module.exports = (sequelize, DataTypes) => {
  const TrainingData = sequelize.define('TrainingData', {
    id: {
      type: DataTypes.UUID,
      defaultValue: DataTypes.UUIDV4,
      primaryKey: true
    },
    model_version_id: {
      type: DataTypes.UUID,
      allowNull: false,
      references: {
        model: 'model_versions',
        key: 'id'
      }
    },
    data_type: {
      type: DataTypes.ENUM('qa_pair', 'plan_pair', 'feedback', 'preference'),
      allowNull: false
    },
    input_text: {
      type: DataTypes.TEXT,
      allowNull: false
    },
    output_text: {
      type: DataTypes.TEXT,
      allowNull: false
    },
    context: {
      type: DataTypes.JSONB,
      defaultValue: {}
    },
    quality_score: {
      type: DataTypes.FLOAT,
      allowNull: true
    },
    is_validated: {
      type: DataTypes.BOOLEAN,
      defaultValue: false
    },
    validation_notes: {
      type: DataTypes.TEXT,
      allowNull: true
    },
    source: {
      type: DataTypes.ENUM('expert', 'user', 'generated', 'feedback'),
      allowNull: false
    },
    metadata: {
      type: DataTypes.JSONB,
      defaultValue: {}
    }
  }, {
    tableName: 'training_data',
    indexes: [
      { fields: ['model_version_id'] },
      { fields: ['data_type'] },
      { fields: ['is_validated'] },
      { fields: ['source'] },
      { fields: ['quality_score'] }
    ]
  });

  return TrainingData;
};