project_id, credentials
        if credentials.respond_to? :project_id
          project_id ||= credentials.project_id
        end
        project_id = project_id.to_s
        raise ArgumentError, "project_id is missing" if project_id.empty?
        project_id
      end

      private_class_method :resolve_project_id

      ##
      # Returns the global default reporter used by middleware and the
      # {Google::Cloud::ErrorReporting.report} convenience method.
      #
      # If the default reporter is already defined, returns it. Otherwise, if
      # a block is given, it is called and the result is set as the default
      # reporter. Otherwise, if no block is given, a reporter is constructed
      # from the default project and credentials.
      #
      # @return [#report]
      #
      def self.default_reporter &block
        @default_reporter_mutex.synchronize do
          @default_reporter ||=
            if block
              block.call
            else
              project_id = Project.default_project_id
              credentials = default_credentials
              AsyncErrorReporter.new(
                new(project_id: project_id, credentials: credentials)
              )
            end
        end
        @default_reporter
      end

      ##
      # @private Default credentials.
      def self.default_credentials scope: nil
        Google::Cloud.configure.error_reporting.credentials ||
          Google::Cloud.configure.credentials ||
          ErrorReporting::Credentials.default(scope: scope)
      end

      private_class_method :default_credentials
    end
  end

  # Aliases for compatibility with older spellings.
  # @private
  module Devtools
    # @private
    Clouderrorreporting = ::Google::Cloud::ErrorReporting unless const_defined? :Clouderrorreporting
  end
end