"""
SixFinger Code - Pollinations API Proxy Backend
Hugging Face Spaces üzerinde çalışır
"""

from fastapi import FastAPI, HTTPException, Header
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from typing import List, Optional, Dict, Any
import requests
import os
import secrets
from datetime import datetime
import time

app = FastAPI(
    title="SixFinger AI Backend",
    description="Pollinations API Proxy for PythonAnywhere",
    version="1.0.0"
)

# CORS - tüm originlere izin ver (production'da domain belirt)
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # Production'da: ["https://yourdomain.pythonanywhere.com"]
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# ============================================
# CONFIGURATION
# ============================================

# API Keys - Space Secrets'tan al
API_KEYS_RAW = os.getenv('AI_API_KEYS', '')

def parse_api_keys():
    """AI_API_KEYS'i parse et"""
    if not API_KEYS_RAW:
        # Fallback - public Pollinations (sınırlı)
        return []
    
    if API_KEYS_RAW.startswith('['):
        import json
        try:
            return json.loads(API_KEYS_RAW)
        except:
            pass
    
    return [k.strip() for k in API_KEYS_RAW.split(',') if k.strip()]

API_KEYS = parse_api_keys()

# Backend API Key (güvenlik için)
BACKEND_API_KEY = os.getenv('BACKEND_API_KEY', secrets.token_urlsafe(32))

# Pollinations URL
POLLINATIONS_URL = "https://api.pollinations.ai/v1/chat/completions"

# Rate limiting
REQUEST_COUNTS = {}
MAX_REQUESTS_PER_MINUTE = 60

# ============================================
# MODELS
# ============================================

class Message(BaseModel):
    role: str
    content: str

class ChatRequest(BaseModel):
    model: str
    messages: List[Message]
    stream: Optional[bool] = False
    temperature: Optional[float] = 0.7
    max_tokens: Optional[int] = 2000

class ChatResponse(BaseModel):
    id: str
    object: str
    created: int
    model: str
    choices: List[Dict[str, Any]]
    usage: Dict[str, int]

class HealthResponse(BaseModel):
    status: str
    timestamp: str
    api_keys_count: int
    version: str

# ============================================
# KEY MANAGER
# ============================================

class APIKeyManager:
    def __init__(self, keys: List[str]):
        self.keys = keys if keys else [None]  # None = keyless mode
        self.failed_keys = {}
        self.current_index = 0
        self.cooldown = 60
    
    def get_working_key(self) -> Optional[str]:
        if not self.keys or self.keys[0] is None:
            return None  # Keyless mode
        
        now = time.time()
        attempts = 0
        
        while attempts < len(self.keys):
            key = self.keys[self.current_index]
            
            if key in self.failed_keys:
                if now - self.failed_keys[key] > self.cooldown:
                    del self.failed_keys[key]
                else:
                    self.current_index = (self.current_index + 1) % len(self.keys)
                    attempts += 1
                    continue
            
            return key
        
        # All keys failed - use oldest
        if self.failed_keys:
            oldest_key = min(self.failed_keys, key=self.failed_keys.get)
            del self.failed_keys[oldest_key]
            return oldest_key
        
        return self.keys[0] if self.keys else None
    
    def mark_failed(self, key: Optional[str]):
        if key:
            self.failed_keys[key] = time.time()
            self.current_index = (self.current_index + 1) % len(self.keys)
    
    def mark_success(self, key: Optional[str]):
        if key and key in self.failed_keys:
            del self.failed_keys[key]

key_manager = APIKeyManager(API_KEYS)

# ============================================
# MIDDLEWARE
# ============================================

def verify_api_key(authorization: Optional[str] = Header(None)):
    """Backend API key doğrulama"""
    if not authorization:
        raise HTTPException(status_code=401, detail="Missing authorization header")
    
    if not authorization.startswith("Bearer "):
        raise HTTPException(status_code=401, detail="Invalid authorization format")
    
    token = authorization.replace("Bearer ", "")
    
    if token != BACKEND_API_KEY:
        raise HTTPException(status_code=401, detail="Invalid API key")
    
    return token

def rate_limit_check(client_id: str):
    """Basit rate limiting"""
    now = time.time()
    minute_ago = now - 60
    
    if client_id not in REQUEST_COUNTS:
        REQUEST_COUNTS[client_id] = []
    
    # Eski istekleri temizle
    REQUEST_COUNTS[client_id] = [
        req_time for req_time in REQUEST_COUNTS[client_id] 
        if req_time > minute_ago
    ]
    
    if len(REQUEST_COUNTS[client_id]) >= MAX_REQUESTS_PER_MINUTE:
        raise HTTPException(status_code=429, detail="Rate limit exceeded")
    
    REQUEST_COUNTS[client_id].append(now)

# ============================================
# ROUTES
# ============================================

@app.get("/", response_model=HealthResponse)
async def health_check():
    """Health check endpoint"""
    return {
        "status": "healthy",
        "timestamp": datetime.utcnow().isoformat(),
        "api_keys_count": len(API_KEYS) if API_KEYS and API_KEYS[0] is not None else 0,
        "version": "1.0.0"
    }

@app.get("/health", response_model=HealthResponse)
async def health():
    """Alias for health check"""
    return await health_check()

@app.post("/v1/chat/completions")
async def chat_completion(
    request: ChatRequest,
    authorization: str = Header(None)
):
    """
    Pollinations API proxy endpoint
    
    Headers:
        Authorization: Bearer YOUR_BACKEND_API_KEY
    
    Body:
        {
            "model": "openai",
            "messages": [{"role": "user", "content": "Hello"}],
            "stream": false
        }
    """
    
    # Verify backend API key
    verify_api_key(authorization)
    
    # Rate limiting (IP bazlı olabilir, şimdilik basit)
    client_id = authorization  # veya request.client.host
    rate_limit_check(client_id)
    
    # Get working API key
    api_key = key_manager.get_working_key()
    
    # Prepare headers
    headers = {
        "Content-Type": "application/json"
    }
    
    if api_key:
        headers["Authorization"] = f"Bearer {api_key}"
    
    # Prepare payload
    payload = {
        "model": request.model,
        "messages": [{"role": m.role, "content": m.content} for m in request.messages],
        "stream": request.stream,
        "temperature": request.temperature,
        "max_tokens": request.max_tokens
    }
    
    # Call Pollinations API
    max_retries = len(API_KEYS) if API_KEYS and API_KEYS[0] is not None else 3
    last_error = None
    
    for attempt in range(max_retries):
        try:
            response = requests.post(
                POLLINATIONS_URL,
                json=payload,
                headers=headers,
                timeout=120
            )
            
            if response.status_code == 200:
                key_manager.mark_success(api_key)
                return response.json()
            
            elif response.status_code == 429:
                # Rate limit - try next key
                key_manager.mark_failed(api_key)
                api_key = key_manager.get_working_key()
                if api_key:
                    headers["Authorization"] = f"Bearer {api_key}"
                time.sleep(1)
                continue
            
            elif response.status_code == 401:
                # Invalid key - try next
                key_manager.mark_failed(api_key)
                api_key = key_manager.get_working_key()
                if api_key:
                    headers["Authorization"] = f"Bearer {api_key}"
                continue
            
            else:
                # Other error
                last_error = f"API error: {response.status_code} - {response.text[:200]}"
                raise HTTPException(status_code=response.status_code, detail=last_error)
        
        except requests.exceptions.Timeout:
            last_error = "Request timeout"
            if attempt < max_retries - 1:
                time.sleep(2)
                continue
            raise HTTPException(status_code=504, detail=last_error)
        
        except requests.exceptions.RequestException as e:
            last_error = str(e)
            if attempt < max_retries - 1:
                time.sleep(1)
                continue
            raise HTTPException(status_code=500, detail=f"Request failed: {last_error}")
    
    # All retries failed
    raise HTTPException(status_code=503, detail=f"All API keys failed: {last_error}")

@app.get("/stats")
async def get_stats(authorization: str = Header(None)):
    """Backend istatistikleri (admin only)"""
    verify_api_key(authorization)
    
    return {
        "total_keys": len(API_KEYS) if API_KEYS and API_KEYS[0] is not None else 0,
        "failed_keys": len(key_manager.failed_keys),
        "active_clients": len(REQUEST_COUNTS),
        "requests_last_minute": sum(len(v) for v in REQUEST_COUNTS.values())
    }

# ============================================
# ERROR HANDLERS
# ============================================

@app.exception_handler(HTTPException)
async def http_exception_handler(request, exc):
    return {
        "error": {
            "message": exc.detail,
            "type": "api_error",
            "code": exc.status_code
        }
    }

@app.exception_handler(Exception)
async def general_exception_handler(request, exc):
    return {
        "error": {
            "message": str(exc),
            "type": "internal_error",
            "code": 500
        }
    }

# ============================================
# STARTUP
# ============================================

@app.on_event("startup")
async def startup_event():
    print("=" * 60)
    print("🚀 SixFinger AI Backend Starting...")
    print("=" * 60)
    print(f"📦 API Keys: {len(API_KEYS) if API_KEYS and API_KEYS[0] is not None else 0}")
    print(f"🔑 Backend API Key: {BACKEND_API_KEY[:10]}...")
    print(f"🌐 Pollinations URL: {POLLINATIONS_URL}")
    print(f"⏱️  Rate Limit: {MAX_REQUESTS_PER_MINUTE} req/min")
    print("=" * 60)
    print("✅ Ready to serve!")
    print("=" * 60)

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=7860)