from flask import Flask, render_template, request, redirect, url_for, jsonify, session
import sqlite3
import string
import random
import os
import sys
import argparse
from datetime import datetime, timedelta
import uuid

app = Flask(__name__)
app.secret_key = 'tu_clave_secreta_aqui'  # Cambiar en producción

# Configuración de la base de datos
DATABASE = 'url_shortener.db'

def init_db():
    """Inicializar la base de datos"""
    conn = sqlite3.connect(DATABASE)
    cursor = conn.cursor()
    
    # Tabla para enlaces acortados
    cursor.execute('''
        CREATE TABLE IF NOT EXISTS urls (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            original_url TEXT NOT NULL,
            short_code TEXT UNIQUE NOT NULL,
            user_session TEXT,
            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
            expires_at TIMESTAMP,
            clicks INTEGER DEFAULT 0
        )
    ''')
    
    # Agregar columna expires_at si no existe (para bases de datos existentes)
    try:
        cursor.execute('ALTER TABLE urls ADD COLUMN expires_at TIMESTAMP')
        conn.commit()
    except sqlite3.OperationalError:
        # La columna ya existe
        pass
    
    conn.commit()
    conn.close()

def generate_short_code(length=6):
    """Generar código corto aleatorio"""
    characters = string.ascii_letters + string.digits
    return ''.join(random.choice(characters) for _ in range(length))

def get_user_session():
    """Obtener o crear sesión de usuario anónimo"""
    if 'user_id' not in session:
        session['user_id'] = str(uuid.uuid4())
    return session['user_id']

@app.route('/')
def index():
    """Página principal"""
    return render_template('index.html')

@app.route('/my-links')
def my_links():
    """Página de enlaces del usuario"""
    user_session = get_user_session()
    
    # Obtener enlaces del usuario
    conn = sqlite3.connect(DATABASE)
    cursor = conn.cursor()
    cursor.execute('''
        SELECT original_url, short_code, created_at, clicks, expires_at 
        FROM urls 
        WHERE user_session = ? 
        ORDER BY created_at DESC
    ''', (user_session,))
    
    user_urls = cursor.fetchall()
    conn.close()
    
    return render_template('my_links.html', user_urls=user_urls)

def calculate_expiration(duration):
    """Calcular fecha de expiración basada en duración"""
    if duration == 'never':
        return None
    elif duration == '1hour':
        return datetime.now() + timedelta(hours=1)
    elif duration == '1day':
        return datetime.now() + timedelta(days=1)
    elif duration == '1week':
        return datetime.now() + timedelta(weeks=1)
    elif duration == '1month':
        return datetime.now() + timedelta(days=30)
    elif duration == '1year':
        return datetime.now() + timedelta(days=365)
    else:
        return None

def is_url_expired(expires_at):
    """Verificar si un URL ha expirado"""
    if expires_at is None:
        return False
    return datetime.now() > datetime.fromisoformat(expires_at)

@app.route('/shorten', methods=['POST'])
def shorten_url():
    """Acortar URL"""
    # Obtener datos tanto de formulario como de JSON
    if request.is_json:
        original_url = request.json.get('url')
        duration = request.json.get('duration', 'never')
    else:
        original_url = request.form.get('url')
        duration = request.form.get('duration', 'never')
    
    if not original_url:
        return jsonify({'error': 'URL es requerida'}), 400
    
    # Agregar http:// si no tiene protocolo
    if not original_url.startswith(('http://', 'https://')):
        original_url = 'http://' + original_url
    
    user_session = get_user_session()
    expires_at = calculate_expiration(duration)
    
    # Generar código corto único
    while True:
        short_code = generate_short_code()
        conn = sqlite3.connect(DATABASE)
        cursor = conn.cursor()
        cursor.execute('SELECT id FROM urls WHERE short_code = ?', (short_code,))
        if not cursor.fetchone():
            break
        conn.close()
    
    # Guardar en base de datos
    cursor.execute('''
        INSERT INTO urls (original_url, short_code, user_session, expires_at)
        VALUES (?, ?, ?, ?)
    ''', (original_url, short_code, user_session, expires_at))
    
    conn.commit()
    conn.close()
    
    short_url = f"https://please.checkthis.space/s/{short_code}"
    
    return jsonify({
        'success': True,
        'short_url': short_url,
        'short_code': short_code,
        'original_url': original_url,
        'expires_at': expires_at.isoformat() if expires_at else None
    })

@app.route('/s/<short_code>')
def redirect_url(short_code):
    """Redirigir a URL original"""
    conn = sqlite3.connect(DATABASE)
    cursor = conn.cursor()
    
    # Buscar URL original y verificar expiración
    cursor.execute('''
        SELECT original_url, expires_at FROM urls WHERE short_code = ?
    ''', (short_code,))
    
    result = cursor.fetchone()
    
    if result:
        original_url, expires_at = result
        
        # Verificar si el enlace ha expirado
        if expires_at and is_url_expired(expires_at):
            conn.close()
            return render_template('404.html', error_message='Este enlace ha expirado'), 404
        
        # Incrementar contador de clicks
        cursor.execute('''
            UPDATE urls SET clicks = clicks + 1 WHERE short_code = ?
        ''', (short_code,))
        
        conn.commit()
        conn.close()
        
        return redirect(original_url)
    else:
        conn.close()
        return render_template('404.html'), 404

@app.route('/delete/<short_code>', methods=['POST'])
def delete_url(short_code):
    """Eliminar URL acortada"""
    user_session = get_user_session()
    
    conn = sqlite3.connect(DATABASE)
    cursor = conn.cursor()
    
    # Verificar que el enlace pertenece al usuario
    cursor.execute('''
        DELETE FROM urls 
        WHERE short_code = ? AND user_session = ?
    ''', (short_code, user_session))
    
    conn.commit()
    affected_rows = cursor.rowcount
    conn.close()
    
    if affected_rows > 0:
        return jsonify({'success': True})
    else:
        return jsonify({'error': 'Enlace no encontrado o no autorizado'}), 404

@app.route('/stats')
def stats():
    """Estadísticas generales"""
    conn = sqlite3.connect(DATABASE)
    cursor = conn.cursor()
    
    # Estadísticas generales
    cursor.execute('SELECT COUNT(*) FROM urls')
    total_urls = cursor.fetchone()[0]
    
    cursor.execute('SELECT SUM(clicks) FROM urls')
    total_clicks = cursor.fetchone()[0] or 0
    
    # URLs más populares
    cursor.execute('''
        SELECT original_url, short_code, clicks, created_at 
        FROM urls 
        ORDER BY clicks DESC 
        LIMIT 10
    ''')
    popular_urls = cursor.fetchall()
    
    conn.close()
    
    return render_template('stats.html', 
                         total_urls=total_urls, 
                         total_clicks=total_clicks,
                         popular_urls=popular_urls)

if __name__ == '__main__':
    init_db()
    
    # Configurar argumentos de línea de comandos
    parser = argparse.ArgumentParser(description='Acortador de URLs')
    parser.add_argument('--port', '-p', type=int, default=5000, 
                       help='Puerto en el que ejecutar la aplicación (por defecto: 5000)')
    
    args = parser.parse_args()
    
    print(f"Ejecutando en puerto {args.port}")
    app.run(debug=True, host='0.0.0.0', port=args.port)