begin
  require 'bdb'
rescue Exception => e
  puts "Got exception: "+e
  puts "rbot couldn't load the bdb module, perhaps you need to install it? try: http://www.ruby-lang.org/en/raa-list.rhtml?name=bdb"
  exit 2
end

# make BTree lookups case insensitive
module BDB
  class CIBtree < Btree
    def bdb_bt_compare(a, b)
      a.downcase <=> b.downcase
    end
  end
end

module Irc

  # DBHash is for tying a hash to disk (using bdb).
  # Call it with an identifier, for example "mydata". It'll look for
  # mydata.db, if it exists, it will load and reference that db.
  # Otherwise it'll create and empty db called mydata.db
  class DBHash
    
    # absfilename:: use +key+ as an actual filename, don't prepend the bot's
    #               config path and don't append ".db"
    def initialize(bot, key, absfilename=false)
      @bot = bot
      @key = key
      if absfilename && File.exist?(key)
        # db already exists, use it
        @db = DBHash.open_db(key)
      elsif File.exist?(@bot.botclass + "/#{key}.db")
        # db already exists, use it
        @db = DBHash.open_db(@bot.botclass + "/#{key}.db")
      elsif absfilename
        # create empty db
        @db = DBHash.create_db(key)
      else
        # create empty db
        @db = DBHash.create_db(@bot.botclass + "/#{key}.db")
      end
    end

    def method_missing(method, *args, &block)
      return @db.send(method, *args, &block)
    end

    def DBHash.create_db(name)
      debug "DBHash: creating empty db #{name}"
      return BDB::Hash.open(name, nil, 
                             BDB::CREATE | BDB::EXCL | BDB::TRUNCATE,
                             0600, "set_pagesize" => 1024,
                             "set_cachesize" => [(0), (32 * 1024), (0)])
    end

    def DBHash.open_db(name)
      debug "DBHash: opening existing db #{name}"
      return BDB::Hash.open(name, nil, 
                             "r+", 0600, "set_pagesize" => 1024,
                             "set_cachesize" => [(0), (32 * 1024), (0)])
    end
    
  end

  
  # DBTree is a BTree equivalent of DBHash, with case insensitive lookups.
  class DBTree
    
    # absfilename:: use +key+ as an actual filename, don't prepend the bot's
    #               config path and don't append ".db"
    def initialize(bot, key, absfilename=false)
      @bot = bot
      @key = key
      if absfilename && File.exist?(key)
        # db already exists, use it
        @db = DBTree.open_db(key)
      elsif absfilename
        # create empty db
        @db = DBTree.create_db(key)
      elsif File.exist?(@bot.botclass + "/#{key}.db")
        # db already exists, use it
        @db = DBTree.open_db(@bot.botclass + "/#{key}.db")
      else
        # create empty db
        @db = DBTree.create_db(@bot.botclass + "/#{key}.db")
      end
    end

    def method_missing(method, *args, &block)
      return @db.send(method, *args, &block)
    end

    def DBTree.create_db(name)
      debug "DBTree: creating empty db #{name}"
      return BDB::CIBtree.open(name, nil, 
                             BDB::CREATE | BDB::EXCL | BDB::TRUNCATE,
                             0600, "set_pagesize" => 1024,
                             "set_cachesize" => [(0), (32 * 1024), (0)])
    end

    def DBTree.open_db(name)
      debug "DBTree: opening existing db #{name}"
      return BDB::CIBtree.open(name, nil, 
                             "r+", 0600, "set_pagesize" => 1024,
                             "set_cachesize" => [0, 32 * 1024, 0])
    end
    
  end

end