from fastapi import FastAPI, Query
import requests

app = FastAPI()

def fetch_ticker_data():
    """
    Fetch all trading pair data from MEXC Exchange.
    Returns: List of trading pair data as JSON.
    """
    url = "https://api.mexc.com/api/v3/ticker/bookTicker"
    try:
        response = requests.get(url, timeout=10)
        response.raise_for_status()
        return response.json()
    except requests.exceptions.RequestException as e:
        print(f"Error fetching ticker data: {e}")
        return []

def fetch_order_book(symbol, limit=10):
    """
    Fetch order book data for a specific trading pair from MEXC Exchange.
    """
    url = f"https://api.mexc.com/api/v3/depth?symbol={symbol}&limit={limit}"
    try:
        response = requests.get(url, timeout=10)
        response.raise_for_status()
        return response.json()
    except requests.exceptions.RequestException as e:
        print(f"Error fetching order book for {symbol}: {e}")
        return {}

def find_large_seller_spread(tickers, result_limit=10):
    """
    Find tokens where the 5th seller bid is 100% greater than the 1st seller bid.
    """
    tokens = []
    for ticker in tickers:
        symbol = ticker.get("symbol")

        if not symbol:
            continue

        order_book = fetch_order_book(symbol, limit=5)
        asks = order_book.get("asks", [])

        if len(asks) >= 5:
            try:
                first_ask = float(asks[0][0])
                fifth_ask = float(asks[4][0])

                if fifth_ask >= 2 * first_ask:
                    tokens.append({
                        "symbol": symbol,
                        "1st_seller_bid": first_ask,
                        "5th_seller_bid": fifth_ask,
                        "difference_percentage": round(((fifth_ask - first_ask) / first_ask) * 100, 2)
                    })
            except (ValueError, IndexError):
                continue

        if len(tokens) >= result_limit:
            break
    return tokens[:result_limit]

@app.get("/")
def read_root():
    return {"message": "Welcome to the MEXC Order Book API!"}

@app.get("/get_tokens/")
def get_tokens(limit: int = Query(10, title="Limit", description="Number of tokens to return")):
    """
    Fetch and return tokens where the 5th seller bid is 100% greater than the 1st seller bid.
    """
    tickers = fetch_ticker_data()
    if not tickers:
        return {"error": "No data available"}

    tokens = find_large_seller_spread(tickers, result_limit=limit)
    return {"count": len(tokens), "tokens": tokens}