# frozen_string_literal: true

require 'securerandom'
require 'google/apis/compute_v1'
require 'google/apis/container_v1'
require 'google/apis/container_v1beta1'
require 'google/apis/cloudbilling_v1'
require 'google/apis/cloudresourcemanager_v1'
require 'google/apis/iam_v1'
require 'google/apis/serviceusage_v1'
require 'google/apis/sqladmin_v1beta4'

module GoogleApi
  module CloudPlatform
    class Client < GoogleApi::Auth
      SCOPE = 'https://www.googleapis.com/auth/cloud-platform https://www.googleapis.com/auth/service.management'
      LEAST_TOKEN_LIFE_TIME = 10.minutes
      CLUSTER_MASTER_AUTH_USERNAME = 'admin'
      CLUSTER_IPV4_CIDR_BLOCK = '/16'
      CLUSTER_OAUTH_SCOPES = [
        "https://www.googleapis.com/auth/devstorage.read_only",
        "https://www.googleapis.com/auth/logging.write",
        "https://www.googleapis.com/auth/monitoring"
      ].freeze
      ROLES_LIST = %w[roles/iam.serviceAccountUser roles/artifactregistry.admin roles/cloudbuild.builds.builder roles/run.admin roles/storage.admin roles/cloudsql.admin roles/browser].freeze
      REVOKE_URL = 'https://oauth2.googleapis.com/revoke'

      class << self
        def session_key_for_token
          :cloud_platform_access_token
        end

        def session_key_for_expires_at
          :cloud_platform_expires_at
        end

        def new_session_key_for_redirect_uri
          SecureRandom.hex.tap do |state|
            yield session_key_for_redirect_uri(state)
          end
        end

        def session_key_for_redirect_uri(state)
          "cloud_platform_second_redirect_uri_#{state}"
        end
      end

      def scope
        SCOPE
      end

      def validate_token(expires_at)
        return false unless access_token
        return false unless expires_at

        # Making sure that the token will have been still alive during the cluster creation.
        return false if token_life_time(expires_at) < LEAST_TOKEN_LIFE_TIME

        true
      end

      def projects_zones_clusters_get(project_id, zone, cluster_id)
        service = Google::Apis::ContainerV1::ContainerService.new
        service.authorization = access_token

        service.get_zone_cluster(project_id, zone, cluster_id, options: user_agent_header)
      end

      def projects_zones_clusters_create(project_id, zone, cluster_name, cluster_size, machine_type:, legacy_abac:, enable_addons: [])
        service = Google::Apis::ContainerV1beta1::ContainerService.new
        service.authorization = access_token

        cluster_options = make_cluster_options(cluster_name, cluster_size, machine_type, legacy_abac, enable_addons)

        request_body = Google::Apis::ContainerV1beta1::CreateClusterRequest.new(**cluster_options)

        service.create_cluster(project_id, zone, request_body, options: user_agent_header)
      end

      def projects_zones_operations(project_id, zone, operation_id)
        service = Google::Apis::ContainerV1::ContainerService.new
        service.authorization = access_token

        service.get_zone_operation(project_id, zone, operation_id, options: user_agent_header)
      end

      def parse_operation_id(self_link)
        m = self_link.match(%r{projects/.*/zones/.*/operations/(.*)})
        m[1] if m
      end

      def list_projects
        result = []

        response = cloud_resource_manager_service.fetch_all(items: :projects) do |token|
          cloud_resource_manager_service.list_projects
        end

        # Google API results are paged by default, so we need to iterate through
        response.each do |project|
          result.append(project)
        end

        result
      end

      def create_service_account(gcp_project_id, display_name, description)
        name = "projects/#{gcp_project_id}"

        # initialize google iam service
        service = Google::Apis::IamV1::IamService.new
        service.authorization = access_token

        # generate account id
        random_account_id = "gitlab-" + SecureRandom.hex(11)

        body_params = { account_id: random_account_id,
                        service_account: { display_name: display_name,
                                           description: description } }

        request_body = Google::Apis::IamV1::CreateServiceAccountRequest.new(**body_params)
        service.create_service_account(name, request_body)
      end

      def create_service_account_key(gcp_project_id, service_account_id)
        service = Google::Apis::IamV1::IamService.new
        service.authorization = access_token

        name = "projects/#{gcp_project_id}/serviceAccounts/#{service_account_id}"
        request_body = Google::Apis::IamV1::CreateServiceAccountKeyRequest.new
        service.create_service_account_key(name, request_body)
      end

      def grant_service_account_roles(gcp_project_id, email)
        body = policy_request_body(gcp_project_id, email)
        cloud_resource_manager_service.set_project_iam_policy(gcp_project_id, body)
      end

      def enable_cloud_run(gcp_project_id)
        enable_service(gcp_project_id, 'run.googleapis.com')
      end

      def enable_artifacts_registry(gcp_project_id)
        enable_service(gcp_project_id, 'artifactregistry.googleapis.com')
      end

      def enable_cloud_build(gcp_project_id)
        enable_service(gcp_project_id, 'cloudbuild.googleapis.com')
      end

      def revoke_authorizations
        uri = URI(REVOKE_URL)
        Gitlab::HTTP.post(uri, body: { 'token' => access_token })
      end

      def create_cloudsql_database(gcp_project_id, instance_name, database_name)
        database = Google::Apis::SqladminV1beta4::Database.new(name: database_name)
        sql_admin_service.insert_database(gcp_project_id, instance_name, database)
      end

      def create_cloudsql_user(gcp_project_id, instance_name, username, password)
        user = Google::Apis::SqladminV1beta4::User.new
        user.name = username
        user.password = password
        sql_admin_service.insert_user(gcp_project_id, instance_name, user)
      end

      def get_cloudsql_instance(gcp_project_id, instance_name)
        sql_admin_service.get_instance(gcp_project_id, instance_name)
      end

      private

      def enable_service(gcp_project_id, service_name)
        name = "projects/#{gcp_project_id}/services/#{service_name}"
        service = Google::Apis::ServiceusageV1::ServiceUsageService.new
        service.authorization = access_token
        service.enable_service(name)
      end

      def make_cluster_options(cluster_name, cluster_size, machine_type, legacy_abac, enable_addons)
        {
          cluster: {
            name: cluster_name,
            initial_node_count: cluster_size,
            node_config: {
              machine_type: machine_type,
              oauth_scopes: CLUSTER_OAUTH_SCOPES
            },
            master_auth: {
              client_certificate_config: {
                issue_client_certificate: true
              }
            },
            legacy_abac: {
              enabled: legacy_abac
            },
            ip_allocation_policy: {
              use_ip_aliases: true,
              cluster_ipv4_cidr_block: CLUSTER_IPV4_CIDR_BLOCK
            },
            addons_config: make_addons_config(enable_addons)
          }
        }
      end

      def make_addons_config(enable_addons)
        enable_addons.each_with_object({}) do |addon, hash|
          hash[addon] = { disabled: false }
        end
      end

      def token_life_time(expires_at)
        DateTime.strptime(expires_at, '%s').to_time.utc - Time.now.utc
      end

      def user_agent_header
        Google::Apis::RequestOptions.new.tap do |options|
          options.header = { 'User-Agent': "GitLab/#{Gitlab::VERSION.match('(\d+\.\d+)').captures.first} (GPN:GitLab;)" }
        end
      end

      def policy_request_body(gcp_project_id, email)
        policy = cloud_resource_manager_service.get_project_iam_policy(gcp_project_id)
        policy.bindings = policy.bindings + additional_policy_bindings("serviceAccount:#{email}")

        Google::Apis::CloudresourcemanagerV1::SetIamPolicyRequest.new(policy: policy)
      end

      def additional_policy_bindings(member)
        ROLES_LIST.map do |role|
          Google::Apis::CloudresourcemanagerV1::Binding.new(role: role, members: [member])
        end
      end

      def cloud_resource_manager_service
        @gpc_service ||= Google::Apis::CloudresourcemanagerV1::CloudResourceManagerService.new.tap { |s| s.authorization = access_token }
      end

      def sql_admin_service
        @sql_admin_service ||= Google::Apis::SqladminV1beta4::SQLAdminService.new.tap { |s| s.authorization = access_token }
      end
    end
  end
end