#! /usr/bin/env python3
"""Interfaces for launching and remotely controlling Web browsers."""
# Maintained by Georg Brandl.

import os
import shlex
import shutil
import sys
import subprocess
import threading

__all__ = ["Error", "open", "open_new", "open_new_tab", "get", "register"]

class Error(Exception):
 pass

_lock = threading.RLock()
_browsers = {} # Dictionary of available browser controllers
_tryorder = None # Preference order of available browsers
_os_preferred_browser = None # The preferred browser

def register(name, klass, instance=None, *, preferred=False):
 """Register a browser connector."""
 with _lock:
 if _tryorder is None:
 register_standard_browsers()
 _browsers[name.lower()] = [klass, instance]

 # Preferred browsers go to the front of the list.
 # Need to match to the default browser returned by xdg-settings, which
 # may be of the form e.g. "firefox.desktop".
 if preferred or (_os_preferred_browser and name in _os_preferred_browser):
 _tryorder.insert(0, name)
 else:
 _tryorder.append(name)

def get(using=None):
 """Return a browser launcher instance appropriate for the environment."""
 if _tryorder is None:
 with _lock:
 if _tryorder is None:
 register_standard_browsers()
 if using is not None:
 alternatives = [using]
 else:
 alternatives = _tryorder
 for browser in alternatives:
 if '%s' in browser:
 # User gave us a command line, split it into name and args
 browser = shlex.split(browser)
 if browser[-1] == '&':
 return BackgroundBrowser(browser[:-1])
 else:
 return GenericBrowser(browser)
 else:
 # User gave us a browser name or path.
 try:
 command = _browsers[browser.lower()]
 except KeyError:
 command = _synthesize(browser)
 if command[1] is not None:
 return command[1]
 elif command[0] is not None:
 return command[0]()
 raise Error("could not locate runnable browser")

# Please note: the following definition hides a builtin function.
# It is recommended one does "import webbrowser" and uses webbrowser.open(url)
# instead of "from webbrowser import *".

def open(url, new=0, autoraise=True):
 if _tryorder is None:
 with _lock:
 if _tryorder is None:
 register_standard_browsers()
 for name in _tryorder:
 browser = get(name)
 if browser.open(url, new, autoraise):
 return True
 return False

def open_new(url):
 return open(url, 1)

def open_new_tab(url):
 return open(url, 2)


def _synthesize(browser, *, preferred=False):
 """Attempt to synthesize a controller base on existing controllers.

 This is useful to create a controller when a user specifies a path to
 an entry in the BROWSER environment variable -- we can copy a general
 controller to operate using a specific installation of the desired
 browser in this way.

 If we can't create a controller in this way, or if there is no
 executable for the requested browser, return [None, None].

 """
 cmd = browser.split()[0]
 if not shutil.which(cmd):
 return [None, None]
 name = os.path.basename(cmd)
 try:
 command = _browsers[name.lower()]
 except KeyError:
 return [None, None]
 # now attempt to clone to fit the new name:
 controller = command[1]
 if controller and name.lower() == controller.basename:
 import copy
 controller = copy.copy(controller)
 controller.name = browser
 controller.basename = os.path.basename(browser)
 register(browser, None, instance=controller, preferred=preferred)
 return [None, controller]
 return [None, None]


# General parent classes

class BaseBrowser(object):
 """Parent class for all browsers. Do not use directly."""

 args = ['%s']

 def __init__(self, name=""):
 self.name = name
 self.basename = name

 def open(self, url, new=0, autoraise=True):
 raise NotImplementedError

 def open_new(self, url):
 return self.open(url, 1)

 def open_new_tab(self, url):
 return self.open(url, 2)


class GenericBrowser(BaseBrowser):
 """Class for all browsers started with a command
 and without remote functionality."""

 def __init__(self, name):
 if isinstance(name, str):
 self.name = name
 self.args = ["%s"]
 else:
 # name should be a list with arguments
 self.name = name[0]
 self.args = name[1:]
 self.basename = os.path.basename(self.name)

 def open(self, url, new=0, autoraise=True):
 sys.audit("webbrowser.open", url)
 cmdline = [self.name] + [arg.replace("%s", url)
 for arg in self.args]
 try:
 if sys.platform[:3] == 'win':
 p = subprocess.Popen(cmdline)
 else:
 p = subprocess.Popen(cmdline, close_fds=True)
 return not p.wait()
 except OSError:
 return False


class BackgroundBrowser(GenericBrowser):
 """Class for all browsers which are to be started in the
 background."""

 def open(self, url, new=0, autoraise=True):
 cmdline = [self.name] + [arg.replace("%s", url)
 for arg in self.args]
 sys.audit("webbrowser.open", url)
 try:
 if sys.platform[:3] == 'win':
 p = subprocess.Popen(cmdline)
 else:
 p = subprocess.Popen(cmdline, close_fds=True,
 start_new_session=True)
 return (p.poll() is None)
 except OSError:
 return False


class UnixBrowser(BaseBrowser):
 """Parent class for all Unix browsers with remote functionality."""

 raise_opts = None
 background = False
 redirect_stdout = True
 # In remote_args, %s will be replaced with the requested URL. %action will
 # be replaced depending on the value of 'new' passed to open.
 # remote_action is used for new=0 (open). If newwin is not None, it is
 # used for new=1 (open_new). If newtab is not None, it is used for
 # new=3 (open_new_tab). After both substitutions are made, any empty
 # strings in the transformed remote_args list will be removed.
 remote_args = ['%action', '%s']
 remote_action = None
 remote_action_newwin = None
 remote_action_newtab = None

 def _invoke(self, args, remote, autoraise, url=None):
 raise_opt = []
 if remote and self.raise_opts:
 # use autoraise argument only for remote invocation
 autoraise = int(autoraise)
 opt = self.raise_opts[autoraise]
 if opt: raise_opt = [opt]

 cmdline = [self.name] + raise_opt + args

 if remote or self.background:
 inout = subprocess.DEVNULL
 else:
 # for TTY browsers, we need stdin/out
 inout = None
 p = subprocess.Popen(cmdline, close_fds=True, stdin=inout,
 stdout=(self.redirect_stdout and inout or None),
 stderr=inout, start_new_session=True)
 if remote:
 # wait at most five seconds. If the subprocess is not finished, the
 # remote invocation has (hopefully) started a new instance.
 try:
 rc = p.wait(5)
 # if remote call failed, open() will try direct invocation
 return not rc
 except subprocess.TimeoutExpired:
 return True
 elif self.background:
 if p.poll() is None:
 return True
 else:
 return False
 else:
 return not p.wait()

 def open(self, url, new=0, autoraise=True):
 sys.audit("webbrowser.open", url)
 if new == 0:
 action = self.remote_action
 elif new == 1:
 action = self.remote_action_newwin
 elif new == 2:
 if self.remote_action_newtab is None:
 action = self.remote_action_newwin
 else:
 action = self.remote_action_newtab
 else:
 raise Error("Bad 'new' parameter to open(); " +
 "expected 0, 1, or 2, got %s" % new)

 args = [arg.replace("%s", url).replace("%action", action)
 for arg in self.remote_args]
 args = [arg for arg in args if arg]
 success = self._invoke(args, True, autoraise, url)
 if not success:
 # remote invocation failed, try straight way
 args = [arg.replace("%s", url) for arg in self.args]
 return self._invoke(args, False, False)
 else:
 return True


class Mozilla(UnixBrowser):
 """Launcher class for Mozilla browsers."""

 remote_args = ['%action', '%s']
 remote_action = ""
 remote_action_newwin = "-new-window"
 remote_action_newtab = "-new-tab"
 background = True


class Netscape(UnixBrowser):
 """Launcher class for Netscape browser."""

 raise_opts = ["-noraise", "-raise"]
 remote_args = ['-remote', 'openURL(%s%action)']
 remote_action = ""
 remote_action_newwin = ",new-window"
 remote_action_newtab = ",new-tab"
 background = True


class Galeon(UnixBrowser):
 """Launcher class for Galeon/Epiphany browsers."""

 raise_opts = ["-noraise", ""]
 remote_args = ['%action', '%s']
 remote_action = "-n"
 remote_action_newwin = "-w"
 background = True


class Chrome(UnixBrowser):
 "Launcher class for Google Chrome browser."

 remote_args = ['%action', '%s']
 remote_action = ""
 remote_action_newwin = "--new-window"
 remote_action_newtab = ""
 background = True

Chromium = Chrome


class Opera(UnixBrowser):
 "Launcher class for Opera browser."

 remote_args = ['%action', '%s']
 remote_action = ""
 remote_action_newwin = "--new-window"
 remote_action_newtab = ""
 background = True


class Elinks(UnixBrowser):
 "Launcher class for Elinks browsers."

 remote_args = ['-remote', 'openURL(%s%action)']
 remote_action = ""
 remote_action_newwin = ",new-window"
 remote_action_newtab = ",new-tab"
 background = False

 # elinks doesn't like its stdout to be redirected -
 # it uses redirected stdout as a signal to do -dump
 redirect_stdout = False


class Konqueror(BaseBrowser):
 """Controller for the KDE File Manager (kfm, or Konqueror).

 See the output of ``kfmclient --commands``
 for more information on the Konqueror remote-control interface.
 """

 def open(self, url, new=0, autoraise=True):
 sys.audit("webbrowser.open", url)
 # XXX Currently I know no way to prevent KFM from opening a new win.
 if new == 2:
 action = "newTab"
 else:
 action = "openURL"

 devnull = subprocess.DEVNULL

 try:
 p = subprocess.Popen(["kfmclient", action, url],
 close_fds=True, stdin=devnull,
 stdout=devnull, stderr=devnull)
 except OSError:
 # fall through to next variant
 pass
 else:
 p.wait()
 # kfmclient's return code unfortunately has no meaning as it seems
 return True

 try:
 p = subprocess.Popen(["konqueror", "--silent", url],
 close_fds=True, stdin=devnull,
 stdout=devnull, stderr=devnull,
 start_new_session=True)
 except OSError:
 # fall through to next variant
 pass
 else:
 if p.poll() is None:
 # Should be running now.
 return True

 try:
 p = subprocess.Popen(["kfm", "-d", url],
 close_fds=True, stdin=devnull,
 stdout=devnull, stderr=devnull,
 start_new_session=True)
 except OSError:
 return False
 else:
 return (p.poll() is None)


class Grail(BaseBrowser):
 # There should be a way to maintain a connection to Grail, but the
 # Grail remote control protocol doesn't really allow that at this
 # point. It probably never will!
 def _find_grail_rc(self):
 import glob
 import pwd
 import socket
 import tempfile
 tempdir = os.path.join(tempfile.gettempdir(),
 ".grail-unix")
 user = pwd.getpwuid(os.getuid())[0]
 filename = os.path.join(tempdir, user + "-*")
 maybes = glob.glob(filename)
 if not maybes:
 return None
 s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
 for fn in maybes:
 # need to PING each one until we find one that's live
 try:
 s.connect(fn)
 except OSError:
 # no good; attempt to clean it out, but don't fail:
 try:
 os.unlink(fn)
 except OSError:
 pass
 else:
 return s

 def _remote(self, action):
 s = self._find_grail_rc()
 if not s:
 return 0
 s.send(action)
 s.close()
 return 1

 def open(self, url, new=0, autoraise=True):
 sys.audit("webbrowser.open", url)
 if new:
 ok = self._remote("LOADNEW " + url)
 else:
 ok = self._remote("LOAD " + url)
 return ok


#
# Platform support for Unix
#

# These are the right tests because all these Unix browsers require either
# a console terminal or an X display to run.

def register_X_browsers():

 # use xdg-open if around
 if shutil.which("xdg-open"):
 register("xdg-open", None, BackgroundBrowser("xdg-open"))

 # The default GNOME3 browser
 if "GNOME_DESKTOP_SESSION_ID" in os.environ and shutil.which("gvfs-open"):
 register("gvfs-open", None, BackgroundBrowser("gvfs-open"))

 # The default GNOME browser
 if "GNOME_DESKTOP_SESSION_ID" in os.environ and shutil.which("gnome-open"):
 register("gnome-open", None, BackgroundBrowser("gnome-open"))

 # The default KDE browser
 if "KDE_FULL_SESSION" in os.environ and shutil.which("kfmclient"):
 register("kfmclient", Konqueror, Konqueror("kfmclient"))

 if shutil.which("x-www-browser"):
 register("x-www-browser", None, BackgroundBrowser("x-www-browser"))

 # The Mozilla browsers
 for browser in ("firefox", "iceweasel", "iceape", "seamonkey"):
 if shutil.which(browser):
 register(browser, None, Mozilla(browser))

 # The Netscape and old Mozilla browsers
 for browser in ("mozilla-firefox",
 "mozilla-firebird", "firebird",
 "mozilla", "netscape"):
 if shutil.which(browser):
 register(browser, None, Netscape(browser))

 # Konqueror/kfm, the KDE browser.
 if shutil.which("kfm"):
 register("kfm", Konqueror, Konqueror("kfm"))
 elif shutil.which("konqueror"):
 register("konqueror", Konqueror, Konqueror("konqueror"))

 # Gnome's Galeon and Epiphany
 for browser in ("galeon", "epiphany"):
 if shutil.which(browser):
 register(browser, None, Galeon(browser))

 # Skipstone, another Gtk/Mozilla based browser
 if shutil.which("skipstone"):
 register("skipstone", None, BackgroundBrowser("skipstone"))

 # Google Chrome/Chromium browsers
 for browser in ("google-chrome", "chrome", "chromium", "chromium-browser"):
 if shutil.which(browser):
 register(browser, None, Chrome(browser))

 # Opera, quite popular
 if shutil.which("opera"):
 register("opera", None, Opera("opera"))

 # Next, Mosaic -- old but still in use.
 if shutil.which("mosaic"):
 register("mosaic", None, BackgroundBrowser("mosaic"))

 # Grail, the Python browser. Does anybody still use it?
 if shutil.which("grail"):
 register("grail", Grail, None)

def register_standard_browsers():
 global _tryorder
 _tryorder = []

 if sys.platform == 'darwin':
 register("MacOSX", None, MacOSXOSAScript('default'))
 register("chrome", None, MacOSXOSAScript('chrome'))
 register("firefox", None, MacOSXOSAScript('firefox'))
 register("safari", None, MacOSXOSAScript('safari'))
 # OS X can use below Unix support (but we prefer using the OS X
 # specific stuff)

 if sys.platform[:3] == "win":
 # First try to use the default Windows browser
 register("windows-default", WindowsDefault)

 # Detect some common Windows browsers, fallback to IE
 iexplore = os.path.join(os.environ.get("PROGRAMFILES", "C:\\Program Files"),
 "Internet Explorer\\IEXPLORE.EXE")
 for browser in ("firefox", "firebird", "seamonkey", "mozilla",
 "netscape", "opera", iexplore):
 if shutil.which(browser):
 register(browser, None, BackgroundBrowser(browser))
 else:
 # Prefer X browsers if present
 if os.environ.get("DISPLAY"):
 try:
 cmd = "xdg-settings get default-web-browser".split()
 raw_result = subprocess.check_output(cmd, stderr=subprocess.DEVNULL)
 result = raw_result.decode().strip()
 except (FileNotFoundError, subprocess.CalledProcessError):
 pass
 else:
 global _os_preferred_browser
 _os_preferred_browser = result

 register_X_browsers()

 # Also try console browsers
 if os.environ.get("TERM"):
 if shutil.which("www-browser"):
 register("www-browser", None, GenericBrowser("www-browser"))
 # The Links/elinks browsers <http://artax.karlin.mff.cuni.cz/~mikulas/links/>
 if shutil.which("links"):
 register("links", None, GenericBrowser("links"))
 if shutil.which("elinks"):
 register("elinks", None, Elinks("elinks"))
 # The Lynx browser <http://lynx.isc.org/>, <http://lynx.browser.org/>
 if shutil.which("lynx"):
 register("lynx", None, GenericBrowser("lynx"))
 # The w3m browser <http://w3m.sourceforge.net/>
 if shutil.which("w3m"):
 register("w3m", None, GenericBrowser("w3m"))

 # OK, now that we know what the default preference orders for each
 # platform are, allow user to override them with the BROWSER variable.
 if "BROWSER" in os.environ:
 userchoices = os.environ["BROWSER"].split(os.pathsep)
 userchoices.reverse()

 # Treat choices in same way as if passed into get() but do register
 # and prepend to _tryorder
 for cmdline in userchoices:
 if cmdline != '':
 cmd = _synthesize(cmdline, preferred=True)
 if cmd[1] is None:
 register(cmdline, None, GenericBrowser(cmdline), preferred=True)

 # what to do if _tryorder is now empty?


#
# Platform support for Windows
#

if sys.platform[:3] == "win":
 class WindowsDefault(BaseBrowser):
 def open(self, url, new=0, autoraise=True):
 sys.audit("webbrowser.open", url)
 try:
 os.startfile(url)
 except OSError:
 # [Error 22] No application is associated with the specified
 # file for this operation: '<URL>'
 return False
 else:
 return True

#
# Platform support for MacOS
#

if sys.platform == 'darwin':
 # Adapted from patch submitted to SourceForge by Steven J. Burr
 class MacOSX(BaseBrowser):
 """Launcher class for Aqua browsers on Mac OS X

 Optionally specify a browser name on instantiation. Note that this
 will not work for Aqua browsers if the user has moved the application
 package after installation.

 If no browser is specified, the default browser, as specified in the
 Internet System Preferences panel, will be used.
 """
 def __init__(self, name):
 self.name = name

 def open(self, url, new=0, autoraise=True):
 sys.audit("webbrowser.open", url)
 assert "'" not in url
 # hack for local urls
 if not ':' in url:
 url = 'file:'+url

 # new must be 0 or 1
 new = int(bool(new))
 if self.name == "default":
 # User called open, open_new or get without a browser parameter
 script = 'open location "%s"' % url.replace('"', '%22') # opens in default browser
 else:
 # User called get and chose a browser
 if self.name == "OmniWeb":
 toWindow = ""
 else:
 # Include toWindow parameter of OpenURL command for browsers
 # that support it. 0 == new window; -1 == existing
 toWindow = "toWindow %d" % (new - 1)
 cmd = 'OpenURL "%s"' % url.replace('"', '%22')
 script = '''tell application "%s"
 activate
 %s %s
 end tell''' % (self.name, cmd, toWindow)
 # Open pipe to AppleScript through osascript command
 osapipe = os.popen("osascript", "w")
 if osapipe is None:
 return False
 # Write script to osascript's stdin
 osapipe.write(script)
 rc = osapipe.close()
 return not rc

 class MacOSXOSAScript(BaseBrowser):
 def __init__(self, name):
 self._name = name

 def open(self, url, new=0, autoraise=True):
 if self._name == 'default':
 script = 'open location "%s"' % url.replace('"', '%22') # opens in default browser
 else:
 script = '''
 tell application "%s"
 activate
 open location "%s"
 end
 '''%(self._name, url.replace('"', '%22'))

 osapipe = os.popen("osascript", "w")
 if osapipe is None:
 return False

 osapipe.write(script)
 rc = osapipe.close()
 return not rc


def main():
 import getopt
 usage = """Usage: %s [-n | -t] url
 -n: open new window
 -t: open new tab""" % sys.argv[0]
 try:
 opts, args = getopt.getopt(sys.argv[1:], 'ntd')
 except getopt.error as msg:
 print(msg, file=sys.stderr)
 print(usage, file=sys.stderr)
 sys.exit(1)
 new_win = 0
 for o, a in opts:
 if o == '-n': new_win = 1
 elif o == '-t': new_win = 2
 if len(args) != 1:
 print(usage, file=sys.stderr)
 sys.exit(1)

 url = args[0]
 open(url, new_win)

 print("\a")

if __name__ == "__main__":
 main()