# encoding: utf-8

module Redwood

class SearchManager
  include Redwood::Singleton

  class ExpansionError < StandardError; end

  attr_reader :predefined_searches

  def initialize fn
    @fn = fn
    @searches = {}
    if File.exist? fn
      IO.foreach(fn) do |l|
        l =~ /^([^:]*): (.*)$/ or raise "can't parse #{fn} line #{l.inspect}"
        @searches[$1] = $2
      end
    end
    @modified = false

    @predefined_searches = { 'All mail' => 'Search all mail.' }
    @predefined_queries  = { 'All mail'.to_sym => { :qobj => Xapian::Query.new('Kmail'),
                                                    :load_spam => false,
                                                    :load_deleted => false,
                                                    :load_killed => false,
                                                    :text => 'Search all mail.'}
    }
    @predefined_searches.each do |k,v|
      @searches[k] = v
    end
  end

  def predefined_queries; return @predefined_queries; end
  def all_searches; return @searches.keys.sort; end
  def search_string_for name;
    if @predefined_searches.keys.member? name
      return name.to_sym
    end
    return @searches[name];
  end
  def valid_name? name; name =~ /^[\w-]+$/; end
  def name_format_hint; "letters, numbers, underscores and dashes only"; end

  def add name, search_string
    return unless valid_name? name
    if @predefined_searches.has_key? name
      warn "cannot add search: #{name} is already taken by a predefined search"
      return
    end
    @searches[name] = search_string
    @modified = true
  end

  def rename old, new
    return unless @searches.has_key? old
    if [old, new].any? { |x| @predefined_searches.has_key? x }
      warn "cannot rename search: #{old} or #{new} is already taken by a predefined search"
      return
    end
    search_string = @searches[old]
    delete old if add new, search_string
  end

  def edit name, search_string
    return unless @searches.has_key? name
    if @predefined_searches.has_key? name
      warn "cannot edit predefined search: #{name}."
      return
    end
    @searches[name] = search_string
    @modified = true
  end

  def delete name
    return unless @searches.has_key? name
    if @predefined_searches.has_key? name
      warn "cannot delete predefined search: #{name}."
      return
    end
    @searches.delete name
    @modified = true
  end

  def expand search_string
    expanded = search_string.dup
    until (matches = expanded.scan(/\{([\w-]+)\}/).flatten).empty?
      if !(unknown = matches - @searches.keys).empty?
        error_message = "Unknown \"#{unknown.join('", "')}\" when expanding \"#{search_string}\""
      elsif expanded.size >= 2048
        error_message = "Check for infinite recursion in \"#{search_string}\""
      end
      if error_message
        warn error_message
        raise ExpansionError, error_message
      end
      matches.each { |n| expanded.gsub! "{#{n}}", "(#{@searches[n]})" if @searches.has_key? n }
    end
    return expanded
  end

  def save
    return unless @modified
    File.open(@fn, "w:UTF-8") { |f| (@searches - @predefined_searches.keys).sort.each { |(n, s)| f.puts "#{n}: #{s}" } }
    @modified = false
  end
end

end