/**
 * Database connection factory.
 * Creates Kysely instances for SQLite or PostgreSQL based on configuration.
 */

import { Kysely, SqliteDialect, PostgresDialect } from 'kysely';
import SqliteDatabase from 'better-sqlite3';
import { Pool } from 'pg';
import type { Database } from './database.js';
import type { DatabaseConfig } from './config.js';

export function createDatabase(config: DatabaseConfig): Kysely<Database> {
  if (config.type === 'sqlite') {
    if (!config.sqlite) {
      throw new Error('SQLite configuration required');
    }

    const sqliteDb = new SqliteDatabase(config.sqlite.path);
    sqliteDb.pragma('journal_mode = WAL');

    return new Kysely<Database>({
      dialect: new SqliteDialect({
        database: sqliteDb,
      }),
    });
  }

  if (config.type === 'postgres') {
    if (!config.postgres) {
      throw new Error('PostgreSQL configuration required');
    }

    // Check if using connection string or individual params
    if ('connectionString' in config.postgres) {
      return new Kysely<Database>({
        dialect: new PostgresDialect({
          pool: new Pool({
            connectionString: config.postgres.connectionString,
          }),
        }),
      });
    } else {
      return new Kysely<Database>({
        dialect: new PostgresDialect({
          pool: new Pool({
            host: config.postgres.host,
            port: config.postgres.port,
            database: config.postgres.database,
            user: config.postgres.user,
            password: config.postgres.password,
          }),
        }),
      });
    }
  }

  throw new Error(`Unsupported database type: ${config.type}`);
}