import { Sequelize } from "sequelize";
import "dotenv/config";

// Import models
import defineFile from "./models/file.js";
import defineQueryCount from "./models/queryCount.js";
import defineMetadata from "./models/metadata.js";

const sequelize = new Sequelize(
  process.env.POSTGRES_DB,
  process.env.POSTGRES_USER,
  process.env.POSTGRES_PASSWORD,
  {
    host: process.env.POSTGRES_HOST || "localhost",
    port: process.env.POSTGRES_PORT || 5432,
    dialect: "postgres",
    logging: process.env.DEBUG === "1" ? console.log : false,
  }
);

// Initialize models
export const File = defineFile(sequelize);
export const QueryCount = defineQueryCount(sequelize);
export const Metadata = defineMetadata(sequelize);
Metadata.hasMany(File);
File.belongsTo(Metadata, { as: "details" });

async function enableTrigram() {
  let query = `SELECT * from PG_extension where extname = 'pg_trgm'`;
  let [result] = await sequelize.query(query, {
    type: sequelize.QueryTypes.SELECT,
  });
  if (!result) {
    const enableTrigramQuery = `CREATE EXTENSION pg_trgm`;
    await sequelize.query(enableTrigramQuery);
  }
  //check if trigram index exists and create it.
  query = `
    SELECT
    t.relname AS table_name,
    i.relname AS index_name,
    a.attname AS column_name
FROM
    pg_class t,
    pg_class i,
    pg_index ix,
    pg_attribute a
WHERE
    t.oid = ix.indrelid
    AND i.oid = ix.indexrelid
    AND a.attrelid = t.oid
    AND a.attnum = ANY(ix.indkey)
    AND t.relkind = 'r'
    AND t.relname = 'Metadata'
   AND i.relname like 'trgm_%'
ORDER BY
    t.relname,
    i.relname
  `;
  [result] = await sequelize.query(query, {
    type: sequelize.QueryTypes.SELECT,
  });
  if (!result) {
    let query = `CREATE INDEX trgm_t_idx ON "Metadata" USING GIN (title gin_trgm_ops)`;
    await sequelize.query(query);
    query = `CREATE INDEX trgm_at_idx ON "Metadata" USING GIN (alternatetitles gin_trgm_ops)`;
    await sequelize.query(query);
  }
}

export async function initDB() {
  try {
    // First try to connect to postgres directly to create database if needed
    const rootSequelize = new Sequelize(
      "postgres",
      process.env.POSTGRES_USER,
      process.env.POSTGRES_PASSWORD,
      {
        host: process.env.POSTGRES_HOST || "localhost",
        port: process.env.POSTGRES_PORT || 5432,
        dialect: "postgres",
        logging: false,
      }
    );

    try {
      // Try to create database if it doesn't exist
      await rootSequelize.query(`CREATE DATABASE ${process.env.POSTGRES_DB};`);
      console.log("Database did not exist, created.");
    } catch (err) {
      // Ignore error if database already exists
      if (!err.message.includes("already exists")) {
        throw err;
      }
    } finally {
      await rootSequelize.close();
    }

    // Now connect to the actual database
    await sequelize.authenticate();
    console.log("DB connected.");

    // Get current database schema
    const queryInterface = sequelize.getQueryInterface();
    const tables = await queryInterface.showAllTables();

    if (!tables.includes("Files") || !tables.includes("QueryCounts")) {
      // If tables don't exist, create them
      console.log("DB doesn't exist, creating initial database schema...");
      await sequelize.sync();
      await enableTrigram();
      console.log("Database schema created.");

      // Initialize QueryCount if it's a new installation
      await QueryCount.create({ count: 0 });
    } else {
      // Auto-migrate existing schema
      console.log("Checking for DB migrations...");
      await sequelize.sync({ alter: true });
      await enableTrigram();
      console.log("DB migrations completed.");
    }

    // Only force sync if explicitly requested
    if (process.env.FORCE_FILE_REBUILD === "1") {
      let queryCount = (await QueryCount.findOne())?.count || 0;
      await sequelize.sync({ force: true });
      await enableTrigram();
      //restore query count after force sync
      await QueryCount.create({ count: queryCount });
      console.log("DB forcefully synchronized.");
    }
  } catch (error) {
    console.error("Unable to connect to the DB:", error);
    process.exit(1);
  }
}

export default sequelize;