#--
# rbmh/suffixes.rb : rbmhshow 0.4.2
#
# Copyright (C) 2004--2005  Merlin Hughes  <ruby AT merlin DOT org>
#
# 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
#++
# MIME suffixes

module RBMH
  class MimeSuffixes
    def initialize(context)
      @context = context
      @suffixes = {}
      profile_init
    end

    # text/plain or text/*
    def [](mime_type)
      @suffixes[mime_type] or @suffixes[mime_type.gsub(SubtypeRE, '*')]
    end

    private

    def profile_init
      cache_file = @context.profile[ProfileCache]
      if cache_file.nil?
        read_profile
      else
        cache_file = File.expand_path(cache_file)
        if (not FileTest.exists?(cache_file)) or
           (profile_mtime > File.stat(cache_file).mtime)
          read_profile
          write_suffixes(cache_file)
        else
          read_suffixes(cache_file)
        end
      end
    end

    def profile_mtime
      mtime = @context.profile.mtime
      filenames = @context.profile[ProfileFiles]
      filenames.scan(FilenameRE) { | filename |
        filename = File.expand_path(filename)
        if FileTest.readable?(filename)
          file_mtime = File.stat(filename).mtime
          mtime = file_mtime if (file_mtime > mtime)
        end
      } if filenames
      mtime
    end

    def read_profile
      filenames = @context.profile[ProfileFiles]
      filenames.scan(FilenameRE) { | filename |
        filename = File.expand_path(filename)
        if FileTest.readable?(filename)
          File.open(filename) { | mime_file |
            mime_file_mtime = mime_file.mtime
            mtime = 
            mime_file.each { | line |
              if line =~ MimeLineRE
                @suffixes[$1.downcase] = $2
              end
            }
          }
        else
          STDERR.puts "rbmh: MIME file #{filename} unreadable"
        end
      } if filenames
      @context.profile.each(ProfileSuffixRE) { |mime_type, suffix|
        @suffixes[mime_type.downcase] = suffix
      }
      @context.profile.each(ProfileAliasRE) { |mime_type, mime_alias|
        @suffixes[mime_type.downcase] = @suffixes[mime_alias.downcase] if
          @suffixes.has_key?(mime_alias.downcase) and not
          @suffixes.has_key?(mime_type.downcase)
      }
    end

    def read_suffixes(cache_file)
      File.open(cache_file) { | file |
        file.each { | line |
          mime_type, suffix = line.split(SpaceRE)
          @suffixes[mime_type] = suffix.chop
        }
      }
    end

    def write_suffixes(cache_file)
      STDERR.puts "rbmh: updating #{cache_file}"
      File.open(cache_file, "w") { | file |
        @suffixes.each { | key, value |
          file.puts "#{key} #{value}"
        }
      }
    end

    # TODO: fix this to match the spec
    MimeTypeRE = /([^\s\/]+\/\S+)/ # $1: type/subtype
    SubtypeRE = /([^\/]+)$/ # $1: subtype
    MimeLineRE = /^#{MimeTypeRE.source}\s+(\w+).*$/ # $1: mimetype, $2: suffix1
    ProfileCache = 'rbmh-mime-cache'
    ProfileFiles = 'rbmh-mime-files'
    ProfileSuffixRE = /^rbmh-mime-suffix-#{MimeTypeRE.source}$/ # $1: mimetype
    ProfileAliasRE = /^rbmh-mime-alias-#{MimeTypeRE.source}$/ # $1: mimetype
    FilenameRE = /\S+/
    SpaceRE = / /
  end # class MimeSuffixes
end # module RBMH