#-- encoding: UTF-8
#-- copyright
# OpenProject is a project management system.
# Copyright (C) 2012-2017 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 doc/COPYRIGHT.rdoc for more details.
#++

require 'open3'
require 'find'
module OpenProject
  module Scm
    module Adapters
      module LocalClient
        def self.included(base)
          base.extend(ClassMethods)
        end

        module ClassMethods
          ##
          # Reads the configuration for this strategy from OpenProject's `configuration.yml`.
          def config
            ['scm', vendor].inject(OpenProject::Configuration) do |acc, key|
              HashWithIndifferentAccess.new acc[key]
            end
          end
        end

        ##
        # Determines local capabilities for SCM creation.
        # Overridden by including classes when SCM may be remote.
        def local?
          true
        end

        ##
        # Determines whether this repository is eligible
        # to count storage.
        def storage_available?
          local? && File.directory?(local_repository_path)
        end

        ##
        # Counts the repository storage requirement immediately
        # or raises an exception if this is impossible for the current repository.
        def count_repository!
          if storage_available?
            count_required_storage
          else
            raise Exceptions::ScmError.new I18n.t('repositories.storage.not_available')
          end
        end

        ##
        # Retrieve the local FS path
        # of this repository.
        #
        # Overriden by some vendors, as not
        # all vendors have a path root_url.
        # (e.g., subversion uses file:// URLs)
        def local_repository_path
          root_url
        end

        def config
          self.class.config
        end

        ##
        # client executable command
        def client_command
          ''
        end

        def client_available
          !client_version.empty?
        end

        ##
        # Returns the version of the scm client
        # Eg: [1, 5, 0] or [] if unknown
        def client_version
          []
        end

        ##
        # Returns the version string of the scm client
        # Eg: '1.5.0' or 'Unknown version' if unknown
        def client_version_string
          v = client_version || 'Unknown version'
          v.is_a?(Array) ? v.join('.') : v.to_s
        end

        ##
        # Returns true if the current client version is above
        # or equals the given one
        # If option is :unknown is set to true, it will return
        # true if the client version is unknown
        def client_version_above?(v, options = {})
          ((client_version <=> v) >= 0) || (client_version.empty? && options[:unknown])
        end

        def supports_cat?
          true
        end

        def supports_annotate?
          respond_to?('annotate')
        end

        def target(path = '')
          base = path.match(/\A\//) ? root_url : url
          "#{base}/#{path}"
        end

        ##
        # Returns true if any line of the IO object
        # has a line that +include?+ the given part.
        #
        # @param [IO] io            An IO object from Open3.
        # @param [String] part      The string parameter to +contains?+
        # @return [Boolean or nil]  True iff any line of io includes the part
        def io_include?(io, part)
          io.each_line do |l|
            return true if l.include?(part)
          end
        end

        # Executes the given arguments for +client_command+ on the shell
        # and returns the resulting stdout.
        #
        # May optionally specify an opts hash with flags for popen3 and Process.spawn
        # (cf., :binmode, :stdin_data in +Open3.capture3+)
        #
        # If the operation throws an exception or the operation yields a non-zero exit code
        # we rethrow a +CommandFailed+ with a meaningful error message
        def capture_out(args, opts = {})
          output, err, code = Open3.capture3(client_command, *args, binmode: opts[:binmode])
          if code != 0
            error_msg = "SCM command failed: Non-zero exit code (#{code}) for `#{client_command}`"
            logger.error(error_msg)
            logger.debug("Error output is #{err}")
            raise Exceptions::CommandFailed.new(client_command, error_msg, err)
          end

          output
        end

        # Executes the given arguments for +client_command+ on the shell
        # and returns stdout, stderr, and the exit code.
        #
        # If the operation throws an exception or the operation we rethrow a
        # +CommandFailed+ with a meaningful error message.
        def popen3(args, opts = {}, &block)
          logger.debug "Shelling out: `#{stripped_command(args)}`"
          Open3.popen3(client_command, *args, opts, &block)
        rescue Exceptions::ScmError => e
          raise e
        rescue => e
          error_msg = "SCM command for `#{client_command}` failed: #{strip_credential(e.message)}"
          logger.error(error_msg)
          raise Exceptions::CommandFailed.new(client_command, error_msg)
        end

        ##
        # Returns the full client command and args with stripped credentials
        def stripped_command(args)
          "#{client_command} #{strip_credential(args.join(' '))}"
        end

        ##
        # Replaces argument values for --username/--password in a given command
        # with a placeholder
        def strip_credential(cmd)
          q = Redmine::Platform.mswin? ? '"' : "'"
          cmd.to_s.gsub(/(\-\-(password|username))\s+(#{q}[^#{q}]+#{q}|[^#{q}]\S+)/, '\\1 xxxx')
        end

        def scm_encode(to, from, str)
          return nil if str.nil?
          return str if to == from
          begin
            str.to_s.encode(to, from)
          rescue Encoding::InvalidByteSequenceError, Encoding::UndefinedConversionError => err
            logger.error("failed to convert from #{from} to #{to}. #{err}")
            nil
          end
        end

        private

        ##
        # Counts the repositories by files in ruby.
        # For sake of compatibility, iterates all files
        # in the repository to determine storage size.
        #
        # This is compatible, but quite inefficient, so should
        # be run asynchronously.
        def count_required_storage
          count_storage_du || count_storage_fallback
        end

        ##
        # Tries to count the required storage with du,
        # as that causes the smallest amount of overhead
        #
        # Compatible only with GNU du due to `-b` (contains `--apparent-size`)
        # being unavailable on, e.g., Mac OS X.
        # On incompatible systems, will fall back to in-ruby counting
        def count_storage_du
          output, err, code = Open3.capture3('du', '-bs', local_repository_path)

          if code == 0 && output =~ /^(\d+)/
            Regexp.last_match(1).to_i
          else
            raise SystemCallError.new "'du' exited with non-zero status #{code}: Output was #{err}"
          end
        rescue SystemCallError => e
          # May be raised when the command is not found.
          # Nothing we can do here.
          Rails.logger.error("Counting with 'du' failed with: '#{e.message}'." +
                             'Falling back to in-ruby counting.')
          nil
        end

        ##
        # Count required storage in pure ruby.
        # Called when `du` didn't seem to be available
        #
        # This is compatible, but quite inefficient
        # being ~25% slower than shelling out to du
        def count_storage_fallback
          ::Find.find(local_repository_path).inject(0) do |sum, f|
            begin
              sum + File.stat(f).size
            rescue SystemCallError
              # File.stat raises for permission and access errors,
              # we won't be able to get this file's size.
              sum
            end
          end
        end
      end
    end
  end
end