"use strict";

/** @type {import('sequelize-cli').Migration} */
module.exports = {
  async up(queryInterface, Sequelize) {
    await queryInterface.sequelize.transaction(async (transaction) => {
      // Rename the existing backlinks table to relationships
      await queryInterface.renameTable("backlinks", "relationships", {
        transaction,
      });

      // Add the type column with default value
      await queryInterface.addColumn(
        "relationships",
        "type",
        {
          type: Sequelize.ENUM("backlink", "similar"),
          allowNull: false,
          defaultValue: "backlink",
        },
        { transaction }
      );

      // Add new indexes for performance (the old indexes on documentId and reverseDocumentId should still exist)
      await queryInterface.addIndex("relationships", ["type"], { transaction });
      await queryInterface.addIndex("relationships", ["documentId", "type"], {
        transaction,
      });

      // Create a view for backward compatibility
      await queryInterface.sequelize.query(
        `
        CREATE VIEW backlinks AS
        SELECT id, "userId", "documentId", "reverseDocumentId", "createdAt", "updatedAt"
        FROM relationships
        WHERE type = 'backlink';
      `,
        { transaction }
      );
    });
  },

  async down(queryInterface, Sequelize) {
    await queryInterface.sequelize.transaction(async (transaction) => {
      // Drop the view
      await queryInterface.sequelize.query("DROP VIEW IF EXISTS backlinks;", {
        transaction,
      });

      // Remove the type-specific indexes
      await queryInterface.removeIndex("relationships", ["type"], {
        transaction,
      });
      await queryInterface.removeIndex(
        "relationships",
        ["documentId", "type"],
        { transaction }
      );

      // Remove the type column
      await queryInterface.removeColumn("relationships", "type", {
        transaction,
      });

      // Drop the enum type
      await queryInterface.sequelize.query(
        'DROP TYPE IF EXISTS "enum_relationships_type";',
        { transaction }
      );

      // Rename the table back to backlinks
      await queryInterface.renameTable("relationships", "backlinks", {
        transaction,
      });
    });
  },
};