Upload api.py

api.py

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+"""
+TechMind PRO - Backend API
+FastAPI + Rate Limiting + Stripe
+"""
+
+from fastapi import FastAPI, HTTPException, Depends, Header
+from fastapi.middleware.cors import CORSMiddleware
+from pydantic import BaseModel, EmailStr
+import sqlite3
+from datetime import datetime, timedelta
+from typing import Optional
+import os
+import hashlib
+import secrets
+
+# Importar función de inferencia
+from inference_techmind import generar_respuesta_api
+
+# =========================================================
+# CONFIGURACIÓN
+# =========================================================
+app = FastAPI(
+    title="TechMind API",
+    description="API para TechMind PRO",
+    version="1.0.0"
+)
+
+# CORS (permite requests desde tu frontend)
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=[
+        "https://techmind-landing.vercel.app",
+        "http://localhost:3000",
+        "http://localhost:8000"
+    ],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Límites
+FREE_DAILY_LIMIT = 10
+PRO_DAILY_LIMIT = 999999
+
+# =========================================================
+# MODELOS PYDANTIC
+# =========================================================
+class QueryRequest(BaseModel):
+    pregunta: str
+    api_key: Optional[str] = None
+
+class QueryResponse(BaseModel):
+    success: bool
+    respuesta: Optional[str] = None
+    tiempo_generacion: Optional[float] = None
+    requests_restantes: Optional[int] = None
+    error: Optional[str] = None
+
+class SignupRequest(BaseModel):
+    email: EmailStr
+
+class APIKeyResponse(BaseModel):
+    api_key: str
+    plan: str
+    expires_at: str
+
+# =========================================================
+# BASE DE DATOS
+# =========================================================
+def init_db():
+    """Inicializa base de datos SQLite"""
+    conn = sqlite3.connect('techmind.db')
+    c = conn.cursor()
+    
+    # Tabla de API keys
+    c.execute('''
+        CREATE TABLE IF NOT EXISTS api_keys (
+            api_key TEXT PRIMARY KEY,
+            email TEXT NOT NULL,
+            plan TEXT NOT NULL,
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            expires_at TIMESTAMP,
+            is_active BOOLEAN DEFAULT 1,
+            stripe_customer_id TEXT,
+            stripe_subscription_id TEXT
+        )
+    ''')
+    
+    # Tabla de requests diarios
+    c.execute('''
+        CREATE TABLE IF NOT EXISTS daily_requests (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            user_id TEXT NOT NULL,
+            date TEXT NOT NULL,
+            count INTEGER DEFAULT 0,
+            UNIQUE(user_id, date)
+        )
+    ''')
+    
+    conn.commit()
+    conn.close()
+
+init_db()
+
+def get_db():
+    """Obtiene conexión a DB"""
+    conn = sqlite3.connect('techmind.db')
+    conn.row_factory = sqlite3.Row
+    return conn
+
+# =========================================================
+# RATE LIMITING
+# =========================================================
+def check_rate_limit(api_key: Optional[str] = None) -> tuple[bool, int, str]:
+    """
+    Verifica límite de requests
+    
+    Returns:
+        (puede_continuar, requests_restantes, user_id)
+    """
+    
+    conn = get_db()
+    c = conn.cursor()
+    
+    # Identificar usuario
+    if api_key:
+        # Usuario Pro
+        c.execute("SELECT plan FROM api_keys WHERE api_key = ? AND is_active = 1", (api_key,))
+        result = c.fetchone()
+        
+        if not result:
+            conn.close()
+            return False, 0, "invalid"
+        
+        user_id = api_key
+        limit = PRO_DAILY_LIMIT
+    else:
+        # Usuario Free (identificar por IP o session)
+        # En producción usarías request.client.host
+        user_id = "free_user"
+        limit = FREE_DAILY_LIMIT
+    
+    # Contar requests hoy
+    today = datetime.now().strftime("%Y-%m-%d")
+    
+    c.execute("""
+        SELECT count FROM daily_requests 
+        WHERE user_id = ? AND date = ?
+    """, (user_id, today))
+    
+    result = c.fetchone()
+    count = result["count"] if result else 0
+    
+    if count >= limit:
+        conn.close()
+        return False, 0, user_id
+    
+    # Incrementar contador
+    c.execute("""
+        INSERT INTO daily_requests (user_id, date, count) 
+        VALUES (?, ?, 1)
+        ON CONFLICT(user_id, date) 
+        DO UPDATE SET count = count + 1
+    """, (user_id, today))
+    
+    conn.commit()
+    conn.close()
+    
+    requests_restantes = limit - count - 1
+    
+    return True, requests_restantes, user_id
+
+# =========================================================
+# ENDPOINTS
+# =========================================================
+
+@app.get("/")
+async def root():
+    """Health check"""
+    return {
+        "status": "ok",
+        "service": "TechMind API",
+        "version": "1.0.0"
+    }
+
+@app.post("/api/query", response_model=QueryResponse)
+async def query_techmind(request: QueryRequest):
+    """
+    Endpoint principal para hacer preguntas a TechMind
+    """
+    
+    # Validar pregunta
+    if not request.pregunta or len(request.pregunta.strip()) < 3:
+        raise HTTPException(400, "Pregunta demasiado corta")
+    
+    if len(request.pregunta) > 500:
+        raise HTTPException(400, "Pregunta demasiado larga (máx 500 caracteres)")
+    
+    # Verificar rate limit
+    puede_continuar, requests_restantes, user_id = check_rate_limit(request.api_key)
+    
+    if not puede_continuar:
+        if user_id == "invalid":
+            raise HTTPException(401, "API key inválida")
+        else:
+            raise HTTPException(
+                429,
+                f"Límite diario alcanzado. Upgrade a Pro para consultas ilimitadas."
+            )
+    
+    # Generar respuesta
+    try:
+        resultado = generar_respuesta_api(request.pregunta)
+        
+        if not resultado["success"]:
+            raise HTTPException(500, resultado.get("error", "Error generando respuesta"))
+        
+        return QueryResponse(
+            success=True,
+            respuesta=resultado["respuesta"],
+            tiempo_generacion=resultado["tiempo_generacion"],
+            requests_restantes=requests_restantes
+        )
+    
+    except Exception as e:
+        raise HTTPException(500, f"Error: {str(e)}")
+
+@app.post("/api/signup", response_model=APIKeyResponse)
+async def signup_free(request: SignupRequest):
+    """
+    Registro gratuito (genera API key)
+    """
+    
+    conn = get_db()
+    c = conn.cursor()
+    
+    # Verificar si email ya existe
+    c.execute("SELECT api_key FROM api_keys WHERE email = ?", (request.email,))
+    existing = c.fetchone()
+    
+    if existing:
+        conn.close()
+        raise HTTPException(400, "Email ya registrado")
+    
+    # Generar API key
+    api_key = f"tm_free_{secrets.token_urlsafe(32)}"
+    
+    # Guardar en DB
+    c.execute("""
+        INSERT INTO api_keys (api_key, email, plan, is_active)
+        VALUES (?, ?, 'free', 1)
+    """, (api_key, request.email))
+    
+    conn.commit()
+    conn.close()
+    
+    return APIKeyResponse(
+        api_key=api_key,
+        plan="free",
+        expires_at="never"
+    )
+
+@app.get("/api/stats")
+async def get_stats(api_key: str = Header(...)):
+    """
+    Obtiene estadísticas de uso
+    """
+    
+    conn = get_db()
+    c = conn.cursor()
+    
+    # Verificar API key
+    c.execute("""
+        SELECT email, plan, created_at 
+        FROM api_keys 
+        WHERE api_key = ? AND is_active = 1
+    """, (api_key,))
+    
+    user = c.fetchone()
+    
+    if not user:
+        conn.close()
+        raise HTTPException(401, "API key inválida")
+    
+    # Obtener requests hoy
+    today = datetime.now().strftime("%Y-%m-%d")
+    
+    c.execute("""
+        SELECT count FROM daily_requests 
+        WHERE user_id = ? AND date = ?
+    """, (api_key, today))
+    
+    result = c.fetchone()
+    requests_hoy = result["count"] if result else 0
+    
+    # Obtener total histórico
+    c.execute("""
+        SELECT SUM(count) as total FROM daily_requests 
+        WHERE user_id = ?
+    """, (api_key,))
+    
+    result = c.fetchone()
+    requests_total = result["total"] if result and result["total"] else 0
+    
+    conn.close()
+    
+    limit = PRO_DAILY_LIMIT if user["plan"] == "pro" else FREE_DAILY_LIMIT
+    
+    return {
+        "email": user["email"],
+        "plan": user["plan"],
+        "requests_hoy": requests_hoy,
+        "requests_total": requests_total,
+        "limite_diario": limit,
+        "requests_restantes": limit - requests_hoy
+    }
+
+# =========================================================
+# WEBHOOK STRIPE (para después)
+# =========================================================
+@app.post("/webhook/stripe")
+async def stripe_webhook():
+    """
+    Webhook para procesar pagos de Stripe
+    TODO: Implementar cuando configures Stripe
+    """
+    return {"status": "pending_implementation"}
+
+# =========================================================
+# ADMIN (opcional - para ti)
+# =========================================================
+@app.get("/admin/users")
+async def list_users(admin_key: str = Header(...)):
+    """
+    Lista todos los usuarios (solo admin)
+    """
+    
+    # Contraseña admin simple (cambiar en producción)
+    if admin_key != "admin_techmind_2025":
+        raise HTTPException(403, "No autorizado")
+    
+    conn = get_db()
+    c = conn.cursor()
+    
+    c.execute("""
+        SELECT email, plan, created_at, is_active 
+        FROM api_keys 
+        ORDER BY created_at DESC 
+        LIMIT 100
+    """)
+    
+    users = [dict(row) for row in c.fetchall()]
+    conn.close()
+    
+    return {"users": users, "total": len(users)}
+
+# =========================================================
+# STARTUP
+# =========================================================
+@app.on_event("startup")
+async def startup_event():
+    """Ejecutar al iniciar el servidor"""
+    print("🚀 TechMind API iniciada")
+    print("📊 Base de datos: techmind.db")
+    print("🔒 CORS habilitado para: techmind-landing.vercel.app")
+    print()
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run(app, host="0.0.0.0", port=8000)