require 'singleton'
require 'geocoder/configuration_hash'

module Geocoder

  ##
  # Configuration options should be set by passing a hash:
  #
  #   Geocoder.configure(
  #     :timeout  => 5,
  #     :lookup   => :yandex,
  #     :api_key  => "2a9fsa983jaslfj982fjasd",
  #     :units    => :km
  #   )
  #
  def self.configure(options = nil, &block)
    if block_given?
      warn "WARNING: Passing a block to Geocoder.configure is DEPRECATED. Please pass a hash instead (eg: Geocoder.configure(:units => ..., :api_key => ...))."
      block.call(Configuration.instance)
    elsif !options.nil?
      Configuration.instance.configure(options)
    else
      warn "WARNING: Use of Geocoder.configure to read or write single config options is DEPRECATED. To write to the config please pass a hash (eg: Geocoder.configure(:units => ...)). To read config options please use the Geocoder.config object (eg: Geocoder.config.units)."
      Configuration.instance
    end
  end

  ##
  # Read-only access to the singleton's config data.
  #
  def self.config
    Configuration.instance.data
  end

  ##
  # Read-only access to lookup-specific config data.
  #
  def self.config_for_lookup(lookup_name)
    data = config.clone
    data.reject!{ |key,value| !Configuration::OPTIONS.include?(key) }
    if config.has_key?(lookup_name)
      data.merge!(config[lookup_name])
    end
    data
  end

  class Configuration
    include Singleton

    OPTIONS = [
      :timeout,
      :lookup,
      :ip_lookup,
      :language,
      :http_headers,
      :use_https,
      :http_proxy,
      :https_proxy,
      :api_key,
      :cache,
      :cache_prefix,
      :always_raise,
      :units,
      :distances
    ]

    attr_accessor :data

    def self.set_defaults
      instance.set_defaults
    end

    OPTIONS.each do |o|
      define_method o do
        @data[o]
      end
      define_method "#{o}=" do |value|
        @data[o] = value
      end
    end

    def configure(options)
      @data.rmerge!(options)
    end

    def initialize # :nodoc
      @data = Geocoder::ConfigurationHash.new
      set_defaults
    end

    def set_defaults

      # geocoding options
      @data[:timeout]      = 3           # geocoding service timeout (secs)
      @data[:lookup]       = :google     # name of street address geocoding service (symbol)
      @data[:ip_lookup]    = :freegeoip  # name of IP address geocoding service (symbol)
      @data[:language]     = :en         # ISO-639 language code
      @data[:http_headers] = {}          # HTTP headers for lookup
      @data[:use_https]    = false       # use HTTPS for lookup requests? (if supported)
      @data[:http_proxy]   = nil         # HTTP proxy server (user:pass@host:port)
      @data[:https_proxy]  = nil         # HTTPS proxy server (user:pass@host:port)
      @data[:api_key]      = nil         # API key for geocoding service
      @data[:cache]        = nil         # cache object (must respond to #[], #[]=, and #keys)
      @data[:cache_prefix] = "geocoder:" # prefix (string) to use for all cache keys

      # exceptions that should not be rescued by default
      # (if you want to implement custom error handling);
      # supports SocketError and TimeoutError
      @data[:always_raise] = []

      # calculation options
      @data[:units]     = :mi      # :mi or :km
      @data[:distances] = :linear  # :linear or :spherical
    end

    instance_eval(OPTIONS.map do |option|
      o = option.to_s
      <<-EOS
      def #{o}
        instance.data[:#{o}]
      end

      def #{o}=(value)
        instance.data[:#{o}] = value
      end
      EOS
    end.join("\n\n"))

  end
end