// Copyright 2016 Google Inc. All rights reserved.
//
// 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.

package gitindex

import (
	"bytes"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"sort"
)

// CloneRepo clones one repository, adding the given config
// settings. It returns the bare repo directory.
func CloneRepo(destDir, name, cloneURL string, settings map[string]string) error {
	parent := filepath.Join(destDir, filepath.Dir(name))
	if err := os.MkdirAll(parent, 0755); err != nil {
		return err
	}

	repoDest := filepath.Join(parent, filepath.Base(name)+".git")
	if _, err := os.Lstat(repoDest); err == nil {
		return nil
	}

	var keys []string
	for k := range settings {
		keys = append(keys, k)
	}
	sort.Strings(keys)

	var config []string
	for _, k := range keys {
		config = append(config, "--config", k+"="+settings[k])
	}

	cmd := exec.Command(
		"git", "clone", "--bare", "--verbose", "--progress",
		// Only fetch branch heads, and ignore note branches.
		"--config", "remote.origin.fetch=+refs/heads/*:refs/heads/*")
	cmd.Args = append(cmd.Args, config...)
	cmd.Args = append(cmd.Args, cloneURL, repoDest)

	// Prevent prompting
	cmd.Stdin = &bytes.Buffer{}
	log.Println("running:", cmd.Args)
	if err := cmd.Run(); err != nil {
		return err
	}
	return nil
}