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.dup
            if theversion.respond_to?(:force_encoding)
              theversion.force_encoding('ASCII-8BIT')
            end
            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 initialize(url, root_url=nil, login=nil, password=nil, path_encoding=nil)
          super
          @path_encoding = path_encoding || 'UTF-8'
        end

        def info
          tip = summary['repository']['tip']
          Info.new(:root_url => CGI.unescape(summary['repository']['root']),
                   :lastrev => Revision.new(:revision => tip['revision'],
                                            :scmid => tip['node']))
        end

        def tags
          as_ary(summary['repository']['tag']).map { |e| e['name'] }
        end

        # Returns map of {'tag' => 'nodeid', ...}
        def tagmap
          alist = as_ary(summary['repository']['tag']).map do |e|
            e.values_at('name', 'node')
          end
          Hash[*alist.flatten]
        end

        def branches
          as_ary(summary['repository']['branch']).map { |e| e['name'] }
        end

        # Returns map of {'branch' => 'nodeid', ...}
        def branchmap
          alist = as_ary(summary['repository']['branch']).map do |e|
            e.values_at('name', 'node')
          end
          Hash[*alist.flatten]
        end

        def summary
          return @summary if @summary 
          hg 'rhsummary' do |io|
            output = io.read
            if output.respond_to?(:force_encoding)
              output.force_encoding('UTF-8')
            end
            begin
              @summary = ActiveSupport::XmlMini.parse(output)['rhsummary']
            rescue
            end
          end
        end
        private :summary

        def entries(path=nil, identifier=nil)
          p1 = scm_iconv(@path_encoding, 'UTF-8', path)
          manifest = hg('rhmanifest', '-r', CGI.escape(hgrev(identifier)),
                        CGI.escape(without_leading_slash(p1.to_s))) do |io|
            output = io.read
            if output.respond_to?(:force_encoding)
              output.force_encoding('UTF-8')
            end
            begin
              ActiveSupport::XmlMini.parse(output)['rhmanifest']['repository']['manifest']
            rescue
            end
          end
          path_prefix = path.blank? ? '' : with_trailling_slash(path)

          entries = Entries.new
          as_ary(manifest['dir']).each do |e|
            n = scm_iconv('UTF-8', @path_encoding, CGI.unescape(e['name']))
            p = "#{path_prefix}#{n}"
            entries << Entry.new(:name => n, :path => p, :kind => 'dir')
          end

          as_ary(manifest['file']).each do |e|
            n = scm_iconv('UTF-8', @path_encoding, CGI.unescape(e['name']))
            p = "#{path_prefix}#{n}"
            lr = Revision.new(:revision => e['revision'], :scmid => e['node'],
                              :identifier => e['node'],
                              :time => Time.at(e['time'].to_i))
            entries << Entry.new(:name => n, :path => p, :kind => 'file',
                                 :size => e['size'].to_i, :lastrev => lr)
          end

          entries
        rescue HgCommandAborted
          nil  # means not found
        end

        def revisions(path=nil, identifier_from=nil, identifier_to=nil, options={})
          revs = Revisions.new
          each_revision(path, identifier_from, identifier_to, options) { |e| revs << e }
          revs
        end

        # Iterates the revisions by using a template file that
        # makes Mercurial produce a xml output.
        def each_revision(path=nil, identifier_from=nil, identifier_to=nil, options={})
          hg_args = ['log', '--debug', '-C', '--style', self.class.template_path]
          hg_args << '-r' << "#{hgrev(identifier_from)}:#{hgrev(identifier_to)}"
          hg_args << '--limit' << options[:limit] if options[:limit]
          hg_args << hgtarget(path) unless path.blank?
          log = hg(*hg_args) do |io|
            output = io.read
            if output.respond_to?(:force_encoding)
              output.force_encoding('UTF-8')
            end
            begin
              # Mercurial < 1.5 does not support footer template for '</log>'
              ActiveSupport::XmlMini.parse("#{output}</log>")['log']
            rescue
            end
          end

          as_ary(log['logentry']).each do |le|
            cpalist = as_ary(le['paths']['path-copied']).map do |e|
              [e['__content__'], e['copyfrom-path']].map do |s|
                scm_iconv('UTF-8', @path_encoding, CGI.unescape(s))
              end
            end
            cpmap = Hash[*cpalist.flatten]

            paths = as_ary(le['paths']['path']).map do |e|
              p = scm_iconv('UTF-8', @path_encoding, CGI.unescape(e['__content__']) )
              {:action => e['action'], :path => with_leading_slash(p),
               :from_path => (cpmap.member?(p) ? with_leading_slash(cpmap[p]) : nil),
               :from_revision => (cpmap.member?(p) ? le['revision'] : nil)}
            end.sort { |a, b| a[:path] <=> b[:path] }

            yield Revision.new(:revision => le['revision'],
                               :scmid => le['node'],
                               :author => (le['author']['__content__'] rescue ''),
                               :time => Time.parse(le['date']['__content__']),
                               :message => le['msg']['__content__'],
                               :paths => paths)
          end
          self
        end

        # Returns list of nodes in the specified branch
        def nodes_in_branch(branch, options={})
          hg_args = ['rhlog', '--template', '{node|short}\n', '--rhbranch', CGI.escape(branch)]
          hg_args << '--from' << CGI.escape(branch)
          hg_args << '--to'   << '0'
          hg_args << '--limit' << options[:limit] if options[:limit]
          hg(*hg_args) { |io| io.readlines.map { |e| e.chomp } }
        end

        def diff(path, identifier_from, identifier_to=nil)
          hg_args = %w|rhdiff|
          if identifier_to
            hg_args << '-r' << hgrev(identifier_to) << '-r' << hgrev(identifier_from)
          else
            hg_args << '-c' << hgrev(identifier_from)
          end
          unless path.blank?
            p = scm_iconv(@path_encoding, 'UTF-8', path)
            hg_args << CGI.escape(hgtarget(p))
          end
          diff = []
          hg *hg_args do |io|
            io.each_line do |line|
              diff << line
            end
          end
          diff
        rescue HgCommandAborted
          nil  # means not found
        end

        def cat(path, identifier=nil)
          p = CGI.escape(scm_iconv(@path_encoding, 'UTF-8', path))
          hg 'rhcat', '-r', CGI.escape(hgrev(identifier)), hgtarget(p) do |io|
            io.binmode
            io.read
          end
        rescue HgCommandAborted
          nil  # means not found
        end

        def annotate(path, identifier=nil)
          p = CGI.escape(scm_iconv(@path_encoding, 'UTF-8', path))
          blame = Annotate.new
          hg 'rhannotate', '-ncu', '-r', CGI.escape(hgrev(identifier)), hgtarget(p) do |io|
            io.each_line do |line|
              line.force_encoding('ASCII-8BIT') if line.respond_to?(:force_encoding)
              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

        def as_ary(o)
          return [] unless o
          o.is_a?(Array) ? o : Array[o]
        end
        private :as_ary
      end
    end
  end
end