import os
import uuid
import yaml
import re
from datetime import datetime
from pathlib import Path
from flask import Flask, render_template, request, redirect, url_for, flash, session
from flask_mail import Mail, Message
from werkzeug.utils import secure_filename
from config import Config

app = Flask(__name__)
app.config.from_object(Config)
mail = Mail(app)

# Ensure applications folder exists
Path(app.config['APPLICATIONS_FOLDER']).mkdir(exist_ok=True)


def get_application_path(session_id):
    """Get the path to an application folder"""
    return os.path.join(app.config['APPLICATIONS_FOLDER'], session_id)


def get_data_file_path(session_id):
    """Get the path to the application data YAML file"""
    return os.path.join(get_application_path(session_id), 'data.yaml')


def get_attachments_path(session_id):
    """Get the path to the attachments folder"""
    return os.path.join(get_application_path(session_id), 'attachments')


def load_application_data(session_id):
    """Load application data from YAML file"""
    data_file = get_data_file_path(session_id)
    if os.path.exists(data_file):
        with open(data_file, 'r', encoding='utf-8') as f:
            return yaml.safe_load(f)
    return None


def save_application_data(session_id, data):
    """Save application data to YAML file"""
    app_path = get_application_path(session_id)
    Path(app_path).mkdir(parents=True, exist_ok=True)

    data_file = get_data_file_path(session_id)
    with open(data_file, 'w', encoding='utf-8') as f:
        yaml.dump(data, f, allow_unicode=True, default_flow_style=False)


def send_resume_email(email, session_id, job_name):
    """Send email with resume link"""
    resume_link = url_for('resume_application', session_id=session_id, _external=True)

    subject = f"Ihre Bewerbung bei {app.config['COMPANY_NAME']} - Link zum Fortsetzen"
    body = f"""Guten Tag,

vielen Dank für Ihr Interesse an der Position "{job_name}" bei {app.config['COMPANY_NAME']}.

Sie können Ihre Bewerbung jederzeit über den folgenden Link fortsetzen:
{resume_link}

Dieser Link bleibt gültig und Sie können Ihre Bewerbung jederzeit bearbeiten.

Mit freundlichen Grüßen
{app.config['COMPANY_NAME']}
"""

    try:
        msg = Message(subject=subject, recipients=[email], body=body)
        mail.send(msg)
        return True
    except Exception as e:
        app.logger.error(f"Failed to send email: {e}")
        return False


def validate_email(email):
    """Validate email format"""
    pattern = r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$'
    return re.match(pattern, email) is not None


def validate_phone(phone):
    """Validate international phone format"""
    # Accepts formats like: +41 79 123 45 67, +41791234567, etc.
    # Remove spaces and check if it matches the pattern
    pattern = r'^\+\d{1,3}[\s\d]{1,20}$'
    if not re.match(pattern, phone):
        return False
    # Ensure there are at least some digits after the country code
    digits_only = re.sub(r'\s', '', phone)
    return len(digits_only) >= 5  # At least +XX XXX format


def validate_year(year):
    """Validate birth year"""
    try:
        year_int = int(year)
        return (app.config['MIN_BIRTH_YEAR'] <= year_int <= app.config['MAX_BIRTH_YEAR']
                and len(str(year)) == 4)
    except ValueError:
        return False


def validate_zip(zip_code):
    """Validate ZIP code"""
    try:
        zip_int = int(zip_code)
        return len(str(zip_code)) <= app.config['MAX_ZIP_DIGITS']
    except ValueError:
        return False


def allowed_file(filename):
    """Check if file extension is allowed"""
    return '.' in filename and \
           filename.rsplit('.', 1)[1].lower() in app.config['ALLOWED_EXTENSIONS']


@app.route('/')
def index():
    """Redirect to apply page"""
    return redirect(url_for('page1_email'))


@app.route('/apply')
def page1_email():
    """Page 1: Email capture and session initialization"""
    job_name = request.args.get('job', 'Offene Position')
    return render_template('page1_email.html', job_name=job_name)


@app.route('/apply/submit-email', methods=['POST'])
def submit_email():
    """Process email submission and create session"""
    email = request.form.get('email', '').strip()
    job_name = request.form.get('job_name', 'Offene Position')

    # Validate email
    if not validate_email(email):
        flash('Bitte geben Sie eine gültige E-Mail-Adresse ein.', 'error')
        return redirect(url_for('page1_email', job=job_name))

    # Generate session ID
    session_id = str(uuid.uuid4())

    # Create application data
    app_data = {
        'session_id': session_id,
        'email': email,
        'job_name': job_name,
        'current_page': 2,
        'created_at': datetime.now().isoformat(),
        'updated_at': datetime.now().isoformat(),
        'personal_info': {},
        'motivation_answers': {},
        'uploaded_files': []
    }

    # Save application data
    save_application_data(session_id, app_data)

    # Send resume email
    if send_resume_email(email, session_id, job_name):
        flash('Eine E-Mail mit einem Link zum Fortsetzen wurde an Ihre Adresse gesendet.', 'success')
    else:
        flash('Warnung: Die E-Mail konnte nicht gesendet werden. Bitte notieren Sie sich diese URL.', 'warning')

    # Store session ID in Flask session
    session['application_id'] = session_id

    return redirect(url_for('page2_personal', session_id=session_id))


@app.route('/apply/<session_id>/personal')
def page2_personal(session_id):
    """Page 2: Basic personal information"""
    app_data = load_application_data(session_id)
    if not app_data:
        flash('Bewerbung nicht gefunden.', 'error')
        return redirect(url_for('page1_email'))

    return render_template('page2_personal.html',
                         session_id=session_id,
                         job_name=app_data['job_name'],
                         data=app_data.get('personal_info', {}))


@app.route('/apply/<session_id>/submit-personal', methods=['POST'])
def submit_personal(session_id):
    """Process personal information submission"""
    app_data = load_application_data(session_id)
    if not app_data:
        flash('Bewerbung nicht gefunden.', 'error')
        return redirect(url_for('page1_email'))

    # Get form data
    name = request.form.get('name', '').strip()
    firstname = request.form.get('firstname', '').strip()
    address = request.form.get('address', '').strip()
    zip_code = request.form.get('zip_code', '').strip()
    city = request.form.get('city', '').strip()
    phone = request.form.get('phone', '').strip()
    birth_year = request.form.get('birth_year', '').strip()
    civil_status = request.form.get('civil_status', '').strip()

    # Validate required fields
    errors = []

    if not name or len(name) > app.config['MAX_STRING_LENGTH']:
        errors.append('Name ist erforderlich und darf maximal 255 Zeichen lang sein.')

    if not firstname or len(firstname) > app.config['MAX_STRING_LENGTH']:
        errors.append('Vorname ist erforderlich und darf maximal 255 Zeichen lang sein.')

    if not address or len(address) > app.config['MAX_STRING_LENGTH']:
        errors.append('Adresse ist erforderlich und darf maximal 255 Zeichen lang sein.')

    if not zip_code or not validate_zip(zip_code):
        errors.append('PLZ ist erforderlich und darf maximal 10 Ziffern lang sein.')

    if not city or len(city) > app.config['MAX_STRING_LENGTH']:
        errors.append('Stadt ist erforderlich und darf maximal 255 Zeichen lang sein.')

    if not phone or not validate_phone(phone):
        errors.append('Telefonnummer ist erforderlich und muss im internationalen Format sein (z.B. +41 79 123 45 67).')

    if not birth_year or not validate_year(birth_year):
        errors.append(f'Geburtsjahr ist erforderlich und muss zwischen {app.config["MIN_BIRTH_YEAR"]} und {app.config["MAX_BIRTH_YEAR"]} liegen.')

    if civil_status and len(civil_status) > app.config['MAX_STRING_LENGTH']:
        errors.append('Zivilstand darf maximal 255 Zeichen lang sein.')

    if errors:
        for error in errors:
            flash(error, 'error')
        return redirect(url_for('page2_personal', session_id=session_id))

    # Save personal information
    app_data['personal_info'] = {
        'name': name,
        'firstname': firstname,
        'address': address,
        'zip_code': zip_code,
        'city': city,
        'phone': phone,
        'birth_year': birth_year,
        'civil_status': civil_status
    }
    app_data['current_page'] = 3
    app_data['updated_at'] = datetime.now().isoformat()

    save_application_data(session_id, app_data)

    return redirect(url_for('page3_motivation', session_id=session_id))


@app.route('/apply/<session_id>/motivation')
def page3_motivation(session_id):
    """Page 3: Motivation and qualification questions"""
    app_data = load_application_data(session_id)
    if not app_data:
        flash('Bewerbung nicht gefunden.', 'error')
        return redirect(url_for('page1_email'))

    return render_template('page3_motivation.html',
                         session_id=session_id,
                         job_name=app_data['job_name'],
                         data=app_data.get('motivation_answers', {}))


@app.route('/apply/<session_id>/submit-motivation', methods=['POST'])
def submit_motivation(session_id):
    """Process motivation questions submission"""
    app_data = load_application_data(session_id)
    if not app_data:
        flash('Bewerbung nicht gefunden.', 'error')
        return redirect(url_for('page1_email'))

    # Get form data
    current_job = request.form.get('current_job', '').strip()
    motivation = request.form.get('motivation', '').strip()
    qualifications = request.form.get('qualifications', '').strip()
    salary = request.form.get('salary', '').strip()

    # Validate length
    errors = []

    if current_job and len(current_job) > app.config['MAX_TEXT_AREA_LENGTH']:
        errors.append(f'Die Beschreibung Ihrer beruflichen Situation darf maximal {app.config["MAX_TEXT_AREA_LENGTH"]} Zeichen lang sein.')

    if motivation and len(motivation) > app.config['MAX_TEXT_AREA_LENGTH']:
        errors.append(f'Die Motivationsbeschreibung darf maximal {app.config["MAX_TEXT_AREA_LENGTH"]} Zeichen lang sein.')

    if qualifications and len(qualifications) > app.config['MAX_TEXT_AREA_LENGTH']:
        errors.append(f'Die Qualifikationsbeschreibung darf maximal {app.config["MAX_TEXT_AREA_LENGTH"]} Zeichen lang sein.')

    if salary and len(salary) > app.config['MAX_TEXT_AREA_LENGTH']:
        errors.append(f'Die Gehaltsvorstellungen dürfen maximal {app.config["MAX_TEXT_AREA_LENGTH"]} Zeichen lang sein.')

    if errors:
        for error in errors:
            flash(error, 'error')
        return redirect(url_for('page3_motivation', session_id=session_id))

    # Save motivation answers
    app_data['motivation_answers'] = {
        'current_job': current_job,
        'motivation': motivation,
        'qualifications': qualifications,
        'salary': salary
    }
    app_data['current_page'] = 4
    app_data['updated_at'] = datetime.now().isoformat()

    save_application_data(session_id, app_data)

    return redirect(url_for('page4_upload', session_id=session_id))


@app.route('/apply/<session_id>/upload')
def page4_upload(session_id):
    """Page 4: Document upload"""
    app_data = load_application_data(session_id)
    if not app_data:
        flash('Bewerbung nicht gefunden.', 'error')
        return redirect(url_for('page1_email'))

    return render_template('page4_upload.html',
                         session_id=session_id,
                         job_name=app_data['job_name'],
                         uploaded_files=app_data.get('uploaded_files', []),
                         max_files=app.config['MAX_FILES'])


@app.route('/apply/<session_id>/upload-file', methods=['POST'])
def upload_file(session_id):
    """Handle file upload"""
    app_data = load_application_data(session_id)
    if not app_data:
        flash('Bewerbung nicht gefunden.', 'error')
        return redirect(url_for('page1_email'))

    # Check file count
    if len(app_data.get('uploaded_files', [])) >= app.config['MAX_FILES']:
        flash(f'Sie können maximal {app.config["MAX_FILES"]} Dokumente hochladen.', 'error')
        return redirect(url_for('page4_upload', session_id=session_id))

    # Check if file was uploaded
    if 'file' not in request.files:
        flash('Keine Datei ausgewählt.', 'error')
        return redirect(url_for('page4_upload', session_id=session_id))

    file = request.files['file']

    if file.filename == '':
        flash('Keine Datei ausgewählt.', 'error')
        return redirect(url_for('page4_upload', session_id=session_id))

    # Validate file
    if not allowed_file(file.filename):
        flash('Ungültiger Dateityp. Erlaubte Formate: PDF, DOC, DOCX, TXT, JPG, JPEG, PNG', 'error')
        return redirect(url_for('page4_upload', session_id=session_id))

    # Check file size
    file.seek(0, os.SEEK_END)
    file_size = file.tell()
    file.seek(0)

    if file_size > app.config['MAX_FILE_SIZE']:
        flash(f'Die Datei ist zu groß. Maximale Größe: 4 MB', 'error')
        return redirect(url_for('page4_upload', session_id=session_id))

    # Save file
    filename = secure_filename(file.filename)
    timestamp = datetime.now().strftime('%Y%m%d_%H%M%S')
    unique_filename = f"{timestamp}_{filename}"

    attachments_path = get_attachments_path(session_id)
    Path(attachments_path).mkdir(parents=True, exist_ok=True)

    file_path = os.path.join(attachments_path, unique_filename)
    file.save(file_path)

    # Update application data
    if 'uploaded_files' not in app_data:
        app_data['uploaded_files'] = []

    app_data['uploaded_files'].append({
        'original_name': filename,
        'stored_name': unique_filename,
        'uploaded_at': datetime.now().isoformat(),
        'size': file_size
    })
    app_data['updated_at'] = datetime.now().isoformat()

    save_application_data(session_id, app_data)

    flash('Datei erfolgreich hochgeladen.', 'success')
    return redirect(url_for('page4_upload', session_id=session_id))


@app.route('/apply/<session_id>/remove-file/<int:file_index>', methods=['POST'])
def remove_file(session_id, file_index):
    """Remove an uploaded file"""
    app_data = load_application_data(session_id)
    if not app_data:
        flash('Bewerbung nicht gefunden.', 'error')
        return redirect(url_for('page1_email'))

    uploaded_files = app_data.get('uploaded_files', [])

    if 0 <= file_index < len(uploaded_files):
        file_info = uploaded_files[file_index]

        # Delete physical file
        file_path = os.path.join(get_attachments_path(session_id), file_info['stored_name'])
        if os.path.exists(file_path):
            os.remove(file_path)

        # Remove from data
        uploaded_files.pop(file_index)
        app_data['updated_at'] = datetime.now().isoformat()
        save_application_data(session_id, app_data)

        flash('Datei erfolgreich entfernt.', 'success')
    else:
        flash('Datei nicht gefunden.', 'error')

    return redirect(url_for('page4_upload', session_id=session_id))


@app.route('/apply/<session_id>/submit-application', methods=['POST'])
def submit_application(session_id):
    """Submit final application"""
    app_data = load_application_data(session_id)
    if not app_data:
        flash('Bewerbung nicht gefunden.', 'error')
        return redirect(url_for('page1_email'))

    # Mark as submitted
    app_data['current_page'] = 5
    app_data['submitted_at'] = datetime.now().isoformat()
    app_data['updated_at'] = datetime.now().isoformat()
    app_data['status'] = 'submitted'

    save_application_data(session_id, app_data)

    return redirect(url_for('page5_confirmation', session_id=session_id))


@app.route('/apply/<session_id>/confirmation')
def page5_confirmation(session_id):
    """Page 5: Confirmation page"""
    app_data = load_application_data(session_id)
    if not app_data:
        flash('Bewerbung nicht gefunden.', 'error')
        return redirect(url_for('page1_email'))

    return render_template('page5_confirmation.html',
                         session_id=session_id,
                         job_name=app_data['job_name'],
                         email=app_data['email'])


@app.route('/resume/<session_id>')
def resume_application(session_id):
    """Resume application from email link"""
    app_data = load_application_data(session_id)
    if not app_data:
        flash('Bewerbung nicht gefunden.', 'error')
        return redirect(url_for('page1_email'))

    # Store session ID in Flask session
    session['application_id'] = session_id

    # Redirect to current page
    current_page = app_data.get('current_page', 2)

    if current_page == 2:
        return redirect(url_for('page2_personal', session_id=session_id))
    elif current_page == 3:
        return redirect(url_for('page3_motivation', session_id=session_id))
    elif current_page == 4:
        return redirect(url_for('page4_upload', session_id=session_id))
    elif current_page == 5:
        return redirect(url_for('page5_confirmation', session_id=session_id))
    else:
        return redirect(url_for('page2_personal', session_id=session_id))


if __name__ == '__main__':
    app.run(debug=True)