// Package metricsscopes provides functions for working with GCP Metrics Scopes
// TODO: add link to metrics scopes
package metricsscopes

import (
	"context"
	"fmt"

	metricsscope "cloud.google.com/go/monitoring/metricsscope/apiv1"
	"cloud.google.com/go/monitoring/metricsscope/apiv1/metricsscopepb"
	"google.golang.org/api/option"
)

// Client allows managing GCP Metrics Scopes for the configured scoping project
type Client struct {
	// ScopingProject can either be the project ID or the project number of the
	// GCP project that will be monitoring other GCP projects
	scopingProject string
	options        []option.ClientOption
}

// New creates a metrics scopes Client for the provided scoping project +
// client creation options.  When using GOOGLE_APPLICATION_CREDENTIALS or
// workload identity, no options are required.
func New(scopingProject string, opts ...option.ClientOption) *Client {
	c := &Client{
		scopingProject: scopingProject,
		options:        opts,
	}

	return c
}

// createClient creates a metrics scopes client, reduces boilerplate in our
// other methods
func (c *Client) createClient(ctx context.Context) (client *metricsscope.MetricsScopesClient, err error) {
	client, err = metricsscope.NewMetricsScopesClient(ctx, c.options...)
	if err != nil {
		return nil, fmt.Errorf("Error creating client: %w", err)
	}
	return
}

// Function AddMonitoredProject takes in Context, GoogleApplication Credentials and ProjectID of the Monitored Project and ProjectID
// of Scoping Proejct and adds the Monitored Project to MetricsScopes of Scoping Prohect.
func (c *Client) AddMonitoredProject(ctx context.Context, projectID string) (*metricsscope.CreateMonitoredProjectOperation, error) {
	// Creates a client for MetricsScopes.
	client, clientErr := c.createClient(ctx)
	if clientErr != nil {
		return nil, clientErr
	}
	defer client.Close()

	// Creates a Request for Adding Monitored Project to Scoping Project MetricsScopes
	createReq := &metricsscopepb.CreateMonitoredProjectRequest{
		Parent: fmt.Sprintf("locations/global/metricsScopes/%s", c.scopingProject),
		MonitoredProject: &metricsscopepb.MonitoredProject{
			Name: fmt.Sprintf("locations/global/metricsScopes/%s/projects/%s", c.scopingProject, projectID),
		},
	}

	createResp, createErr := client.CreateMonitoredProject(ctx, createReq)

	return createResp, createErr
}

// QueryMetricsScope returns the list of projects currently being monitored by
// the scoping project
func (c *Client) QueryMetricsScope(ctx context.Context) (*metricsscopepb.MetricsScope, error) {
	// Creates a client for MetricsScopes.
	client, clientErr := c.createClient(ctx)
	if clientErr != nil {
		return nil, clientErr
	}
	defer client.Close()

	//Creates a Request for getting Scoping Project MetricsScopes
	scopesReq := &metricsscopepb.GetMetricsScopeRequest{
		Name: fmt.Sprintf("locations/global/metricsScopes/%s", c.scopingProject),
	}

	scopesResp, scopesErr := client.GetMetricsScope(ctx, scopesReq)

	return scopesResp, scopesErr
}

// ListMetricsScope returns the list of projects currently monitoring the input
// project (i.e., the scoping projects for the input project ID)
func (c *Client) ListMetricsScope(ctx context.Context, projectID string) (*metricsscopepb.ListMetricsScopesByMonitoredProjectResponse, error) {
	// Creates a client for MetricsScopes.
	client, clientErr := c.createClient(ctx)
	if clientErr != nil {
		return nil, clientErr
	}
	defer client.Close()

	//Creates a Request for Listing MetricsScopes by Monitored Project.
	listReq := &metricsscopepb.ListMetricsScopesByMonitoredProjectRequest{
		MonitoredResourceContainer: fmt.Sprintf("projects/%s", projectID),
	}

	listResp, listErr := client.ListMetricsScopesByMonitoredProject(ctx, listReq)

	return listResp, listErr
}

// RemoteMetricsScope removes a monitored project from a scoping project
func (c *Client) RemoveMetricsScope(ctx context.Context, projectID string) (*metricsscope.DeleteMonitoredProjectOperation, error) {
	// Creates a client for MetricsScopes.
	client, clientErr := c.createClient(ctx)
	if clientErr != nil {
		return nil, clientErr
	}
	defer client.Close()

	// Creates a request for deleting monitored project from the Scoping Project MetricsScopes.
	deleteReq := &metricsscopepb.DeleteMonitoredProjectRequest{
		Name: fmt.Sprintf("locations/global/metricsScopes/%s/projects/%s", c.scopingProject, projectID),
	}

	deleteResp, deleteErr := client.DeleteMonitoredProject(ctx, deleteReq)

	return deleteResp, deleteErr
}