const { DataTypes } = require('sequelize');

module.exports = (sequelize) => {
  const Heartbeat = sequelize.define('Heartbeat', {
    id: {
      type: DataTypes.UUID,
      defaultValue: sequelize.Sequelize.UUIDV4,
      primaryKey: true
    },
    device_id: {
      type: DataTypes.INTEGER,
      allowNull: false,
      references: {
        model: 'devices',
        key: 'id'
      },
      comment: 'ID of the device sending heartbeat'
    },
    device_key: {
      type: DataTypes.STRING,
      allowNull: true, // Allow null for testing
      defaultValue: 'test-device-key',
      comment: 'Unique key of the sensor from heartbeat message'
    },
    signal_strength: {
      type: DataTypes.INTEGER,
      allowNull: true,
      comment: 'Signal strength at time of heartbeat'
    },
    battery_level: {
      type: DataTypes.INTEGER,
      allowNull: true,
      comment: 'Battery level percentage (0-100)'
    },
    temperature: {
      type: DataTypes.DECIMAL(4, 1),
      allowNull: true,
      comment: 'Device temperature in Celsius'
    },
    uptime: {
      type: DataTypes.BIGINT,
      allowNull: true,
      comment: 'Device uptime in seconds'
    },
    memory_usage: {
      type: DataTypes.INTEGER,
      allowNull: true,
      comment: 'Memory usage percentage'
    },
    firmware_version: {
      type: DataTypes.STRING,
      allowNull: true,
      comment: 'Firmware version reported in heartbeat'
    },
    received_at: {
      type: DataTypes.DATE,
      defaultValue: sequelize.Sequelize.NOW,
      comment: 'When heartbeat was received by server'
    },
    raw_payload: {
      type: DataTypes.JSON,
      allowNull: true,
      comment: 'Complete raw payload received from detector (for debugging)'
    },
    created_at: {
      type: DataTypes.DATE,
      defaultValue: sequelize.Sequelize.NOW
    }
  }, {
    tableName: 'heartbeats',
    timestamps: true,
    createdAt: 'created_at',
    updatedAt: false,
    indexes: [
      {
        fields: ['device_id']
      },
      {
        fields: ['received_at']
      },
      {
        fields: ['device_id', 'received_at']
      }
    ]
  });

  return Heartbeat;
};