require 'pusher-signature'

module Pusher
  class Client
    attr_accessor :scheme, :host, :port, :app_id, :key, :secret, :notification_host, :notification_scheme
    attr_reader :http_proxy, :proxy
    attr_writer :connect_timeout, :send_timeout, :receive_timeout,
                :keep_alive_timeout

    ## CONFIGURATION ##

    # Loads the configuration from an url in the environment
    def self.from_env(key = 'PUSHER_URL')
      url = ENV[key] || raise(ConfigurationError, key)
      from_url(url)
    end

    # Loads the configuration from a url
    def self.from_url(url)
      client = new
      client.url = url
      client
    end

    def initialize(options = {})
      default_options = {
        :scheme => 'http',
        :port => 80,
      }

      if options[:use_tls] || options[:encrypted]
        default_options[:scheme] = "https"
        default_options[:port] = 443
      end

      merged_options = default_options.merge(options)

      if options.has_key?(:host)
        merged_options[:host] = options[:host]
      elsif options.has_key?(:cluster)
        merged_options[:host] = "api-#{options[:cluster]}.pusher.com"
      else
        merged_options[:host] = "api.pusherapp.com"
      end

      # TODO: Change host name when finalized
      merged_options[:notification_host] =
        options.fetch(:notification_host, "nativepush-cluster1.pusher.com")

      merged_options[:notification_scheme] =
        options.fetch(:notification_scheme, "https")

      @scheme, @host, @port, @app_id, @key, @secret, @notification_host, @notification_scheme =
        merged_options.values_at(
          :scheme, :host, :port, :app_id, :key, :secret, :notification_host, :notification_scheme
        )

      @http_proxy = nil
      self.http_proxy = options[:http_proxy] if options[:http_proxy]

      # Default timeouts
      @connect_timeout = 5
      @send_timeout = 5
      @receive_timeout = 5
      @keep_alive_timeout = 30
    end

    # @private Returns the authentication token for the client
    def authentication_token
      raise ConfigurationError, :key unless @key
      raise ConfigurationError, :secret unless @secret
      Pusher::Signature::Token.new(@key, @secret)
    end

    # @private Builds a url for this app, optionally appending a path
    def url(path = nil)
      raise ConfigurationError, :app_id unless @app_id
      URI::Generic.build({
        :scheme => @scheme,
        :host => @host,
        :port => @port,
        :path => "/apps/#{@app_id}#{path}"
      })
    end

    # Configure Pusher connection by providing a url rather than specifying
    # scheme, key, secret, and app_id separately.
    #
    # @example
    #   Pusher.url = http://KEY:SECRET@api.pusherapp.com/apps/APP_ID
    #
    def url=(url)
      uri = URI.parse(url)
      @scheme = uri.scheme
      @app_id = uri.path.split('/').last
      @key    = uri.user
      @secret = uri.password
      @host   = uri.host
      @port   = uri.port
    end

    def http_proxy=(http_proxy)
      @http_proxy = http_proxy
      uri = URI.parse(http_proxy)
      @proxy = {
        :scheme => uri.scheme,
        :host => uri.host,
        :port => uri.port,
        :user => uri.user,
        :password => uri.password
      }
      @http_proxy
    end

    # Configure whether Pusher API calls should be made over SSL
    # (default false)
    #
    # @example
    #   Pusher.encrypted = true
    #
    def encrypted=(boolean)
      @scheme = boolean ? 'https' : 'http'
      # Configure port if it hasn't already been configured
      @port = boolean ? 443 : 80
    end

    def encrypted?
      @scheme == 'https'
    end

    def cluster=(cluster)
      @host = "api-#{cluster}.pusher.com"
    end

    # Convenience method to set all timeouts to the same value (in seconds).
    # For more control, use the individual writers.
    def timeout=(value)
      @connect_timeout, @send_timeout, @receive_timeout = value, value, value
    end

    ## INTERACT WITH THE API ##

    def resource(path)
      Resource.new(self, path)
    end

    # GET arbitrary REST API resource using a synchronous http client.
    # All request signing is handled automatically.
    #
    # @example
    #   begin
    #     Pusher.get('/channels', filter_by_prefix: 'private-')
    #   rescue Pusher::Error => e
    #     # Handle error
    #   end
    #
    # @param path [String] Path excluding /apps/APP_ID
    # @param params [Hash] API params (see http://pusher.com/docs/rest_api)
    #
    # @return [Hash] See Pusher API docs
    #
    # @raise [Pusher::Error] Unsuccessful response - see the error message
    # @raise [Pusher::HTTPError] Error raised inside http client. The original error is wrapped in error.original_error
    #
    def get(path, params = {})
      resource(path).get(params)
    end

    # GET arbitrary REST API resource using an asynchronous http client.
    # All request signing is handled automatically.
    #
    # When the eventmachine reactor is running, the em-http-request gem is used;
    # otherwise an async request is made using httpclient. See README for
    # details and examples.
    #
    # @param path [String] Path excluding /apps/APP_ID
    # @param params [Hash] API params (see http://pusher.com/docs/rest_api)
    #
    # @return Either an EM::DefaultDeferrable or a HTTPClient::Connection
    #
    def get_async(path, params = {})
      resource(path).get_async(params)
    end

    # POST arbitrary REST API resource using a synchronous http client.
    # Works identially to get method, but posts params as JSON in post body.
    def post(path, params = {})
      resource(path).post(params)
    end

    # POST arbitrary REST API resource using an asynchronous http client.
    # Works identially to get_async method, but posts params as JSON in post
    # body.
    def post_async(path, params = {})
      resource(path).post_async(params)
    end

    ## HELPER METHODS ##

    # Convenience method for creating a new WebHook instance for validating
    # and extracting info from a received WebHook
    #
    # @param request [Rack::Request] Either a Rack::Request or a Hash containing :key, :signature, :body, and optionally :content_type.
    #
    def webhook(request)
      WebHook.new(request, self)
    end

    # Return a convenience channel object by name that delegates operations
    # on a channel. No API request is made.
    #
    # @example
    #   Pusher['my-channel']
    # @return [Channel]
    # @raise [Pusher::Error] if the channel name is invalid.
    #   Channel names should be less than 200 characters, and
    #   should not contain anything other than letters, numbers, or the
    #   characters "_\-=@,.;"
    def channel(channel_name)
      Channel.new(nil, channel_name, self)
    end

    alias :[] :channel

    # Request a list of occupied channels from the API
    #
    # GET /apps/[id]/channels
    #
    # @param params [Hash] Hash of parameters for the API - see REST API docs
    #
    # @return [Hash] See Pusher API docs
    #
    # @raise [Pusher::Error] Unsuccessful response - see the error message
    # @raise [Pusher::HTTPError] Error raised inside http client. The original error is wrapped in error.original_error
    #
    def channels(params = {})
      get('/channels', params)
    end

    # Request info for a specific channel
    #
    # GET /apps/[id]/channels/[channel_name]
    #
    # @param channel_name [String] Channel name (max 200 characters)
    # @param params [Hash] Hash of parameters for the API - see REST API docs
    #
    # @return [Hash] See Pusher API docs
    #
    # @raise [Pusher::Error] Unsuccessful response - see the error message
    # @raise [Pusher::HTTPError] Error raised inside http client. The original error is wrapped in error.original_error
    #
    def channel_info(channel_name, params = {})
      get("/channels/#{channel_name}", params)
    end

    # Request info for users of a presence channel
    #
    # GET /apps/[id]/channels/[channel_name]/users
    #
    # @param channel_name [String] Channel name (max 200 characters)
    # @param params [Hash] Hash of parameters for the API - see REST API docs
    #
    # @return [Hash] See Pusher API docs
    #
    # @raise [Pusher::Error] Unsuccessful response - see the error message
    # @raise [Pusher::HTTPError] Error raised inside http client. The original error is wrapped in error.original_error
    #
    def channel_users(channel_name, params = {})
      get("/channels/#{channel_name}/users", params)
    end

    # Trigger an event on one or more channels
    #
    # POST /apps/[app_id]/events
    #
    # @param channels [String or Array] 1-10 channel names
    # @param event_name [String]
    # @param data [Object] Event data to be triggered in javascript.
    #   Objects other than strings will be converted to JSON
    # @param params [Hash] Additional parameters to send to api, e.g socket_id
    #
    # @return [Hash] See Pusher API docs
    #
    # @raise [Pusher::Error] Unsuccessful response - see the error message
    # @raise [Pusher::HTTPError] Error raised inside http client. The original error is wrapped in error.original_error
    #
    def trigger(channels, event_name, data, params = {})
      post('/events', trigger_params(channels, event_name, data, params))
    end

    # Trigger multiple events at the same time
    #
    # POST /apps/[app_id]/batch_events
    #
    # @param events [Array] List of events to publish
    #
    # @return [Hash] See Pusher API docs
    #
    # @raise [Pusher::Error] Unsuccessful response - see the error message
    # @raise [Pusher::HTTPError] Error raised inside http client. The original error is wrapped in error.original_error
    #
    def trigger_batch(*events)
      post('/batch_events', trigger_batch_params(events.flatten))
    end

    # Trigger an event on one or more channels asynchronously.
    # For parameters see #trigger
    #
    def trigger_async(channels, event_name, data, params = {})
      post_async('/events', trigger_params(channels, event_name, data, params))
    end

    # Trigger multiple events asynchronously.
    # For parameters see #trigger_batch
    #
    def trigger_batch_async(*events)
      post_async('/batch_events', trigger_batch_params(events.flatten))
    end

    def notification_client
      @notification_client ||=
        NativeNotification::Client.new(@app_id, @notification_host, @notification_scheme, self)
    end


    # Send a push notification
    #
    # POST /apps/[app_id]/notifications
    #
    # @param interests [Array] An array of interests
    # @param message [String] Message to send
    # @param options [Hash] Additional platform specific options
    #
    # @return [Hash]
    def notify(interests, data = {})
      notification_client.notify(interests, data)
    end

    # Generate the expected response for an authentication endpoint.
    # See http://pusher.com/docs/authenticating_users for details.
    #
    # @example Private channels
    #   render :json => Pusher.authenticate('private-my_channel', params[:socket_id])
    #
    # @example Presence channels
    #   render :json => Pusher.authenticate('presence-my_channel', params[:socket_id], {
    #     :user_id => current_user.id, # => required
    #     :user_info => { # => optional - for example
    #       :name => current_user.name,
    #       :email => current_user.email
    #     }
    #   })
    #
    # @param socket_id [String]
    # @param custom_data [Hash] used for example by private channels
    #
    # @return [Hash]
    #
    # @raise [Pusher::Error] if channel_name or socket_id are invalid
    #
    # @private Custom data is sent to server as JSON-encoded string
    #
    def authenticate(channel_name, socket_id, custom_data = nil)
      channel_instance = channel(channel_name)
      channel_instance.authenticate(socket_id, custom_data)
    end

    # @private Construct a net/http http client
    def sync_http_client
      @client ||= begin
        require 'httpclient'

        HTTPClient.new(@http_proxy).tap do |c|
          c.connect_timeout = @connect_timeout
          c.send_timeout = @send_timeout
          c.receive_timeout = @receive_timeout
          c.keep_alive_timeout = @keep_alive_timeout
        end
      end
    end

    # @private Construct an em-http-request http client
    def em_http_client(uri)
      begin
        unless defined?(EventMachine) && EventMachine.reactor_running?
          raise Error, "In order to use async calling you must be running inside an eventmachine loop"
        end
        require 'em-http' unless defined?(EventMachine::HttpRequest)

        connection_opts = {
          :connect_timeout => @connect_timeout,
          :inactivity_timeout => @receive_timeout,
        }

        if defined?(@proxy)
          proxy_opts = {
            :host => @proxy[:host],
            :port => @proxy[:port]
          }
          if @proxy[:user]
            proxy_opts[:authorization] = [@proxy[:user], @proxy[:password]]
          end
          connection_opts[:proxy] = proxy_opts
        end

        EventMachine::HttpRequest.new(uri, connection_opts)
      end
    end

    private

    def trigger_params(channels, event_name, data, params)
      channels = Array(channels).map(&:to_s)
      raise Pusher::Error, "Too many channels (#{channels.length}), max 10" if channels.length > 10

      params.merge({
        name: event_name,
        channels: channels,
        data: encode_data(data),
      })
    end

    def trigger_batch_params(events)
      {
        batch: events.map do |event|
          event.dup.tap do |e|
            e[:data] = encode_data(e[:data])
          end
        end
      }
    end

    # JSON-encode the data if it's not a string
    def encode_data(data)
      return data if data.is_a? String
      MultiJson.encode(data)
    end

    def configured?
      host && scheme && key && secret && app_id
    end
  end
end