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#       to you under the Apache License, Version 2.0 (the
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#
#         http://www.apache.org/licenses/LICENSE-2.0
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from __future__ import unicode_literals
from __future__ import absolute_import
import os
import os.path
import logging
import shutil
import codecs

import tg
from tg import app_globals as g, tmpl_context as c

from allura.tasks import mail_tasks
from allura.lib.decorators import task
from allura.lib import helpers as h
from allura.model.repository import zipdir


log = logging.getLogger(__name__)


@task
def bulk_export(tools, filename=None, send_email=True, with_attachments=False):
    '''
    Export the current project data.  Send notification to current user.

    :param list tools: list of mount_points to export
    :param str filename: optional filename to use
    '''
    # it's very handy to use c.* within a @task,
    # but let's be explicit and keep it separate from the main code
    return BulkExport().process(c.project, tools, c.user, filename, send_email, with_attachments)


class BulkExport(object):

    def process(self, project, tools, user, filename=None, send_email=True, with_attachments=False):
        export_filename = filename or project.bulk_export_filename()
        tmp_path = os.path.join(
            project.bulk_export_path(rootdir=tg.config.get('bulk_export_tmpdir', tg.config['bulk_export_path'])),
            os.path.splitext(export_filename)[0],  # e.g. test-backup-2018-06-26-210524 without the .zip
        )
        export_path = project.bulk_export_path(rootdir=tg.config['bulk_export_path'])
        export_fullpath = os.path.join(export_path, export_filename)
        if not os.path.exists(tmp_path):
            os.makedirs(tmp_path)
        if not os.path.exists(export_path):
            os.makedirs(export_path)
        apps = [project.app_instance(tool) for tool in tools]
        exportable = self.filter_exportable(apps)
        results = [self.export(tmp_path, app, with_attachments) for app in exportable]
        exported = self.filter_successful(results)
        if exported:
            zipdir(tmp_path, export_fullpath)
        shutil.rmtree(tmp_path.encode('utf8'))  # must encode into bytes or it'll fail on non-ascii filenames

        if not user:
            log.info('No user. Skipping notification.')
            return
        if not send_email:
            return

        tmpl = g.jinja2_env.get_template('allura:templates/mail/bulk_export.html')
        instructions = tg.config.get('bulk_export_download_instructions', '')
        instructions = instructions.format(
            project=project.shortname,
            filename=export_filename,
            c=c,
        )
        exported_names = [a.config.options.mount_point for a in exported]
        tmpl_context = {
            'instructions': instructions,
            'project': project,
            'tools': exported_names,
            'not_exported_tools': list(set(tools) - set(exported_names)),
        }

        mail_tasks.send_system_mail_to_user(user,
                                            'Bulk export for project %s completed' % project.shortname,
                                            tmpl.render(tmpl_context))

    def filter_exportable(self, apps):
        return [app for app in apps if app and app.exportable]

    def export(self, export_path, app, with_attachments=False):
        tool = app.config.options.mount_point
        json_file = os.path.join(export_path, '%s.json' % tool)
        try:
            with codecs.open(json_file, 'w', encoding='utf-8') as f:
                app.bulk_export(f, export_path, with_attachments)
        except Exception:
            log.error('Error exporting: %s on %s', tool,
                      app.project.shortname, exc_info=True)
            try:
                os.remove(json_file)
            except Exception:
                pass
            return None
        else:
            return app

    def filter_successful(self, results):
        return [result for result in results if result is not None]