#!/usr/bin/env ruby
# encoding: UTF-8

# --
# Copyright (C) 2008-2010 10gen Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ++

require 'rubygems'
require 'bson'

# Note that this will not properly round-trip in all cases
# from the output generated by j2bson.
begin
require 'yajl'
rescue LoadError
  puts "This script requires yajl. Please install as follows:"
  puts "  gem install yajl-ruby" 
  Process.exit
end

# Convert all documents in an IO into JSON.
def print_b2json(io)
  while not io.eof? do
    bsonobj = BSON.read_bson_document(io)
    Yajl::Encoder.encode(bsonobj, STDOUT)
    STDOUT << "\n"
  end
end

# print usage
def usage()
    STDERR << <<END_OF_USAGE
usage:  b2json [-h] [file1 [file2]]

   Converts a BSON file to JSON on STDOUT.
   You can pass multiple filenames.
   If no filenames are passed, then STDIN is consumed.

END_OF_USAGE
    exit
end

# no arg, use STDIN
# -h, print usage and exit
# otherwise loop of filenames
if ARGV.empty? then
    print_b2json(STDIN)
    exit
elsif ARGV[0] == "-h" then
    usage()
else
    ARGV.each { |fname| print_b2json(File.new(fname)) }
end