from flask import Flask, request, jsonify, Response, stream_with_context, render_template
import hmac, hashlib, secrets, time, logging, json, requests, os
from datetime import datetime, timedelta, timezone

# Logging Configuration (Console Only)
logging.basicConfig(
    level=logging.INFO,  # Set logging level to INFO
    format="%(asctime)s - %(levelname)s - %(message)s",
    handlers=[logging.StreamHandler()]  # Log to console only
)

logger = logging.getLogger(__name__)  # Logger instance
app = Flask(__name__)

# 🔑 Secret key for API authentication
SECRET_KEY = os.getenv("SECRET_KEY")
SPECIAL_API_KEY = os.getenv("SPECIAL_API_KEY")
ENDPOINT = os.getenv("ENDPOINT")
SYSTEM_PROMPT = os.getenv("SYSTEM_PROMPT")
EXCEPTION = os.getenv("EXCEPTION")
AVAILABLE_MODELS = [
    "deepseek-r1",
    "gpt-4-turbo",
    "gpt-4",
    "gpt-3.5-turbo",
    "mistral-7b",
    "gemini-pro",
    "claude-3-sonnet",
    "claude-3-haiku",
    "llama-3-8b",
    "llama-3-70b"
]

# Track API statistics
api_usage = {}  # Stores {api_key: {"count": X, "reset_time": timestamp}}

# ✅ Request Limit Configuration
REQUEST_LIMIT = 10 # Max requests per day

# Track API statistics
request_count = 0
start_time = time.time()

# Validate API Key
def validate_api_key(api_key):
    parts = api_key.split("-")
    if len(parts) != 3 or parts[0] != "TrueSyncAI":
        return False
    
    random_part, received_signature = parts[1], parts[2]
    expected_signature = hmac.new(SECRET_KEY.encode(), random_part.encode(), hashlib.sha256).hexdigest()[:16]
    return expected_signature == received_signature

# ✅ Generator function for streaming response
def stream_response(api_payload):
    try:
        response = requests.post(
            ENDPOINT,
            json=api_payload,
            stream=True
        )

        if response.status_code == 200 and response.ok:
            for value in response.iter_lines(decode_unicode=True):
                if value and "[DONE]" not in value:
                    try:
                        data = json.loads(value[6:])
                        content = data['choices'][0]['delta']['content']
                        yield content
                    except:
                        continue
        else:
            yield f"Status Code: {response.status_code}, Response: {response.content}"
    except:
        yield EXCEPTION

# ✅ Function for normal (non-streaming) response
def non_stream_response(api_payload) -> str:
    try:
        response = requests.post(ENDPOINT, json=api_payload)
        if response.status_code==200 and  response.ok:
            return response.json()["choices"][0]["message"]["content"]
        else:
            return f"Status Code: {response.status_code}, Response: {response.content}"
    except:
        return EXCEPTION

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

@app.route('/status', methods=['GET'])
def status():
    global request_count
    uptime_seconds = int(time.time() - start_time)

    # Convert uptime to days, hours, minutes, and seconds
    days = uptime_seconds // 86400
    hours = (uptime_seconds % 86400) // 3600
    minutes = (uptime_seconds % 3600) // 60
    seconds = uptime_seconds % 60

    uptime_str = f"{days} days, {hours} hours, {minutes} minutes and {seconds} seconds"
    logger.info(f"🕒 Status Check | Uptime: {uptime_str} | Total Requests: {request_count}")

    return jsonify({
        "status": "API is running",
        "total_requests": request_count,
        "uptime": uptime_str
    })

@app.route("/usage", methods=["GET"])
def usage():
    api_key = request.args.get("api_key")

    if not api_key or not validate_api_key(api_key):
        return jsonify({"error": "Invalid API Key"}), 401
    
    now = datetime.now(timezone.utc)  # ✅ Use timezone-aware datetime
    user_data = api_usage.get(api_key, {"count": 0, "reset_time": now + timedelta(days=1)})
    
    remaining_requests = max(0, REQUEST_LIMIT - user_data["count"])
    reset_time = user_data["reset_time"].strftime("%Y-%m-%d %H:%M:%S UTC")
    logger.info("📊 API Usage requested")
    return jsonify({
        "api_key": api_key,
        "requests_used": user_data["count"],
        "remaining_requests": remaining_requests,
        "reset_time": reset_time
    })

@app.route("/v1/models", methods=["GET"])
def get_available_models():
    """
    Returns a list of available AI models.
    """
    logger.info("📜 Model list requested")
    return jsonify({
        "models": ", ".join(AVAILABLE_MODELS),
    })

# Generate API Key
@app.route("/generate_api_key", methods=["POST"])
def generate_api_key():
    random_part = secrets.token_hex(16)
    signature = hmac.new(SECRET_KEY.encode(), random_part.encode(), hashlib.sha256).hexdigest()[:16]
    api_key = f"TrueSyncAI-{random_part}-{signature}"
    logger.info("🔑 API Key requested")
    return jsonify({"api_key": api_key})
    
# ✅ Chat API with configurable parameters
@app.route("/v1/chat/completions", methods=["POST"])
def chat():
    global request_count
    data = request.json
    api_key = data.get("api_key")
    message = data.get("message", "").strip()

    logger.info(f"🔹 Incoming Chat Request | API Key: {api_key} | Message: {message}")
    
    if not api_key or not validate_api_key(api_key):
        logger.warning("❌ Invalid API Key Attempt")
        return jsonify({"error": "Invalid API Key"}), 401
    
    # Validate required message field
    if not message:
        logger.warning("⚠️ Empty message received")
        return jsonify({"error": "Message cannot be empty"}), 400
    
    # ✅ Apply Limit to the Specific API Key
    if api_key == SPECIAL_API_KEY:
        now = datetime.now(timezone.utc)
        user_data = api_usage.get(api_key, {"count": 0, "reset_time": now + timedelta(days=1)})
        
        # Reset count if reset time has passed
        if now >= user_data["reset_time"]:
            user_data = {"count": 0, "reset_time": now + timedelta(days=1)}
        
        # Block requests if limit exceeded
        if user_data["count"] >= REQUEST_LIMIT:
            return jsonify({"error": "Request limit reached. This is a testing API key for developers. The limit resets daily. Please wait or use a different key."}), 429
        
        # Increase request count
        user_data["count"] += 1
        api_usage[api_key] = user_data  # Update storage

    # Extract optional parameters with defaults
    stream = data.get("stream", False)
    model = data.get("model", "deepseek-r1")
    temperature = data.get("temperature", 0.2)
    presence_penalty = data.get("presence_penalty", 0)
    frequency_penalty = data.get("frequency_penalty", 0)
    top_p = data.get("top_p", 1)
    max_tokens = data.get("max_tokens", 4000)

    api_payload = {
        "messages": [
            {'role': 'system', 'content': SYSTEM_PROMPT},
            {'role': 'user', 'content': message}
        ],
        "stream": stream,
        "model": model,
        "temperature": temperature,
        "presence_penalty": presence_penalty,
        "frequency_penalty": frequency_penalty,
        "top_p": top_p,
        "max_tokens": max_tokens
    }

    request_count += 1
    
    # Return streaming or normal response based on user request
    if stream:
        return Response(stream_with_context(stream_response(api_payload)))
    else:
        response_text = non_stream_response(api_payload)
        logger.info(f"✅ Response Sent | API Key: {api_key} | Token Usage: {len(response_text)} chars")
        return jsonify({"response": response_text})

if __name__ == "__main__":
    logger.info("🚀 TrueSyncAI API is starting...")
    app.run(host="0.0.0.0", port=7860)  # Hugging Face Spaces default port