module.exports = (sequelize, DataTypes) => {
  const ModelVersion = sequelize.define('ModelVersion', {
    id: {
      type: DataTypes.UUID,
      defaultValue: DataTypes.UUIDV4,
      primaryKey: true
    },
    model_name: {
      type: DataTypes.STRING,
      allowNull: false
    },
    version: {
      type: DataTypes.STRING,
      allowNull: false
    },
    model_type: {
      type: DataTypes.ENUM('MODEL1', 'QUERYMODEL'),
      allowNull: false
    },
    base_model: {
      type: DataTypes.STRING,
      allowNull: false
    },
    fine_tuning_method: {
      type: DataTypes.ENUM('SFT', 'DPO', 'PPO', 'LoRA', 'QLoRA'),
      allowNull: true
    },
    training_data_count: {
      type: DataTypes.INTEGER,
      defaultValue: 0
    },
    performance_metrics: {
      type: DataTypes.JSONB,
      defaultValue: {}
    },
    is_active: {
      type: DataTypes.BOOLEAN,
      defaultValue: false
    },
    deployment_status: {
      type: DataTypes.ENUM('training', 'testing', 'deployed', 'deprecated'),
      defaultValue: 'training'
    },
    model_path: {
      type: DataTypes.STRING,
      allowNull: true
    },
    hyperparameters: {
      type: DataTypes.JSONB,
      defaultValue: {}
    },
    training_log: {
      type: DataTypes.JSONB,
      defaultValue: {}
    },
    metadata: {
      type: DataTypes.JSONB,
      defaultValue: {}
    }
  }, {
    tableName: 'model_versions',
    indexes: [
      { fields: ['model_name'] },
      { fields: ['model_type'] },
      { fields: ['is_active'] },
      { fields: ['deployment_status'] },
      { fields: ['created_at'] }
    ]
  });

  return ModelVersion;
};