package ssh

import (
	ice "github.com/shylinux/icebergs"
	"github.com/shylinux/icebergs/base/aaa"
	"github.com/shylinux/icebergs/base/mdb"
	"github.com/shylinux/icebergs/base/nfs"
	"github.com/shylinux/icebergs/base/tcp"
	kit "github.com/shylinux/toolkits"

	"bytes"
	"encoding/base64"
	"encoding/binary"
	"errors"
	"fmt"
	"io"
	"net"
	"os"
	"os/exec"
	"path"
	"strings"
	"syscall"
	"time"
	"unsafe"

	"github.com/kr/pty"
	"golang.org/x/crypto/ssh"
)

type Winsize struct {
	Height uint16
	Width  uint16
	x      uint16
	y      uint16
}

func _ssh_size(fd uintptr, b []byte) {
	w := binary.BigEndian.Uint32(b)
	h := binary.BigEndian.Uint32(b[4:])

	ws := &Winsize{Width: uint16(w), Height: uint16(h)}
	syscall.Syscall(syscall.SYS_IOCTL, fd, uintptr(syscall.TIOCSWINSZ), uintptr(unsafe.Pointer(ws)))
}
func _ssh_exec(m *ice.Message, cmd string, arg []string, env []string, tty io.ReadWriter, done func()) {
	m.Log_IMPORT("cmd", cmd, "arg", arg, "env", env)
	c := exec.Command(cmd, arg...)
	// c.Env = env

	c.Stdin = tty
	c.Stdout = tty
	c.Stderr = tty

	err := c.Start()
	m.Assert(err)

	m.Gos(m, func(m *ice.Message) {
		defer done()
		c.Process.Wait()
	})
}
func _ssh_close(m *ice.Message, c net.Conn, channel ssh.Channel) {
	defer channel.Close()
	channel.Write([]byte(m.Conf(PUBLIC, "meta.goodbye")))
}
func _ssh_reopen(m *ice.Message, c net.Conn, channel ssh.Channel) {
}
func _ssh_handle(m *ice.Message, hostname string, c net.Conn, channel ssh.Channel, requests <-chan *ssh.Request) {
	m.Logs(CHANNEL, aaa.HOSTPORT, c.RemoteAddr(), "->", c.LocalAddr())
	defer m.Logs("dischan", aaa.HOSTPORT, c.RemoteAddr(), "->", c.LocalAddr())

	shell := kit.Select("bash", os.Getenv("SHELL"))
	list := []string{"PATH=" + os.Getenv("PATH")}

	tty, f, err := pty.Open()
	if m.Warn(err != nil, err) {
		return
	}
	defer f.Close()

	h := m.Cmdx(mdb.INSERT, m.Prefix(SESSION), "", mdb.HASH, aaa.HOSTPORT, c.RemoteAddr().String(), kit.MDB_STATUS, "open", "tty", tty.Name())

	for request := range requests {
		m.Logs(REQUEST, aaa.HOSTPORT, c.RemoteAddr(), "type", request.Type)

		switch request.Type {
		case "pty-req":
			termLen := request.Payload[3]
			termEnv := string(request.Payload[4 : termLen+4])
			_ssh_size(tty.Fd(), request.Payload[termLen+4:])
			list = append(list, "TERM="+termEnv)

		case "window-change":
			_ssh_size(tty.Fd(), request.Payload)

		case "env":
			var env struct {
				Name  string
				Value string
			}
			if err := ssh.Unmarshal(request.Payload, &env); err != nil {
				continue
			}
			list = append(list, env.Name+"="+env.Value)

		case "exec":
			_ssh_exec(m, shell, []string{"-c", string(request.Payload[4 : request.Payload[3]+4])}, list,
				channel, func() { channel.Close() })
		case "shell":
			_ssh_exec(m, shell, nil, list, f, func() {
				defer m.Cmd(mdb.MODIFY, m.Prefix(SESSION), "", mdb.HASH, kit.MDB_HASH, h, kit.MDB_STATUS, "close")
				_ssh_close(m, c, channel)
			})
			m.Gos(m, func(m *ice.Message) {
				r, w := io.Pipe()
				bio := io.TeeReader(channel, w)
				m.Gos(m, func(m *ice.Message) {
					i, buf := 0, make([]byte, 1024)
					for {
						n, e := bio.Read(buf[i:])
						if e != nil {
							break
						}
						switch buf[i] {
						case ' ':
						case '\r', '\n':
							cmd := strings.TrimSpace(string(buf[:i+n]))
							m.Cmd(mdb.MODIFY, m.Prefix(SESSION), "", mdb.HASH, kit.MDB_HASH, h, "cmd", cmd)
							m.Log_IMPORT(h, hostname, "cmd", cmd)
							i = 0
						}
						if i += n; i >= 1024 {
							i = 0
						}
					}
				})
				io.Copy(tty, r)
			})
			m.Gos(m, func(m *ice.Message) {
				io.Copy(channel, tty)
			})
		}
		request.Reply(true, nil)
	}
}
func _ssh_listen(m *ice.Message, hostport string) {
	h := m.Cmdx(mdb.INSERT, m.Prefix(LISTEN), "", mdb.HASH, aaa.HOSTPORT, hostport, kit.MDB_STATUS, "listen")
	defer m.Cmd(mdb.MODIFY, m.Prefix(LISTEN), "", mdb.HASH, kit.MDB_HASH, h, kit.MDB_STATUS, "close")

	config := _ssh_config(m)

	l, e := net.Listen("tcp", hostport)
	m.Assert(e)
	defer l.Close()
	m.Logs(LISTEN, ADDRESS, l.Addr())

	for {
		c, e := l.Accept()
		if m.Warn(e != nil, e) {
			continue
		}

		func(c net.Conn) {
			m.Gos(m.Spawn(), func(msg *ice.Message) {
				defer c.Close()

				m.Logs(CONNECT, aaa.HOSTPORT, c.RemoteAddr(), "->", c.LocalAddr())
				defer m.Logs("disconn", aaa.HOSTPORT, c.RemoteAddr(), "->", c.LocalAddr())

				sc, sessions, req, err := ssh.NewServerConn(c, config)
				if m.Warn(err != nil, err) {
					return
				}

				hostname := sc.Permissions.Extensions["hostname"]
				begin := time.Now()
				h := m.Cmdx(mdb.INSERT, m.Prefix(CONNECT), "", mdb.HASH, aaa.HOSTPORT, c.RemoteAddr().String(), kit.MDB_STATUS, "connect", "hostname", hostname)
				defer m.Cmd(mdb.MODIFY, m.Prefix(CONNECT), "", mdb.HASH, kit.MDB_HASH, h, kit.MDB_STATUS, "close", "close_time", time.Now().Format(ice.MOD_TIME), "duration", time.Now().Sub(begin).String())

				m.Gos(m, func(m *ice.Message) {
					ssh.DiscardRequests(req)
				})

				for session := range sessions {
					channel, requests, err := session.Accept()
					if m.Warn(err != nil, err) {
						continue
					}

					func(channel ssh.Channel, requests <-chan *ssh.Request) {
						m.Gos(m, func(m *ice.Message) {
							_ssh_handle(m, hostname, c, channel, requests)
						})
					}(channel, requests)
				}
			})
		}(c)
	}
}
func _ssh_config(m *ice.Message) *ssh.ServerConfig {
	config := &ssh.ServerConfig{
		BannerCallback: func(conn ssh.ConnMetadata) string {
			m.Log_IMPORT(aaa.HOSTPORT, conn.RemoteAddr(), aaa.USERNAME, conn.User())
			return m.Conf(PUBLIC, "meta.welcome")
		},
		PublicKeyCallback: func(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
			meta, res := map[string]string{}, errors.New(ice.ErrNotAuth)
			m.Richs(PUBLIC, "", kit.MDB_FOREACH, func(k string, value map[string]interface{}) {
				if !strings.HasPrefix(kit.Format(value[kit.MDB_NAME]), conn.User()+"@") {
					return
				}
				if s, e := base64.StdEncoding.DecodeString(kit.Format(value[kit.MDB_TEXT])); !m.Warn(e != nil, e) {
					if pub, e := ssh.ParsePublicKey([]byte(s)); !m.Warn(e != nil) {
						if bytes.Compare(pub.Marshal(), key.Marshal()) == 0 {
							m.Log_AUTH(aaa.HOSTPORT, conn.RemoteAddr(), aaa.USERNAME, conn.User(), "publickey", value[kit.MDB_NAME])
							meta["hostname"] = kit.Format(value[kit.MDB_NAME])
							res = nil
						}
					}
				}
			})
			if tcp.IPIsLocal(m, strings.Split(conn.RemoteAddr().String(), ":")[0]) {
				res = nil
			}
			return &ssh.Permissions{Extensions: meta}, res
		},
		PasswordCallback: func(conn ssh.ConnMetadata, password []byte) (*ssh.Permissions, error) {
			res := errors.New(ice.ErrNotAuth)
			m.Richs(aaa.USER, "", conn.User(), func(k string, value map[string]interface{}) {
				if string(password) == kit.Format(value[aaa.PASSWORD]) {
					m.Log_AUTH(aaa.HOSTPORT, conn.RemoteAddr(), aaa.USERNAME, conn.User(), aaa.PASSWORD, strings.Repeat("*", len(kit.Format(value[aaa.PASSWORD]))))
					res = nil
				}
			})
			return &ssh.Permissions{}, res
		},
	}

	if key, err := ssh.ParsePrivateKey([]byte(m.Cmdx(nfs.CAT, path.Join(os.Getenv("HOME"), m.Conf(PUBLIC, "meta.private"))))); m.Assert(err) {
		config.AddHostKey(key)
	}
	return config
}
func _ssh_dial(m *ice.Message, username, hostport string) (*ssh.Client, error) {
	methods := []ssh.AuthMethod{}
	if key, e := ssh.ParsePrivateKey([]byte(m.Cmdx(nfs.CAT, path.Join(os.Getenv("HOME"), m.Conf(PUBLIC, "meta.private"))))); !m.Warn(e != nil) {
		methods = append(methods, ssh.PublicKeys(key))
	} else {
		return nil, e
	}

	connect, e := ssh.Dial("tcp", hostport, &ssh.ClientConfig{User: username, Auth: methods,
		HostKeyCallback: func(hostname string, remote net.Addr, key ssh.PublicKey) error {
			m.Logs(CONNECT, "hostname", hostname, aaa.HOSTPORT, remote.String())
			return nil
		},
	})
	return connect, e
}

const (
	ADDRESS = "address"
	CONNECT = "connect"
	CHANNEL = "channel"
	SESSION = "session"
	REQUEST = "request"
)
const (
	METHOD = "method"
	PUBLIC = "public"
	LISTEN = "listen"
	DIAL   = "dial"
)

func init() {
	Index.Merge(&ice.Context{
		Configs: map[string]*ice.Config{
			PUBLIC: {Name: PUBLIC, Help: "公钥", Value: kit.Data(
				"private", ".ssh/id_rsa", "public", ".ssh/id_rsa.pub",
				"welcome", "\r\nwelcome to context world\r\n",
				"goodbye", "\r\ngoodbye of context world\r\n",
				kit.MDB_SHORT, kit.MDB_TEXT,
			)},
			LISTEN: {Name: LISTEN, Help: "服务", Value: kit.Data(kit.MDB_SHORT, aaa.HOSTPORT,
				mdb.FIELDS, "time,hash,hostport,status",
			)},
			CONNECT: {Name: CONNECT, Help: "连接", Value: kit.Data(
				mdb.FIELDS, "time,hash,hostport,status,duration,close_time,hostname",
			)},
			SESSION: {Name: SESSION, Help: "会话", Value: kit.Data(
				mdb.FIELDS, "time,hash,hostport,status,tty,cmd",
			)},

			DIAL: {Name: DIAL, Help: "连接", Value: kit.Data(
				mdb.FIELDS, "time,hash,hostport,username",
			)},
		},
		Commands: map[string]*ice.Command{
			PUBLIC: {Name: "public hash=auto auto 添加 导出 导入", Help: "公钥", Action: map[string]*ice.Action{
				mdb.IMPORT: {Name: "import", Help: "导入", List: kit.List(
					kit.MDB_INPUT, "text", kit.MDB_NAME, "file", kit.MDB_VALUE, ".ssh/authorized_keys",
				), Hand: func(m *ice.Message, arg ...string) {
					p := path.Join(os.Getenv("HOME"), kit.Select(arg[0], arg, 1))
					for _, pub := range strings.Split(m.Cmdx(nfs.CAT, p), "\n") {
						if len(pub) > 10 {
							m.Cmd(PUBLIC, mdb.CREATE, pub)
						}
					}
					m.Echo(p)
				}},
				mdb.EXPORT: {Name: "export", Help: "导出", List: kit.List(
					kit.MDB_INPUT, "text", kit.MDB_NAME, "file", kit.MDB_VALUE, ".ssh/authorized_keys",
				), Hand: func(m *ice.Message, arg ...string) {
					list := []string{}
					m.Richs(PUBLIC, "", kit.MDB_FOREACH, func(key string, value map[string]interface{}) {
						list = append(list, fmt.Sprintf("%s %s %s", value[kit.MDB_TYPE], value[kit.MDB_TEXT], value[kit.MDB_NAME]))
					})
					if len(list) > 0 {
						m.Cmdy(nfs.SAVE, path.Join(os.Getenv("HOME"), kit.Select(arg[0], arg, 1)), strings.Join(list, "\n")+"\n")
					}
				}},
				mdb.CREATE: {Name: "create", Help: "添加", List: kit.List(
					kit.MDB_INPUT, "textarea", kit.MDB_NAME, "publickey", kit.MDB_VALUE, "", kit.MDB_STYLE, kit.Dict("width", "800", "height", "100"),
				), Hand: func(m *ice.Message, arg ...string) {
					ls := kit.Split(kit.Select(arg[0], arg, 1))
					m.Cmdy(mdb.INSERT, m.Prefix(PUBLIC), "", mdb.HASH, kit.MDB_TYPE, ls[0],
						kit.MDB_NAME, ls[len(ls)-1], kit.MDB_TEXT, strings.Join(ls[1:len(ls)-1], "+"))
				}},
				mdb.DELETE: {Name: "delete", Help: "删除", Hand: func(m *ice.Message, arg ...string) {
					m.Cmdy(mdb.DELETE, m.Prefix(PUBLIC), "", mdb.HASH, kit.MDB_HASH, m.Option(kit.MDB_HASH))
				}},
			}, Hand: func(m *ice.Message, c *ice.Context, cmd string, arg ...string) {
				if len(arg) > 0 {
					m.Option(mdb.FIELDS, "detail")
				}
				m.Cmdy(mdb.SELECT, m.Prefix(PUBLIC), "", mdb.HASH, kit.MDB_HASH, arg)
				m.PushAction("删除")
			}},

			LISTEN: {Name: "listen hash auto", Help: "服务", Hand: func(m *ice.Message, c *ice.Context, cmd string, arg ...string) {
				if len(arg) == 0 {
					m.Option(mdb.FIELDS, m.Conf(LISTEN, kit.META_FIELDS))
					m.Cmdy(mdb.SELECT, m.Prefix(LISTEN), "", mdb.HASH)
					return
				}
				m.Gos(m, func(m *ice.Message) { _ssh_listen(m, arg[0]) })
			}},
			CONNECT: {Name: "connect hash auto 清理", Help: "连接", Action: map[string]*ice.Action{
				mdb.PRUNES: {Name: "prunes", Help: "清理", Hand: func(m *ice.Message, arg ...string) {
					m.Cmdy(mdb.PRUNES, m.Prefix(CONNECT), "", mdb.HASH, kit.MDB_STATUS, "close")
				}},
			}, Hand: func(m *ice.Message, c *ice.Context, cmd string, arg ...string) {
				if len(arg) == 0 {
					m.Option(mdb.FIELDS, m.Conf(CONNECT, kit.META_FIELDS))
				} else {
					m.Option(mdb.FIELDS, "detail")
				}
				m.Cmdy(mdb.SELECT, m.Prefix(CONNECT), "", mdb.HASH, kit.MDB_HASH, arg)
			}},
			SESSION: {Name: "session hash auto 清理", Help: "会话", Action: map[string]*ice.Action{
				mdb.PRUNES: {Name: "prunes", Help: "清理", Hand: func(m *ice.Message, arg ...string) {
					m.Cmdy(mdb.PRUNES, m.Prefix(SESSION), "", mdb.HASH, kit.MDB_STATUS, "close")
				}},
			}, Hand: func(m *ice.Message, c *ice.Context, cmd string, arg ...string) {
				if len(arg) == 0 {
					m.Option(mdb.FIELDS, m.Conf(SESSION, kit.META_FIELDS))
				} else {
					m.Option(mdb.FIELDS, "detail")
				}
				m.Cmdy(mdb.SELECT, m.Prefix(SESSION), "", mdb.HASH, kit.MDB_HASH, arg)
			}},

			DIAL: {Name: "dial hash auto 登录 cmd:textarea=pwd", Help: "连接", Action: map[string]*ice.Action{
				mdb.CREATE: {Name: "create", Help: "登录", List: kit.List(
					kit.MDB_INPUT, "text", kit.MDB_NAME, aaa.USERNAME, kit.MDB_VALUE, "shy",
					kit.MDB_INPUT, "text", kit.MDB_NAME, aaa.HOSTPORT, kit.MDB_VALUE, "shylinux.com:22",
				), Hand: func(m *ice.Message, arg ...string) {
					for i := 0; i < len(arg); i += 2 {
						m.Option(arg[i], arg[i+1])
					}

					connect, e := _ssh_dial(m, m.Option(aaa.USERNAME), m.Option(aaa.HOSTPORT))
					m.Assert(e)

					h := m.Rich(DIAL, "", kit.Dict(
						aaa.USERNAME, m.Option(aaa.USERNAME),
						aaa.HOSTPORT, m.Option(aaa.HOSTPORT),
						CONNECT, connect,
					))
					m.Echo(h)
				}},

				mdb.DELETE: {Name: "delete", Help: "删除", Hand: func(m *ice.Message, arg ...string) {
					m.Cmdy(mdb.DELETE, m.Prefix(DIAL), "", mdb.HASH, kit.MDB_HASH, m.Option(kit.MDB_HASH))
				}},
			}, Hand: func(m *ice.Message, c *ice.Context, cmd string, arg ...string) {
				if len(arg) == 0 || arg[0] == "" {
					m.Option(mdb.FIELDS, m.Conf(DIAL, kit.META_FIELDS))
					m.Cmdy(mdb.SELECT, m.Prefix(DIAL), "", mdb.HASH)
					m.PushAction("删除")
					return
				}

				m.Richs(DIAL, "", arg[0], func(key string, value map[string]interface{}) {
					connect, ok := value[CONNECT].(*ssh.Client)
					if !ok {
						if c, e := _ssh_dial(m, kit.Format(value[aaa.USERNAME]), kit.Format(value[aaa.HOSTPORT])); m.Assert(e) {
							connect, value[CONNECT] = c, c
						}
					}

					session, e := connect.NewSession()
					m.Assert(e)
					defer session.Close()

					var b bytes.Buffer
					session.Stdout = &b

					err := session.Run(arg[1])
					m.Assert(err)
					m.Echo(b.String())
				})
			}},
		},
	}, nil)
}