import * as SQLite from 'expo-sqlite';
import * as FileSystem from 'expo-file-system';
import { Asset } from 'expo-asset';

let db1: SQLite.SQLiteDatabase | null = null;
let db2: SQLite.SQLiteDatabase | null = null;
const nmRegionsDBname = 'nmRegions.db';
const darePlacesDBname = 'darePlaces.db';
const sqliteDirectory = 'SQLite';
const sqliteFullPath = FileSystem.documentDirectory + sqliteDirectory;
const DS = '/';

async function copyDatabaseFile(dbName: string, dbAsset: Asset) {
  console.log("DB copy start - " + dbName);
  await dbAsset.downloadAsync();
  await FileSystem.downloadAsync(
    dbAsset.uri,
    sqliteFullPath + DS + dbName
  );

  const dbUri = sqliteFullPath + DS + dbName;

  await FileSystem.copyAsync({
    from: dbAsset.localUri ?? '',
    to: dbUri,
  });
  return dbUri;
}

export async function openDatabases() {
  try {
    const fileInfo = await FileSystem.getInfoAsync(sqliteFullPath);
    if (!fileInfo.exists) {
      await FileSystem.makeDirectoryAsync(sqliteFullPath, { intermediates: true });
    }

    const nmRegionsDB = await FileSystem.getInfoAsync(sqliteFullPath + DS + nmRegionsDBname, { size: true });
    if (!nmRegionsDB.exists) {
      await copyDatabaseFile(nmRegionsDBname, Asset.fromModule(require('../../assets/db/' + nmRegionsDBname)));
    }
    if (nmRegionsDB.size == 0) {
      await FileSystem.deleteAsync(sqliteFullPath + DS + nmRegionsDBname);
      await copyDatabaseFile(nmRegionsDBname, Asset.fromModule(require('../../assets/db/' + nmRegionsDBname)));
    }


    const darePlacesDB = await FileSystem.getInfoAsync(sqliteFullPath + DS + nmRegionsDBname, { size: true });
    if (!darePlacesDB.exists) {
      await copyDatabaseFile(darePlacesDBname, Asset.fromModule(require('../../assets/db/' + darePlacesDBname)));
    }
    
    if (darePlacesDB.size == 0) {
      await FileSystem.deleteAsync(sqliteFullPath + DS + darePlacesDBname);
      await copyDatabaseFile(darePlacesDBname, Asset.fromModule(require('../../assets/db/' + darePlacesDBname)));
    }

    const openDatabase = (dbName: string) => SQLite.openDatabase(dbName);
    db1 = openDatabase(nmRegionsDBname);
    db2 = openDatabase(darePlacesDBname);
  } catch (error) {
    console.error('openDatabases - Error:');
    console.error(JSON.stringify(error, null, 2));
  }
}

export async function refreshDatabases() {
  try {
    const fileInfo = await FileSystem.getInfoAsync(sqliteFullPath);
    if (!fileInfo.exists) {
      await FileSystem.makeDirectoryAsync(sqliteFullPath, { intermediates: true });
    }
    await FileSystem.deleteAsync(sqliteFullPath + DS + nmRegionsDBname, {idempotent: true});
    await copyDatabaseFile(nmRegionsDBname, Asset.fromModule(require('../../assets/db/' + nmRegionsDBname)));

    await FileSystem.deleteAsync(sqliteFullPath + DS +  darePlacesDBname , {idempotent: true} );
    await copyDatabaseFile(darePlacesDBname, Asset.fromModule(require('../../assets/db/' + darePlacesDBname)));

    const openDatabase = (dbName: string) => SQLite.openDatabase(dbName);
    db1 = null;
    db2 = null;
    db1 = openDatabase(nmRegionsDBname);
    db2 = openDatabase(darePlacesDBname);
  } catch (error) {
    console.error('refreshDatabases - Error:');
    console.error(JSON.stringify(error, null, 2));
  }
}

export function getFirstDatabase() {
  return db1;
}

export function getSecondDatabase() {
  return db2;
}