# frozen_string_literal: true

require_relative 'context'
require_relative 'finder_methods'
require_relative 'pagination_methods'
require_relative 'persistence'
require_relative 'query_methods'

module ErpIntegration
  module Fulfil
    class ApiResource
      include Context
      include Enumerable
      include FinderMethods
      include PaginationMethods
      include Persistence
      include QueryMethods

      attr_accessor :resource_klass
      delegate :client, :model_name, to: 'self.class'

      def initialize(resource_klass)
        @resource_klass = resource_klass
      end

      # The `client` exposes the `ErpIntegration::Fulfil::Client` to the class.
      # @return [ErpIntegration::Fulfil::Client] The HTTP client for Fulfil.
      def self.client
        Client.new(
          api_key: config.fulfil_api_key,
          merchant_id: config.fulfil_merchant_id,
          logger: config.logger
        )
      end

      # The `config` exposes the gem's configuration to the `ApiResource`.
      # @return [ErpIntegration::Configuration] The gem's configuration object.
      def self.config
        ErpIntegration.config
      end

      # Fulfil doesn't use logical naming conventions. However, we do need
      # the name of a model to build the resource URI.
      #
      # By manually setting the model name, we allow the `Fulfil::Connection`
      # module to connect to the correct API endpoint.
      #
      # @param name [String] The logical path name in Fulfil.
      # @return [String] The model name
      def self.model_name=(name)
        instance_variable_set(:@model_name, name)
      end

      def self.model_name
        instance_variable_get(:@model_name)
      end

      # The `where` and `includes` methods lazyly build a search/read query
      # for Fulfil. By calling `all`, the prepared search/read query will actually
      # be executed and the results will be fetched.
      # @return [Array] An enumerable collection object with all API results.
      def all
        return @results if defined?(@results)

        @results =
          client.put(
            api_resource_path,
            Query.new(
              fields: selected_fields,
              filters: where_clauses,
              alternative_filters: or_clauses,
              limit: limit_value,
              offset: calculated_offset
            )
          ).map { |item| resource_klass.new(item) }
      end

      # As with the `all` method, the `query methods` lazyly build a search/read
      # or search/count query for Fulfil.
      # By calling `count`, the prepared search/count will actually be executed and
      # the result will be fetched
      # @return [Integer] The count of records that match with the query in Fulfil
      def count
        return @count if defined?(@count)

        @count =
          client.put(
            "model/#{model_name}/search_count",
            Query.new(
              fields: nil,
              filters: where_clauses,
              alternative_filters: or_clauses
            ).to_h.except(:fields)
          )
      end

      # The `each` method turns the `ApiResource` instance into an enumerable object.
      # For more information, see https://ruby-doc.org/core-3.0.2/Enumerable.html
      def each(&block)
        all.each(&block)
      end

      # Iterates over each page of results and yields it for processing.
      #
      # It fetches each page of results and yields it to the provided block for
      # processing. The loop continues until there are no more results to process.
      #
      # @example
      # ErpIntegration::SalesOrder.select(:id, :total_amount, :state).find_each do |orders|
      #   orders.each do |order|
      #     puts "#{order.id},$#{order.total_amount['decimal']},#{order.state}"
      #   end
      # end
      #
      # => 5887403,$478.12,draft
      # => 5884252,$1497.03,draft
      # ...
      # => 5742565,$78.75,draft
      #
      # @yield [results] Yields the current page of results to the provided block
      #   for processing.
      # @yieldparam results [Array] An array of results for the current page.
      # @return [nil]
      def find_each
        page = 1
        while (results = clone.page(page)).any?
          yield results
          page += 1
        end
      end

      private

      # Builds the relative resource path and adds the context if needed.
      #
      # @return [String]
      def api_resource_path
        base_path = "model/#{model_name}/search_read"
        return base_path unless context?

        "#{base_path}?context=#{context.to_json}"
      end
    end
  end
end