# frozen_string_literal: true

require "spec_helper"
require "shared/order_as_specified_examples"
require "config/test_setup_migration"

RSpec.describe "PostgreSQL" do
  before :all do
    ActiveRecord::Base.establish_connection(:postgresql_test)
    TestSetupMigration.migrate(:up)
  end

  after(:all) { ActiveRecord::Base.remove_connection }

  include_examples ".order_as_specified"

  context "when using DISTINCT ON" do
    subject do
      TestClass.order_as_specified(
        distinct_on: true,
        field: shuffled_object_fields
      )
    end

    let(:shuffled_objects) do
      fields = Array.new(3) { |i| "Field #{i}" } * 2
      Array.new(5) { |i| TestClass.create(field: fields[i]) }.shuffle
    end

    it "returns distinct objects" do
      expect(subject.length).to eq 3
    end

    context "input safety" do
      before(:each) { TestClass.create(field: "foo") }

      it "sanitizes column values" do
        # Attempt to inject code to add a 'hi' field to each record. If the SQL
        # inputs are properly sanitized, the code will be ignored and the
        # returned model instances will not respond to #hi. If not, the code
        # will execute and each of the returned model instances will have a #hi
        #  method to access the new field.
        bad_value = "foo') field, 'hi'::varchar AS hi FROM test_classes --"
        record = TestClass.order_as_specified(
          distinct_on: true,
          field: [bad_value]
        ).to_a.first
        expect(record).to_not respond_to(:hi)
      end

      it "quotes column and table names" do
        table = "association_test_classes"
        quoted_table = AssociationTestClass.connection.quote_table_name(table)

        column = "id"
        quoted_column = AssociationTestClass.
                        connection.
                        quote_column_name(column)

        sql = TestClass.order_as_specified(
          distinct_on: true,
          table => { column => ["foo"] }
        ).to_sql
        pattern = "DISTINCT ON (CASE WHEN #{quoted_table}.#{quoted_column}"
        expect(sql).to include(pattern)
      end
    end
  end
end