package main

import (
	"encoding/json"
	"fmt"
	"io"
	"os"
	"regexp"
	"runtime"
	"strings"
	"time"

	shlex "github.com/anmitsu/go-shlex"
	"github.com/gliderlabs/ssh"
	"github.com/jinzhu/gorm"
	"github.com/moby/moby/pkg/namesgenerator"
	"github.com/olekukonko/tablewriter"
	"github.com/urfave/cli"
	"golang.org/x/crypto/ssh/terminal"
)

var banner = `

    __________ _____           __       __
   / __/ __/ // / _ \___  ____/ /____ _/ /
  _\ \_\ \/ _  / ___/ _ \/ __/ __/ _ '/ /
 /___/___/_//_/_/   \___/_/  \__/\_,_/_/


`
var isNameValid = regexp.MustCompile(`^[A-Za-z0-9_-]+$`).MatchString
var startTime = time.Now()

func shell(globalContext *cli.Context, s ssh.Session, sshCommand []string, db *gorm.DB) error {
	if len(sshCommand) == 0 {
		io.WriteString(s, banner)
	}

	cli.AppHelpTemplate = `COMMANDS:
{{range .Commands}}{{if not .HideHelp}}   {{join .Names ", "}}{{ "\t"}}{{.Usage}}{{ "\n" }}{{end}}{{end}}{{if .VisibleFlags}}
GLOBAL OPTIONS:
   {{range .VisibleFlags}}{{.}}
   {{end}}{{end}}
`
	cli.OsExiter = func(c int) {
		// FIXME: forward valid exit code
		io.WriteString(s, fmt.Sprintf("exit: %d\n", c))
	}
	app := cli.NewApp()
	app.Writer = s
	app.HideVersion = true
	app.Commands = []cli.Command{
		{
			Name:  "host",
			Usage: "Manage hosts",
			Subcommands: []cli.Command{
				{
					Name:        "create",
					Usage:       "Create a new host",
					ArgsUsage:   "<user>[:<password>]@<host>[:<port>]",
					Description: "$> host create bart@foo.org\n   $> host create bob:marley@example.com:2222",
					Flags: []cli.Flag{
						cli.StringFlag{Name: "name", Usage: "Assign a name to the host"},
						cli.StringFlag{Name: "password", Usage: "If present, sshportal will use password-based authentication"},
						cli.StringFlag{Name: "fingerprint", Usage: "SSH host key fingerprint"},
						cli.StringFlag{Name: "comment"},
						cli.StringFlag{Name: "key", Usage: "ID or name of the key to use for authentication"},
					},
					Action: func(c *cli.Context) error {
						if c.NArg() != 1 {
							return fmt.Errorf("invalid usage")
						}
						host, err := NewHostFromURL(c.Args().First())
						if err != nil {
							return err
						}
						if c.String("password") != "" {
							host.Password = c.String("password")
						}
						host.Fingerprint = c.String("fingerprint")
						host.Name = strings.Split(host.Hostname(), ".")[0]

						if c.String("name") != "" {
							host.Name = c.String("name")
						}
						if !isNameValid(host.Name) {
							return fmt.Errorf("invalid name %q", host.Name)
						}
						// FIXME: check if name already exists

						host.Comment = c.String("comment")
						inputKey := c.String("key")
						if inputKey == "" && host.Password == "" {
							inputKey = "default"
						}
						if inputKey != "" {
							key, err := FindKeyByIdOrName(db, inputKey)
							if err != nil {
								return err
							}
							host.SSHKeyID = key.ID
						}

						if err := db.Create(&host).Error; err != nil {
							return err
						}
						fmt.Fprintf(s, "%d\n", host.ID)
						return nil
					},
				},
				{
					Name:      "inspect",
					Usage:     "Display detailed information on one or more hosts",
					ArgsUsage: "<id or name> [<id or name> [<ir or name>...]]",
					Action: func(c *cli.Context) error {
						if c.NArg() < 1 {
							return fmt.Errorf("invalid usage")
						}

						hosts, err := FindHostsByIdOrName(db, c.Args())
						if err != nil {
							return nil
						}

						enc := json.NewEncoder(s)
						enc.SetIndent("", "  ")
						return enc.Encode(hosts)
					},
				},
				{
					Name:  "ls",
					Usage: "List hosts",
					Action: func(c *cli.Context) error {
						var hosts []Host
						if err := db.Find(&hosts).Error; err != nil {
							return err
						}
						table := tablewriter.NewWriter(s)
						table.SetHeader([]string{"ID", "Name", "URL", "Key", "Pass", "Comment"})
						table.SetBorder(false)
						table.SetCaption(true, fmt.Sprintf("Total: %d hosts.", len(hosts)))
						for _, host := range hosts {
							authKey, authPass := "", ""
							if host.Password != "" {
								authPass = "X"
							}
							if host.SSHKeyID > 0 {
								var key SSHKey
								db.Model(&host).Related(&key)
								authKey = key.Name
							}
							table.Append([]string{
								fmt.Sprintf("%d", host.ID),
								host.Name,
								host.URL(),
								authKey,
								authPass,
								host.Comment,
								//FIXME: add some stats about last access time etc
								//FIXME: add creation date
							})
						}
						table.Render()
						return nil
					},
				},
				{
					Name:      "rm",
					Usage:     "Remove one or more hosts",
					ArgsUsage: "<id or name> [<id or name> [<ir or name>...]]",
					Action: func(c *cli.Context) error {
						if c.NArg() < 1 {
							return fmt.Errorf("invalid usage")
						}

						hosts, err := FindHostsByIdOrName(db, c.Args())
						if err != nil {
							return nil
						}

						for _, host := range hosts {
							db.Where("id = ?", host.ID).Delete(&Host{})
							fmt.Fprintf(s, "%d\n", host.ID)
						}
						return nil
					},
				},
			},
		}, {
			Name:  "info",
			Usage: "Display system-wide information",
			Action: func(c *cli.Context) error {
				fmt.Fprintf(s, "Debug mode (server): %v\n", globalContext.Bool("debug"))
				hostname, _ := os.Hostname()
				fmt.Fprintf(s, "Hostname: %s\n", hostname)
				fmt.Fprintf(s, "CPUs: %d\n", runtime.NumCPU())
				fmt.Fprintf(s, "Demo mode: %v\n", globalContext.Bool("demo"))
				fmt.Fprintf(s, "DB Driver: %s\n", globalContext.String("db-driver"))
				fmt.Fprintf(s, "DB Conn: %s\n", globalContext.String("db-conn"))
				fmt.Fprintf(s, "Bind Address: %s\n", globalContext.String("bind-address"))
				fmt.Fprintf(s, "System Time: %v\n", time.Now().Format(time.RFC3339Nano))
				fmt.Fprintf(s, "OS Type: %s\n", runtime.GOOS)
				fmt.Fprintf(s, "OS Architecture: %s\n", runtime.GOARCH)
				fmt.Fprintf(s, "Go routines: %d\n", runtime.NumGoroutine())
				fmt.Fprintf(s, "Go version (build): %v\n", runtime.Version())
				fmt.Fprintf(s, "Uptime: %v\n", time.Since(startTime))
				// FIXME: add version
				// FIXME: add info about current server (network, cpu, ram, OS)
				// FIXME: add info about current user
				// FIXME: add active connections
				// FIXME: stats
				return nil
			},
		}, {
			Name:  "key",
			Usage: "Manage keys",
			Subcommands: []cli.Command{
				{
					Name:        "create",
					Usage:       "Create a new key",
					Description: "$> key create\n   $> key create --name=mykey",
					Flags: []cli.Flag{
						cli.StringFlag{Name: "name", Usage: "Assign a name to the host"},
						cli.StringFlag{Name: "type", Value: "rsa"},
						cli.UintFlag{Name: "length", Value: 2048},
						cli.StringFlag{Name: "comment"},
					},
					Action: func(c *cli.Context) error {
						name := namesgenerator.GetRandomName(0)
						if c.String("name") != "" {
							name = c.String("name")
						}
						if name == "" || !isNameValid(name) {
							return fmt.Errorf("invalid name %q", name)
						}
						// FIXME: check if name already exists

						key, err := NewSSHKey(c.String("type"), c.Uint("length"))
						if err != nil {
							return err
						}
						key.Name = name
						key.Comment = c.String("comment")

						// save the key in database
						if err := db.Create(&key).Error; err != nil {
							return err
						}
						fmt.Fprintf(s, "%d\n", key.ID)
						return nil
					},
				},
				{
					Name:      "inspect",
					Usage:     "Display detailed information on one or more keys",
					ArgsUsage: "<id or name> [<id or name> [<ir or name>...]]",
					Action: func(c *cli.Context) error {
						if c.NArg() < 1 {
							return fmt.Errorf("invalid usage")
						}

						keys, err := FindKeysByIdOrName(db, c.Args())
						if err != nil {
							return nil
						}

						enc := json.NewEncoder(s)
						enc.SetIndent("", "  ")
						return enc.Encode(keys)
					},
				},
				{
					Name:  "ls",
					Usage: "List keys",
					Action: func(c *cli.Context) error {
						var keys []SSHKey
						if err := db.Find(&keys).Error; err != nil {
							return err
						}
						table := tablewriter.NewWriter(s)
						table.SetHeader([]string{"ID", "Name", "Type", "Length", "Comment"})
						table.SetBorder(false)
						table.SetCaption(true, fmt.Sprintf("Total: %d keys.", len(keys)))
						for _, key := range keys {
							table.Append([]string{
								fmt.Sprintf("%d", key.ID),
								key.Name,
								key.Type,
								fmt.Sprintf("%d", key.Length),
								//key.Fingerprint,
								key.Comment,
								//FIXME: add some stats
								//FIXME: add creation date
							})
						}
						table.Render()
						return nil
					},
				},
				{
					Name:      "rm",
					Usage:     "Remove one or more keys",
					ArgsUsage: "<id or name> [<id or name> [<ir or name>...]]",
					Action: func(c *cli.Context) error {
						if c.NArg() < 1 {
							return fmt.Errorf("invalid usage")
						}

						keys, err := FindKeysByIdOrName(db, c.Args())
						if err != nil {
							return nil
						}

						for _, key := range keys {
							db.Where("id = ?", key.ID).Delete(&SSHKey{})
							fmt.Fprintf(s, "%d\n", key.ID)
						}
						return nil
					},
				},
			},
		}, {
			Name:  "user",
			Usage: "Manage users",
			Subcommands: []cli.Command{
				{
					Name:   "create",
					Usage:  "Create a new user",
					Action: func(c *cli.Context) error { return nil },
				},
				{
					Name:   "inspect",
					Usage:  "Display detailed information on one or more users",
					Action: func(c *cli.Context) error { return nil },
				},
				{
					Name:   "ls",
					Usage:  "List users",
					Action: func(c *cli.Context) error { return nil },
				},
				{
					Name:   "rm",
					Usage:  "Remove one or more users",
					Action: func(c *cli.Context) error { return nil },
				},
			},
		}, {
			Name:  "version",
			Usage: "Show the SSHPortal version information",
			Action: func(c *cli.Context) error {
				fmt.Fprintf(s, "%s\n", version)
				return nil
			},
		},
	}

	if len(sshCommand) == 0 { // interactive mode
		term := terminal.NewTerminal(s, "config> ")
		for {
			line, err := term.ReadLine()
			if err != nil {
				return err
			}

			words, err := shlex.Split(line, true)
			if err != nil {
				io.WriteString(s, "syntax error.\n")
				continue
			}
			if err := app.Run(append([]string{"config"}, words...)); err != nil {
				io.WriteString(s, fmt.Sprintf("error: %v\n", err))
			}
		}
	} else { // oneshot mode
		if err := app.Run(append([]string{"config"}, sshCommand...)); err != nil {
			io.WriteString(s, fmt.Sprintf("error: %v\n", err))
		}
	}

	return nil
}