import os
import uuid
from flask import Flask, render_template, request, jsonify, send_file, redirect, url_for, flash
from werkzeug.utils import secure_filename
from PIL import Image
import PyPDF2
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import letter, A4
from reportlab.lib.utils import ImageReader
import io
import zipfile
import pdf2image
import tempfile
import shutil
from datetime import datetime

app = Flask(__name__)
app.secret_key = 'your-secret-key-change-this'

# Konfiguration
UPLOAD_FOLDER = 'uploads'
OUTPUT_FOLDER = 'output'
ALLOWED_IMAGE_EXTENSIONS = {'png', 'jpg', 'jpeg', 'gif', 'bmp', 'tiff'}
ALLOWED_PDF_EXTENSIONS = {'pdf'}
MAX_FILE_SIZE = 16 * 1024 * 1024  # 16MB

app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
app.config['OUTPUT_FOLDER'] = OUTPUT_FOLDER
app.config['MAX_CONTENT_LENGTH'] = MAX_FILE_SIZE

def allowed_file(filename, extensions):
    """Überprüft ob die Datei erlaubt ist"""
    return '.' in filename and \
           filename.rsplit('.', 1)[1].lower() in extensions

def create_unique_filename(filename):
    """Erstellt einen eindeutigen Dateinamen"""
    name, ext = os.path.splitext(filename)
    unique_id = str(uuid.uuid4())[:8]
    return f"{name}_{unique_id}{ext}"

def cleanup_old_files():
    """Löscht alte Dateien aus Upload und Output Ordnern"""
    current_time = datetime.now()
    
    for folder in [UPLOAD_FOLDER, OUTPUT_FOLDER]:
        if os.path.exists(folder):
            for filename in os.listdir(folder):
                file_path = os.path.join(folder, filename)
                if os.path.isfile(file_path):
                    file_time = datetime.fromtimestamp(os.path.getctime(file_path))
                    # Lösche Dateien die älter als 1 Stunde sind
                    if (current_time - file_time).seconds > 3600:
                        os.remove(file_path)

@app.route('/')
def index():
    """Hauptseite mit Navigation"""
    cleanup_old_files()
    return render_template('index.html')

@app.route('/images-to-pdf')
def images_to_pdf_page():
    """Seite für Bilder zu PDF Konvertierung"""
    return render_template('images_to_pdf.html')

@app.route('/pdf-tools')
def pdf_tools_page():
    """Seite für PDF Tools"""
    return render_template('pdf_tools.html')

@app.route('/api/upload-images', methods=['POST'])
def upload_images():
    """API Endpunkt für Bilder Upload"""
    try:
        if 'files' not in request.files:
            return jsonify({'error': 'Keine Dateien ausgewählt'}), 400
        
        files = request.files.getlist('files')
        
        if not files or files[0].filename == '':
            return jsonify({'error': 'Keine Dateien ausgewählt'}), 400
        
        uploaded_files = []
        
        for file in files:
            if file and allowed_file(file.filename, ALLOWED_IMAGE_EXTENSIONS):
                filename = secure_filename(file.filename)
                unique_filename = create_unique_filename(filename)
                file_path = os.path.join(UPLOAD_FOLDER, unique_filename)
                file.save(file_path)
                uploaded_files.append({
                    'filename': unique_filename,
                    'original_name': filename,
                    'size': os.path.getsize(file_path)
                })
        
        if not uploaded_files:
            return jsonify({'error': 'Keine gültigen Bilddateien gefunden'}), 400
        
        return jsonify({
            'success': True,
            'files': uploaded_files,
            'message': f'{len(uploaded_files)} Dateien erfolgreich hochgeladen'
        })
    
    except Exception as e:
        return jsonify({'error': f'Fehler beim Upload: {str(e)}'}), 500

@app.route('/api/convert-images-to-pdf', methods=['POST'])
def convert_images_to_pdf():
    """Konvertiert hochgeladene Bilder zu PDF"""
    try:
        data = request.get_json()
        files_data = data.get('files', [])
        
        if not files_data:
            return jsonify({'error': 'Keine Dateien ausgewählt'}), 400
        
        # PDF erstellen
        output_filename = f"converted_images_{str(uuid.uuid4())[:8]}.pdf"
        output_path = os.path.join(OUTPUT_FOLDER, output_filename)
        
        # Reportlab für PDF Erstellung
        c = canvas.Canvas(output_path, pagesize=A4)
        page_width, page_height = A4
        
        for file_data in files_data:
            filename = file_data.get('filename')
            rotation = file_data.get('rotation', 0)
            
            file_path = os.path.join(UPLOAD_FOLDER, filename)
            
            if os.path.exists(file_path):
                # Bild öffnen und rotieren
                with Image.open(file_path) as img:
                    # Bild rotieren falls nötig
                    if rotation != 0:
                        img = img.rotate(-rotation, expand=True)  # Negative Rotation für korrekte Richtung
                    
                    img_width, img_height = img.size
                    
                    # Seitenverhältnis berechnen
                    aspect_ratio = img_width / img_height
                    
                    # Maximale Größe auf der Seite (mit Rändern)
                    max_width = page_width - 40
                    max_height = page_height - 40
                    
                    if aspect_ratio > 1:  # Querformat
                        new_width = min(max_width, img_width)
                        new_height = new_width / aspect_ratio
                    else:  # Hochformat
                        new_height = min(max_height, img_height)
                        new_width = new_height * aspect_ratio
                    
                    # Zentrieren
                    x = (page_width - new_width) / 2
                    y = (page_height - new_height) / 2
                    
                    # Temporäres rotiertes Bild speichern
                    if rotation != 0:
                        temp_path = os.path.join(UPLOAD_FOLDER, f"temp_rotated_{filename}")
                        img.save(temp_path)
                        c.drawImage(temp_path, x, y, width=new_width, height=new_height)
                        # Temporäre Datei löschen
                        os.remove(temp_path)
                    else:
                        c.drawImage(file_path, x, y, width=new_width, height=new_height)
                    
                    c.showPage()
        
        c.save()
        
        return jsonify({
            'success': True,
            'filename': output_filename,
            'message': 'PDF erfolgreich erstellt'
        })
    
    except Exception as e:
        return jsonify({'error': f'Fehler bei der Konvertierung: {str(e)}'}), 500

@app.route('/api/upload-pdf', methods=['POST'])
def upload_pdf():
    """API Endpunkt für PDF Upload"""
    try:
        if 'file' not in request.files:
            return jsonify({'error': 'Keine Datei ausgewählt'}), 400
        
        file = request.files['file']
        
        if file.filename == '':
            return jsonify({'error': 'Keine Datei ausgewählt'}), 400
        
        if file and allowed_file(file.filename, ALLOWED_PDF_EXTENSIONS):
            filename = secure_filename(file.filename)
            unique_filename = create_unique_filename(filename)
            file_path = os.path.join(UPLOAD_FOLDER, unique_filename)
            file.save(file_path)
            
            # PDF Info lesen
            with open(file_path, 'rb') as pdf_file:
                pdf_reader = PyPDF2.PdfReader(pdf_file)
                page_count = len(pdf_reader.pages)
            
            # PDF Vorschau erstellen
            preview_filename = create_pdf_preview(unique_filename)
            
            return jsonify({
                'success': True,
                'filename': unique_filename,
                'original_name': filename,
                'page_count': page_count,
                'size': os.path.getsize(file_path),
                'preview': preview_filename,
                'rotation': 0  # Standardrotation
            })
        
        return jsonify({'error': 'Nur PDF-Dateien sind erlaubt'}), 400
    
    except Exception as e:
        return jsonify({'error': f'Fehler beim Upload: {str(e)}'}), 500

def create_pdf_preview(pdf_filename):
    """Erstellt eine Vorschau der ersten PDF-Seite"""
    try:
        pdf_path = os.path.join(UPLOAD_FOLDER, pdf_filename)
        
        # PDF zu Bild konvertieren (nur erste Seite)
        images = pdf2image.convert_from_path(pdf_path, first_page=1, last_page=1, dpi=150)
        
        if images:
            # Vorschau-Dateiname generieren
            preview_filename = f"preview_{pdf_filename.rsplit('.', 1)[0]}.png"
            preview_path = os.path.join(UPLOAD_FOLDER, preview_filename)
            
            # Bild speichern
            images[0].save(preview_path, 'PNG')
            return preview_filename
        
        return None
    
    except Exception as e:
        print(f"Fehler beim Erstellen der PDF-Vorschau: {str(e)}")
        return None

@app.route('/api/pdf-to-images', methods=['POST'])
def pdf_to_images():
    """Konvertiert PDF zu Bildern"""
    try:
        data = request.get_json()
        filename = data.get('filename')
        
        if not filename:
            return jsonify({'error': 'Keine Datei angegeben'}), 400
        
        file_path = os.path.join(UPLOAD_FOLDER, filename)
        
        if not os.path.exists(file_path):
            return jsonify({'error': 'Datei nicht gefunden'}), 404
        
        # PDF zu Bildern konvertieren
        images = pdf2image.convert_from_path(file_path, dpi=200)
        
        # ZIP-Datei erstellen
        zip_filename = f"pdf_images_{str(uuid.uuid4())[:8]}.zip"
        zip_path = os.path.join(OUTPUT_FOLDER, zip_filename)
        
        with zipfile.ZipFile(zip_path, 'w') as zip_file:
            for i, image in enumerate(images):
                img_filename = f"page_{i+1}.png"
                img_buffer = io.BytesIO()
                image.save(img_buffer, format='PNG')
                img_buffer.seek(0)
                zip_file.writestr(img_filename, img_buffer.read())
        
        return jsonify({
            'success': True,
            'filename': zip_filename,
            'page_count': len(images),
            'message': f'{len(images)} Seiten als Bilder exportiert'
        })
    
    except Exception as e:
        return jsonify({'error': f'Fehler bei der Konvertierung: {str(e)}'}), 500

@app.route('/api/merge-pdfs', methods=['POST'])
def merge_pdfs():
    """Fügt mehrere PDFs zusammen"""
    try:
        data = request.get_json()
        files_data = data.get('files', [])
        
        if len(files_data) < 2:
            return jsonify({'error': 'Mindestens 2 PDF-Dateien erforderlich'}), 400
        
        # PDF Merger erstellen
        merger = PyPDF2.PdfMerger()
        
        for file_data in files_data:
            filename = file_data.get('filename')
            rotation = file_data.get('rotation', 0)
            
            file_path = os.path.join(UPLOAD_FOLDER, filename)
            if os.path.exists(file_path):
                if rotation != 0:
                    # PDF mit Rotation erstellen
                    rotated_pdf_path = create_rotated_pdf(file_path, rotation)
                    if rotated_pdf_path:
                        merger.append(rotated_pdf_path)
                        # Temporäre rotierte PDF löschen nach dem Hinzufügen
                        os.remove(rotated_pdf_path)
                    else:
                        merger.append(file_path)  # Fallback ohne Rotation
                else:
                    merger.append(file_path)
        
        # Zusammengeführte PDF speichern
        output_filename = f"merged_pdf_{str(uuid.uuid4())[:8]}.pdf"
        output_path = os.path.join(OUTPUT_FOLDER, output_filename)
        
        with open(output_path, 'wb') as output_file:
            merger.write(output_file)
        
        merger.close()
        
        return jsonify({
            'success': True,
            'filename': output_filename,
            'message': f'{len(files_data)} PDFs erfolgreich zusammengeführt'
        })
    
    except Exception as e:
        return jsonify({'error': f'Fehler beim Zusammenführen: {str(e)}'}), 500

def create_rotated_pdf(pdf_path, rotation):
    """Erstellt eine rotierte Version der PDF"""
    try:
        # Temporären Dateinamen für rotierte PDF erstellen
        temp_filename = f"temp_rotated_{str(uuid.uuid4())[:8]}.pdf"
        temp_path = os.path.join(UPLOAD_FOLDER, temp_filename)
        
        with open(pdf_path, 'rb') as input_file:
            pdf_reader = PyPDF2.PdfReader(input_file)
            pdf_writer = PyPDF2.PdfWriter()
            
            for page in pdf_reader.pages:
                # Seite rotieren
                rotated_page = page.rotate(rotation)
                pdf_writer.add_page(rotated_page)
            
            with open(temp_path, 'wb') as output_file:
                pdf_writer.write(output_file)
        
        return temp_path
    
    except Exception as e:
        print(f"Fehler beim Rotieren der PDF: {str(e)}")
        return None

@app.route('/uploads/<filename>')
def serve_uploaded_file(filename):
    """Serviert hochgeladene Dateien für die Vorschau"""
    try:
        file_path = os.path.join(UPLOAD_FOLDER, filename)
        
        if not os.path.exists(file_path):
            return "Datei nicht gefunden", 404
        
        return send_file(file_path)
    
    except Exception as e:
        return f"Fehler beim Laden der Datei: {str(e)}", 500

@app.route('/download/<filename>')
def download_file(filename):
    """Download einer generierten Datei"""
    try:
        file_path = os.path.join(OUTPUT_FOLDER, filename)
        
        if not os.path.exists(file_path):
            flash('Datei nicht gefunden', 'error')
            return redirect(url_for('index'))
        
        return send_file(file_path, as_attachment=True)
    
    except Exception as e:
        flash(f'Fehler beim Download: {str(e)}', 'error')
        return redirect(url_for('index'))

if __name__ == '__main__':
    # Ordner erstellen falls sie nicht existieren
    os.makedirs(UPLOAD_FOLDER, exist_ok=True)
    os.makedirs(OUTPUT_FOLDER, exist_ok=True)
    
    app.run(debug=True, host='127.0.0.1', port=5000)