// Helper copied to the remote host to run commands and deploy configuration

// Copyright (C) 2021  Simon Ruderich
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package remote

import (
	"fmt"
	"log"
	"os"

	"golang.org/x/term"

	"ruderich.org/simon/safcm"
	"ruderich.org/simon/safcm/remote/ainsl"
	"ruderich.org/simon/safcm/remote/info"
	"ruderich.org/simon/safcm/remote/run"
	"ruderich.org/simon/safcm/remote/sync"
)

func usage() {
	log.Fatalf("usage: %[1]s sync\n"+
		"usage: %[1]s ainsl [options] <path> <line>",
		os.Args[0])
}

func Main() {
	// Timestamps are added by `safcm`
	log.SetFlags(0)

	if len(os.Args) < 2 {
		usage()
	}

	var err error
	switch os.Args[1] {
	case "sync":
		if len(os.Args) != 2 {
			usage()
		}
		err = mainLoop()
	case "ainsl":
		err = ainsl.Main(os.Args)
	default:
		usage()
	}

	if err != nil {
		log.Fatalf("%s: %v", os.Args[0], err)
	}
}

func mainLoop() error {
	if term.IsTerminal(int(os.Stdin.Fd())) ||
		term.IsTerminal(int(os.Stdout.Fd())) {
		return fmt.Errorf("sync should only be called from `safcm` " +
			"(redirect stdin/stdout to circumvent this check)")
	}

	conn := safcm.NewGobConn(os.Stdin, os.Stdout)

	var logLevel safcm.LogLevel
	logFunc := func(level safcm.LogLevel, msg string) {
		if logLevel >= level {
			conn.Send(safcm.MsgLog{
				Level: level,
				Text:  msg,
			})
		}
	}

	var quitResp safcm.MsgQuitResp
	for {
		x, err := conn.Recv()
		if err != nil {
			return err
		}

		var resp safcm.Msg
		switch x := x.(type) {
		case safcm.MsgInfoReq:
			logLevel = x.LogLevel // set log level globally
			resp = info.Handle(x, run.ExecRunner{}, logFunc)
		case safcm.MsgSyncReq:
			resp = sync.Handle(x, run.ExecRunner{}, logFunc)
		case safcm.MsgQuitReq:
			resp = quitResp
		default:
			return fmt.Errorf("unsupported message %#v", x)
		}

		err = conn.Send(resp)
		if err != nil {
			return err
		}
		if resp == quitResp {
			break
		}
	}
	return nil
}