// Copyright (c) 2020 TypeFox GmbH. All rights reserved.
// Licensed under the GNU Affero General Public License (AGPL).
// See License-AGPL.txt in the project root for license information.

package cmd

import (
	"bufio"
	"fmt"
	"log"
	"os"
	"os/exec"
	"regexp"
	"strconv"
	"strings"

	"github.com/gitpod-io/gitpod/gitpod-cli/pkg/theialib"
	"github.com/spf13/cobra"
)

var credentialHelper = &cobra.Command{
	Use:    "credential-helper get",
	Short:  "Gitpod Credential Helper for Git",
	Long:   "Supports reading of credentials per host.",
	Args:   cobra.MinimumNArgs(1),
	Hidden: true,
	Run: func(cmd *cobra.Command, args []string) {
		action := args[0]
		if action != "get" {
			return
		}

		f, err := os.OpenFile(os.Getenv("HOME")+"/git-credential-helper.log", os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
		if err != nil {
			log.Fatal(err)
		}
		defer f.Close()
		log.SetOutput(f)

		url, gitCommand := parsePstree()
		host := parseHostFromStdin()
		if len(host) == 0 {
			log.Println("'host' is missing")
		}

		service, err := theialib.NewServiceFromEnv()
		if err != nil {
			log.Fatal(err)
		}

		resp, err := service.GetGitToken(theialib.GetGitTokenRequest{
			Command: gitCommand,
			Host:    host,
			RepoURL: url,
		})
		if err != nil {
			log.Fatal(err)
		}

		fmt.Printf("username=%s\npassword=%s\n", resp.User, resp.Token)
	},
}

func parseHostFromStdin() string {
	host := ""
	scanner := bufio.NewScanner(os.Stdin)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if len(line) > 0 {
			tuple := strings.Split(line, "=")
			if len(tuple) == 2 {
				if strings.TrimSpace(tuple[0]) == "host" {
					host = strings.TrimSpace(tuple[1])
				}
			}
		}
	}
	if err := scanner.Err(); err != nil {
		log.Println(err)
	}
	return host
}

func logDebug(v ...interface{}) {
	if os.Getenv("CREDENTIAL_HELPER_DEBUG_LOG") == "true" {
		log.Println(v...)
	}
}

func parsePstree() (string, string) {
	url := ""
	gitCommand := ""
	cmd := exec.Command("pstree", "-sa", strconv.Itoa(os.Getpid()))
	msg, err := cmd.CombinedOutput()
	if err != nil {
		log.Println(err)
	} else {
		pstree := string(msg)
		logDebug("debug> pstree: ")
		logDebug(pstree)

		// git command
		re := regexp.MustCompile("git(,\\d+\\s+|\\s+)(push|clone|fetch|pull|diff)")
		match := re.FindStringSubmatch(pstree)
		if len(match) == 3 {
			gitCommand = match[2]
		}

		// url
		re = regexp.MustCompile("origin\\s*(https:.*\\.git)\\n")
		match = re.FindStringSubmatch(pstree)
		if len(match) == 2 {
			url = match[1]
		}
	}
	return url, gitCommand
}

func init() {
	rootCmd.AddCommand(credentialHelper)
}