#    Gedit snippets plugin
#    Copyright (C) 2005-2006  Jesse van den Kieboom <jesse@icecrew.nl>
#
#    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; if not, write to the Free Software
#    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

import traceback
import re
import sys
import signal
import locale
import subprocess
from gi.repository import GObject, Gtk

from . import helper
from .substitutionparser import SubstitutionParser

# These are places in a view where the cursor can go and do things
class Placeholder:
    def __init__(self, view, tabstop, environ, defaults, begin):
        self.ok = True
        self.done = False
        self.buf = view.get_buffer()
        self.view = view
        self.has_references = False
        self.mirrors = []
        self.leave_mirrors = []
        self.tabstop = tabstop
        self.environ = environ
        self.set_default(defaults)
        self.prev_contents = self.default
        self.set_mark_gravity()

        if begin:
            self.begin = self.buf.create_mark(None, begin, self.mark_gravity[0])
        else:
            self.begin = None

        self.end = None

    def get_environ(self):
        return self.environ['utf8']

    def __str__(self):
        return '%s (%s)' % (str(self.__class__), str(self.default))

    def set_mark_gravity(self):
        self.mark_gravity = [True, False]

    def set_default(self, defaults):
        self.default = None
        self.defaults = []

        if not defaults:
            return

        for d in defaults:
            dm = self.expand_environment(d)

            if dm:
                self.defaults.append(dm)

                if not self.default:
                    self.default = dm

                if dm != d:
                    break

    def literal(self, s):
        return repr(s)

    def format_environment(self, s):
        return s

    def re_environment(self, m):
        env = self.get_environ()

        if m.group(1) or not m.group(2) in env:
            return '$' + m.group(2)
        else:
            return self.format_environment(env[m.group(2)])

    def expand_environment(self, text):
        if not text:
            return text

        return re.sub('(\\\\)?\\$([A-Z_]+)', self.re_environment, text)

    def get_iter(self, mark):
        if mark and not mark.get_deleted():
            return self.buf.get_iter_at_mark(mark)
        else:
            return None

    def begin_iter(self):
        return self.get_iter(self.begin)

    def end_iter(self):
        return self.get_iter(self.end)

    def run_last(self, placeholders):
        begin = self.begin_iter()
        self.end = self.buf.create_mark(None, begin, self.mark_gravity[1])

        if self.default:
            helper.insert_with_indent(self.view, begin, self.default, False, self)

    def remove(self, force = False):
        if self.begin and not self.begin.get_deleted():
            self.buf.delete_mark(self.begin)

        if self.end and not self.end.get_deleted():
            self.buf.delete_mark(self.end)

    # Do something on beginning this placeholder
    def enter(self):
        if not self.begin or self.begin.get_deleted():
            return

        self.buf.move_mark(self.buf.get_insert(), self.begin_iter())

        if self.end:
            self.buf.move_mark(self.buf.get_selection_bound(), self.end_iter())
        else:
            self.buf.move_mark(self.buf.get_selection_bound(), self.begin_iter())

    def get_text(self):
        if self.begin and self.end:
            biter = self.begin_iter()
            eiter = self.end_iter()

            if biter and eiter:
                return self.buf.get_text(self.begin_iter(), self.end_iter(), False)
            else:
                return ''
        else:
            return ''

    def add_mirror(self, mirror, onleave = False):
        mirror.has_references = True

        if onleave:
            self.leave_mirrors.append(mirror)
        else:
            self.mirrors.append(mirror)

    def set_text(self, text):
        if self.begin.get_deleted() or self.end.get_deleted():
            return

        # Set from self.begin to self.end to text!
        self.buf.begin_user_action()
        # Remove everything between self.begin and self.end
        begin = self.begin_iter()
        self.buf.delete(begin, self.end_iter())

        # Insert the text from the mirror
        helper.insert_with_indent(self.view, begin, text, True, self)
        self.buf.end_user_action()

        self.update_contents()

    def update_contents(self):
        prev = self.prev_contents
        self.prev_contents = self.get_text()

        if prev != self.get_text():
            for mirror in self.mirrors:
                if not mirror.update(self):
                    return

    def update_leave_mirrors(self):
        # Notify mirrors
        for mirror in self.leave_mirrors:
            if not mirror.update(self):
                return

    # Do something on ending this placeholder
    def leave(self):
           self.update_leave_mirrors()

    def find_mirrors(self, text, placeholders):
        mirrors = []

        while (True):
            m = re.search('(\\\\)?\\$(?:{([0-9]+)}|([0-9]+))', text)

            if not m:
                break

            # Skip escaped mirrors
            if m.group(1):
                text = text[m.end():]
                continue

            tabstop = int(m.group(2) or m.group(3))

            if tabstop in placeholders:
                if not tabstop in mirrors:
                    mirrors.append(tabstop)

                text = text[m.end():]
            else:
                self.ok = False
                return None

        return mirrors

# This is an placeholder which inserts a mirror of another Placeholder
class PlaceholderMirror(Placeholder):
    def __init__(self, view, tabstop, environ, begin):
        Placeholder.__init__(self, view, -1, environ, None, begin)
        self.mirror_stop = tabstop

    def update(self, mirror):
        self.set_text(mirror.get_text())
        return True

    def run_last(self, placeholders):
        Placeholder.run_last(self, placeholders)

        if self.mirror_stop in placeholders:
            mirror = placeholders[self.mirror_stop]

            mirror.add_mirror(self)

            if mirror.default:
                self.set_text(mirror.default)
        else:
            self.ok = False

# This placeholder indicates the end of a snippet
class PlaceholderEnd(Placeholder):
    def __init__(self, view, environ, begin, default):
        Placeholder.__init__(self, view, 0, environ, default, begin)

    def run_last(self, placeholders):
        Placeholder.run_last(self, placeholders)

        # Remove the begin mark and set the begin mark
        # to the end mark, this is needed so the end placeholder won't contain
        # any text

        if not self.default:
            self.mark_gravity[0] = False
            self.buf.delete_mark(self.begin)
            self.begin = self.buf.create_mark(None, self.end_iter(), self.mark_gravity[0])

    def enter(self):
        if self.begin and not self.begin.get_deleted():
            self.buf.move_mark(self.buf.get_insert(), self.begin_iter())

        if self.end and not self.end.get_deleted():
            self.buf.move_mark(self.buf.get_selection_bound(), self.end_iter())

    def leave(self):
        self.enter()

# This placeholder is used to expand a command with embedded mirrors
class PlaceholderExpand(Placeholder):
    def __init__(self, view, tabstop, environ, begin, s):
        Placeholder.__init__(self, view, tabstop, environ, None, begin)

        self.mirror_text = {0: ''}
        self.timeout_id = None
        self.cmd = s
        self.instant_update = False

    def __str__(self):
        s = Placeholder.__str__(self)

        return s + ' ' + self.cmd

    def get_mirrors(self, placeholders):
        return self.find_mirrors(self.cmd, placeholders)

    # Check if all substitution placeholders are accounted for
    def run_last(self, placeholders):
        Placeholder.run_last(self, placeholders)

        self.ok = True
        mirrors = self.get_mirrors(placeholders)

        if mirrors:
            allDefault = True

            for mirror in mirrors:
                p = placeholders[mirror]
                p.add_mirror(self, not self.instant_update)
                self.mirror_text[p.tabstop] = p.default

                if not p.default and not isinstance(p, PlaceholderExpand):
                    allDefault = False

            if allDefault:
                self.update(None)
                self.default = self.get_text() or None
        else:
            self.update(None)
            self.default = self.get_text() or None

            if self.tabstop == -1:
                self.done = True

    def re_placeholder(self, m, formatter):
        if m.group(1):
            return '"$' + m.group(2) + '"'
        else:
            if m.group(3):
                index = int(m.group(3))
            else:
                index = int(m.group(4))

            return formatter(self.mirror_text[index])

    def remove_timeout(self):
        if self.timeout_id != None:
            GObject.source_remove(self.timeout_id)
            self.timeout_id = None

    def install_timeout(self):
        self.remove_timeout()
        self.timeout_id = GObject.timeout_add(1000, self.timeout_cb)

    def timeout_cb(self):
        self.timeout_id = None

        return False

    def format_environment(self, text):
        return self.literal(text)

    def substitute(self, text, formatter = None):
        formatter = formatter or self.literal

        # substitute all mirrors, but also environmental variables
        text = re.sub('(\\\\)?\\$({([0-9]+)}|([0-9]+))', lambda m: self.re_placeholder(m, formatter),
                text)

        return self.expand_environment(text)

    def run_update(self):
        text = self.substitute(self.cmd)

        if text:
            ret = self.expand(text)

            if ret:
                self.update_leave_mirrors()
        else:
            ret = True

        return ret

    def update(self, mirror):
        if mirror:
            self.mirror_text[mirror.tabstop] = mirror.get_text()

            # Check if all substitutions have been made
            for tabstop in self.mirror_text:
                if tabstop == 0:
                    continue

                if self.mirror_text[tabstop] == None:
                    return False

        return self.run_update()

    def expand(self, text):
        return True

# The shell placeholder executes commands in a subshell
class PlaceholderShell(PlaceholderExpand):
    def __init__(self, view, tabstop, environ, begin, s):
        PlaceholderExpand.__init__(self, view, tabstop, environ, begin, s)

        self.shell = None
        self.remove_me = False

    def get_environ(self):
        return self.environ['noenc']

    def close_shell(self):
        self.shell.stdout.close()
        self.shell = None

    def timeout_cb(self):
        PlaceholderExpand.timeout_cb(self)
        self.remove_timeout()

        if not self.shell:
            return False

        GObject.source_remove(self.watch_id)
        self.close_shell()

        if self.remove_me:
            PlaceholderExpand.remove(self)

        helper.message_dialog(None, Gtk.MessageType.ERROR, 'Execution of the shell ' \
                'command (%s) exceeded the maximum time; ' \
                'execution aborted.' % self.command)

        return False

    def process_close(self):
        self.close_shell()
        self.remove_timeout()

        self.set_text(str.join('', self.shell_output).rstrip('\n'))

        if self.default == None:
            self.default = self.get_text()
            self.leave()

        if self.remove_me:
            PlaceholderExpand.remove(self, True)

    def process_cb(self, source, condition):
        if condition & GObject.IO_IN:
            line = source.readline()

            if len(line) > 0:
                try:
                    line = line.decode('utf-8')
                except UnicodeDecodeError:
                    line = line.decode(locale.getdefaultlocale()[1], errors='replace')

                self.shell_output += line
                self.install_timeout()

                return True

        self.process_close()
        return False

    def literal_replace(self, match):
        return "\\%s" % (match.group(0))

    def literal(self, text):
        return '"' + re.sub('([\\\\"])', self.literal_replace, text) + '"'

    def expand(self, text):
        self.remove_timeout()

        if self.shell:
            GObject.source_remove(self.watch_id)
            self.close_shell()

        popen_args = {
            'cwd': None,
            'shell': True,
            'env': self.get_environ(),
            'stdout': subprocess.PIPE
        }

        self.command = text
        self.shell = subprocess.Popen(text, **popen_args)
        self.shell_output = ''
        self.watch_id = GObject.io_add_watch(self.shell.stdout, GObject.IO_IN | \
                GObject.IO_HUP, self.process_cb)
        self.install_timeout()

        return True

    def remove(self, force = False):
        if not force and self.shell:
            # Still executing shell command
            self.remove_me = True
        else:
            if force:
                self.remove_timeout()

                if self.shell:
                    self.close_shell()

            PlaceholderExpand.remove(self, force)

class TimeoutError(Exception):
    def __init__(self, value):
        self.value = value

    def __str__(self):
        return repr(self.value)

# The python placeholder evaluates commands in python
class PlaceholderEval(PlaceholderExpand):
    def __init__(self, view, tabstop, environ, refs, begin, s, namespace):
        PlaceholderExpand.__init__(self, view, tabstop, environ, begin, s)

        self.fdread = 0
        self.remove_me = False
        self.namespace = namespace

        self.refs = []

        if refs:
            for ref in refs:
                self.refs.append(int(ref.strip()))

    def get_mirrors(self, placeholders):
        mirrors = PlaceholderExpand.get_mirrors(self, placeholders)

        if not self.ok:
            return None

        for ref in self.refs:
            if ref in placeholders:
                if ref not in mirrors:
                    mirrors.append(ref)
            else:
                self.ok = False
                return None

        return mirrors

    # SIGALRM is not supported on all platforms (e.g. windows). Timeout
    # with SIGALRM will not be used on those platforms. This will
    # potentially block gedit if you have a placeholder which gets stuck,
    # but it's better than not supporting them at all. At some point we
    # might have proper thread support and we can fix this in a better way
    def timeout_supported(self):
        return hasattr(signal, 'SIGALRM')

    def timeout_cb(self, signum = 0, frame = 0):
        raise TimeoutError("Operation timed out (>2 seconds)")

    def install_timeout(self):
        if not self.timeout_supported():
            return

        if self.timeout_id != None:
            self.remove_timeout()

        self.timeout_id = signal.signal(signal.SIGALRM, self.timeout_cb)
        signal.alarm(2)

    def remove_timeout(self):
        if not self.timeout_supported():
            return

        if self.timeout_id != None:
            signal.alarm(0)

            signal.signal(signal.SIGALRM, self.timeout_id)

            self.timeout_id = None

    def expand(self, text):
        self.remove_timeout()

        text = text.strip()
        self.command = text

        if not self.command or self.command == '':
            self.set_text('')
            return

        text = "def process_snippet():\n\t" + "\n\t".join(text.split("\n"))

        if 'process_snippet' in self.namespace:
            del self.namespace['process_snippet']

        try:
            exec(text, self.namespace)
        except:
            traceback.print_exc()

        if 'process_snippet' in self.namespace:
            try:
                # Install a sigalarm signal. This is a HACK to make sure
                # gedit doesn't get freezed by someone creating a python
                # placeholder which for instance loops indefinately. Since
                # the code is executed synchronously it will hang gedit. With
                # the alarm signal we raise an exception and catch this
                # (see below). We show an error message and return False.
                # ___this is a HACK___ and should be fixed properly (I just
                # don't know how)
                self.install_timeout()
                result = self.namespace['process_snippet']()
                self.remove_timeout()
            except TimeoutError:
                self.remove_timeout()

                helper.message_dialog(None, Gtk.MessageType.ERROR, \
                    _('Execution of the Python command (%s) exceeds the maximum ' \
                    'time, execution aborted.') % self.command)

                return False
            except Exception as detail:
                self.remove_timeout()

                helper.message_dialog(None, Gtk.MessageType.ERROR,
                    _('Execution of the Python command (%s) failed: %s') %
                    (self.command, detail))

                return False

            if result == None:
                # sys.stderr.write("%s:\n>> %s\n" % (_('The following python code, run in a snippet, does not return a value'), "\n>> ".join(self.command.split("\n"))))
                result = ''

            self.set_text(str(result))

        return True

# Regular expression placeholder
class PlaceholderRegex(PlaceholderExpand):
    def __init__(self, view, tabstop, environ, begin, inp, pattern, substitution, modifiers):
        PlaceholderExpand.__init__(self, view, tabstop, environ, begin, '')

        self.instant_update = True
        self.inp = inp
        self.pattern = pattern
        self.substitution = substitution

        self.init_modifiers(modifiers)

    def init_modifiers(self, modifiers):
        mods = {'I': re.I,
            'L': re.L,
            'M': re.M,
            'S': re.S,
            'U': re.U,
            'X': re.X}

        self.modifiers = 0

        for modifier in modifiers:
            if modifier in mods:
                self.modifiers |= mods[modifier]

    def get_mirrors(self, placeholders):
        mirrors = self.find_mirrors(self.pattern, placeholders) + self.find_mirrors(self.substitution, placeholders)

        if isinstance(self.inp, int):
            if self.inp not in placeholders:
                self.ok = False
                return None
            elif self.inp not in mirrors:
                mirrors.append(self.inp)

        return mirrors

    def literal(self, s):
        return re.escape(s)

    def get_input(self):
        env = self.get_environ()

        if isinstance(self.inp, int):
            return self.mirror_text[self.inp]
        elif self.inp in env:
            return env[self.inp]
        else:
            return ''

    def run_update(self):
        pattern = self.substitute(self.pattern)
        substitution = self.substitute(self.substitution, SubstitutionParser.escape_substitution)

        if pattern:
            return self.expand(pattern, substitution)

        return True

    def expand(self, pattern, substitution):
        # Try to compile pattern
        try:
            regex = re.compile(pattern, self.modifiers)
        except re.error as message:
            sys.stderr.write('Could not compile regular expression: %s\n%s\n' % (pattern, message))
            return False

        inp = self.get_input()
        match = regex.search(inp)

        if not match:
            self.set_text(inp)
        else:
            groups = match.groupdict()

            idx = 0
            for group in match.groups():
                groups[str(idx + 1)] = group
                idx += 1

            groups['0'] = match.group(0)

            parser = SubstitutionParser(substitution, groups)
            self.set_text(parser.parse())

        return True

# ex:ts=4:et:
