app.post("/api/user", (req, res) => {

        const userId = new ObjectId(req.user._id);

      const { age, sex, height, weight, activity, goalAction } = req.body; // These are from the name attributes in the ejs file

      // Parsing user inputs
      const parsedHeight = parseFloat(height); 
      const parsedWeight = parseFloat(weight); 
      const parsedAge = parseInt(age); 
      const activityFactor = parseFloat(activity);  



      // Was parsing a success?
      if (isNaN(parsedHeight) || isNaN(parsedWeight) || isNaN(parsedAge) || isNaN(activityFactor)) {
      return res.status(400).send('Invalid input values.');
      }

      // calculatig the BMR
      let bmr;
      if (sex === 'female') {
          bmr = 10 * parsedWeight + 6.25 * parsedHeight - 5 * parsedAge - 161;  // Female equation
      } else {
          bmr = 10 * parsedWeight + 6.25 * parsedHeight - 5 * parsedAge + 5;    // Male equation
      }

      // calculate TDEE based on activity level
      const tdee = bmr * activityFactor;

      // adjustigg for weight goal
      let dailyCalories;
      switch (goalAction) {
          case 'maintain-goal':
              dailyCalories = tdee;
              break;
          case 'lose-goal-one':
              dailyCalories = tdee - 500;
              break;
          case 'lose-goal-half':
              dailyCalories = tdee - 250;
              break;
          case 'gain-weight-one':
              dailyCalories = tdee + 500;
              break;
          case 'gain-weight-half':
              dailyCalories = tdee + 250;
              break;
          default:

      // Did I do dailyCalories right?
      if (isNaN(dailyCalories)) {
      return res.status(500).send('Error calculating daily caloric intake.')};

      // saving the caloric intake to the CaloricIntake model
      const caloricIntakeData = new CaloricIntake({
        userId: userId,
        weightGoal: goalAction, 
        activity: activity,   
        weight: parsedWeight, 
        height: parsedHeight,  
        sex: sex,           
        age: parsedAge,
        bmr: bmr.toFixed(0),
        tdee: tdee.toFixed(0),
        dailyCalories: dailyCalories.toFixed(0),
        });

        if (!req.user || !req.user._id) {
            return res.status(400).send('User is not authenticated or ID missing.');
          }          

  // So I can see the values from the <form> element inside req.body

            caloricCollection.insertOne(caloricIntakeData)
            .then(result => {
            res.redirect('/profile'); 
            })
            .catch(error => {
            res.status(500).send('Error saving data');
            });

    });