'use strict';

/**
 * 迁移 020：为 zhongzhi_submissions / gaozhi_submissions 增加 question_type 列
 *
 * 背景（Bug #11 / B11）：选择题(choice_questions)与判断题(judge_questions)的 id
 * 在不同表中数值重叠（如 choice#5 与 judge#5 均为 5），原 saveAnswers 仅按
 * (aggregation_uid, question_uid) 查找并 upsert，导致同 id 的选择题与判断题被
 * 折叠成一条记录，考生作答数少于抽题数、部分答案静默丢失。
 *
 * 修复：新增 question_type 列（choice/judge），与 question_uid 联合唯一标识一道题；
 * service.saveAnswers 的查找/写入键改为 (aggregation_uid, question_uid, question_type)；
 * autoScore 判分不受影响（其本就按 question_type 选模型 + 用原始 id 作主键）。
 */
module.exports = {
  up: async (queryInterface, Sequelize) => {
    const addCol = async (table) => {
      await queryInterface.addColumn(table, 'question_type', {
        type: Sequelize.STRING(16),
        allowNull: false,
        defaultValue: '',
        comment: '题型：choice/judge，与 question_uid 联合区分题目',
      });
      await queryInterface.addIndex(
        table,
        ['aggregation_uid', 'question_uid', 'question_type'],
        { name: `idx_${table}_agg_qtype` }
      );
    };
    await addCol('zhongzhi_submissions');
    await addCol('gaozhi_submissions');
  },

  down: async (queryInterface, Sequelize) => {
    await queryInterface.removeIndex('zhongzhi_submissions', 'idx_zhongzhi_submissions_agg_qtype');
    await queryInterface.removeColumn('zhongzhi_submissions', 'question_type');
    await queryInterface.removeIndex('gaozhi_submissions', 'idx_gaozhi_submissions_agg_qtype');
    await queryInterface.removeColumn('gaozhi_submissions', 'question_type');
  },
};