#--
# gravaty
# Copyright © 2013, 2014, 2015, 2016, 2017, 2018, 2019  Marco Bresciani
#
# This file is part of gravaty.
#
# gravaty is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation, either version 3 of the License, or (at your
# option) any later version.
#
# gravaty is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
#
# You should have received a copy of the GNU General Public License
# along with gravaty. If not, see <http://www.gnu.org/licenses/>.
#++

require 'digest'
require 'i18n'
require 'json'
require 'uri'
require 'xmlrpc/client'

require_relative 'utils/downloader'
require_relative 'utils/rfc5322'
require_relative 'utils/rpc_connector'

module Gravaty

  # This class is a simple API to retrieve an URL with specified options
  # from Gravatar site. It can be used to read data for avatars,
  # profiles or for XML-RPC APi calls. The only needed parameter to
  # create a Gravaty object is the reference +email+ address.
  # Author:: {Marco Bresciani}[mailto:marcobresciani_1974@libero.it]
  # Copyright:: Copyright © 2013, 2014, 2015, 2016, 2017, 2018,
  # 2019  Marco Bresciani
  # License:: GNU General Public License version 3
  class Gravaty
    include Comparable

    # Provides the MD5 signature (of the small caps version) of the
    # +email+ address used to build the object.
    attr_reader :digest

    # Provides the (small caps version of) +email+ address used to build
    # the object.
    attr_reader :email

    # Creates a +Gravaty+ object described by the user's +email+. Throws
    # an +ArgumentError+ exception if the supplied +email+ address is
    # +nil+ or not valid according to RFC5322.
    #
    # Usage:: <tt>new_gravaty = Gravaty.new email, parser</tt>
    # Params::
    #   - +email_address+, the user's email address (a syntactically
    # valid one).
    #   - +parser+, a parser duck-responding to the +parse+ method with
    # two parameters, +method+ name and +value+ string
    # Returns:: a +Gravaty+ object for the specified +email+ address.
    # Raises:: +ArgumentError+, if the supplied +email+ address is +nil+
    # or not valid according to RFC 5322.
    def initialize(email_address, parser)
      I18n.load_path = Dir[File.join(File.dirname(__FILE__),
                                     '/locales/', '*.yml')]

      raise ArgumentError, I18n.t('error.nil') if email_address.nil?
      raise ArgumentError, I18n.t('error.invalid', value: email_address) unless Utils::Rfc5322::EMAIL.match email_address # thanks Peter!

      @email = email_address.strip.downcase
      @digest = Digest::MD5.hexdigest email
      @gravaty = email
      @parser = parser
    end

    # Returns a string containing the URI of the gravatar associated to
    # internal (provided) email address. Valid keys for the +args+ hash
    # are: :type, :pixel_size, :force, :secure, :rating, :default.
    #
    # Usage::
    #   - <tt>a_string = new_gravaty.avatar</tt>
    #   - <tt>a_string = new_gravaty.avatar</tt>
    #   - <tt>a_string = new_gravaty.avatar pixel_size: 42</tt>
    #   - <tt>a_string = new_gravaty.avatar pixel_size: 42, type:
    # png'</tt>
    #   - <tt>a_string = new_gravaty.avatar secure: false</tt>
    #   - <tt>a_string = new_gravaty.avatar type: 'jpg', force:
    # true</tt>
    #   - <tt>a_string = new_gravaty.avatar secure: true, pixel_size:
    # 42, type: 'png'</tt>
    #   - <tt>a_string = new_gravaty.avatar rating: pg, type: 'gif'</tt>
    #   - <tt>a_string = new_gravaty.avatar default: monsterid,
    # pixel_size: 42</tt>
    # Params::
    #   - +type+: [String] is the possibly desired specific image
    # format. Valid formats are jp(e)g, png or gif. Default to no
    # extension. Will be downcased. Raises <code>ArgumentError</code>
    # for invalid formats.
    #   - +pixel_size+: [Integer] is the size in pixel of the image.
    # From 1 to 2048. Default to no value. Raises
    # <code>ArgumentError</code> for invalid sizes.
    #   - +force+: [TrueClass || FalseClass] is a boolean to specify if
    # the default has to be forced when no image is found. Default to
    # false.
    #   - +secure+: [TrueClass || FalseClass] is a boolean to specify
    # whether the resulting URL shall be HTTPS or HTTP type. Default to
    # true (HTTPS).
    #   - +rating+: [String] is the rating type of the image. Valid
    # values are 'g', 'pg', 'r' and 'x'.
    #   - +default+: [String] is the default type of the image (valid
    # values are '404', 'mm', 'identicon', 'monsterid', 'wavatar',
    # 'retro' and 'blank'), or the URI for an own default image. For the
    # URI validation see:
    # http://it.gravatar.com/site/implement/images/#default-image .
    # Returns:: a +String+ containing the Gravatar site URI with
    # specified options and configuration parameters.
    def avatar(args = {})
      secure = true
      type = nil

      array = []
      unless args.nil?
        type = args.fetch(:type, nil)
        secure = args.fetch(:secure, secure)

        [:pixelsize, :force, :default, :rating].each do |param|
          array << @parser.parse(param.to_s, args[param]) unless args[param].nil?
        end
      end

      build_uri(secure, true) + digest +
          @parser.parse('type', type) + build_query_string(array)
    end

    # See avatar method. This banged version saves the resulting string
    # as internal state.
    def avatar!(args = {})
      @gravaty = avatar(args)
    end

    # Returns a string containing the URI of the gravatar profile
    # associated to internal (provided) email address. Valid keys for
    # the +args+ hash are: :secure, :format.
    #
    # Usage::
    #   - <tt>a_string = new_gravaty.profile</tt>
    #   - <tt>a_string = new_gravaty.profile secure: false</tt>
    #   - <tt>a_string = new_gravaty.profile format: 'php', secure:
    # true</tt>
    # Params::
    #   - +format+: [String] is the possibly desired specific profile
    # format. Valid formats are 'json', 'xml', 'php', 'vcf' and 'qr'.
    # Default to no extension. Will be downcased. Defaults to no
    # extension for invalid formats.
    #   - +secure+: [TrueClass || FalseClass] is a boolean to specify
    # whether the resulting URL shall be HTTPS or HTTP type. Default to
    # true (HTTPS).
    # Returns:: a +String+ containing the Gravatar site URI with
    # specified options and configuration parameters.
    def profile(args = {})
      secure = true
      format = nil

      array = []
      unless args.nil?
        format = args[:format].downcase unless args[:format].nil?
        secure = args.fetch(:secure, secure)

        unless (format.nil?) and (PROFILES.include? format)
          selected = (format == 'json' ? 'callback' : 'pixelsize')

          array << @parser.parse(selected, args[selected.to_sym]) unless args[selected.to_sym].nil?
        end
      end

      build_uri(secure, false) + digest +
          @parser.parse('format', format) + build_query_string(array)
    end

    # See profile method. This banged version saves the resulting strin
    # as internal state.
    def profile!(args = {})
      @gravaty = profile(args)
    end

    # Saves a file, with specified +filename+, that contains the current
    # gravaty configuration. Uses the internal state to retrieve data
    # from the URI. Defaults to 'gravaty' with no specific extension.
    #
    # Usage::
    #   - <tt>a_string = new_gravaty.download filename</tt>
    # Params::
    #   - +filename+: [String] is the filename to be saved.
    def download(filename = nil)
      filename = URI.parse(@gravaty).path.rpartition('/')
                     .last if filename.nil?
      Utils::Downloader::Downloader
          .download_file @gravaty, filename # thanks Jon!
    end

    # See profile method. Customized version for QRCode-specific
    # requests.
    #
    # Usage::
    #   - <tt>a_string = new_gravaty.qrcode</tt>
    #   - <tt>a_string = new_gravaty.qrcode pixel_size: 42</tt>
    #   - <tt>a_string = new_gravaty.qrcode secure: false, pixel_size:
    # 42</tt>
    # Params::
    #   - +secure+: [TrueClass || FalseClass] is a boolean to specify
    # whether the resulting URL shall be HTTPS or HTTP type. Default to
    # true (HTTPS).
    #   - +pixel_size+: [Integer] is the size in pixel of the image.
    # From 1 to 2048. Default to no value. Raises
    # <code>ArgumentError</code> for invalid sizes.
    # Returns:: a +String+ containing the Gravatar site URI with
    # specified options and configuration parameters, in QRCode format.
    def qrcode(args = {})
      secure = true
      size = nil

      unless args.nil?
        size = args.fetch(:pixelsize, nil)
        secure = args.fetch(:secure, secure)
      end

      profile format: 'qr', secure: secure, pixelsize: size
    end

    # See qrcode method. This banged version saves the resulting string
    # as internal state.
    def qrcode!(args = {})
      @gravaty = qrcode(args)
    end

    # See profile method. Customized version for JSON-specific requests.
    #
    # Usage::
    #   - <tt>a_string = new_gravaty.json</tt>
    #   - <tt>a_string = new_gravaty.json callback: 'alert'</tt>
    #   - <tt>a_string = new_gravaty.qrcode secure: false, callback:
    # 'alert'</tt>
    # Params::
    #   - +secure+: [TrueClass || FalseClass] is a boolean to specify
    # whether the resulting URL shall be HTTPS or HTTP type. Default to
    # true (HTTPS).
    #   - +callback+: [String] See
    # https://secure.gravatar.com/site/implement/profiles/json/#request-options.
    # No check on parameter meaning or validity, except for +nil+.
    # Returns:: a +String+ containing the Gravatar site URI with
    # specified options and configuration parameters, in JSON format.
    def json(args = {})
      secure = true
      callback = nil

      unless args.nil?
        callback = args.fetch(:callback, nil)
        secure = args.fetch(:secure, secure)
      end

      profile format: 'json', secure: secure, callback: callback
    end

    # See json method. This banged version saves the resulting string as
    # internal state.
    def json!(args = {})
      @gravaty = json(args)
    end

    # Restores the original status cleaning up the (possibly) previously
    # saved URIs restoring the default +to_s+.
    def reset
      @gravaty = email
    end

    # Interfaces with the Gravatar XML-RPC API.
    #
    # Usage::
    #   - <tt>response = new_gravaty.xmlrpc 'grav.test',
    # my_password</tt>
    # Params::
    #   - +a_method+: [String] is a valid method supported by Gravatar
    # XML-RPC API. See https://en.gravatar.com/site/implement/xmlrpc/ .
    #   - +password+: [String] is a valid password associated to user's
    # +email_address+ specified to build the Gravaty object.
    #   - +args+: See https://en.gravatar.com/site/implement/xmlrpc/ for
    # possible parameters, depending on called method.
    # Returns:: See https://en.gravatar.com/site/implement/xmlrpc/ for
    # possible return values, depending on called method.
    def xmlrpc(a_method = RPC_TEST_METHOD, password = nil, args = {})
      raise ArgumentError, I18n.t('error.nil') if password.nil?
      raise ArgumentError, I18n.t('error.invalid', value: a_method) unless RPC_METHODS.include? a_method

      @rpc_connector = Utils::RpcConnector::RpcConnector
                           .new(digest, password) if @rpc_connector.nil?
      @rpc_connector.call a_method, args unless @rpc_connector.nil?
    end

    # Returns a JSon object representing the Gravaty object.
    #
    #
    # Usage::
    #   - <tt>a_json = new_gravaty.to_json</tt>
    # Returns:: a +JSON+ containing the Gravaty object representation
    # with currently saved options and configuration parameters.
    def to_json
      result = Hash.new
      result[email] = digest

      result.to_json
    end

    # Returns a string representing the Gravaty object.
    #
    #
    # Usage::
    #   - <tt>a_string = new_gravaty.to_s</tt>
    # Returns:: a +String+ containing the Gravaty object representation
    # with currently saved options and configuration parameters.
    def to_s
      @gravaty.to_s
    end

    def <=>(other_gravaty)
      @email <=> other_gravaty.email
    end

    # -------------------------- here starts the list of private methods

    private

    # Builds the query string with the array of parameters.
    def build_query_string(params_array = [])
      parameters = nil

      unless params_array.nil?
        parameters = params_array.reject {|p| p.nil? or p.empty?}
                         .join('&')
      end

      return ('?' + parameters) unless parameters.nil? or parameters
                                                              .empty?
      ''
    end

    # Return the basic URI structure according to type and security.
    def build_uri(secure = false, avatar = true)
      @parser.parse('secure', secure) + '.gravatar.com/' +
          @parser.parse('avatar', avatar)
    end
  end
end