#    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 os
import weakref
import sys
import re

from gi.repository import Gdk, Gtk

import xml.etree.ElementTree as et
from . import helper

class NamespacedId:
    def __init__(self, namespace, id):
        if not id:
            self.id = None
        else:
            if namespace:
                self.id = namespace + '-'
            else:
                self.id = 'global-'

            self.id += id

class SnippetData:
    PROPS = {'tag': '', 'text': '', 'description': 'New snippet',
            'accelerator': '', 'drop-targets': ''}

    def __init__(self, node, library):
        self.priv_id = node.attrib.get('id')

        self.set_library(library)
        self.valid = False
        self.set_node(node)

    def can_modify(self):
        return (self.library and (isinstance(self.library(), SnippetsUserFile)))

    def set_library(self, library):
        if library:
            self.library = weakref.ref(library)
        else:
            self.library = None

        self.id = NamespacedId(self.language(), self.priv_id).id

    def set_node(self, node):
        if self.can_modify():
            self.node = node
        else:
            self.node = None

        self.init_snippet_data(node)

    def init_snippet_data(self, node):
        if node == None:
            return

        self.override = node.attrib.get('override')

        self.properties = {}
        props = SnippetData.PROPS.copy()

        # Store all properties present
        for child in node:
            if child.tag in props:
                del props[child.tag]

                # Normalize accelerator
                if child.tag == 'accelerator' and child.text != None:
                    keyval, mod = Gtk.accelerator_parse(child.text)

                    if Gtk.accelerator_valid(keyval, mod):
                        child.text = Gtk.accelerator_name(keyval, mod)
                    else:
                        child.text = ''

                if self.can_modify():
                    self.properties[child.tag] = child
                else:
                    self.properties[child.tag] = child.text or ''

        # Create all the props that were not found so we stay consistent
        for prop in props:
            if self.can_modify():
                child = et.SubElement(node, prop)

                child.text = props[prop]
                self.properties[prop] = child
            else:
                self.properties[prop] = props[prop]

        self.check_validation()

    def check_validation(self):
        if not self['tag'] and not self['accelerator'] and not self['drop-targets']:
            return False

        library = Library()
        keyval, mod = Gtk.accelerator_parse(self['accelerator'])

        self.valid = library.valid_tab_trigger(self['tag']) and \
                (not self['accelerator'] or library.valid_accelerator(keyval, mod))

    def _format_prop(self, prop, value):
        if prop == 'drop-targets' and value != '':
            return re.split('\\s*[,;]\\s*', value)
        else:
            return value

    def __getitem__(self, prop):
        if prop in self.properties:
            if self.can_modify():
                return self._format_prop(prop, self.properties[prop].text or '')
            else:
                return self._format_prop(prop, self.properties[prop] or '')

        return self._format_prop(prop, '')

    def __setitem__(self, prop, value):
        if not prop in self.properties:
            return

        if isinstance(value, list):
            value = ','.join(value)

        if not self.can_modify() and self.properties[prop] != value:
            # ohoh, this is not can_modify, but it needs to be changed...
            # make sure it is transfered to the changes file and set all the
            # fields.
            # This snippet data container will effectively become the container
            # for the newly created node, but transparently to whoever uses
            # it
            self._override()

        if self.can_modify() and self.properties[prop].text != value:
            if self.library():
                self.library().tainted = True

            oldvalue = self.properties[prop].text
            self.properties[prop].text = value

            if prop == 'tag' or prop == 'accelerator' or prop == 'drop-targets':
                container = Library().container(self.language())
                container.prop_changed(self, prop, oldvalue)

        self.check_validation()

    def language(self):
        if self.library and self.library():
            return self.library().language
        else:
            return None

    def is_override(self):
        return self.override and Library().overridden[self.override]

    def to_xml(self):
        return self._create_xml()

    def _create_xml(self, parent=None, update=False, attrib={}):
        # Create a new node
        if parent != None:
            element = et.SubElement(parent, 'snippet', attrib)
        else:
            element = et.Element('snippet')

        # Create all the properties
        for p in self.properties:
            prop = et.SubElement(element, p)
            prop.text = self[p]

            if update:
                self.properties[p] = prop

        return element

    def _override(self):
        # Find the user file
        target = Library().get_user_library(self.language())

        # Create a new node there with override
        element = self._create_xml(target.root, True, {'override': self.id})

        # Create an override snippet data, feed it element so that it stores
        # all the values and then set the node to None so that it only contains
        # the values in .properties
        override = SnippetData(element, self.library())
        override.set_node(None)
        override.id = self.id

        # Set our node to the new element
        self.node = element

        # Set the override to our id
        self.override = self.id
        self.id = None

        # Set the new library
        self.set_library(target)

        # The library is tainted because we added this snippet
        target.tainted = True

        # Add the override
        Library().overridden[self.override] = override

    def revert(self, snippet):
        userlib = self.library()
        self.set_library(snippet.library())

        userlib.remove(self.node)

        self.set_node(None)

        # Copy the properties
        self.properties = snippet.properties

        # Set the id
        self.id = snippet.id

        # Reset the override flag
        self.override = None

class SnippetsTreeBuilder(et.TreeBuilder):
    def __init__(self, start=None, end=None):
        et.TreeBuilder.__init__(self)
        self.set_start(start)
        self.set_end(end)

    def set_start(self, start):
        self._start_cb = start

    def set_end(self, end):
        self._end_cb = end

    def start(self, tag, attrs):
        result = et.TreeBuilder.start(self, tag, attrs)

        if self._start_cb:
            self._start_cb(result)

        return result

    def end(self, tag):
        result = et.TreeBuilder.end(self, tag)

        if self._end_cb:
            self._end_cb(result)

        return result

class LanguageContainer:
    def __init__(self, language):
        self.language = language
        self.snippets = []
        self.snippets_by_prop = {'tag': {}, 'accelerator': {}, 'drop-targets': {}}
        self.accel_group = Gtk.AccelGroup()
        self._refs = 0

    def _add_prop(self, snippet, prop, value=0):
        if value == 0:
            value = snippet[prop]

        if not value or value == '':
            return

        helper.snippets_debug('Added ', prop ,' ', value, ' to ', str(self.language))

        if prop == 'accelerator':
            keyval, mod = Gtk.accelerator_parse(value)
            self.accel_group.connect(keyval, mod, 0, \
                    Library().accelerator_activated)

        snippets = self.snippets_by_prop[prop]

        if not isinstance(value, list):
            value = [value]

        for val in value:
            if val in snippets:
                snippets[val].append(snippet)
            else:
                snippets[val] = [snippet]

    def _remove_prop(self, snippet, prop, value=0):
        if value == 0:
            value = snippet[prop]

        if not value or value == '':
            return

        helper.snippets_debug('Removed ', prop, ' ', value, ' from ', str(self.language))

        if prop == 'accelerator':
            keyval, mod = Gtk.accelerator_parse(value)
            self.accel_group.disconnect_key(keyval, mod)

        snippets = self.snippets_by_prop[prop]

        if not isinstance(value, list):
            value = [value]

        for val in value:
            try:
                snippets[val].remove(snippet)
            except:
                True

    def append(self, snippet):
        self.snippets.append(snippet)

        self._add_prop(snippet, 'tag')
        self._add_prop(snippet, 'accelerator')
        self._add_prop(snippet, 'drop-targets')

        return snippet

    def remove(self, snippet):
        try:
            self.snippets.remove(snippet)
        except:
            True

        self._remove_prop(snippet, 'tag')
        self._remove_prop(snippet, 'accelerator')
        self._remove_prop(snippet, 'drop-targets')

    def prop_changed(self, snippet, prop, oldvalue):
        helper.snippets_debug('PROP CHANGED (', prop, ')', oldvalue)

        self._remove_prop(snippet, prop, oldvalue)
        self._add_prop(snippet, prop)

    def from_prop(self, prop, value):
        snippets = self.snippets_by_prop[prop]

        if prop == 'drop-targets':
            s = []

            # FIXME: change this to use
            # gnomevfs.mime_type_get_equivalence when it comes
            # available
            for key, val in snippets.items():
                if not value.startswith(key):
                    continue

                for snippet in snippets[key]:
                    if not snippet in s:
                        s.append(snippet)

            return s
        else:
            if value in snippets:
                return snippets[value]
            else:
                return []

    def ref(self):
        self._refs += 1

        return True

    def unref(self):
        if self._refs > 0:
            self._refs -= 1

        return self._refs != 0

class SnippetsSystemFile:
    def __init__(self, path=None):
        self.path = path
        self.loaded = False
        self.language = None
        self.ok = True
        self.need_id = True

    def load_error(self, message):
        sys.stderr.write("An error occurred loading " + self.path + ":\n")
        sys.stderr.write(message + "\nSnippets in this file will not be " \
                "available, please correct or remove the file.\n")

    def _add_snippet(self, element):
        if not self.need_id or element.attrib.get('id'):
            self.loading_elements.append(element)

    def set_language(self, element):
        self.language = element.attrib.get('language')

        if self.language:
            self.language = self.language.lower()

    def _set_root(self, element):
        self.set_language(element)

    def _preprocess_element(self, element):
        if not self.loaded:
            if not element.tag == "snippets":
                self.load_error("Root element should be `snippets' instead " \
                        "of `%s'" % element.tag)
                return False
            else:
                self._set_root(element)
                self.loaded = True
        elif element.tag != 'snippet' and not self.insnippet:
            self.load_error("Element should be `snippet' instead of `%s'" \
                    % element.tag)
            return False
        else:
            self.insnippet = True

        return True

    def _process_element(self, element):
        if element.tag == 'snippet':
            self._add_snippet(element)
            self.insnippet = False

        return True

    def ensure(self):
        if not self.ok or self.loaded:
            return

        self.load()

    def parse_xml(self, readsize=16384):
        if not self.path:
            return

        elements = []

        builder = SnippetsTreeBuilder( \
                lambda node: elements.append((node, True)), \
                lambda node: elements.append((node, False)))

        parser = et.XMLParser(target=builder)
        self.insnippet = False

        try:
            f = open(self.path, "r", encoding='utf-8')
        except IOError:
            self.ok = False
            return

        while True:
            try:
                data = f.read(readsize)
            except IOError:
                self.ok = False
                break

            if not data:
                break

            try:
                parser.feed(data)
            except Exception:
                self.ok = False
                break

            for element in elements:
                yield element

            del elements[:]

        f.close()

    def load(self):
        if not self.ok:
            return

        helper.snippets_debug("Loading library (" + str(self.language) + "): " + \
                self.path)

        self.loaded = False
        self.ok = False
        self.loading_elements = []

        for element in self.parse_xml():
            if element[1]:
                if not self._preprocess_element(element[0]):
                    del self.loading_elements[:]
                    return
            else:
                if not self._process_element(element[0]):
                    del self.loading_elements[:]
                    return

        for element in self.loading_elements:
            Library().add_snippet(self, element)

        del self.loading_elements[:]
        self.ok = True

    # This function will get the language for a file by just inspecting the
    # root element of the file. This is provided so that a cache can be built
    # for which file contains which language.
    # It returns the name of the language
    def ensure_language(self):
        if not self.loaded:
            self.ok = False

            for element in self.parse_xml(256):
                if element[1]:
                    if element[0].tag == 'snippets':
                        self.set_language(element[0])
                        self.ok = True

                    break

    def unload(self):
        helper.snippets_debug("Unloading library (" + str(self.language) + "): " + \
                self.path)
        self.language = None
        self.loaded = False
        self.ok = True

class SnippetsUserFile(SnippetsSystemFile):
    def __init__(self, path=None):
        SnippetsSystemFile.__init__(self, path)
        self.tainted = False
        self.need_id = False

    def _set_root(self, element):
        SnippetsSystemFile._set_root(self, element)
        self.root = element

    def add_prop(self, node, tag, data):
        if data[tag]:
            prop = et.SubElement(node, tag)
            prop.text = data[tag]

            return prop
        else:
            return None

    def new_snippet(self, properties=None):
        if (not self.ok) or self.root == None:
            return None

        element = et.SubElement(self.root, 'snippet')

        if properties:
            for prop in properties:
                sub = et.SubElement(element, prop)
                sub.text = properties[prop]

        self.tainted = True

        return Library().add_snippet(self, element)

    def set_language(self, element):
        SnippetsSystemFile.set_language(self, element)

        filename = os.path.basename(self.path).lower()

        if not self.language and filename == "global.xml":
            self.modifier = True
        elif self.language and filename == self.language + ".xml":
            self.modifier = True
        else:
            self.modifier = False

    def create_root(self, language):
        if self.loaded:
            helper.snippets_debug('Not creating root, already loaded')
            return

        if language:
            root = et.Element('snippets', {'language': language})
            self.path = os.path.join(Library().userdir, language.lower() + '.xml')
        else:
            root = et.Element('snippets')
            self.path = os.path.join(Library().userdir, 'global.xml')

        self._set_root(root)
        self.loaded = True
        self.ok = True
        self.tainted = True
        self.save()

    def remove(self, element):
        try:
            self.root.remove(element)
            self.tainted = True
        except:
            return

        try:
            self.root[0]
        except:
            # No more elements, this library is useless now
            Library().remove_library(self)

    def save(self):
        if not self.ok or self.root == None or not self.tainted:
            return

        path = os.path.dirname(self.path)

        try:
            if not os.path.isdir(path):
                os.makedirs(path, 0o755)
        except OSError:
            # TODO: this is bad...
            sys.stderr.write("Error in making dirs\n")

        try:
            helper.write_xml(self.root, self.path, ('text', 'accelerator'))
            self.tainted = False
        except IOError:
            # Couldn't save, what to do
            sys.stderr.write("Could not save user snippets file to " + \
                    self.path + "\n")

    def unload(self):
        SnippetsSystemFile.unload(self)
        self.root = None

class Singleton(object):
    _instance = None

    def __new__(cls, *args, **kwargs):
        if not cls._instance:
            cls._instance = super(Singleton, cls).__new__(
                     cls, *args, **kwargs)
            cls._instance.__init_once__()

        return cls._instance

class Library(Singleton):
    def __init_once__(self):
        self._accelerator_activated_cb = []
        self.loaded = False
        self.check_buffer = Gtk.TextBuffer()

    def set_dirs(self, userdir, systemdirs):
        self.userdir = userdir
        self.systemdirs = systemdirs

        self.libraries = {}
        self.containers = {}
        self.overridden = {}
        self.loaded_ids = []

        self.loaded = False

    def add_accelerator_callback(self, cb):
        self._accelerator_activated_cb.append(cb)

    def remove_accelerator_callback(self, cb):
        self._accelerator_activated_cb.remove(cb)

    def accelerator_activated(self, group, obj, keyval, mod):
        ret = False

        for cb in self._accelerator_activated_cb:
            ret = cb(group, obj, keyval, mod)

            if ret:
                break

        return ret

    def add_snippet(self, library, element):
        container = self.container(library.language)
        overrided = self.overrided(library, element)

        if overrided:
            overrided.set_library(library)
            helper.snippets_debug('Snippet is overriden: ' + overrided['description'])
            return None

        snippet = SnippetData(element, library)

        if snippet.id in self.loaded_ids:
            helper.snippets_debug('Not added snippet ' + str(library.language) + \
                    '::' + snippet['description'] + ' (duplicate)')
            return None

        snippet = container.append(snippet)
        helper.snippets_debug('Added snippet ' + str(library.language) + '::' + \
                snippet['description'])

        if snippet and snippet.override:
            self.add_override(snippet)

        if snippet.id:
            self.loaded_ids.append(snippet.id)

        return snippet

    def container(self, language):
        language = self.normalize_language(language)

        if not language in self.containers:
            self.containers[language] = LanguageContainer(language)

        return self.containers[language]

    def get_user_library(self, language):
        target = None

        if language in self.libraries:
            for library in self.libraries[language]:
                if isinstance(library, SnippetsUserFile) and library.modifier:
                    target = library
                elif not isinstance(library, SnippetsUserFile):
                    break

        if not target:
            # Create a new user file then
            helper.snippets_debug('Creating a new user file for language ' + \
                    str(language))
            target = SnippetsUserFile()
            target.create_root(language)
            self.add_library(target)

        return target

    def new_snippet(self, language, properties=None):
        language = self.normalize_language(language)
        library = self.get_user_library(language)

        return library.new_snippet(properties)

    def revert_snippet(self, snippet):
        # This will revert the snippet to the one it overrides
        if not snippet.can_modify() or not snippet.override in self.overridden:
            # It can't be reverted, shouldn't happen, but oh..
            return

        # The snippet in self.overriden only contains the property contents and
        # the library it belongs to
        revertto = self.overridden[snippet.override]
        del self.overridden[snippet.override]

        if revertto:
            snippet.revert(revertto)

            if revertto.id:
                self.loaded_ids.append(revertto.id)

    def remove_snippet(self, snippet):
        if not snippet.can_modify() or snippet.is_override():
            return

        # Remove from the library
        userlib = snippet.library()
        userlib.remove(snippet.node)

        # Remove from the container
        container = self.containers[userlib.language]
        container.remove(snippet)

    def overrided(self, library, element):
        id = NamespacedId(library.language, element.attrib.get('id')).id

        if id in self.overridden:
            snippet = SnippetData(element, None)
            snippet.set_node(None)

            self.overridden[id] = snippet
            return snippet
        else:
            return None

    def add_override(self, snippet):
        helper.snippets_debug('Add override:', snippet.override)
        if not snippet.override in self.overridden:
            self.overridden[snippet.override] = None

    def add_library(self, library):
        library.ensure_language()

        if not library.ok:
            helper.snippets_debug('Library in wrong format, ignoring')
            return False

        helper.snippets_debug('Adding library (' + str(library.language) + '): ' + \
                library.path)

        if library.language in self.libraries:
            # Make sure all the user files are before the system files
            if isinstance(library, SnippetsUserFile):
                self.libraries[library.language].insert(0, library)
            else:
                self.libraries[library.language].append(library)
        else:
            self.libraries[library.language] = [library]

        return True

    def remove_library(self, library):
        if not library.ok:
            return

        if library.path and os.path.isfile(library.path):
            os.unlink(library.path)

        try:
            self.libraries[library.language].remove(library)
        except KeyError:
            True

        container = self.containers[library.language]

        for snippet in list(container.snippets):
            if snippet.library() == library:
                container.remove(snippet)

    def add_user_library(self, path):
        library = SnippetsUserFile(path)
        return self.add_library(library)

    def add_system_library(self, path):
        library = SnippetsSystemFile(path)
        return self.add_library(library)

    def find_libraries(self, path, searched, addcb):
        helper.snippets_debug("Finding in: " + path)

        if not os.path.isdir(path):
            return searched

        files = os.listdir(path)
        searched.append(path)

        for f in files:
            f = os.path.realpath(os.path.join(path, f))

            # Determine what language this file provides snippets for
            if os.path.isfile(f):
                addcb(f)

        return searched

    def normalize_language(self, language):
        if language:
            return language.lower()

        return language

    def remove_container(self, language):
        for snippet in self.containers[language].snippets:
            if snippet.id in self.loaded_ids:
                self.loaded_ids.remove(snippet.id)

            if snippet.override in self.overridden:
                del self.overridden[snippet.override]

        del self.containers[language]

    def get_accel_group(self, language):
        language = self.normalize_language(language)
        container = self.container(language)

        self.ensure(language)
        return container.accel_group

    def save(self, language):
        language = self.normalize_language(language)

        if language in self.libraries:
            for library in self.libraries[language]:
                if isinstance(library, SnippetsUserFile):
                    library.save()
                else:
                    break

    def ref(self, language):
        language = self.normalize_language(language)

        helper.snippets_debug('Ref:', language)
        self.container(language).ref()

    def unref(self, language):
        language = self.normalize_language(language)

        helper.snippets_debug('Unref:', language)

        if language in self.containers:
            if not self.containers[language].unref() and \
                    language in self.libraries:

                for library in self.libraries[language]:
                    library.unload()

                self.remove_container(language)

    def ensure(self, language):
        self.ensure_files()
        language = self.normalize_language(language)

        # Ensure language as well as the global snippets (None)
        for lang in (None, language):
            if lang in self.libraries:
                # Ensure the container exists
                self.container(lang)

                for library in self.libraries[lang]:
                    library.ensure()

    def ensure_files(self):
        if self.loaded:
            return

        searched = []
        searched = self.find_libraries(self.userdir, searched, \
                self.add_user_library)

        for d in self.systemdirs:
            searched = self.find_libraries(d, searched, \
                    self.add_system_library)

        self.loaded = True

    def valid_accelerator(self, keyval, mod):
        mod &= Gtk.accelerator_get_default_mod_mask()

        return (mod and (Gdk.keyval_to_unicode(keyval) or \
                keyval in range(Gdk.KEY_F1, Gdk.KEY_F12 + 1)))

    def valid_tab_trigger(self, trigger):
        if not trigger:
            return True

        return helper.is_tab_trigger(trigger)

    # Snippet getters
    # ===============
    def _from_prop(self, prop, value, language=None):
        self.ensure_files()

        result = []
        language = self.normalize_language(language)

        if not language in self.containers:
            return []

        self.ensure(language)
        result = self.containers[language].from_prop(prop, value)

        if len(result) == 0 and language and None in self.containers:
            result = self.containers[None].from_prop(prop, value)

        return result

    # Get snippets for a given language
    def get_snippets(self, language=None):
        self.ensure_files()
        language = self.normalize_language(language)

        if not language in self.libraries:
            return []

        self.ensure(language)

        return list(self.containers[language].snippets)

    # Get snippets for a given accelerator
    def from_accelerator(self, accelerator, language=None):
        return self._from_prop('accelerator', accelerator, language)

    # Get snippets for a given tag
    def from_tag(self, tag, language=None):
        return self._from_prop('tag', tag, language)

    # Get snippets for a given drop target
    def from_drop_target(self, drop_target, language=None):
        return self._from_prop('drop-targets', drop_target, language)

# ex:ts=4:et:
