'use strict';

/**
 * Older generated SRS data contained the number word "Baynte" as the
 * currency phrase "20 Peso". Baynte itself means twenty, so the expected
 * answer must be the number without a currency unit.
 */
module.exports = {
  async up(queryInterface) {
    await queryInterface.sequelize.query(`
      WITH affected AS (
        SELECT
          id,
          user_id,
          course_id,
          lesson_id,
          direction,
          CASE
            WHEN LOWER(TRIM(learning)) = 'baynte' THEN 'baynte'
            ELSE '20'
          END AS corrected_learning,
          CASE
            WHEN LOWER(TRIM(reference)) = 'baynte' THEN 'baynte'
            ELSE '20'
          END AS corrected_reference
        FROM community.vocab_srs_item
        WHERE (LOWER(TRIM(learning)) = 'baynte' AND LOWER(TRIM(reference)) IN ('20 peso', '20 pesos'))
           OR (LOWER(TRIM(reference)) = 'baynte' AND LOWER(TRIM(learning)) IN ('20 peso', '20 pesos'))
      ),
      keyed AS (
        SELECT
          affected.*,
          ENCODE(DIGEST(CONCAT_WS(
            '|',
            course_id::text,
            COALESCE(lesson_id::text, 'course'),
            UPPER(direction),
            corrected_learning,
            corrected_reference
          ), 'sha1'), 'hex') AS corrected_item_key
        FROM affected
      )
      UPDATE community.vocab_srs_item item
      SET learning = keyed.corrected_learning,
          reference = keyed.corrected_reference,
          item_key = keyed.corrected_item_key,
          updated_at = NOW()
      FROM keyed
      WHERE item.id = keyed.id
        AND NOT EXISTS (
          SELECT 1
          FROM community.vocab_srs_item duplicate
          WHERE duplicate.user_id = keyed.user_id
            AND duplicate.item_key = keyed.corrected_item_key
            AND duplicate.id <> keyed.id
        );
    `);
  },

  async down() {
    // The old answer was semantically incorrect and must not be restored.
  },
};