# Copyright (C) 2009 W. Trevor King <wking@drexel.edu>
#
# 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.

"""
Handle conversion between the various BE storage formats.
"""

import codecs
import os, os.path
import sys

import libbe
import libbe.bug
import libbe.storage.util.mapfile as mapfile
from libbe.storage import STORAGE_VERSIONS, STORAGE_VERSION
#import libbe.storage.vcs # delay import to avoid cyclic dependency
import libbe.ui.util.editor
import libbe.util
import libbe.util.encoding as encoding
import libbe.util.id


class Upgrader (object):
    "Class for converting between different on-disk BE storage formats."
    initial_version = None
    final_version = None
    def __init__(self, repo):
        import libbe.storage.vcs

        self.repo = repo
        vcs_name = self._get_vcs_name()
        if vcs_name == None:
            vcs_name = 'None'
        self.vcs = libbe.storage.vcs.vcs_by_name(vcs_name)
        self.vcs.repo = self.repo
        self.vcs.root()

    def get_path(self, *args):
        """
        Return the absolute path using args relative to .be.
        """
        dir = os.path.join(self.repo, '.be')
        if len(args) == 0:
            return dir
        return os.path.join(dir, *args)

    def _get_vcs_name(self):
        return None

    def check_initial_version(self):
        path = self.get_path('version')
        version = encoding.get_file_contents(path, decode=True).rstrip('\n')
        assert version == self.initial_version, '%s: %s' % (path, version)

    def set_version(self):
        path = self.get_path('version')
        encoding.set_file_contents(path, self.final_version+'\n')
        self.vcs._vcs_update(path)

    def upgrade(self):
        print >> sys.stderr, 'upgrading bugdir from "%s" to "%s"' \
            % (self.initial_version, self.final_version)
        self.check_initial_version()
        self.set_version()
        self._upgrade()

    def _upgrade(self):
        raise NotImplementedError


class Upgrade_1_0_to_1_1 (Upgrader):
    initial_version = "Bugs Everywhere Tree 1 0"
    final_version = "Bugs Everywhere Directory v1.1"
    def _get_vcs_name(self):
        path = self.get_path('settings')
        settings = encoding.get_file_contents(path)
        for line in settings.splitlines(False):
            fields = line.split('=')
            if len(fields) == 2 and fields[0] == 'rcs_name':
                return fields[1]
        return None
            
    def _upgrade_mapfile(self, path):
        contents = encoding.get_file_contents(path, decode=True)
        old_format = False
        for line in contents.splitlines():
            if len(line.split('=')) == 2:
                old_format = True
                break
        if old_format == True:
            # translate to YAML.
            newlines = []
            for line in contents.splitlines():
                line = line.rstrip('\n')
                if len(line) == 0:
                    continue
                fields = line.split("=")
                if len(fields) == 2:
                    key,value = fields
                    newlines.append('%s: "%s"' % (key, value.replace('"','\\"')))
                else:
                    newlines.append(line)
            contents = '\n'.join(newlines)
            # load the YAML and save
            map = mapfile.parse(contents)
            contents = mapfile.generate(map)
            encoding.set_file_contents(path, contents)
            self.vcs._vcs_update(path)

    def _upgrade(self):
        """
        Comment value field "From" -> "Author".
        Homegrown mapfile -> YAML.
        """
        path = self.get_path('settings')
        self._upgrade_mapfile(path)
        for bug_uuid in os.listdir(self.get_path('bugs')):
            path = self.get_path('bugs', bug_uuid, 'values')
            self._upgrade_mapfile(path)
            c_path = ['bugs', bug_uuid, 'comments']
            if not os.path.exists(self.get_path(*c_path)):
                continue # no comments for this bug
            for comment_uuid in os.listdir(self.get_path(*c_path)):
                path_list = c_path + [comment_uuid, 'values']
                path = self.get_path(*path_list)
                self._upgrade_mapfile(path)
                settings = mapfile.parse(
                    encoding.get_file_contents(path))
                if 'From' in settings:
                    settings['Author'] = settings.pop('From')
                    encoding.set_file_contents(
                        path, mapfile.generate(settings))
                    self.vcs._vcs_update(path)


class Upgrade_1_1_to_1_2 (Upgrader):
    initial_version = "Bugs Everywhere Directory v1.1"
    final_version = "Bugs Everywhere Directory v1.2"
    def _get_vcs_name(self):
        path = self.get_path('settings')
        settings = mapfile.parse(encoding.get_file_contents(path))
        if 'rcs_name' in settings:
            return settings['rcs_name']
        return None
            
    def _upgrade(self):
        """
        BugDir settings field "rcs_name" -> "vcs_name".
        """
        path = self.get_path('settings')
        settings = mapfile.parse(encoding.get_file_contents(path))
        if 'rcs_name' in settings:
            settings['vcs_name'] = settings.pop('rcs_name')
            encoding.set_file_contents(path, mapfile.generate(settings))
            self.vcs._vcs_update(path)

class Upgrade_1_2_to_1_3 (Upgrader):
    initial_version = "Bugs Everywhere Directory v1.2"
    final_version = "Bugs Everywhere Directory v1.3"
    def __init__(self, *args, **kwargs):
        Upgrader.__init__(self, *args, **kwargs)
        self._targets = {} # key: target text,value: new target bug

    def _get_vcs_name(self):
        path = self.get_path('settings')
        settings = mapfile.parse(encoding.get_file_contents(path))
        if 'vcs_name' in settings:
            return settings['vcs_name']
        return None

    def _save_bug_settings(self, bug):
        # The target bugs don't have comments
        path = self.get_path('bugs', bug.uuid, 'values')
        if not os.path.exists(path):
            self.vcs._add_path(path, directory=False)
        path = self.get_path('bugs', bug.uuid, 'values')
        mf = mapfile.generate(bug._get_saved_settings())
        encoding.set_file_contents(path, mf)
        self.vcs._vcs_update(path)

    def _target_bug(self, target_text):
        if target_text not in self._targets:
            bug = libbe.bug.Bug(summary=target_text)
            bug.severity = 'target'
            self._targets[target_text] = bug
        return self._targets[target_text]

    def _upgrade_bugdir_mapfile(self):
        path = self.get_path('settings')
        mf = encoding.get_file_contents(path)
        if mf == libbe.util.InvalidObject:
            return # settings file does not exist
        settings = mapfile.parse(mf)
        if 'target' in settings:
            settings['target'] = self._target_bug(settings['target']).uuid
            mf = mapfile.generate(settings)
            encoding.set_file_contents(path, mf)
            self.vcs._vcs_update(path)

    def _upgrade_bug_mapfile(self, bug_uuid):
        import libbe.command.depend as dep
        path = self.get_path('bugs', bug_uuid, 'values')
        mf = encoding.get_file_contents(path)
        if mf == libbe.util.InvalidObject:
            return # settings file does not exist
        settings = mapfile.parse(mf)
        if 'target' in settings:
            target_bug = self._target_bug(settings['target'])

            blocked_by_string = '%s%s' % (dep.BLOCKED_BY_TAG, bug_uuid)
            dep._add_remove_extra_string(target_bug, blocked_by_string, add=True)
            blocks_string = dep._generate_blocks_string(target_bug)
            estrs = settings.get('extra_strings', [])
            estrs.append(blocks_string)
            settings['extra_strings'] = sorted(estrs)

            settings.pop('target')
            mf = mapfile.generate(settings)
            encoding.set_file_contents(path, mf)
            self.vcs._vcs_update(path)

    def _upgrade(self):
        """
        Bug value field "target" -> target bugs.
        Bugdir value field "target" -> pointer to current target bug.
        """
        for bug_uuid in os.listdir(self.get_path('bugs')):
            self._upgrade_bug_mapfile(bug_uuid)
        self._upgrade_bugdir_mapfile()
        for bug in self._targets.values():
            self._save_bug_settings(bug)

class Upgrade_1_3_to_1_4 (Upgrader):
    initial_version = "Bugs Everywhere Directory v1.3"
    final_version = "Bugs Everywhere Directory v1.4"
    def _get_vcs_name(self):
        path = self.get_path('settings')
        settings = mapfile.parse(encoding.get_file_contents(path))
        if 'vcs_name' in settings:
            return settings['vcs_name']
        return None

    def _upgrade(self):
        """
        add new directory "./be/BUGDIR-UUID"
        "./be/bugs" -> "./be/BUGDIR-UUID/bugs"
        "./be/settings" -> "./be/BUGDIR-UUID/settings"
        """
        self.repo = os.path.abspath(self.repo)
        basenames = [p for p in os.listdir(self.get_path())]
        if not 'bugs' in basenames and not 'settings' in basenames \
                and len([p for p in basenames if len(p)==36]) == 1:
            return # the user has upgraded the directory.
        basenames = [p for p in basenames if p in ['bugs','settings']]
        uuid = libbe.util.id.uuid_gen()
        add = [self.get_path(uuid)]
        move = [(self.get_path(p), self.get_path(uuid, p)) for p in basenames]
        msg = ['Upgrading BE directory version v1.3 to v1.4',
               '',
               "Because BE's VCS drivers don't support 'move',",
               'please make the following changes with your VCS',
               'and re-run BE.  Note that you can choose a different',
               'bugdir UUID to preserve uniformity across branches',
               'of a distributed repository.'
               '',
               'add',
               '  ' + '\n  '.join(add),
               'move',
               '  ' + '\n  '.join(['%s %s' % (a,b) for a,b in move]),
               ]
        self.vcs._cached_path_id.destroy()
        raise Exception('Need user assistance\n%s' % '\n'.join(msg))


upgraders = [Upgrade_1_0_to_1_1,
             Upgrade_1_1_to_1_2,
             Upgrade_1_2_to_1_3,
             Upgrade_1_3_to_1_4]
upgrade_classes = {}
for upgrader in upgraders:
    upgrade_classes[(upgrader.initial_version,upgrader.final_version)]=upgrader

def upgrade(path, current_version,
            target_version=STORAGE_VERSION):
    """
    Call the appropriate upgrade function to convert current_version
    to target_version.  If a direct conversion function does not exist,
    use consecutive conversion functions.
    """
    if current_version not in STORAGE_VERSIONS:
        raise NotImplementedError, \
            "Cannot handle version '%s' yet." % current_version
    if target_version not in STORAGE_VERSIONS:
        raise NotImplementedError, \
            "Cannot handle version '%s' yet." % current_version

    if (current_version, target_version) in upgrade_classes:
        # direct conversion
        upgrade_class = upgrade_classes[(current_version, target_version)]
        u = upgrade_class(path)
        u.upgrade()
    else:
        # consecutive single-step conversion
        i = STORAGE_VERSIONS.index(current_version)
        while True:
            version_a = STORAGE_VERSIONS[i]
            version_b = STORAGE_VERSIONS[i+1]
            try:
                upgrade_class = upgrade_classes[(version_a, version_b)]
            except KeyError:
                raise NotImplementedError, \
                    "Cannot convert version '%s' to '%s' yet." \
                    % (version_a, version_b)
            u = upgrade_class(path)
            u.upgrade()
            if version_b == target_version:
                break
            i += 1