package apiv1

import (
	"net/http"
	"strconv"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/iotbzh/xds-server/lib/common"
)

// ExecArgs JSON parameters of /exec command
type ExecArgs struct {
	ID            string   `json:"id" binding:"required"`
	SdkID         string   `json:"sdkid"` // sdk ID to use for setting env
	Cmd           string   `json:"cmd" binding:"required"`
	Args          []string `json:"args"`
	Env           []string `json:"env"`
	RPath         string   `json:"rpath"`         // relative path into project
	ExitImmediate bool     `json:"exitImmediate"` // when true, exit event sent immediately when command exited (IOW, don't wait file synchronization)
	CmdTimeout    int      `json:"timeout"`       // command completion timeout in Second
}

// ExecOutMsg Message send on each output (stdout+stderr) of executed command
type ExecOutMsg struct {
	CmdID     string `json:"cmdID"`
	Timestamp string `json:"timestamp"`
	Stdout    string `json:"stdout"`
	Stderr    string `json:"stderr"`
}

// ExecExitMsg Message send when executed command exited
type ExecExitMsg struct {
	CmdID     string `json:"cmdID"`
	Timestamp string `json:"timestamp"`
	Code      int    `json:"code"`
	Error     error  `json:"error"`
}

// ExecOutEvent Event send in WS when characters are received
const ExecOutEvent = "exec:output"

// ExecExitEvent Event send in WS when program exited
const ExecExitEvent = "exec:exit"

var execCommandID = 1

// ExecCmd executes remotely a command
func (s *APIService) execCmd(c *gin.Context) {
	var args ExecArgs
	if c.BindJSON(&args) != nil {
		common.APIError(c, "Invalid arguments")
		return
	}

	// TODO: add permission ?

	// Retrieve session info
	sess := s.sessions.Get(c)
	if sess == nil {
		common.APIError(c, "Unknown sessions")
		return
	}
	sop := sess.IOSocket
	if sop == nil {
		common.APIError(c, "Websocket not established")
		return
	}

	// Allow to pass id in url (/exec/:id) or as JSON argument
	id := c.Param("id")
	if id == "" {
		id = args.ID
	}
	if id == "" {
		common.APIError(c, "Invalid id")
		return
	}

	prj := s.mfolder.GetFolderFromID(id)
	if prj == nil {
		common.APIError(c, "Unknown id")
		return
	}

	execTmo := args.CmdTimeout
	if execTmo == 0 {
		// TODO get default timeout from config.json file
		execTmo = 24 * 60 * 60 // 1 day
	}

	// Define callback for output
	var oCB common.EmitOutputCB
	oCB = func(sid string, id int, stdout, stderr string, data *map[string]interface{}) {
		// IO socket can be nil when disconnected
		so := s.sessions.IOSocketGet(sid)
		if so == nil {
			s.log.Infof("%s not emitted: WS closed - sid: %s - msg id:%d", ExecOutEvent, sid, id)
			return
		}

		// Retrieve project ID and RootPath
		prjID := (*data)["ID"].(string)
		prjRootPath := (*data)["RootPath"].(string)

		// Cleanup any references to internal rootpath in stdout & stderr
		stdout = strings.Replace(stdout, prjRootPath, "", -1)
		stderr = strings.Replace(stderr, prjRootPath, "", -1)

		s.log.Debugf("%s emitted - WS sid %s - id:%d - prjID:%s", ExecOutEvent, sid, id, prjID)

		// FIXME replace by .BroadcastTo a room
		err := (*so).Emit(ExecOutEvent, ExecOutMsg{
			CmdID:     strconv.Itoa(id),
			Timestamp: time.Now().String(),
			Stdout:    stdout,
			Stderr:    stderr,
		})
		if err != nil {
			s.log.Errorf("WS Emit : %v", err)
		}
	}

	// Define callback for output
	eCB := func(sid string, id int, code int, err error, data *map[string]interface{}) {
		s.log.Debugf("Command [Cmd ID %d] exited: code %d, error: %v", id, code, err)

		// IO socket can be nil when disconnected
		so := s.sessions.IOSocketGet(sid)
		if so == nil {
			s.log.Infof("%s not emitted - WS closed (id:%d", ExecExitEvent, id)
			return
		}

		// Retrieve project ID and RootPath
		prjID := (*data)["ID"].(string)
		exitImm := (*data)["ExitImmediate"].(bool)

		// XXX - workaround to be sure that Syncthing detected all changes
		if err := s.mfolder.ForceSync(prjID); err != nil {
			s.log.Errorf("Error while syncing folder %s: %v", prjID, err)
		}
		if !exitImm {
			// Wait end of file sync
			// FIXME pass as argument
			tmo := 60
			for t := tmo; t > 0; t-- {
				s.log.Debugf("Wait file insync for %s (%d/%d)", prjID, t, tmo)
				if sync, err := s.mfolder.IsFolderInSync(prjID); sync || err != nil {
					if err != nil {
						s.log.Errorf("ERROR IsFolderInSync (%s): %v", prjID, err)
					}
					break
				}
				time.Sleep(time.Second)
			}
		}

		// FIXME replace by .BroadcastTo a room
		e := (*so).Emit(ExecExitEvent, ExecExitMsg{
			CmdID:     strconv.Itoa(id),
			Timestamp: time.Now().String(),
			Code:      code,
			Error:     err,
		})
		if e != nil {
			s.log.Errorf("WS Emit : %v", e)
		}
	}

	cmdID := execCommandID
	execCommandID++
	cmd := []string{}

	// Setup env var regarding Sdk ID (used for example to setup cross toolchain)
	if envCmd := s.sdks.GetEnvCmd(args.SdkID, prj.DefaultSdk); len(envCmd) > 0 {
		cmd = append(cmd, envCmd...)
		cmd = append(cmd, "&&")
	}

	cmd = append(cmd, "cd", prj.GetFullPath(args.RPath), "&&", args.Cmd)
	if len(args.Args) > 0 {
		cmd = append(cmd, args.Args...)
	}

	s.log.Debugf("Execute [Cmd ID %d]: %v", cmdID, cmd)

	data := make(map[string]interface{})
	data["ID"] = prj.ID
	data["RootPath"] = prj.RootPath
	data["ExitImmediate"] = args.ExitImmediate

	err := common.ExecPipeWs(cmd, args.Env, sop, sess.ID, cmdID, execTmo, s.log, oCB, eCB, &data)
	if err != nil {
		common.APIError(c, err.Error())
		return
	}

	c.JSON(http.StatusOK,
		gin.H{
			"status": "OK",
			"cmdID":  cmdID,
		})
}