# -*- coding: utf-8 eval: (blacken-mode 1) -*-
#
# July 24 2021, Christian Hopps <chopps@labn.net>
#
# Copyright (c) 2021, LabN Consulting, L.L.C.
#
# 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 2
# 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; see the file COPYING; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
import argparse
import datetime
import logging
import os
import pdb
import pty
import re
import readline
import select
import shlex
import socket
import subprocess
import sys
import tempfile
import termios
import time as time_mod
import traceback
import tty


ENDMARKER = b"\x00END\x00"


def lineiter(sock):
    s = ""
    while True:
        sb = sock.recv(256)
        if not sb:
            return

        s += sb.decode("utf-8")
        i = s.find("\n")
        if i != -1:
            yield s[:i]
            s = s[i + 1 :]


def spawn(unet, host, cmd):
    if sys.stdin.isatty():
        old_tty = termios.tcgetattr(sys.stdin)
        tty.setraw(sys.stdin.fileno())
    try:
        master_fd, slave_fd = pty.openpty()

        # use os.setsid() make it run in a new process group, or bash job
        # control will not be enabled
        p = unet.hosts[host].popen(
            cmd,
            preexec_fn=os.setsid,
            stdin=slave_fd,
            stdout=slave_fd,
            stderr=slave_fd,
            universal_newlines=True,
        )

        while p.poll() is None:
            r, w, e = select.select([sys.stdin, master_fd], [], [], 0.25)
            if sys.stdin in r:
                d = os.read(sys.stdin.fileno(), 10240)
                os.write(master_fd, d)
            elif master_fd in r:
                o = os.read(master_fd, 10240)
                if o:
                    os.write(sys.stdout.fileno(), o)
    finally:
        # restore tty settings back
        if sys.stdin.isatty():
            termios.tcsetattr(sys.stdin, termios.TCSADRAIN, old_tty)


def doline(unet, line, writef):
    def host_cmd_split(unet, cmd):
        csplit = cmd.split()
        for i, e in enumerate(csplit):
            if e not in unet.hosts:
                break
        hosts = csplit[:i]
        if not hosts:
            hosts = sorted(unet.hosts.keys())
        cmd = " ".join(csplit[i:])
        return hosts, cmd

    line = line.strip()
    m = re.match(r"^(\S+)(?:\s+(.*))?$", line)
    if not m:
        return True

    cmd = m.group(1)
    oargs = m.group(2) if m.group(2) else ""
    if cmd == "q" or cmd == "quit":
        return False
    if cmd == "hosts":
        writef("%% hosts: %s\n" % " ".join(sorted(unet.hosts.keys())))
    elif cmd in ["term", "vtysh", "xterm"]:
        args = oargs.split()
        if not args or (len(args) == 1 and args[0] == "*"):
            args = sorted(unet.hosts.keys())
        hosts = [unet.hosts[x] for x in args]
        for host in hosts:
            if cmd == "t" or cmd == "term":
                host.run_in_window("bash")
            elif cmd == "v" or cmd == "vtysh":
                host.run_in_window("vtysh")
            elif cmd == "x" or cmd == "xterm":
                host.run_in_window("bash", forcex=True)
    elif cmd == "sh":
        hosts, cmd = host_cmd_split(unet, oargs)
        for host in hosts:
            if sys.stdin.isatty():
                spawn(unet, host, cmd)
            else:
                if len(hosts) > 1:
                    writef("------ Host: %s ------\n" % host)
                output = unet.hosts[host].cmd_legacy(cmd)
                writef(output)
                if len(hosts) > 1:
                    writef("------- End: %s ------\n" % host)
        writef("\n")
    elif cmd == "h" or cmd == "help":
        writef(
            """
Commands:
  help                       :: this help
  sh [hosts] <shell-command> :: execute <shell-command> on <host>
  term [hosts]               :: open shell terminals for hosts
  vtysh [hosts]              :: open vtysh terminals for hosts
  [hosts] <vtysh-command>    :: execute vtysh-command on hosts\n\n"""
        )
    else:
        hosts, cmd = host_cmd_split(unet, line)
        for host in hosts:
            if len(hosts) > 1:
                writef("------ Host: %s ------\n" % host)
            output = unet.hosts[host].cmd_legacy('vtysh -c "{}"'.format(cmd))
            writef(output)
            if len(hosts) > 1:
                writef("------- End: %s ------\n" % host)
        writef("\n")
    return True


def cli_server_setup(unet):
    sockdir = tempfile.mkdtemp("-sockdir", "pyt")
    sockpath = os.path.join(sockdir, "cli-server.sock")
    try:
        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
        sock.settimeout(10)
        sock.bind(sockpath)
        sock.listen(1)
        return sock, sockdir, sockpath
    except Exception:
        unet.cmd_status("rm -rf " + sockdir)
        raise


def cli_server(unet, server_sock):
    sock, addr = server_sock.accept()

    # Go into full non-blocking mode now
    sock.settimeout(None)

    for line in lineiter(sock):
        line = line.strip()
        def writef(x):
            xb = x.encode("utf-8")
            sock.send(xb)
        if not doline(unet, line, writef):
            return
        sock.send(ENDMARKER)


def cli_client(sockpath, prompt="unet> "):
    sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
    sock.settimeout(10)
    sock.connect(sockpath)

    # Go into full non-blocking mode now
    sock.settimeout(None)

    print("\n--- Micronet CLI Starting ---\n\n")
    while True:
        if sys.version_info[0] == 2:
            line = raw_input(prompt)  # pylint: disable=E0602
        else:
            line = input(prompt)
        if line is None:
            return

        # Need to put \n back
        line += "\n"

        # Send the CLI command
        sock.send(line.encode("utf-8"))

        def bendswith(b, sentinel):
            slen = len(sentinel)
            return len(b) >= slen and b[-slen:] == sentinel

        # Collect the output
        rb = b""
        while not bendswith(rb, ENDMARKER):
            lb = sock.recv(4096)
            if not lb:
                return
            rb += lb

        # Remove the marker
        rb = rb[:-len(ENDMARKER)]

        # Write the output
        sys.stdout.write(rb.decode("utf-8"))


def local_cli(unet, outf, prompt="unet> "):
    print("\n--- Micronet CLI Starting ---\n\n")
    while True:
        if sys.version_info[0] == 2:
            line = raw_input(prompt)  # pylint: disable=E0602
        else:
            line = input(prompt)
        if line is None:
            return
        if not doline(unet, line, outf.write):
            return


def cli(unet, histfile=None, sockpath=None, force_window=False, title=None, prompt=None, background=True):
    if prompt is None:
        prompt = "unet> "

    if force_window or not sys.stdin.isatty():
        # Run CLI in another window b/c we have no tty.
        sock, sockdir, sockpath = cli_server_setup(unet)

        python_path = unet.get_exec_path(["python3", "python"])
        us = os.path.realpath(__file__)
        cmd = "{} {}".format(python_path, us)
        if histfile:
            cmd += " --histfile=" + histfile
        if title:
            cmd += " --prompt={}".format(title)
        cmd += " " + sockpath

        try:
            unet.run_in_window(cmd, new_window=True, title=title, background=background)
            return cli_server(unet, sock)
        finally:
            unet.cmd_status("rm -rf " + sockdir)

    if not unet:
        logger.debug("client-cli using sockpath %s", sockpath)

    try:
        if histfile is None:
            histfile = os.path.expanduser("~/.micronet-history.txt")
            if not os.path.exists(histfile):
                if unet:
                    unet.cmd("touch " + histfile)
                else:
                    subprocess.run("touch " + histfile)
        if histfile:
            readline.read_history_file(histfile)
    except Exception:
        pass

    try:
        if sockpath:
            cli_client(sockpath, prompt=prompt)
        else:
            local_cli(unet, sys.stdout, prompt=prompt)
    except EOFError:
        pass
    except Exception as ex:
        logger.critical("cli: got exception: %s", ex, exc_info=True)
        raise
    finally:
        readline.write_history_file(histfile)


if __name__ == "__main__":
    logging.basicConfig(level=logging.DEBUG, filename="/tmp/topotests/cli-client.log")
    logger = logging.getLogger("cli-client")
    logger.info("Start logging cli-client")

    parser = argparse.ArgumentParser()
    parser.add_argument("--histfile", help="file to user for history")
    parser.add_argument("--prompt-text", help="prompt string to use")
    parser.add_argument("socket", help="path to pair of sockets to communicate over")
    args = parser.parse_args()

    prompt = "{}> ".format(args.prompt_text) if args.prompt_text else "unet> "
    cli(None, args.histfile, args.socket, prompt=prompt)