import { DefaultNamingStrategy, NamingStrategyInterface } from 'typeorm';

function toSnakeCase(str: string): string {
  return str.replace(/([A-Z])/g, '_$1').toLowerCase().replace(/^_/, '');
}

export class SnakeNamingStrategy extends DefaultNamingStrategy implements NamingStrategyInterface {
  tableName(className: string, customName: string): string {
    return customName || toSnakeCase(className);
  }

  columnName(propertyName: string, customName: string, embeddedPrefixes: string[]): string {
    const prefix = embeddedPrefixes.length ? toSnakeCase(embeddedPrefixes.join('_')) + '_' : '';
    return prefix + (customName || toSnakeCase(propertyName));
  }

  relationName(propertyName: string): string {
    return toSnakeCase(propertyName);
  }

  joinColumnName(relationName: string, referencedColumnName: string): string {
    return toSnakeCase(relationName) + '_' + referencedColumnName;
  }

  joinTableColumnName(tableName: string, propertyName: string, columnName?: string): string {
    return toSnakeCase(tableName) + '_' + (columnName || toSnakeCase(propertyName));
  }
}