# redMine - project management software
# Copyright (C) 2006-2007  Jean-Philippe Lang
#
# 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.

require 'redmine/scm/adapters/abstract_adapter'
require 'cgi'

module Redmine
  module Scm
    module Adapters
      class MercurialAdapter < AbstractAdapter

        # Mercurial executable name
        HG_BIN = Redmine::Configuration['scm_mercurial_command'] || "hg"
        HELPERS_DIR = File.dirname(__FILE__) + "/mercurial"
        HG_HELPER_EXT = "#{HELPERS_DIR}/redminehelper.py"
        TEMPLATE_NAME = "hg-template"
        TEMPLATE_EXTENSION = "tmpl"

        # raised if hg command exited with error, e.g. unknown revision.
        class HgCommandAborted < CommandFailed; end

        class << self
          def client_command
            @@bin    ||= HG_BIN
          end

          def sq_bin
            @@sq_bin ||= shell_quote(HG_BIN)
          end

          def client_version
            @@client_version ||= (hgversion || [])
          end

          def client_available
            !client_version.empty?
          end

          def hgversion
            # The hg version is expressed either as a
            # release number (eg 0.9.5 or 1.0) or as a revision
            # id composed of 12 hexa characters.
            theversion = hgversion_from_command_line
            if m = theversion.match(%r{\A(.*?)((\d+\.)+\d+)})
              m[2].scan(%r{\d+}).collect(&:to_i)
            end
          end

          def hgversion_from_command_line
            shellout("#{sq_bin} --version") { |io| io.read }.to_s
          end

          def template_path
            @@template_path ||= template_path_for(client_version)
          end

          def template_path_for(version)
            if ((version <=> [0,9,5]) > 0) || version.empty?
              ver = "1.0"
            else
              ver = "0.9.5"
            end
            "#{HELPERS_DIR}/#{TEMPLATE_NAME}-#{ver}.#{TEMPLATE_EXTENSION}"
          end
        end

        def info
          cmd = "#{self.class.sq_bin} -R #{target('')} root"
          root_url = nil
          shellout(cmd) do |io|
            root_url = io.read
          end
          return nil if $? && $?.exitstatus != 0
          info = Info.new({:root_url => root_url.chomp,
                            :lastrev => revisions(nil,nil,nil,{:limit => 1}).last
                          })
          info
        rescue CommandFailed
          return nil
        end

        def entries(path=nil, identifier=nil)
          path ||= ''
          entries = Entries.new
          cmd = "#{self.class.sq_bin} -R #{target('')} --cwd #{target('')} locate"
          cmd << " -r #{hgrev(identifier, true)}"
          cmd << " " + shell_quote("path:#{path}") unless path.empty?
          shellout(cmd) do |io|
            io.each_line do |line|
              # HG uses antislashs as separator on Windows
              line = line.gsub(/\\/, "/")
              if path.empty? or e = line.gsub!(%r{^#{with_trailling_slash(path)}},'')
                e ||= line
                e = e.chomp.split(%r{[\/\\]})
                entries << Entry.new({:name => e.first,
                                       :path => (path.nil? or path.empty? ? e.first : "#{with_trailling_slash(path)}#{e.first}"),
                                       :kind => (e.size > 1 ? 'dir' : 'file'),
                                       :lastrev => Revision.new
                                     }) unless e.empty? || entries.detect{|entry| entry.name == e.first}
              end
            end
          end
          return nil if $? && $?.exitstatus != 0
          entries.sort_by_name
        end

        # Fetch the revisions by using a template file that 
        # makes Mercurial produce a xml output.
        def revisions(path=nil, identifier_from=nil, identifier_to=nil, options={})  
          revisions = Revisions.new
          cmd = "#{self.class.sq_bin} --debug --encoding utf8 -R #{target('')} log -C --style #{shell_quote self.class.template_path}"
          if identifier_from && identifier_to
            cmd << " -r #{hgrev(identifier_from, true)}:#{hgrev(identifier_to, true)}"
          elsif identifier_from
            cmd << " -r #{hgrev(identifier_from, true)}:"
          end
          cmd << " --limit #{options[:limit].to_i}" if options[:limit]
          cmd << " #{shell_quote path}" unless path.blank?
          shellout(cmd) do |io|
            begin
              # HG doesn't close the XML Document...
              doc = REXML::Document.new(io.read << "</log>")
              doc.elements.each("log/logentry") do |logentry|
                paths = []
                copies = logentry.get_elements('paths/path-copied')
                logentry.elements.each("paths/path") do |path|
                  # Detect if the added file is a copy
                  if path.attributes['action'] == 'A' and c = copies.find{ |e| e.text == path.text }
                    from_path = c.attributes['copyfrom-path']
                    from_rev = logentry.attributes['revision']
                  end
                  paths << {:action => path.attributes['action'],
                    :path => "/#{CGI.unescape(path.text)}",
                    :from_path => from_path ? "/#{CGI.unescape(from_path)}" : nil,
                    :from_revision => from_rev ? from_rev : nil
                  }
                end
                paths.sort! { |x,y| x[:path] <=> y[:path] }

                revisions << Revision.new({:identifier => logentry.attributes['revision'],
                                            :scmid => logentry.attributes['node'],
                                            :author => (logentry.elements['author'] ? logentry.elements['author'].text : ""),
                                            :time => Time.parse(logentry.elements['date'].text).localtime,
                                            :message => logentry.elements['msg'].text,
                                            :paths => paths
                                          })
              end
            rescue
              logger.debug($!)
            end
          end
          return nil if $? && $?.exitstatus != 0
          revisions
        end

        def diff(path, identifier_from, identifier_to=nil)
          path ||= ''
          diff_args = ''
          diff = []
          if identifier_to
            diff_args = "-r #{hgrev(identifier_to, true)} -r #{hgrev(identifier_from, true)}"
          else
            if self.class.client_version_above?([1, 2])
              diff_args = "-c #{hgrev(identifier_from, true)}"
            else
              return []
            end
          end
          cmd = "#{self.class.sq_bin} -R #{target('')} --config diff.git=false diff --nodates #{diff_args}"
          cmd << " -I #{target(path)}" unless path.empty?
          shellout(cmd) do |io|
            io.each_line do |line|
              diff << line
            end
          end
          return nil if $? && $?.exitstatus != 0
          diff
        end

        def cat(path, identifier=nil)
          hg 'cat', '-r', hgrev(identifier), hgtarget(path) do |io|
            io.binmode
            io.read
          end
        rescue HgCommandAborted
          nil  # means not found
        end

        def annotate(path, identifier=nil)
          blame = Annotate.new
          hg 'annotate', '-ncu', '-r', hgrev(identifier), hgtarget(path) do |io|
            io.each_line do |line|
              next unless line =~ %r{^([^:]+)\s(\d+)\s([0-9a-f]+):\s(.*)$}
              r = Revision.new(:author => $1.strip, :revision => $2, :scmid => $3,
                               :identifier => $3)
              blame.add_line($4.rstrip, r)
            end
          end
          blame
        rescue HgCommandAborted
          nil  # means not found or cannot be annotated
        end

        class Revision < Redmine::Scm::Adapters::Revision
          # Returns the readable identifier
          def format_identifier
            "#{revision}:#{scmid}"
          end
        end

        # Runs 'hg' command with the given args
        def hg(*args, &block)
          repo_path = root_url || url
          full_args = [HG_BIN, '-R', repo_path, '--encoding', 'utf-8']
          full_args << '--config' << "extensions.redminehelper=#{HG_HELPER_EXT}"
          full_args << '--config' << 'diff.git=false'
          full_args += args
          ret = shellout(full_args.map { |e| shell_quote e.to_s }.join(' '), &block)
          if $? && $?.exitstatus != 0
            raise HgCommandAborted, "hg exited with non-zero status: #{$?.exitstatus}"
          end
          ret
        end
        private :hg

        # Returns correct revision identifier
        def hgrev(identifier, sq=false)
          rev = identifier.blank? ? 'tip' : identifier.to_s
          rev = shell_quote(rev) if sq
          rev
        end
        private :hgrev

        def hgtarget(path)
          path ||= ''
          root_url + '/' + without_leading_slash(path)
        end
        private :hgtarget
      end
    end
  end
end