// Copyright (c) 2014-2018, b3log.org & hacpai.com
//
// 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 git

import (
	"bufio"
	"encoding/json"
	"io"
	"io/ioutil"
	"math/rand"
	"net/http"
	"os"
	"os/exec"

	"github.com/b3log/wide/conf"
	"github.com/b3log/wide/i18n"
	"github.com/b3log/wide/log"
	"github.com/b3log/wide/session"
	"github.com/b3log/wide/util"
)

// Logger.
var logger = log.NewLogger(os.Stdout)

// Clone handles request of git clone.
func CloneHandler(w http.ResponseWriter, r *http.Request) {
	result := util.NewResult()
	defer util.RetResult(w, r, result)

	httpSession, _ := session.HTTPSession.Get(r, "wide-session")
	if httpSession.IsNew {
		http.Error(w, "Forbidden", http.StatusForbidden)

		return
	}
	username := httpSession.Values["username"].(string)
	locale := conf.GetUser(username).Locale

	var args map[string]interface{}
	if err := json.NewDecoder(r.Body).Decode(&args); err != nil {
		logger.Error(err)
		result.Succ = false

		return
	}

	sid := args["sid"].(string)
	path := args["path"].(string)
	repository := args["repository"].(string)

	cmd := exec.Command("git", "clone", repository)
	cmd.Dir = path

	stdout, err := cmd.StdoutPipe()
	if nil != err {
		logger.Error(err)
		result.Succ = false

		return
	}

	stderr, err := cmd.StderrPipe()
	if nil != err {
		logger.Error(err)
		result.Succ = false

		return
	}

	if !result.Succ {
		return
	}

	channelRet := map[string]interface{}{}

	if nil != session.OutputWS[sid] {
		// display "START [git clone]" in front-end browser

		channelRet["output"] = "<span class='start-get'>" + i18n.Get(locale, "start-git_clone").(string) + "</span>\n"
		channelRet["cmd"] = "start-git_clone"

		wsChannel := session.OutputWS[sid]

		err := wsChannel.WriteJSON(&channelRet)
		if nil != err {
			logger.Warn(err)
			return
		}

		wsChannel.Refresh()
	}

	reader := bufio.NewReader(io.MultiReader(stdout, stderr))

	if err := cmd.Start(); nil != err {
		logger.Error(err)
		result.Succ = false

		return
	}

	go func(runningId int) {
		defer util.Recover()
		defer cmd.Wait()

		logger.Debugf("User [%s, %s] is running [git clone] [runningId=%d]", username, sid, runningId)

		channelRet := map[string]interface{}{}
		channelRet["cmd"] = "git clone"

		// read all
		buf, err := ioutil.ReadAll(reader)
		if nil != err {
			logger.Warn(err)

			// TODO: handle clone error
		}

		logger.Debugf("User [%s, %s] 's running [git clone] [runningId=%d] has done: %s", username, sid, runningId, string(buf))

		channelRet["output"] = "<span class='get-succ'>" + i18n.Get(locale, "git_clone-done").(string) + "</span>\n"

		if nil != session.OutputWS[sid] {
			wsChannel := session.OutputWS[sid]

			err := wsChannel.WriteJSON(&channelRet)
			if nil != err {
				logger.Warn(err)
			}

			wsChannel.Refresh()
		}
	}(rand.Int())
}