from flask import Flask, request, render_template, redirect, url_for, session, send_file
import cv2
import numpy as np
import os
import pickle
import logging
from werkzeug.utils import secure_filename
from datetime import datetime
from reportlab.lib.pagesizes import A4
from reportlab.pdfgen import canvas

app = Flask(__name__)
app.secret_key = os.getenv("FLASK_SECRET_KEY", "fallback_secret_key")

# Set up logging
app.logger.setLevel(logging.DEBUG)

# Base directory (works when run from project root or Docker /app)
BASE_DIR = os.path.dirname(os.path.abspath(__file__))
TEMP_DIR = os.path.join(BASE_DIR, 'temp')
model_path = os.path.join(BASE_DIR, 'breast_cancer_detector.pickle')

# Load trained cancer detection model
cancer_detection_model = None
try:
    if os.path.isfile(model_path):
        with open(model_path, 'rb') as model_file:
            cancer_detection_model = pickle.load(model_file)
            app.logger.info(f"Model loaded successfully from {model_path}")
    else:
        app.logger.warning(f"Model file not found at {model_path}. Run: python train_model.py")
except Exception as e:
    app.logger.error(f"Error loading model: {e}")
    raise

# Ensure the temp directory exists for saving uploaded images and PDFs
if not os.path.exists(TEMP_DIR):
    os.makedirs(TEMP_DIR)

@app.route('/')
def home():
    return redirect(url_for('upload'))

# Upload page
@app.route('/upload')
def upload():
    app.logger.debug('Upload page accessed')
    return render_template('upload.html')

# Handle image upload and cancer detection
@app.route('/detect-cancer', methods=['POST'])
def detect_cancer():
    app.logger.debug('Detect Cancer page accessed')
    if request.method == 'POST':
        user_name = request.form.get('name', '').strip()
        session['user_name'] = user_name
        session['upload_date'] = datetime.now().strftime('%Y-%m-%d %H:%M:%S')

        # Get the uploaded image
        file = request.files.get('image')
        if file and allowed_file(file.filename):
            filename = secure_filename(file.filename)
            filepath = os.path.join(TEMP_DIR, filename)
            file.save(filepath)
            session['image_path'] = filepath

            if cancer_detection_model is None:
                return render_template('error.html', error_message="Model not loaded. Run train_model.py to create the model.")

            try:
                preprocessed_image = preprocess_image(filepath)
                prediction = cancer_detection_model.predict(preprocessed_image)
                result_message = 'Cancer Detected' if prediction[0] == 1 else 'No Cancer Detected'
                session['detection_result'] = result_message

                # Generate PDF report
                pdf_path = generate_pdf_report(user_name, session['upload_date'], filepath, result_message)
                session['pdf_path'] = pdf_path

                return redirect(url_for('show_result', result=result_message))

            except Exception as e:
                app.logger.error(f"Error during prediction: {e}")
                return render_template('error.html', error_message="Error processing the image. Try again.")
        else:
            app.logger.warning('Invalid file type')
            return render_template('error.html', error_message="Invalid file type. Upload a valid image.")

    return redirect(url_for('upload'))

# Display the result and provide PDF download link
@app.route('/result')
def show_result():
    result = request.args.get('result', 'No result available')
    user_name = session.get('user_name', 'User')
    pdf_path = session.get('pdf_path')

    return render_template('result.html', result=result, user_name=user_name, pdf_path=pdf_path)

# Download the PDF report
@app.route('/download-report')
def download_report():
    pdf_path = session.get('pdf_path')
    if pdf_path and os.path.exists(pdf_path):
        session.clear()  # Clear session after download
        return send_file(pdf_path, as_attachment=True)
    else:
        return "Report not found."

# Preprocess the uploaded image
def preprocess_image(image_path):
    try:
        image = cv2.imread(image_path, cv2.IMREAD_GRAYSCALE)
        if image is None:
            raise ValueError("Could not read image file; file may be corrupt or not a valid image.")
        resized_image = cv2.resize(image, (5, 6))
        flattened_image = resized_image.flatten()
        reshaped_image = flattened_image.reshape(1, -1)
        return reshaped_image
    except Exception as e:
        app.logger.error(f"Error in preprocessing image: {e}")
        raise

# Generate PDF report
def generate_pdf_report(user_name, upload_date, image_path, result):
    safe_name = "".join(c if c.isalnum() or c in "._- " else "_" for c in (user_name or "User"))
    pdf_name = f'report_{safe_name}_{datetime.now().strftime("%Y%m%d_%H%M%S")}.pdf'
    pdf_path = os.path.join(TEMP_DIR, pdf_name)
    c = canvas.Canvas(pdf_path, pagesize=A4)
    width, height = A4

    # Add content to PDF
    c.drawString(50, height - 50, "Cancer Detection Report")
    c.drawString(50, height - 100, f"User Name: {user_name}")
    c.drawString(50, height - 120, f"Upload Date: {upload_date}")
    c.drawString(50, height - 140, f"Detection Result: {result}")
    c.drawString(50, height - 160, "Image Processing Details:")
    c.drawString(70, height - 180, "- Resized to 5x6 pixels")
    c.drawString(70, height - 200, "- Converted to grayscale")

    # Add recommendations if cancer is detected
    if result == "Cancer Detected":
        c.drawString(50, height - 240, "Recommendations:")
        c.drawString(70, height - 260, "- Consult a healthcare provider.")
        c.drawString(70, height - 280, "- Schedule additional diagnostic tests.")

    c.showPage()
    c.save()
    return pdf_path

# Check if the uploaded file is an allowed image
ALLOWED_EXTENSIONS = {'png', 'jpg', 'jpeg'}

def allowed_file(filename):
    return '.' in filename and filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS

# Custom Error Pages
@app.errorhandler(404)
def page_not_found(error):
    return render_template('error.html', error_message="Page not found. Check the URL."), 404

@app.errorhandler(500)
def internal_server_error(error):
    return render_template('error.html', error_message="Unexpected error. Try again."), 500