# Copyright 2010 Sean Cribbs, Sonian Inc., and Basho Technologies, 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 'riak'
require 'tempfile'
require 'delegate'

module Riak
  # A client connection to Riak.
  class Client
    include Util::Translation
    include Util::Escape

    autoload :HTTPBackend,    "riak/client/http_backend"
    autoload :NetHTTPBackend, "riak/client/net_http_backend"
    autoload :CurbBackend,    "riak/client/curb_backend"
    autoload :ExconBackend,   "riak/client/excon_backend"

    # When using integer client IDs, the exclusive upper-bound of valid values.
    MAX_CLIENT_ID = 4294967296

    # Regexp for validating hostnames, lifted from uri.rb in Ruby 1.8.6
    HOST_REGEX = /^(?:(?:(?:[a-zA-Z\d](?:[-a-zA-Z\d]*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:[-a-zA-Z\d]*[a-zA-Z\d])?)\.?|\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}|\[(?:(?:[a-fA-F\d]{1,4}:)*(?:[a-fA-F\d]{1,4}|\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})|(?:(?:[a-fA-F\d]{1,4}:)*[a-fA-F\d]{1,4})?::(?:(?:[a-fA-F\d]{1,4}:)*(?:[a-fA-F\d]{1,4}|\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}))?)\])$/n

    # @return [String] The host or IP address for the Riak endpoint
    attr_reader :host

    # @return [Fixnum] The port of the Riak HTTP endpoint
    attr_reader :port

    # @return [String] The internal client ID used by Riak to route responses
    attr_reader :client_id

    # @return [String] The URL path prefix to the "raw" HTTP endpoint
    attr_accessor :prefix

    # @return [String] The URL path to the map-reduce HTTP endpoint
    attr_accessor :mapred

    # @return [String] The URL path to the luwak HTTP endpoint
    attr_accessor :luwak

    # @return [Symbol] The HTTP backend/client to use
    attr_accessor :http_backend

    # Creates a client connection to Riak
    # @param [Hash] options configuration options for the client
    # @option options [String] :host ('127.0.0.1') The host or IP address for the Riak endpoint
    # @option options [Fixnum] :port (8098) The port of the Riak HTTP endpoint
    # @option options [String] :prefix ('/riak/') The URL path prefix to the main HTTP endpoint
    # @option options [String] :mapred ('/mapred') The path to the map-reduce HTTP endpoint
    # @option options [Fixnum, String] :client_id (rand(MAX_CLIENT_ID)) The internal client ID used by Riak to route responses
    # @option options [String, Symbol] :http_backend (:NetHTTP) which  HTTP backend to use
    # @raise [ArgumentError] raised if any options are invalid
    def initialize(options={})
      unless (options.keys - [:host, :port, :prefix, :client_id, :mapred, :luwak, :http_backend]).empty?
        raise ArgumentError, "invalid options"
      end
      self.host         = options[:host]         || "127.0.0.1"
      self.port         = options[:port]         || 8098
      self.client_id    = options[:client_id]    || make_client_id
      self.prefix       = options[:prefix]       || "/riak/"
      self.mapred       = options[:mapred]       || "/mapred"
      self.luwak        = options[:luwak]        || "/luwak"
      self.http_backend = options[:http_backend] || :NetHTTP
      raise ArgumentError, t("missing_host_and_port") unless @host && @port
    end

    # Set the client ID for this client. Must be a string or Fixnum value 0 =< value < MAX_CLIENT_ID.
    # @param [String, Fixnum] value The internal client ID used by Riak to route responses
    # @raise [ArgumentError] when an invalid client ID is given
    # @return [String] the assigned client ID
    def client_id=(value)
      @client_id = case value
                   when 0...MAX_CLIENT_ID
                     b64encode(value)
                   when String
                     value
                   else
                     raise ArgumentError, t("invalid_client_id", :max_id => MAX_CLIENT_ID)
                   end
    end

    # Set the hostname of the Riak endpoint. Must be an IPv4, IPv6, or valid hostname
    # @param [String] value The host or IP address for the Riak endpoint
    # @raise [ArgumentError] if an invalid hostname is given
    # @return [String] the assigned hostname
    def host=(value)
      raise ArgumentError, t("hostname_invalid") unless String === value && value.present? && value =~ HOST_REGEX
      @host = value
    end

    # Set the port number of the Riak endpoint. This must be an integer between 0 and 65535.
    # @param [Fixnum] value The port number of the Riak endpoint
    # @raise [ArgumentError] if an invalid port number is given
    # @return [Fixnum] the assigned port number
    def port=(value)
      raise ArgumentError, t("port_invalid") unless (0..65535).include?(value)
      @port = value
    end

    # Sets the desired HTTP backend
    def http_backend=(value)
      @http = nil
      @http_backend = value
    end

    # Automatically detects and returns an appropriate HTTP backend.
    # The HTTP backend is used internally by the Riak client, but can also
    # be used to access the server directly.
    # @return [HTTPBackend] the HTTP backend for this client
    def http
      @http ||= begin
                  klass = self.class.const_get("#{@http_backend}Backend")
                  if klass.configured?
                    klass.new(self)
                  else
                    raise t('http_configuration', :backend => @http_backend)
                  end
                end
    end

    # Retrieves a bucket from Riak.
    # @param [String] bucket the bucket to retrieve
    # @param [Hash] options options for retrieving the bucket
    # @option options [Boolean] :keys (true) whether to retrieve the bucket keys
    # @option options [Boolean] :props (true) whether to retreive the bucket properties
    # @return [Bucket] the requested bucket
    def bucket(name, options={})
      unless (options.keys - [:keys, :props]).empty?
        raise ArgumentError, "invalid options"
      end
      response = http.get(200, prefix, escape(name), {:keys => false}.merge(options), {})
      Bucket.new(self, name).load(response)
    end
    alias :[] :bucket

    # Stores a large file/IO object in Riak via the "Luwak" interface.
    # @overload store_file(filename, content_type, data)
    #   Stores the file at the given key/filename
    #   @param [String] filename the key/filename for the object
    #   @param [String] content_type the MIME Content-Type for the data
    #   @param [IO, String] data the contents of the file
    # @overload store_file(content_type, data)
    #   Stores the file with a server-determined key/filename
    #   @param [String] content_type the MIME Content-Type for the data
    #   @param [IO, String] data the contents of the file
    # @return [String] the key/filename where the object was stored
    def store_file(*args)
      data, content_type, filename = args.reverse
      if filename
        http.put(204, luwak, escape(filename), data, {"Content-Type" => content_type})
        filename
      else
        response = http.post(201, luwak, data, {"Content-Type" => content_type})
        response[:headers]["location"].first.split("/").last
      end
    end

    # Retrieves a large file/IO object from Riak via the "Luwak"
    # interface. Streams the data to a temporary file unless a block
    # is given.
    # @param [String] filename the key/filename for the object
    # @return [IO, nil] the file (also having content_type and
    #   original_filename accessors). The file will need to be
    #   reopened to be read. nil will be returned if a block is given.
    # @yield [chunk] stream contents of the file through the
    #     block. Passing the block will result in nil being returned
    #     from the method.
    # @yieldparam [String] chunk a single chunk of the object's data
    def get_file(filename, &block)
      if block_given?
        http.get(200, luwak, escape(filename), &block)
        nil
      else
        tmpfile = LuwakFile.new(escape(filename))
        begin
          response = http.get(200, luwak, escape(filename)) do |chunk|
            tmpfile.write chunk
          end
          tmpfile.content_type = response[:headers]['content-type'].first
          tmpfile
        ensure
          tmpfile.close
        end
      end
    end

    # Deletes a file stored via the "Luwak" interface
    # @param [String] filename the key/filename to delete
    def delete_file(filename)
      http.delete([204,404], luwak, escape(filename))
      true
    end

    # Checks whether a file exists in "Luwak".
    # @param [String] key the key to check
    # @return [true, false] whether the key exists in "Luwak"
    def file_exists?(key)
      result = http.head([200,404], luwak, escape(key))
      result[:code] == 200
    end
    alias :file_exist? :file_exists?

    # @return [String] A representation suitable for IRB and debugging output.
    def inspect
      "#<Riak::Client #{http.root_uri.to_s}>"
    end

    private
    def make_client_id
      b64encode(rand(MAX_CLIENT_ID))
    end

    def b64encode(n)
      Base64.encode64([n].pack("N")).chomp
    end

    # @private
    class LuwakFile < DelegateClass(Tempfile)
      attr_accessor :original_filename, :content_type
      alias :key :original_filename
      def initialize(fn)
        super(Tempfile.new(fn))
        @original_filename = fn
      end
    end
  end
end