const { DataTypes } = require("sequelize");
const sequelize = require("../../config/db.config");

const AssessmentSession = sequelize.define("AssessmentSession", {
  session_id:    { type: DataTypes.BIGINT, primaryKey: true, autoIncrement: true },
  uuid:          { type: DataTypes.UUID, defaultValue: DataTypes.UUIDV4, unique: true },
  user_id:       { type: DataTypes.BIGINT, allowNull: false },
  assessment_id: { type: DataTypes.BIGINT, allowNull: false },
  course_id:     { type: DataTypes.BIGINT, allowNull: true },
  started_at:    { type: DataTypes.DATE, allowNull: false, defaultValue: DataTypes.NOW },
  expires_at:    { type: DataTypes.DATE, allowNull: true },   // null = no time limit
  status:        { type: DataTypes.STRING(20), allowNull: false, defaultValue: 'in_progress' }, // 'in_progress' | 'completed' | 'expired'
  attempt_id:       { type: DataTypes.BIGINT, allowNull: true },  // FK → quiz_attempts once graded/expired
  draft_answers:    { type: DataTypes.JSONB, allowNull: true, defaultValue: null },
  last_heartbeat_at: { type: DataTypes.DATE, allowNull: true, defaultValue: null },
}, {
  tableName: "assessment_sessions",
  timestamps: true,
});

module.exports = AssessmentSession;