Add functionality to import/export readings in csv format

app/routes.py

@@ -1,9 +1,12 @@
-from flask import Blueprint, render_template, redirect, request, url_for, flash
+import csv
+from io import StringIO
+from flask import Blueprint, render_template, redirect, request, send_file, url_for, flash
 from werkzeug.security import generate_password_hash, check_password_hash
 from app.models import Profile, Reading, db, User
 from app.forms import DeleteForm, LoginForm, ProfileForm, ReadingForm, SignupForm
 from flask_login import login_user, login_required, current_user, logout_user
 import base64
+from datetime import datetime, timedelta
 
 main = Blueprint('main', __name__)
 auth = Blueprint('auth', __name__)
@@ -45,8 +48,6 @@ def logout():
 @main.route('/', methods=['GET', 'POST'])
 @login_required
 def dashboard():
-    from datetime import datetime, timedelta
-
     # Default values
     start_date = None
     end_date = None
@@ -197,3 +198,66 @@ def profile():
         return redirect(url_for('user.profile'))
 
     return render_template('profile.html', form=form, profile=profile)
+
+@main.route('/data', methods=['GET', 'POST'])
+@login_required
+def manage_data():
+    if request.method == 'POST':
+        # Handle CSV file upload
+        file = request.files.get('file')
+        if file and file.filename.endswith('.csv'):
+            try:
+                csv_data = csv.reader(StringIO(file.read().decode('utf-8')))
+                next(csv_data)  # Skip the header row
+                for row in csv_data:
+                    timestamp, systolic, diastolic, heart_rate = row
+                    reading = Reading(
+                        user_id=current_user.id,
+                        timestamp=datetime.strptime(timestamp, '%Y-%m-%d %H:%M:%S'),
+                        systolic=int(systolic),
+                        diastolic=int(diastolic),
+                        heart_rate=int(heart_rate),
+                    )
+                    db.session.add(reading)
+                db.session.commit()
+                flash('Data imported successfully!', 'success')
+            except Exception as e:
+                flash(f'Error importing data: {str(e)}', 'danger')
+        else:
+            flash('Please upload a valid CSV file.', 'danger')
+        return redirect(url_for('main.manage_data'))
+
+    return render_template('data.html')
+
+@main.route('/data/export', methods=['GET'])
+@login_required
+def export_data():
+    import io
+
+    output = io.StringIO()
+    writer = csv.writer(output)
+
+    # Write CSV header
+    writer.writerow(['Timestamp', 'Systolic', 'Diastolic', 'Heart Rate'])
+
+    # Write user readings to the CSV
+    readings = Reading.query.filter_by(user_id=current_user.id).all()
+    for reading in readings:
+        writer.writerow([
+            reading.timestamp.strftime('%Y-%m-%d %H:%M:%S'),
+            reading.systolic,
+            reading.diastolic,
+            reading.heart_rate,
+        ])
+
+    # Convert text to bytes for `send_file`
+    output.seek(0)
+    response = io.BytesIO(output.getvalue().encode('utf-8'))
+    output.close()
+
+    return send_file(
+        response,
+        mimetype='text/csv',
+        as_attachment=True,
+        download_name='readings.csv'
+    )