# encoding: UTF-8
#
# Copyright (c) 2010-2017 GoodData Corporation. All rights reserved.
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

require_relative '../metadata'

require_relative 'metadata'

require_relative '../../mixins/is_attribute'

module GoodData
  class Attribute < MdObject
    include Mixin::IsAttribute

    ATTRIBUTE_BASE_AGGREGATIONS = [:count]

    class << self
      # Method intended to get all objects of that type in a specified project
      #
      # @param options [Hash] the options hash
      # @option options [Boolean] :full if passed true the subclass can decide
      # to pull in full objects. This is desirable from the usability POV
      # but unfortunately has negative impact on performance so it is
      # not the default.
      # @return [Array<GoodData::MdObject> | Array<Hash>] Return the appropriate metadata objects or their representation
      def all(options = { :client => GoodData.connection, :project => GoodData.project })
        query('attribute', Attribute, options)
      end

      # Finds the value of an atribute and gives you the textual form for the label that is acquired by calling primary_label method
      #
      # @param uri [String] Uri of the element. in the form of /gdc/md/PID/obj/OBJ_ID/elements?id=21
      # @return [String] Textual representation of a particular attribute element
      def find_element_value(stuff, opts = { :project => GoodData.project })
        stuff.scan(%r{([^\[\]]*)\/elements\?id=(\d+)}).pmap do |a, id|
          opts[:project].attributes(a).primary_label.find_element_value(id.to_i)
        end.first
      end
    end

    def drill_down(attribute)
      attribute = Attribute[attribute, client: client, project: project]
      content['drillDownStepAttributeDF'] = attribute.primary_label.meta['uri']
      save
    end

    # Returns the labels of an attribute
    # @return [Array<GoodData::Label>]
    def display_forms
      content['displayForms'].pmap { |df| project.labels(df['meta']['uri']) }
    end
    alias_method :labels, :display_forms

    def dimension
      uri = content['dimension']
      return nil if uri.nil?
      GoodData::Dimension[uri, client: client, project: project]
    end

    # Tells you if an attribute is a date dimension. This happens by inspecting
    # an identifier if it conforms to a particular scheme.
    #
    # @return [Boolean] Is the attribute a date attribute?
    def date_attribute?
      things = [
        'week',
        'euweek.in.year',
        'day.in.week',
        'day.in.month',
        'day.in.quarter',
        'day.in.euweek',
        'date',
        'quarter.in.year',
        'week.in.year',
        'day.in.year',
        'month',
        'quarter',
        'month.in.quarter',
        'week.in.quarter',
        'year',
        'euweek',
        'euweek.in.quarter',
        'month.in.year'
      ]
      potential_id = identifier.split('.')[1..-1].join('.')
      things.include?(potential_id) ? true : false
    end

    # Returns the first display form which is the primary one
    # @return [GoodData::Label] Primary label
    def primary_display_form
      labels.first
    end
    alias_method :primary_label, :primary_display_form

    # Creates the basic count metric with the attribute used. If you need to
    # compute the attribute on a different dataset you can specify that in
    # params. The metric created is not saved.
    # @param [Hash] options the options to pass to the value list
    # @option options [Symbol] :type type of aggregation function.
    # @option options [Symbol] :attribute Use this attribute if you need to
    # express different dataset for performing the computation on. It basically
    # serves for creating metrics like SELECT COUNT(User, Opportunity).
    # @return [GoodData::Metric]
    def create_metric(options = {})
      an_attribute = options[:attribute]
      a_type = options[:type] || :count
      unless ATTRIBUTE_BASE_AGGREGATIONS.include?(a_type)
        fail 'Suggested aggreagtion function (#{a_type}) does not exist for ' \
             'base metric created out of attribute. You can use only one of' \
             "#{ATTRIBUTE_BASE_AGGREGATIONS.map { |x| ':' + x.to_s }.join(',')}"
      end
      a_title = options[:title] || "#{a_type} of #{title}"
      if an_attribute
        project.create_metric("SELECT #{a_type.to_s.upcase}([#{uri}], [#{an_attribute.uri}])", title: a_title, extended_notation: false)
      else
        project.create_metric("SELECT #{a_type.to_s.upcase}([#{uri}])", title: a_title, extended_notation: false)
      end
    end

    alias_method :create_measure, :create_metric

    # For an element id find values (titles) for all display forms. Element id can be given as both number id or URI as a string beginning with /
    # @param [Object] element_id Element identifier either Number or a uri as a String
    # @return [Array] list of values for certain element. Returned in the same order as is the order of labels
    def values_for(element_id)
      # element_id = element_id.is_a?(String) ? element_id.match(/\?id=(\d)/)[1] : element_id
      labels.pmap do |label|
        label.find_element_value(element_id)
      end
    end

    # Returns all values for all labels. This is for inspection purposes only since obviously there can be huge number of elements.
    # @param [Hash] options the options to pass to the value list
    # @option options [Number] :limit limits the number of values to certain number. Default is 100
    # @return [Array]
    def values
      results = labels.map(&:values)
      results.first.zip(*results[1..-1])
    end

    # Allows to search in attribute labels by name. It uses the string as a basis for regexp and tries to match either a title or an identifier. Returns first match.
    # @param name [String] name used as a basis for regular expression
    # @return [GoodData::Label]
    def label_by_name(name)
      labels.find { |label| label.title =~ /#{name}/ || label.identifier =~ /#{name}/ }
    end

    def computed_attribute?
      content['rel'] && !content['rel'].empty?
    end
  end
end