# zeroconf.py - zeroconf support for Mercurial
#
# Copyright 2005-2007 Olivia Mackall <olivia@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''discover and advertise repositories on the local network

The zeroconf extension will advertise :hg:`serve` instances over
DNS-SD so that they can be discovered using the :hg:`paths` command
without knowing the server's IP address.

To allow other people to discover your repository using run
:hg:`serve` in your repository::

  $ cd test
  $ hg serve

You can discover Zeroconf-enabled repositories by running
:hg:`paths`::

  $ hg paths
  zc-test = http://example.com:8000/test
'''

from __future__ import annotations

import os
import socket
import time

from . import Zeroconf
from mercurial import (
    dispatch,
    encoding,
    extensions,
    hg,
    pycompat,
    ui as uimod,
)
from mercurial.configuration import rcutil
from mercurial.hgweb import server as servermod

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = b'ships-with-hg-core'

# publish

server = None
localip = None


def getip():
    # finds external-facing interface without sending any packets (Linux)
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        s.connect(('1.0.0.1', 0))
        ip = s.getsockname()[0]
        return ip
    except OSError:
        pass

    # Generic method, sometimes gives useless results
    try:
        dumbip = socket.gethostbyaddr(socket.gethostname())[2][0]
        if ':' in dumbip:
            dumbip = '127.0.0.1'
        if not dumbip.startswith('127.'):
            return dumbip
    except (socket.gaierror, socket.herror):
        dumbip = '127.0.0.1'

    # works elsewhere, but actually sends a packet
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        s.connect(('1.0.0.1', 1))
        ip = s.getsockname()[0]
        return ip
    except OSError:
        pass

    return dumbip


def publish(name, desc, path, port):
    global server, localip
    if not server:
        ip = getip()
        if ip.startswith('127.'):
            # if we have no internet connection, this can happen.
            return
        localip = socket.inet_aton(ip)
        server = Zeroconf.Zeroconf(ip)

    hostname = socket.gethostname().split('.')[0]
    host = hostname + ".local"
    name = "%s-%s" % (hostname, name)

    # advertise to browsers
    svc = Zeroconf.ServiceInfo(
        b'_http._tcp.local.',
        pycompat.bytestr(name + '._http._tcp.local.'),
        server=host,
        port=port,
        properties={b'description': desc, b'path': b"/" + path},
        address=localip,
        weight=0,
        priority=0,
    )
    server.registerService(svc)

    # advertise to Mercurial clients
    svc = Zeroconf.ServiceInfo(
        b'_hg._tcp.local.',
        pycompat.bytestr(name + '._hg._tcp.local.'),
        server=host,
        port=port,
        properties={b'description': desc, b'path': b"/" + path},
        address=localip,
        weight=0,
        priority=0,
    )
    server.registerService(svc)


def zc_create_server(create_server, ui, app):
    httpd = create_server(ui, app)
    port = httpd.port

    try:
        repos = app.repos
    except AttributeError:
        # single repo
        with app._obtainrepo() as repo:
            name = app.reponame or os.path.basename(repo.root)
            path = repo.ui.config(b"web", b"prefix", b"").strip(b'/')
            desc = repo.ui.config(b"web", b"description")
            if not desc:
                desc = name
        publish(name, desc, path, port)
    else:
        # webdir
        prefix = app.ui.config(b"web", b"prefix", b"").strip(b'/') + b'/'
        for repo, path in repos:
            u = app.ui.copy()
            if rcutil.use_repo_hgrc():
                u.readconfig(os.path.join(path, b'.hg', b'hgrc'))
            name = os.path.basename(repo)
            path = (prefix + repo).strip(b'/')
            desc = u.config(b'web', b'description')
            if not desc:
                desc = name
            publish(name, desc, path, port)
    return httpd


# listen


class listener:
    def __init__(self):
        self.found = {}

    def removeService(self, server, type, name):
        if repr(name) in self.found:
            del self.found[repr(name)]

    def addService(self, server, type, name):
        self.found[repr(name)] = server.getServiceInfo(type, name)


def getzcpaths():
    ip = getip()
    if ip.startswith('127.'):
        return
    server = Zeroconf.Zeroconf(ip)
    l = listener()
    Zeroconf.ServiceBrowser(server, b"_hg._tcp.local.", l)
    time.sleep(1)
    server.close()
    for value in l.found.values():
        name = value.name[: value.name.index(b'.')]
        url = "http://%s:%s%s" % (
            socket.inet_ntoa(value.address),
            value.port,
            value.properties.get("path", "/"),
        )
        yield b"zc-" + name, pycompat.bytestr(url)


def config(orig, self, section, key, *args, **kwargs):
    if section == b"paths" and key.startswith(b"zc-"):
        for name, path in getzcpaths():
            if name == key:
                return path
    return orig(self, section, key, *args, **kwargs)


def configitems(orig, self, section, *args, **kwargs):
    repos = orig(self, section, *args, **kwargs)
    if section == b"paths":
        repos += getzcpaths()
    return repos


def configsuboptions(orig, self, section, name, *args, **kwargs):
    opt, sub = orig(self, section, name, *args, **kwargs)
    if section == b"paths" and name.startswith(b"zc-"):
        # We have to find the URL in the zeroconf paths.  We can't cons up any
        # suboptions, so we use any that we found in the original config.
        for zcname, zcurl in getzcpaths():
            if zcname == name:
                return zcurl, sub
    return opt, sub


def defaultdest(orig, source):
    for name, path in getzcpaths():
        if path == source:
            return name.encode(encoding.encoding)
    return orig(source)


def cleanupafterdispatch(orig, ui, options, cmd, cmdfunc):
    try:
        return orig(ui, options, cmd, cmdfunc)
    finally:
        # we need to call close() on the server to notify() the various
        # threading Conditions and allow the background threads to exit
        global server
        if server:
            server.close()


extensions.wrapfunction(dispatch, '_runcommand', cleanupafterdispatch)

extensions.wrapfunction(uimod.ui, 'config', config)
extensions.wrapfunction(uimod.ui, 'configitems', configitems)
extensions.wrapfunction(uimod.ui, 'configsuboptions', configsuboptions)
extensions.wrapfunction(hg, 'defaultdest', defaultdest)
extensions.wrapfunction(servermod, 'create_server', zc_create_server)
