import fs from 'fs';
import path from 'path';
import { DataSource } from 'typeorm';
import {
  AuthUserEntity,
  ServerEntity,
  JoinRequestEntity,
  ServerMembershipEntity,
  ServerInviteEntity,
  ServerBanEntity
} from '../entities';
import { serverMigrations } from '../migrations';
import { findExistingPath, resolveRuntimePath } from '../runtime-paths';

const DATA_DIR = resolveRuntimePath('data');
const DB_FILE = path.join(DATA_DIR, 'metoyou.sqlite');

let applicationDataSource: DataSource | undefined;

function resolveSqlJsConfig(): { locateFile: (file: string) => string } {
  return {
    locateFile: (file) => {
      const bundledBinaryPath = path.join(__dirname, '..', '..', 'node_modules', 'sql.js', 'dist', file);

      return findExistingPath(
        resolveRuntimePath(file),
        bundledBinaryPath
      ) ?? bundledBinaryPath;
    }
  };
}

export function getDataSource(): DataSource {
  if (!applicationDataSource?.isInitialized) {
    throw new Error('DataSource not initialised');
  }

  return applicationDataSource;
}

export async function initDatabase(): Promise<void> {
  if (!fs.existsSync(DATA_DIR))
    fs.mkdirSync(DATA_DIR, { recursive: true });

  let database: Uint8Array | undefined;

  if (fs.existsSync(DB_FILE))
    database = fs.readFileSync(DB_FILE);

  try {
    applicationDataSource = new DataSource({
      type: 'sqljs',
      database,
      entities: [
        AuthUserEntity,
        ServerEntity,
        JoinRequestEntity,
        ServerMembershipEntity,
        ServerInviteEntity,
        ServerBanEntity
      ],
      migrations: serverMigrations,
      synchronize: false,
      logging: false,
      autoSave: true,
      location: DB_FILE,
      sqlJsConfig: resolveSqlJsConfig()
    });
  } catch (error) {
    console.error('[DB] Failed to configure the sql.js data source', error);
    throw error;
  }

  try {
    await applicationDataSource.initialize();
  } catch (error) {
    console.error('[DB] Failed to initialise the sql.js data source', error);
    throw error;
  }

  console.log('[DB] Connection initialised at:', DB_FILE);

  await applicationDataSource.runMigrations();
  console.log('[DB] Migrations executed');
}

export async function destroyDatabase(): Promise<void> {
  if (applicationDataSource?.isInitialized) {
    await applicationDataSource.destroy();
    applicationDataSource = undefined;
    console.log('[DB] Connection closed');
  }
}