#-- encoding: UTF-8
#-- copyright
# OpenProject is a project management system.
# Copyright (C) 2012-2018 the OpenProject Foundation (OPF)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License version 3.
#
# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
# Copyright (C) 2006-2017 Jean-Philippe Lang
# Copyright (C) 2010-2013 the ChiliProject Team
#
# 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.
#
# See docs/COPYRIGHT.rdoc for more details.
#++

require 'tempfile'
require 'fileutils'

namespace :backup do
  namespace :database do
    desc 'Creates a database dump which can be used as a backup.'
    task :create, [:path_to_backup] => [:environment] do |_task, args|
      args.with_defaults(path_to_backup: default_db_filename)
      FileUtils.mkdir_p(Pathname.new(args[:path_to_backup]).dirname)

      config = database_configuration

      with_config_file(config) do |config_file|
        pg_dump_call = ['pg_dump',
                        '--clean',
                        "--file=#{args[:path_to_backup]}",
                        '--format=custom',
                        '--no-owner']
        pg_dump_call << "--host=#{config['host']}" if config['host']
        pg_dump_call << "--port=#{config['port']}" if config['port']
        user = config.values_at('user', 'username').compact.first
        pg_dump_call << "--username=#{user}" if user
        pg_dump_call << config['database'].to_s

        if config['password']
          Kernel.system({ 'PGPASSFILE' => config_file }, *pg_dump_call)
        else
          Kernel.system(*pg_dump_call)
        end
      end
    end

    desc 'Restores a database dump created by the :create task.'
    task :restore, [:path_to_backup] => [:environment] do |_task, args|
      raise 'You must provide the path to the database dump' unless args[:path_to_backup]
      raise "File '#{args[:path_to_backup]}' is not readable" unless File.readable?(args[:path_to_backup])

      config = database_configuration

      with_config_file(config) do |config_file|
        pg_restore_call = ['pg_restore',
                           '--clean',
                           '--no-owner',
                           '--single-transaction',
                           "--dbname=#{config['database']}"]
        pg_restore_call << "--host=#{config['host']}" if config['host']
        pg_restore_call << "--port=#{config['port']}" if config['port']
        user = config.values_at('user', 'username').compact.first
        pg_restore_call << "--username=#{user}" if user
        pg_restore_call << args[:path_to_backup].to_s

        if config['password']
          Kernel.system({ 'PGPASSFILE' => config_file }, *pg_restore_call)
        else
          Kernel.system(*pg_restore_call)
        end
      end
    end

    private

    def database_configuration
      ActiveRecord::Base.configurations[Rails.env] || Rails.application.config.database_configuration[Rails.env]
    end

    def with_config_file(config, &blk)
      file = Tempfile.new('op_pg_config')
      file.write "*:*:*:*:#{config['password']}"
      file.close
      blk.yield file.path
      file.unlink
    end

    def sql_dump_tempfile(config)
      t =  "[client]\n"
      t << "password=\"#{config['password']}\"\n"
      t << "user=\"#{config.values_at('user', 'username').compact.first}\"\n"
      t << "host=\"#{config['host'] || '127.0.0.1'}\"\n"
      t << "port=\"#{config['port']}\"\n" if config['port']
      t << "ssl-key=\"#{config['sslkey']}\"\n" if config['sslkey']
      t << "ssl-cert=\"#{config['sslcert']}\"\n" if config['sslcert']
      t << "ssl-ca=\"#{config['sslca']}\"\n" if config['sslca']
      t
    end

    def default_db_filename
      filename = "openproject-#{Rails.env}-db-#{date_string}.backup"
      Rails.root.join('backup', sanitize_filename(filename))
    end

    def date_string
      Time.now.strftime('%Y%m%dT%H%M%S%z') # e.g. "20141020T165335+0200"
    end

    def sanitize_filename(filename)
      filename.gsub(/[^0-9A-Za-z.-]/, '_')
    end
  end
end