drift/drift_dev/lib/src/writer/utils/column_constraints.dart

import 'package:drift/sqlite_keywords.dart';
import 'package:sqlparser/sqlparser.dart';

import '../../model/column.dart';

String defaultConstraints(DriftColumn column) {
  final defaultConstraints = <String>[];

  var wrotePkConstraint = false;

  for (final feature in column.features) {
    if (feature is PrimaryKey) {
      if (!wrotePkConstraint) {
        defaultConstraints.add(feature is AutoIncrement
            ? 'PRIMARY KEY AUTOINCREMENT'
            : 'PRIMARY KEY');

        wrotePkConstraint = true;
        break;
      }
    }
  }

  if (!wrotePkConstraint) {
    for (final feature in column.features) {
      if (feature is UniqueKey) {
        defaultConstraints.add('UNIQUE');
        break;
      }
    }
  }

  for (final feature in column.features) {
    if (feature is ResolvedDartForeignKeyReference) {
      final tableName = escapeIfNeeded(feature.otherTable.sqlName);
      final columnName = escapeIfNeeded(feature.otherColumn.name.name);

      var constraint = 'REFERENCES $tableName ($columnName)';

      final onUpdate = feature.onUpdate;
      final onDelete = feature.onDelete;

      if (onUpdate != null) {
        constraint = '$constraint ON UPDATE ${onUpdate.description}';
      }

      if (onDelete != null) {
        constraint = '$constraint ON DELETE ${onDelete.description}';
      }

      defaultConstraints.add(constraint);
    } else if (feature is DefaultConstraintsFromSchemaFile) {
      return feature.defaultConstraints;
    }
  }

  if (column.type == ColumnType.boolean) {
    final name = escapeIfNeeded(column.name.name);
    defaultConstraints.add('CHECK ($name IN (0, 1))');
  }

  return defaultConstraints.join(' ');
}

extension on ReferenceAction {
  String get description {
    switch (this) {
      case ReferenceAction.setNull:
        return 'SET NULL';
      case ReferenceAction.setDefault:
        return 'SET DEFAULT';
      case ReferenceAction.cascade:
        return 'CASCADE';
      case ReferenceAction.restrict:
        return 'RESTRICT';
      case ReferenceAction.noAction:
        return 'NO ACTION';
    }
  }
}