package main

import (
	"context"
	"fmt"
	"math/rand"
	"net"
	"net/http"
	"os"
	"os/exec"
	"os/signal"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"github.com/pkg/browser"
	"go.coder.com/flog"
	"golang.org/x/xerrors"
)

const codeServerPath = "~/.cache/sshcode/sshcode-server"

type options struct {
	skipSync   bool
	syncBack   bool
	noOpen     bool
	localPort  string
	remotePort string
	sshFlags   string
}

func sshCode(host, dir string, o options) error {
	flog.Info("ensuring code-server is updated...")

	host, extraSSHFlags, err := parseHost(host)
	if err != nil {
		return xerrors.Errorf("failed to parse host IP: %w", err)
	}
	if extraSSHFlags != "" {
		o.sshFlags = strings.Join([]string{extraSSHFlags, o.sshFlags}, " ")
	}

	dlScript := downloadScript(codeServerPath)

	// Downloads the latest code-server and allows it to be executed.
	sshCmdStr := fmt.Sprintf("ssh %v %v /bin/bash", o.sshFlags, host)

	sshCmd := exec.Command("sh", "-c", sshCmdStr)
	sshCmd.Stdout = os.Stdout
	sshCmd.Stderr = os.Stderr
	sshCmd.Stdin = strings.NewReader(dlScript)
	err = sshCmd.Run()
	if err != nil {
		return xerrors.Errorf("failed to update code-server: \n---ssh cmd---\n%s\n---download script---\n%s: %w",
			sshCmdStr,
			dlScript,
			err,
		)
	}

	if !o.skipSync {
		start := time.Now()
		flog.Info("syncing settings")
		err = syncUserSettings(o.sshFlags, host, false)
		if err != nil {
			return xerrors.Errorf("failed to sync settings: %w", err)
		}

		flog.Info("synced settings in %s", time.Since(start))

		flog.Info("syncing extensions")
		err = syncExtensions(o.sshFlags, host, false)
		if err != nil {
			return xerrors.Errorf("failed to sync extensions: %w", err)
		}
		flog.Info("synced extensions in %s", time.Since(start))
	}

	flog.Info("starting code-server...")

	if o.localPort == "" {
		o.localPort, err = randomPort()
	}
	if err != nil {
		return xerrors.Errorf("failed to find available local port: %w", err)
	}

	if o.remotePort == "" {
		o.remotePort, err = randomPort()
	}
	if err != nil {
		return xerrors.Errorf("failed to find available remote port: %w", err)
	}

	flog.Info("Tunneling local port %v to remote port %v", o.localPort, o.remotePort)

	sshCmdStr = fmt.Sprintf("ssh -tt -q -L %v %v %v 'cd %v; %v --host 127.0.0.1 --allow-http --no-auth --port=%v'",
		o.localPort+":localhost:"+o.remotePort, o.sshFlags, host, dir, codeServerPath, o.remotePort,
	)

	// Starts code-server and forwards the remote port.
	sshCmd = exec.Command("sh", "-c", sshCmdStr)
	sshCmd.Stdin = os.Stdin
	sshCmd.Stdout = os.Stdout
	sshCmd.Stderr = os.Stderr
	err = sshCmd.Start()
	if err != nil {
		return xerrors.Errorf("failed to start code-server: %w", err)
	}

	url := "http://127.0.0.1:" + o.localPort
	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()

	client := http.Client{
		Timeout: time.Second * 3,
	}
	for {
		if ctx.Err() != nil {
			return xerrors.Errorf("code-server didn't start in time: %w", ctx.Err())
		}
		// Waits for code-server to be available before opening the browser.
		resp, err := client.Get(url)
		if err != nil {
			continue
		}
		resp.Body.Close()
		break
	}

	ctx, cancel = context.WithCancel(context.Background())

	if !o.noOpen {
		openBrowser(url)
	}

	go func() {
		defer cancel()
		sshCmd.Wait()
	}()

	c := make(chan os.Signal)
	signal.Notify(c, os.Interrupt)

	select {
	case