"""
SixFingerDev Arena - Multi-Model Agentic Backend
Supports: GPT-5.1-Codex, Claude Opus 4.5, o3, o3-mini
Hugging Face Spaces üzerinde çalışır
"""

from fastapi import FastAPI, HTTPException, Header, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import StreamingResponse, JSONResponse
from pydantic import BaseModel
from typing import List, Optional, Dict, Any, AsyncGenerator
import requests
import os
import secrets
from datetime import datetime
import time
import json
import asyncio
from collections import defaultdict

app = FastAPI(
    title="SixFingerDev Arena Backend",
    description="Multi-Model AI Backend with Task Routing",
    version="2.0.0"
)

# CORS
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

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

# Model configurations
MODEL_CONFIGS = {
    "gpt-5.1-codex": {
        "provider": "pollinations",
        "api_name": "openai",
        "capabilities": ["code", "debug", "test"],
        "max_tokens": 200000,
        "temperature": 0.7
    },
    "claude-opus-4.5": {
        "provider": "pollinations",
        "api_name": "claude-opus-4",
        "capabilities": ["plan", "modify", "test"],
        "max_tokens": 200000,
        "temperature": 0.7
    },
    "o3": {
        "provider": "pollinations",
        "api_name": "openai",
        "capabilities": ["debug", "test"],
        "max_tokens": 4096,
        "temperature": 0.7
    },
    "o3-mini": {
        "provider": "pollinations",
        "api_name": "openai",
        "capabilities": ["test"],
        "max_tokens": 2048,
        "temperature": 0.7
    }
}

# Task to Model mapping (Optimized Elon Musk config)
TASK_MODELS = {
    "Planner":   "claude-opus-4.5",       # Mimari vizyon + roadmap
    "Coder":     "gpt-5.1-codex",         # State-of-the-art kod üretimi
    "Tester":    "claude-opus-4.5",       # Farklı perspektif, edge case coverage
    "Debugger":  "gpt-5.1-codex",         # Cybersecurity + vulnerability detection
    "Modifier":  "claude-opus-4.5"        # Safe refactoring
}

# API Keys
API_KEYS_RAW = os.getenv('AI_API_KEYS', '')
BACKEND_API_KEY = os.getenv('BACKEND_API_KEY', secrets.token_urlsafe(32))

def parse_api_keys():
    if not API_KEYS_RAW:
        return []
    if API_KEYS_RAW.startswith('['):
        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()

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

# Rate limiting
REQUEST_COUNTS = defaultdict(list)
MAX_REQUESTS_PER_MINUTE = 60

# Session storage (in-memory)
SESSIONS = {}

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

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

class ChatRequest(BaseModel):
    session_id: str
    message: str
    model: Optional[str] = None  # Auto-detect if None
    task_type: Optional[str] = None  # Planner, Coder, Tester, Debugger, Modifier
    stream: Optional[bool] = True
    temperature: Optional[float] = None
    max_tokens: Optional[int] = None

class TaskDetectionRequest(BaseModel):
    message: str
    context: Optional[List[Message]] = []

class HealthResponse(BaseModel):
    status: str
    timestamp: str
    available_models: List[str]
    task_mappings: Dict[str, str]
    version: str

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

class APIKeyManager:
    def __init__(self, keys: List[str]):
        self.keys = keys if keys else [None]
        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
        
        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
        
        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)

# ============================================
# TASK DETECTION
# ============================================

def detect_task_type(message: str) -> str:
    """Mesajdan task type'ı otomatik tespit et"""
    message_lower = message.lower()
    
    # Keyword-based detection
    if any(word in message_lower for word in ['plan', 'tasarla', 'mimari', 'architecture', 'design', 'roadmap']):
        return "Planner"
    
    elif any(word in message_lower for word in ['kod yaz', 'implement', 'create', 'build', 'develop', 'function']):
        return "Coder"
    
    elif any(word in message_lower for word in ['test', 'kontrol et', 'check', 'verify', 'validate']):
        return "Tester"
    
    elif any(word in message_lower for word in ['hata', 'bug', 'debug', 'fix', 'error', 'düzelt']):
        return "Debugger"
    
    elif any(word in message_lower for word in ['değiştir', 'modify', 'update', 'refactor', 'optimize']):
        return "Modifier"
    
    # Default: Genel sohbet için Coder
    return "Coder"

# ============================================
# SESSION MANAGEMENT
# ============================================

def get_or_create_session(session_id: str) -> Dict:
    """Session al veya oluştur"""
    if session_id not in SESSIONS:
        SESSIONS[session_id] = {
            "messages": [],
            "created_at": datetime.utcnow().isoformat(),
            "last_activity": datetime.utcnow().isoformat(),
            "metadata": {}
        }
    
    SESSIONS[session_id]["last_activity"] = datetime.utcnow().isoformat()
    return SESSIONS[session_id]

def add_message_to_session(session_id: str, role: str, content: str):
    """Session'a mesaj ekle"""
    session = get_or_create_session(session_id)
    session["messages"].append({
        "role": role,
        "content": content,
        "timestamp": datetime.utcnow().isoformat()
    })

# ============================================
# 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):
    """Rate limiting"""
    now = time.time()
    minute_ago = now - 60
    
    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)

# ============================================
# CORE API FUNCTIONS
# ============================================

async def call_model_api(
    model: str,
    messages: List[Dict],
    stream: bool = False,
    temperature: Optional[float] = None,
    max_tokens: Optional[int] = None
) -> Any:
    """Model API'sini çağır"""
    
    if model not in MODEL_CONFIGS:
        raise HTTPException(status_code=400, detail=f"Unknown model: {model}")
    
    config = MODEL_CONFIGS[model]
    api_key = key_manager.get_working_key()
    
    headers = {"Content-Type": "application/json"}
    if api_key:
        headers["Authorization"] = f"Bearer {api_key}"
    
    payload = {
        "model": config["api_name"],
        "messages": messages,
        "stream": stream,
        "temperature": temperature or config["temperature"],
        "max_tokens": max_tokens or config["max_tokens"]
    }
    
    max_retries = 3
    last_error = None
    
    for attempt in range(max_retries):
        try:
            response = requests.post(
                POLLINATIONS_URL,
                json=payload,
                headers=headers,
                stream=stream,
                timeout=120
            )
            
            if response.status_code == 200:
                key_manager.mark_success(api_key)
                
                if stream:
                    return response
                else:
                    return response.json()
            
            elif response.status_code in [403, 429]:
                key_manager.mark_failed(api_key)
                api_key = key_manager.get_working_key()
                if api_key:
                    headers["Authorization"] = f"Bearer {api_key}"
                await asyncio.sleep(1)
                continue
            
            elif response.status_code == 401:
                key_manager.mark_failed(api_key)
                api_key = key_manager.get_working_key()
                if api_key:
                    headers["Authorization"] = f"Bearer {api_key}"
                continue
            
            else:
                last_error = f"API error: {response.status_code}"
                if attempt < max_retries - 1:
                    await asyncio.sleep(2)
                    continue
                raise HTTPException(status_code=response.status_code, detail=last_error)
        
        except requests.exceptions.Timeout:
            if attempt < max_retries - 1:
                await asyncio.sleep(2)
                continue
            raise HTTPException(status_code=504, detail="Request timeout")
        
        except requests.exceptions.RequestException as e:
            if attempt < max_retries - 1:
                await asyncio.sleep(1)
                continue
            raise HTTPException(status_code=500, detail=f"Request failed: {str(e)}")
    
    raise HTTPException(status_code=503, detail="All retries failed")

async def stream_generator(response) -> AsyncGenerator[str, None]:
    """Stream response'u SSE formatına çevir"""
    try:
        for line in response.iter_lines():
            if line:
                line_decoded = line.decode('utf-8')
                
                if line_decoded.startswith("data: "):
                    data_str = line_decoded[6:]
                    
                    if data_str.strip() == "[DONE]":
                        yield f"data: {json.dumps({'done': True})}\n\n"
                        break
                    
                    try:
                        data = json.loads(data_str)
                        
                        if "choices" in data and len(data["choices"]) > 0:
                            delta = data["choices"][0].get("delta", {})
                            content = delta.get("content", "")
                            
                            if content:
                                yield f"data: {json.dumps({'chunk': content})}\n\n"
                    
                    except json.JSONDecodeError:
                        continue
        
        yield f"data: {json.dumps({'done': True})}\n\n"
    
    finally:
        response.close()

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

@app.get("/", response_model=HealthResponse)
async def health_check():
    """Health check"""
    return {
        "status": "healthy",
        "timestamp": datetime.utcnow().isoformat(),
        "available_models": list(MODEL_CONFIGS.keys()),
        "task_mappings": TASK_MODELS,
        "version": "2.0.0"
    }

@app.post("/api/chat")
async def chat(request: ChatRequest):
    """
    Ana chat endpoint - Task-based routing ile
    
    Body:
        {
            "session_id": "sf_xxx",
            "message": "Kayra için tokenizer yaz",
            "model": "gpt-5.1-codex",  // optional
            "task_type": "Coder",       // optional
            "stream": true
        }
    """
    
    # Rate limiting
    rate_limit_check(request.session_id)
    
    # Session'ı al/oluştur
    session = get_or_create_session(request.session_id)
    
    # User mesajını ekle
    add_message_to_session(request.session_id, "user", request.message)
    
    # Task type'ı belirle
    task_type = request.task_type or detect_task_type(request.message)
    
    # Model'i belirle
    model = request.model or TASK_MODELS.get(task_type, "gpt-5.1-codex")
    
    # Messages'ı hazırla
    messages = [
        {"role": msg["role"], "content": msg["content"]}
        for msg in session["messages"]
    ]
    
    # System prompt ekle (task-specific)
    system_prompts = {
        "Planner": "Sen deneyimli bir yazılım mimarısın. Detaylı planlama ve tasarım yap.",
        "Coder": "Sen expert bir kod geliştiricisisin. Temiz, okunabilir ve performanslı kod yaz.",
        "Tester": "Sen titiz bir test mühendisisin. Comprehensive test senaryoları oluştur.",
        "Debugger": "Sen yetenekli bir debugger'sın. Hataları kök nedenine inip çöz.",
        "Modifier": "Sen dikkatli bir refactoring uzmanısın. Mevcut kodu bozmadan değiştir."
    }
    
    if task_type in system_prompts:
        messages.insert(0, {"role": "system", "content": system_prompts[task_type]})
    
    # API'yi çağır
    if request.stream:
        response = await call_model_api(
            model=model,
            messages=messages,
            stream=True,
            temperature=request.temperature,
            max_tokens=request.max_tokens
        )
        
        return StreamingResponse(
            stream_generator(response),
            media_type="text/event-stream"
        )
    else:
        result = await call_model_api(
            model=model,
            messages=messages,
            stream=False,
            temperature=request.temperature,
            max_tokens=request.max_tokens
        )
        
        # Assistant yanıtını session'a ekle
        assistant_message = result["choices"][0]["message"]["content"]
        add_message_to_session(request.session_id, "assistant", assistant_message)
        
        return result

@app.post("/api/detect-task")
async def detect_task(request: TaskDetectionRequest):
    """Task type'ı tespit et"""
    task_type = detect_task_type(request.message)
    recommended_model = TASK_MODELS.get(task_type)
    
    return {
        "task_type": task_type,
        "recommended_model": recommended_model,
        "model_config": MODEL_CONFIGS.get(recommended_model, {})
    }

@app.get("/api/session/{session_id}")
async def get_session(session_id: str):
    """Session bilgilerini getir"""
    if session_id not in SESSIONS:
        raise HTTPException(status_code=404, detail="Session not found")
    
    return SESSIONS[session_id]

@app.delete("/api/session/{session_id}")
async def delete_session(session_id: str):
    """Session'ı sil"""
    if session_id in SESSIONS:
        del SESSIONS[session_id]
        return {"status": "deleted"}
    
    raise HTTPException(status_code=404, detail="Session not found")

@app.get("/api/models")
async def list_models():
    """Kullanılabilir modelleri listele"""
    return {
        "models": MODEL_CONFIGS,
        "task_mappings": TASK_MODELS
    }

@app.get("/api/stats")
async def get_stats():
    """İstatistikler"""
    return {
        "total_sessions": len(SESSIONS),
        "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()),
        "available_models": list(MODEL_CONFIGS.keys())
    }

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

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

@app.exception_handler(Exception)
async def general_exception_handler(request, exc):
    print(f"Unhandled exception: {exc}")
    return JSONResponse(
        status_code=500,
        content={
            "error": {
                "message": "Internal server error",
                "type": "internal_error",
                "code": 500
            }
        }
    )

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

@app.on_event("startup")
async def startup_event():
    print("=" * 60)
    print("🚀 SixFingerDev Arena Starting...")
    print("=" * 60)
    print(f"📦 Available Models: {', '.join(MODEL_CONFIGS.keys())}")
    print(f"🎯 Task Mappings:")
    for task, model in TASK_MODELS.items():
        print(f"   {task}: {model}")
    print(f"🔑 API Keys: {len(API_KEYS) if API_KEYS and API_KEYS[0] is not None else 0}")
    print(f"🔐 Backend Key: {BACKEND_API_KEY[:10]}...")
    print(f"⏱️  Rate Limit: {MAX_REQUESTS_PER_MINUTE} req/min")
    print("=" * 60)
    print("✅ Arena Ready!")
    print("=" * 60)

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