# -*- 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 print_function
import imp
import posixpath
import shutil
import re
import sys
import os
import subprocess
from datetime import datetime
from contextlib import closing
from compileall import compile_dir
from io import BytesIO

from weboob.tools.exceptions import BrowserHTTPError, BrowserHTTPNotFound
from .modules import Module
from weboob.tools.log import getLogger
from weboob.tools.misc import to_unicode
try:
    from ConfigParser import RawConfigParser, DEFAULTSECT
except ImportError:
    from configparser import RawConfigParser, DEFAULTSECT


__all__ = ['IProgress', 'ModuleInstallError', 'ModuleInfo', 'RepositoryUnavailable',
           'Repository', 'Versions', 'Repositories', 'InvalidSignature', 'Keyring']


class ModuleInfo(object):
    """
    Information about a module available on a repository.
    """
    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'].strip() or None
        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 or ''),
                ('urls', self.urls),
               )


class RepositoryUnavailable(Exception):
    """
    Repository in not available.
    """


class Repository(object):
    """
    Represents a repository.
    """
    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 is True

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

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

        :param repo_path: path to save the downloaded index file.
        :type repo_path: str
        """
        if self.local:
            # Repository is local, open the file.
            filename = os.path.join(self.localurl2path(), self.INDEX)
            try:
                fp = open(filename, 'r')
            except IOError as 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
            try:
                fp = BytesIO(browser.open(posixpath.join(self.url, self.INDEX)).content)
            except BrowserHTTPError as 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, browser, 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
            try:
                keyring_data = browser.open(posixpath.join(self.url, self.KEYRING)).content
                sig_data = browser.open(posixpath.join(self.url, self.KEYRING + '.sig')).content
            except BrowserHTTPError as e:
                raise RepositoryUnavailable(unicode(e))
            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: file descriptor to read
        :type fp: buffer
        """
        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 as e:
            raise RepositoryUnavailable('Missing global parameters in repository: %s' % e)
        except ValueError as 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: path of the repository
        :type path: str
        :param filename: file to save index
        :type filename: str
        """
        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

        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:
                fp, pathname, description = imp.find_module(name, [path])
                try:
                    module = Module(imp.load_module(name, fp, pathname, description))
                finally:
                    if fp:
                        fp.close()
            except Exception as e:
                print('Unable to build module %s: [%s] %s' % (name, type(e).__name__, e), file=sys.stderr)
            else:
                m = ModuleInfo(module.name)
                m.version = self.get_tree_mtime(module_path)
                m.capabilities = list(set([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

        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: path to file to save repository.
        :type filename: str
        :param private: if enabled, save URL of repository.
        :type private: bool
        """
        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(object):
    def progress(self, percent, message):
        print('=== [%3.0f%%] %s' % (percent*100, message))

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


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/

# 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.browser = None

        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.version)
        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 load_browser(self):
        from weboob.tools.browser2.browser import BaseBrowser, Weboob as WeboobProfile
        class WeboobBrowser(BaseBrowser):
            PROFILE = WeboobProfile(self.version)
        if self.browser is None:
            self.browser = WeboobBrowser()

    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: filter on capabilities:
        :type caps: list[str]
        :rtype: dict[:class:`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 ~/.local/share/weboob/repositories/.
        """
        self.repositories = []
        for name in sorted(os.listdir(self.repos_dir)):
            path = os.path.join(self.repos_dir, name)
            try:
                repository = Repository(path)
                self.repositories.append(repository)
            except RepositoryUnavailable as e:
                print('Unable to load repository %s (%s), try to update repositories.' % (name, e), file=sys.stderr)

    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 ~/.local/share/weboob/icons/.
        """
        self.load_browser()
        if not isinstance(module, ModuleInfo):
            module = self.get_module_info(module)

        dest_path = self.get_module_icon_path(module)

        icon_url = module.icon
        if not icon_url:
            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
            else:
                icon_url = module.url.replace('.tar.gz', '.png')

        try:
            icon = self.browser.open(icon_url)
        except BrowserHTTPNotFound:
            pass  # no icon, no problem
        else:
            with open(dest_path, 'wb') as fp:
                fp.write(icon.content)

    def _parse_source_list(self):
        l = []
        with open(self.sources_list, 'r') as f:
            for line in f:
                line = line.strip() % {'version': self.version}
                m = re.match('(file|https?)://.*', line)
                if m:
                    l.append(line)
        return l

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

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

        gpgv = Keyring.find_gpgv()
        for line in self._parse_source_list():
            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(self.browser, repo_path)
                if gpgv:
                    repository.retrieve_keyring(self.browser, keyring_path)
                else:
                    progress.error('Cannot find gpgv to check for repository authenticity.\n'
                                    'You should install GPG for better security.')
            except RepositoryUnavailable as e:
                progress.error('Unable to load repository: %s' % e)
            else:
                self.repositories.append(repository)

    def check_repositories(self):
        """
        Check if sources.list is consistent with repositories
        """
        l = []
        for line in self._parse_source_list():
            repository = Repository(line)
            filename = self.url2filename(repository.url)
            prio_filename = '%02d-%s' % (len(l), filename)
            repo_path = os.path.join(self.repos_dir, prio_filename)
            if not os.path.isfile(repo_path):
                return False
            l.append(repository)
        return True

    def update(self, progress=IProgress()):
        """
        Update repositories and install new packages versions.

        :param progress: observer object.
        :type progress: :class:`IProgress`
        """
        self.update_repositories()

        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 as e:
                inst_progress.progress(1.0, unicode(e))

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

        :param module: module to install
        :type module: :class:`str` or :class:`ModuleInfo`
        :param progress: observer object
        :type progress: :class:`IProgress`
        """
        import tarfile
        self.load_browser()

        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 %s is not installed yet' % module.name)
        elif module.version > installed:
            progress.progress(0.3, 'A new version of %s is available' % module.name)
        else:
            raise ModuleInstallError('The latest version of %s is already installed' % module.name)

        progress.progress(0.2, 'Downloading module...')
        try:
            tardata = self.browser.open(module.url).content
        except BrowserHTTPError as e:
            raise ModuleInstallError('Unable to fetch module: %s' % e)

        # Check signature
        if module.signed and Keyring.find_gpgv():
            progress.progress(0.5, 'Checking module authenticity...')
            sig_data = self.browser.open(posixpath.join(module.url + '.sig')).content
            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, sig_data):
                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', BytesIO(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

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

    def exists(self):
        if not os.path.exists(self.vpath):
            return False
        if os.path.exists(self.path):
            # Check the file is not empty.
            # This is because there was a bug creating empty keyring files.
            with open(self.path, 'r') as fp:
                if len(fp.read().strip()):
                    return True
        return False

    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:
            for ex in ('gpgv2', 'gpgv'):
                fpath = os.path.join(path, ex)
                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()
        from tempfile import NamedTemporaryFile
        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(out, err, file=sys.stderr)
                return False
        return True

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