#!/usr/bin/ruby

#
# This script will update the values of a particular couchdb document. The benefit of this little script over
# using a simple curl command for updating a document is this:
#
#   * exit non-zero status if document was not updated.
#   * updates existing documents easily, taking care of the _rev id for you.
#   * if document doesn't exist, it is created
#
# REQUIREMENTS
#
#   gem 'couchrest'
#
# USAGE
#
#   couch-doc-update --host <host> --db <db> --id <doc_id> --data <json>
#
# EXAMPLE
#
#   create a new user:
#     couch-doc-update --db _users --id org.couchdb.user:ca_daemon --data '{"type": "user", "name": "ca_daemon", "roles": ["certs"], "password": "sshhhh"}'
#
#   update a user:
#     couch-doc-update --db _users --id org.couchdb.user:ca_daemon --data '{"password":"sssshhh"}'
#
# To update the _users DB on bigcouch, you must connect to port 5986 instead of the default couchdb port 5984
#

begin; require 'rubygems'; rescue LoadError; end # optionally load rubygems
require 'couchrest'
require 'json'

def main
  #
  # parse options
  #
  @host       = nil
  @db_name    = nil
  @doc_id     = nil
  @new_data   = nil
  loop do
    case ARGV[0]
      when '--host' then ARGV.shift; @host     = ARGV.shift
      when '--db'   then ARGV.shift; @db_name  = ARGV.shift
      when '--id'   then ARGV.shift; @doc_id   = ARGV.shift
      when '--data' then ARGV.shift; @new_data = ARGV.shift
      when /^-/     then usage("Unknown option: #{ARGV[0].inspect}")
      else break
    end
  end
  usage("Missing required option") unless @db_name && @doc_id && @new_data
  @new_data = JSON.parse(@new_data)
	
  #
  # update document
  #
  begin
    @db  = CouchRest.database(connection_string(@db_name, @host))
    @doc = get_document(@db, @doc_id)
    result = if @doc
      update_document(@db, @doc, @new_data)
    else
      create_document(@db, @doc_id, @new_data)
    end
    exit 0 if result['ok']
    raise StandardError.new(result.inspect)
  rescue StandardError => exc
    puts "ERROR: " + exc.to_s
    exit 1
  end
end

def get_document(db, doc_id)
  begin
    db.get(doc_id)
  rescue RestClient::ResourceNotFound
    nil
  end
end

def update_document(db, doc, data)
  data.each do |key, value|
    doc[key] = value
  end
  db.save_doc(doc)
end

def create_document(db, doc_id, data)
  data["_id"] = doc_id
  db.save_doc(data)
end

def connection_string(database, host)
  protocol  = "http"
  #hostname  = "127.0.0.1"
  port      = "5984"
  username  = "admin"
  password  = ""

  netrc = File.read('/etc/couchdb/couchdb.netrc')
  netrc.scan(/\w+ [\w\.]+/).each do |key_value|
    key, value = key_value.split ' '
    case key
      when "machine"  then host ||= value + ':' + port
      when "login"    then username = value
      when "password" then password = value
    end
  end

  host ||= '127.0.0.1:5984'

  "%s://%s:%s@%s/%s" % [protocol, username, password, host, database]
end

def usage(s)
  $stderr.puts(s)
  $stderr.puts("Usage: #{File.basename($0)} --host <host> --db <db> --id <doc_id> --data <json>")
  exit(2)
end

main()