# encoding: utf-8
module Moped

  # Parses MongoDB uri
  #
  # @since 1.3.0
  class Uri

    # Get the scheme pattern.
    #
    # @since 1.3.0
    SCHEME = /(mongodb:\/\/)/

    # The user name pattern.
    #
    # @since 1.3.0
    USER = /([-.\w:]+)/

    # The password pattern.
    #
    # @since 1.3.0
    PASS = /([^@,]+)/

    # The nodes pattern.
    #
    # @since 1.3.0
    NODES = /((([-.\w]+)(?::(\w+))?,?)+)/

    # The database pattern.
    #
    # @since 1.3.0
    DATABASE = /(?:\/([-\w]+))?/

    # The options pattern.
    #
    # @since 1.3.0
    OPTIONS  = /(?:\?(.+))/

    # The full URI pattern.
    #
    # @since 1.3.0
    URI = /#{SCHEME}(#{USER}:#{PASS}@)?#{NODES}#{DATABASE}#{OPTIONS}?/

    # The options that have to do with write concerns.
    #
    # @since 2.0.0
    WRITE_OPTIONS = [ "w", "j", "fsync", "wtimeout" ].freeze

    # The mappings from read preferences in the URI to Moped's.
    #
    # @since 2.0.0
    READ_MAPPINGS = {
      "nearest" => :nearest,
      "primary" => :primary,
      "primarypreferred" => :primary_preferred,
      "secondary" => :secondary,
      "secondarypreferred" => :secondary_preferred
    }.freeze

    # @!attribute match
    #   @return [ Array ] The uri match.
    attr_reader :match

    # Helper to determine if authentication is provided
    #
    # @example Boolean response if username/password given
    #   uri.auth_provided?
    #
    # @return [ true, false ] If authorization is provided.
    #
    # @since 1.3.0
    def auth_provided?
      !username.nil? && !password.nil?
    end

    # Get the database provided in the URI.
    #
    # @example Get the database.
    #   uri.database
    #
    # @return [ String ] The database.
    #
    # @since 1.3.0
    def database
      @database ||= match[9]
    end

    # Get the hosts provided in the URI.
    #
    # @example Get the hosts.
    #   uri.hosts
    #
    # @return [ Array<String> ] The hosts.
    #
    # @since 1.3.0
    def hosts
      @hosts ||= match[5].split(",")
    end

    # Create the new uri from the provided string.
    #
    # @example Create the new uri.
    #   MongoUri.new(uri)
    #
    # @param [ String ] string The uri string.
    #
    # @since 1.3.0
    def initialize(string)
      @match = string.match(URI)
      invalid_uri!(string) unless @match
    end

    # Raise a human readable error when improper URI provided
    #
    # @example Raise error and provide guidance on invalid URI
    #   MongoUri.invalid!(uri)
    #
    # @param [ String ] Invalid string
    #
    # @since 1.3.1
    def invalid_uri!(string)
      scrubbed = string.gsub(/[^:]+@/, '<password>@')
      raise Errors::InvalidMongoURI, "The provided connection string is not a value URI: #{scrubbed}"
    end

    # Get the options provided in the URI.
    #
    # @example Get the options
    #   uri.options
    #
    # @note The options provided in the URI string must match the MongoDB
    #   specification.
    #
    # @return [ Hash ] Options hash usable by Moped
    #
    # @see http://docs.mongodb.org/manual/reference/connection-string/#connections-connection-options
    #
    # @since 1.3.0
    def options
      options_string, options = match[10], { database: database }
      unless options_string.nil?
        options_string.split(/\&/).each do |option_string|
          key, value = option_string.split(/=/)
          if WRITE_OPTIONS.include?(key)
            options[:write] = { key.to_sym => cast(value) }
          elsif read = READ_MAPPINGS[value.downcase]
            options[:read] = read
          else
            options[key.to_sym] = cast(value)
          end
        end
      end
      options
    end

    # Get the password provided in the URI.
    #
    # @example Get the password.
    #   uri.password
    #
    # @return [ String ] The password.
    #
    # @since 1.3.0
    def password
      @password ||= match[4]
    end

    # Get the uri as a Mongoid friendly configuration hash.
    #
    # @example Get the uri as a hash.
    #   uri.to_hash
    #
    # @return [ Hash ] The uri as options.
    #
    # @since 1.3.0
    def to_hash
      config = { database: database, hosts: hosts }
      if username && password
        config.merge!(username: username, password: password)
      end
      config
    end

    # Create Moped usable arguments
    #
    # @example Get the moped args
    #   uri.moped_arguments
    #
    # @return [ Array ] Array of arguments usable by Moped
    #
    # @since 1.3.0
    def moped_arguments
      [ hosts, options ]
    end

    # Get the username provided in the URI.
    #
    # @example Get the username.
    #   uri.username
    #
    # @return [ String ] The username.
    #
    # @since 1.3.0
    def username
      @username ||= match[3]
    end

    private

    def cast(value)
      if value == "true"
        true
      elsif value == "false"
        false
      elsif value =~ /[\d]/
        value.to_i
      else
        value.to_sym
      end
    end
  end
end