# -*- coding: utf-8 -*-

# Copyright(C) 2010-2012 Romain Bignon, Laurent Bachelier
#
# This file is part of weboob.
#
# weboob is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# weboob 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with weboob. If not, see <http://www.gnu.org/licenses/>.

from __future__ import with_statement

import tarfile
import posixpath
import shutil
import re
import sys
import os
import subprocess
import hashlib
from tempfile import NamedTemporaryFile
from datetime import datetime
from contextlib import closing
from compileall import compile_dir
from StringIO import StringIO

from .modules import Module
from weboob.tools.log import getLogger
from weboob.tools.misc import to_unicode
from weboob.tools.browser import StandardBrowser, BrowserUnavailable
from ConfigParser import RawConfigParser, DEFAULTSECT

class ModuleInfo(object):
    def __init__(self, name):
        self.name = name

        # path to the local directory containing this module.
        self.path = None
        self.url = None
        self.repo_url = None

        self.version = 0
        self.capabilities = ()
        self.description = u''
        self.maintainer = u''
        self.license = u''
        self.icon = u''
        self.urls = u''

    def load(self, items):
        self.version = int(items['version'])
        self.capabilities = items['capabilities'].split()
        self.description = to_unicode(items['description'])
        self.maintainer = to_unicode(items['maintainer'])
        self.license = to_unicode(items['license'])
        self.icon = items['icon']
        self.urls = items['urls']

    def has_caps(self, caps):
        if not isinstance(caps, (list, tuple)):
            caps = [caps]
        for c in caps:
            if type(c) == type:
                c = c.__name__
            if c in self.capabilities:
                return True
        return False

    def is_installed(self):
        return self.path is not None

    def is_local(self):
        return self.url is None

    def dump(self):
        return (('version', self.version),
                ('capabilities', ' '.join(self.capabilities)),
                ('description', self.description),
                ('maintainer', self.maintainer),
                ('license', self.license),
                ('icon', self.icon),
                ('urls', self.urls),
               )

class RepositoryUnavailable(Exception):
    pass

class Repository(object):
    INDEX = 'modules.list'
    KEYDIR = '.keys'
    KEYRING = 'trusted.gpg'

    def __init__(self, url):
        self.url = url
        self.name = u''
        self.update = 0
        self.maintainer = u''
        self.local = None
        self.signed = False
        self.key_update = 0

        self.modules = {}

        if self.url.startswith('file://'):
            self.local = True
        elif re.match('https?://.*', self.url):
            self.local = False
        else:
            # This is probably a file in ~/.weboob/repositories/, we
            # don't know if this is a local or a remote repository.
            with open(self.url, 'r') as fp:
                self.parse_index(fp)

    def __repr__(self):
        return '<Repository %r>' % self.name

    def localurl2path(self):
        """
        Get a local path of a file:// URL.
        """
        assert self.local == True

        if self.url.startswith('file://'):
            return self.url[len('file://'):]
        return self.url

    def retrieve_index(self, repo_path):
        """
        Retrieve the index file of this repository. It can use network
        if this is a remote repository.

        @param repo_path [str]  path to save the downloaded index file.
        """
        if self.local:
            # Repository is local, open the file.
            filename = os.path.join(self.localurl2path(), self.INDEX)
            try:
                fp = open(filename, 'r')
            except IOError, e:
                # This local repository doesn't contain a built modules.list index.
                self.name = Repositories.url2filename(self.url)
                self.build_index(self.localurl2path(), filename)
                fp = open(filename, 'r')
        else:
            # This is a remote repository, download file
            browser = StandardBrowser()
            try:
                fp = browser.openurl(posixpath.join(self.url, self.INDEX))
            except BrowserUnavailable, e:
                raise RepositoryUnavailable(unicode(e))

        self.parse_index(fp)

        if self.local:
            # Always rebuild index of a local repository.
            self.build_index(self.localurl2path(), filename)

        # Save the repository index in ~/.weboob/repositories/
        self.save(repo_path, private=True)

    def retrieve_keyring(self, keyring_path):
        # ignore local
        if self.local:
            return

        keyring = Keyring(keyring_path)
        # prevent previously signed repos from going unsigned
        if not self.signed and keyring.exists():
            raise RepositoryUnavailable('Previously signed repository can not go unsigned')
        if not self.signed:
            return

        if not keyring.exists() or self.key_update > keyring.version:
            # This is a remote repository, download file
            browser = StandardBrowser()
            try:
                fpkr = browser.openurl(posixpath.join(self.url, self.KEYRING))
                fpkrsig = browser.openurl(posixpath.join(self.url, self.KEYRING + '.sig'))
            except BrowserUnavailable, e:
                raise RepositoryUnavailable(unicode(e))
            keyring_data = fpkr.read()
            sig_data = fpkrsig.read()
            if keyring.exists():
                if not keyring.is_valid(keyring_data, sig_data):
                    raise InvalidSignature('the keyring itself')
                print 'The keyring was updated (and validated by the previous one).'
            else:
                print 'First time saving the keyring, blindly accepted.'
            keyring.save(keyring_data, self.key_update)
            print keyring

    def parse_index(self, fp):
        """
        Parse index of a repository

        @param fp [buffer]  file descriptor to read
        """
        config = RawConfigParser()
        config.readfp(fp)

        # Read default parameters
        items = dict(config.items(DEFAULTSECT))
        try:
            self.name = items['name']
            self.update = int(items['update'])
            self.maintainer = items['maintainer']
            self.signed = bool(int(items.get('signed', '0')))
            self.key_update = int(items.get('key_update', '0'))
        except KeyError, e:
            raise RepositoryUnavailable('Missing global parameters in repository: %s' % e)
        except ValueError, e:
            raise RepositoryUnavailable('Incorrect value in repository parameters: %s' % e)

        if len(self.name) == 0:
            raise RepositoryUnavailable('Name is empty')

        if 'url' in items:
            self.url = items['url']
            self.local = self.url.startswith('file://')
        elif self.local is None:
            raise RepositoryUnavailable('Missing "url" key in settings')

        # Load modules
        self.modules.clear()
        for section in config.sections():
            module = ModuleInfo(section)
            module.load(dict(config.items(section)))
            if not self.local:
                module.url = posixpath.join(self.url, '%s.tar.gz' % module.name)
                module.repo_url = self.url
                module.signed = self.signed
            self.modules[section] = module

    def build_index(self, path, filename):
        """
        Rebuild index of modules of repository.

        @param path [str]  path of the repository
        @param filename [str]  file to save index
        """
        print 'Rebuild index'
        self.modules.clear()

        if os.path.isdir(os.path.join(path, self.KEYDIR)):
            self.signed = True
            self.key_update = self.get_tree_mtime(os.path.join(path, self.KEYDIR), True)
        else:
            self.signed = False
            self.key_update = 0

        sys.path.append(path)
        for name in sorted(os.listdir(path)):
            module_path = os.path.join(path, name)
            if not os.path.isdir(module_path) or '.' in name or name == self.KEYDIR:
                continue

            try:
                module = Module(__import__(name, fromlist=[str(name)]))
            except Exception, e:
                print >>sys.stderr, 'Unable to build module %s: %s' % (name, e)
            else:
                m = ModuleInfo(module.name)
                m.version = self.get_tree_mtime(module_path)
                m.capabilities = [c.__name__ for c in module.iter_caps()]
                m.description = module.description
                m.maintainer = module.maintainer
                m.license = module.license
                m.icon = module.icon or ''
                self.modules[module.name] = m
        sys.path.remove(path)

        self.update = int(datetime.now().strftime('%Y%m%d%H%M'))
        self.save(filename)

    @staticmethod
    def get_tree_mtime(path, include_root=False):
        mtime = 0
        if include_root:
            mtime = int(datetime.fromtimestamp(os.path.getmtime(path)).strftime('%Y%m%d%H%M'))
        for root, dirs, files in os.walk(path):
            for f in files:
                if f.endswith('.pyc'):
                    continue
                m = int(datetime.fromtimestamp(os.path.getmtime(os.path.join(root, f))).strftime('%Y%m%d%H%M'))
                mtime = max(mtime, m)

        return mtime

    def save(self, filename, private=False):
        """
        Save repository into a file (modules.list for example).

        @param filename [str]  path to file to save repository.
        @param private [bool]  if enabled, save URL of repository.
        """
        config = RawConfigParser()
        config.set(DEFAULTSECT, 'name', self.name)
        config.set(DEFAULTSECT, 'update', self.update)
        config.set(DEFAULTSECT, 'maintainer', self.maintainer)
        config.set(DEFAULTSECT, 'signed', int(self.signed))
        config.set(DEFAULTSECT, 'key_update', self.key_update)
        if private:
            config.set(DEFAULTSECT, 'url', self.url)

        for module in self.modules.itervalues():
            config.add_section(module.name)
            for key, value in module.dump():
                config.set(module.name, key, to_unicode(value).encode('utf-8'))

        with open(filename, 'wb') as f:
            config.write(f)

class Versions(object):
    VERSIONS_LIST = 'versions.list'

    def __init__(self, path):
        self.path = path
        self.versions = {}

        try:
            with open(os.path.join(self.path, self.VERSIONS_LIST), 'r') as fp:
                config = RawConfigParser()
                config.readfp(fp)

                # Read default parameters
                for key, value in config.items(DEFAULTSECT):
                    self.versions[key] = int(value)
        except IOError:
            pass

    def get(self, name):
        return self.versions.get(name, None)

    def set(self, name, version):
        self.versions[name] = int(version)
        self.save()

    def save(self):
        config = RawConfigParser()
        for name, version in self.versions.iteritems():
            config.set(DEFAULTSECT, name, version)
        with open(os.path.join(self.path, self.VERSIONS_LIST), 'wb') as fp:
            config.write(fp)

class IProgress:
    def progress(self, percent, message):
        print '=== [%3.0f%%] %s' % (percent*100, message)

    def error(self, message):
        print >>sys.stderr, 'ERROR: %s' % message

class ModuleInstallError(Exception):
    pass

DEFAULT_SOURCES_LIST = \
"""# List of Weboob repositories
#
# The entries below override the entries above (with
# backends of the same name).

http://updates.weboob.org/%(version)s/main/

# To enable Not Safe For Work backends, uncomment the
# following line:
#http://updates.weboob.org/%(version)s/nsfw/

# DEVELOPMENT
# If you want to hack on Weboob modules, you may add a
# reference to sources, for example:
#file:///home/rom1/src/weboob/modules/
"""

class Repositories(object):
    SOURCES_LIST = 'sources.list'
    MODULES_DIR = 'modules'
    REPOS_DIR = 'repositories'
    KEYRINGS_DIR = 'keyrings'
    ICONS_DIR = 'icons'

    SHARE_DIRS = [MODULES_DIR, REPOS_DIR, KEYRINGS_DIR, ICONS_DIR]

    def __init__(self, workdir, datadir, version):
        self.logger = getLogger('repositories')
        self.version = version
        self.workdir = workdir
        self.datadir = datadir
        self.sources_list = os.path.join(self.workdir, self.SOURCES_LIST)
        self.modules_dir = os.path.join(self.datadir, self.MODULES_DIR)
        self.repos_dir = os.path.join(self.datadir, self.REPOS_DIR)
        self.keyrings_dir = os.path.join(self.datadir, self.KEYRINGS_DIR)
        self.icons_dir = os.path.join(self.datadir, self.ICONS_DIR)

        self.create_dir(self.datadir)
        self.create_dir(self.modules_dir)
        self.create_dir(self.repos_dir)
        self.create_dir(self.keyrings_dir)
        self.create_dir(self.icons_dir)

        self.versions = Versions(self.modules_dir)

        self.repositories = []

        if not os.path.exists(self.sources_list):
            with open(self.sources_list, 'w') as f:
                f.write(DEFAULT_SOURCES_LIST)
            self.update()
        else:
            self.load()

    def create_dir(self, name):
        if not os.path.exists(name):
            os.makedirs(name)
        elif not os.path.isdir(name):
            self.logger.error(u'"%s" is not a directory' % name)

    def _extend_module_info(self, repo, info):
        if repo.local:
            info.path = repo.localurl2path()
        elif self.versions.get(info.name) is not None:
            info.path = self.modules_dir

        return info

    def get_all_modules_info(self, caps=None):
        """
        Get all ModuleInfo instances available.

        @param caps [list(str)]  Filter on capabilities.
        @return [dict(ModuleInfo)]
        """
        modules = {}
        for repos in reversed(self.repositories):
            for name, info in repos.modules.iteritems():
                if not name in modules and (not caps or info.has_caps(caps)):
                    modules[name] = self._extend_module_info(repos, info)
        return modules

    def get_module_info(self, name):
        """
        Get ModuleInfo object of a module.

        It tries all repositories from last to first, and set
        the 'path' attribute of ModuleInfo if it is installed.
        """
        for repos in reversed(self.repositories):
            if name in repos.modules:
                m = repos.modules[name]
                self._extend_module_info(repos, m)
                return m
        return None

    def load(self):
        """
        Load repositories from ~/.weboob/repositories/.
        """
        self.repositories = []
        for name in sorted(os.listdir(self.repos_dir)):
            repository = Repository(os.path.join(self.repos_dir, name))
            self.repositories.append(repository)

    def get_module_icon_path(self, module):
        return os.path.join(self.icons_dir, '%s.png' % module.name)

    def retrieve_icon(self, module):
        """
        Retrieve the icon of a module and save it in ~/.weboob/icons/.
        """
        if not isinstance(module, ModuleInfo):
            module = self.get_module_info(module)

        dest_path = self.get_module_icon_path(module)

        if module.is_local():
            icon_path = os.path.join(module.path, module.name, 'favicon.png')
            if module.path and os.path.exists(icon_path):
                shutil.copy(icon_path, dest_path)
            return

        if module.icon:
            icon_url = module.icon
        else:
            icon_url = module.url.replace('.tar.gz', '.png')

        browser = StandardBrowser()
        try:
            icon = browser.openurl(icon_url)
        except BrowserUnavailable:
            pass # no icon, no problem
        else:
            with open(dest_path, 'wb') as fp:
                fp.write(icon.read())

    def update(self, progress=IProgress()):
        """
        Update list of repositories by downloading them
        and put them in ~/.weboob/repositories/.

        @param progress [IProgress]  observer object.
        """
        self.repositories = []
        for name in os.listdir(self.repos_dir):
            os.remove(os.path.join(self.repos_dir, name))

        gpgv = Keyring.find_gpgv()
        with open(self.sources_list, 'r') as f:
            for line in f.xreadlines():
                line = line.strip() % {'version': self.version}
                m = re.match('(file|https?)://.*', line)
                if m:
                    progress.progress(0.0, 'Getting %s' % line)
                    repository = Repository(line)
                    filename = self.url2filename(repository.url)
                    prio_filename = '%02d-%s' % (len(self.repositories), filename)
                    repo_path = os.path.join(self.repos_dir, prio_filename)
                    keyring_path = os.path.join(self.keyrings_dir, filename)
                    try:
                        repository.retrieve_index(repo_path)
                        if gpgv:
                            repository.retrieve_keyring(keyring_path)
                        else:
                            progress.error('Cannot find gpgv to check for repository authenticity.\n'
                                           'You should install GPG for better security.')
                    except RepositoryUnavailable, e:
                        progress.error('Unable to load repository: %s' % e)
                    else:
                        self.repositories.append(repository)

        to_update = []
        for name, info in self.get_all_modules_info().iteritems():
            if not info.is_local() and info.is_installed():
                to_update.append(info)

        class InstallProgress(IProgress):
            def __init__(self, n):
                self.n = n

            def progress(self, percent, message):
                progress.progress(float(self.n)/len(to_update) + 1.0/len(to_update)*percent, message)

        for n, info in enumerate(to_update):
            inst_progress = InstallProgress(n)
            try:
                self.install(info, inst_progress)
            except ModuleInstallError, e:
                inst_progress.progress(1.0, unicode(e))

    def install(self, module, progress=IProgress()):
        """
        Install a module.

        @paran module [str,ModuleInfo] module to install.
        @param progress [IProgress]  observer object.
        """
        if isinstance(module, ModuleInfo):
            info = module
        elif isinstance(module, basestring):
            progress.progress(0.0, 'Looking for module %s' % module)
            info = self.get_module_info(module)
            if not info:
                raise ModuleInstallError('Module "%s" does not exist' % module)
        else:
            raise ValueError('"module" parameter might be a ModuleInfo object or a string, not %r' % module)

        module = info

        if module.is_local():
            raise ModuleInstallError('%s is available on local.' % module.name)

        module_dir = os.path.join(self.modules_dir, module.name)
        installed = self.versions.get(module.name)
        if installed is None or not os.path.exists(module_dir):
            progress.progress(0.3, 'Module is not installed yet')
        elif module.version > installed:
            progress.progress(0.3, 'A new version of this module is available')
        else:
            raise ModuleInstallError('The last version of %s is already installed' % module.name)

        browser = StandardBrowser()
        progress.progress(0.2, 'Downloading module...')
        try:
            fp = browser.openurl(module.url)
        except BrowserUnavailable, e:
            raise ModuleInstallError('Unable to fetch module: %s' % e)
        tardata = fp.read()


        # Check signature
        if module.signed and Keyring.find_gpgv():
            progress.progress(0.5, 'Checking module authenticity...')
            fpsig = browser.openurl(posixpath.join(module.url + '.sig'))
            keyring_path = os.path.join(self.keyrings_dir, self.url2filename(module.repo_url))
            keyring = Keyring(keyring_path)
            if not keyring.exists():
                raise ModuleInstallError('No keyring found, please update repos.')
            if not keyring.is_valid(tardata, fpsig.read()):
                raise ModuleInstallError('Invalid signature for %s.' % module.name)


        # Extract module from tarball.
        if os.path.isdir(module_dir):
            shutil.rmtree(module_dir)
        progress.progress(0.7, 'Setting up module...')
        with closing(tarfile.open('', 'r:gz', StringIO(tardata))) as tar:
            tar.extractall(self.modules_dir)
        if not os.path.isdir(module_dir):
            raise ModuleInstallError('The archive for %s looks invalid.' % module.name)
        # Precompile
        compile_dir(module_dir, quiet=True)

        self.versions.set(module.name, module.version)

        progress.progress(0.9, 'Downloading icon...')
        self.retrieve_icon(module)

        progress.progress(1.0, 'Module %s has been installed!' % module.name)

    @staticmethod
    def url2filename(url):
        """
        Get a safe file name for an URL
        All non-alphanumeric characters are replaced by _.
        """
        return ''.join([l if l.isalnum() else '_' for l in url])


class InvalidSignature(Exception):
    def __init__(self, filename):
        self.filename = filename
        Exception.__init__(self, 'Invalid signature for %s' % filename)


class Keyring(object):
    EXTENSION = '.gpg'

    def __init__(self, path):
        self.path = path + self.EXTENSION
        self.vpath = path + '.version'
        self.version = 0
        # We must have both files, else it is invalid
        if not os.path.exists(self.vpath) and os.path.exists(self.path):
            os.remove(self.path)
        if os.path.exists(self.vpath) and not os.path.exists(self.path):
            os.remove(self.vpath)

        if self.exists():
            with open(self.vpath, 'r') as f:
                self.version = int(f.read().strip())

    def exists(self):
        return os.path.exists(self.path)

    def save(self, keyring_data, version):
        with open(self.path, 'wb') as fp:
            fp.write(keyring_data)
        self.version = version
        with open(self.vpath, 'wb') as fp:
            fp.write(str(version))

    @staticmethod
    def find_gpgv():
        if os.getenv('GPGV_EXECUTABLE'):
            return os.getenv('GPGV_EXECUTABLE')
        paths = os.getenv('PATH', os.defpath).split(os.pathsep)
        for path in paths:
            fpath = os.path.join(path, 'gpgv')
            if os.path.exists(fpath) and os.access(fpath, os.X_OK):
                return fpath

    def is_valid(self, data, sigdata):
        """
        Check if the data is signed by an accepted key.
        data and sigdata should be strings.
        """
        gpgv = self.find_gpgv()
        with NamedTemporaryFile(suffix='.sig') as sigfile:
            sigfile.write(sigdata)
            sigfile.flush()  # very important
            assert isinstance(data, basestring)
            # Yes, all of it is necessary
            proc = subprocess.Popen([gpgv,
                    '--status-fd', '1',
                    '--keyring', os.path.realpath(self.path),
                    os.path.realpath(sigfile.name),
                    '-'],
                stdin=subprocess.PIPE,
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE)
            out, err = proc.communicate(data)
            if proc.returncode or 'GOODSIG' not in out or 'VALIDSIG' not in out:
                print >>sys.stderr, out, err
                return False
        return True

    def __str__(self):
        if self.exists():
            with open(self.vpath, 'r') as f:
                h = hashlib.sha1(f.read()).hexdigest()
            return 'Keyring version %s, checksum %s' % (self.version, h)
        return 'NO KEYRING'