// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package main

import (
	"context"
	"fmt"

	"go.chromium.org/luci/auth"
	"go.chromium.org/luci/common/api/gitiles"
	gitilespb "go.chromium.org/luci/common/proto/gitiles"
)

// gitilesClientWrapper provides utilities for interacting with a Gitiles project.
type gitilesClientWrapper struct {
	client  gitilespb.GitilesClient
	project string
}

// newGitilesClient returns an authenticated gitilesClientWrapper.
func newGitilesClient(ctx context.Context, host, project string, authOpts auth.Options) (*gitilesClientWrapper, error) {
	authClient, err := newAuthClient(ctx, authOpts)
	if err != nil {
		return nil, err
	}
	client, err := gitiles.NewRESTClient(authClient, host, true)
	if err != nil {
		return nil, err
	}
	return &gitilesClientWrapper{client: client, project: project}, nil
}

// getLatestCommit returns the revision at refs/heads/master HEAD.
func (c *gitilesClientWrapper) getLatestCommit(ctx context.Context) (string, error) {
	resp, err := c.client.Log(ctx, &gitilespb.LogRequest{
		Project:    c.project,
		Committish: "refs/heads/master",
		PageSize:   1,
	})
	if err != nil {
		return "", err
	}
	if len(resp.Log) == 0 {
		return "", fmt.Errorf("empty log for project %s", c.project)
	}
	return resp.Log[0].GetId(), nil
}