import asyncio
import sys
import logging
import json
import os
import math
from collections import defaultdict
from cryptofeed import FeedHandler
from cryptofeed.callback import TickerCallback
from cryptofeed.defines import TICKER

# Import only the Binance exchange class
from cryptofeed.exchanges import Binance  # CHANGED

# --- Configuration for Binance Only ---
TICKER_FILE = "testtickers.txt"         # File containing desired tickers (e.g., BTC/USDT)
JSON_FILENAME = "binance_prices.json"   # Output JSON file name (CHANGED)
WRITE_INTERVAL = 2.0                    # How often to write the JSON file (in seconds)

# Binance Specifics (CHANGED)
EXCHANGE_CLASS = Binance
EXCHANGE_INTERNAL_NAME = "BINANCE"     # Name used internally by cryptofeed
EXCHANGE_DISPLAY_NAME = "Binance"      # Name to use in the output JSON

# Symbol limit per connection for Binance tickers (often high, 100 is safe)
SYMBOL_LIMIT_PER_CONNECTION = 100

# --- End Configuration ---

# Configure logging (KEEP DEBUG ENABLED FOR CONNECTIONS)
logging.basicConfig(level=logging.DEBUG, format='%(asctime)s - %(name)s - %(levelname)s - %(message)s')
logger = logging.getLogger(__name__)

# Enable DEBUG logging for websockets and cryptofeed connection libraries (KEEP THESE)
logging.getLogger('websockets').setLevel(logging.DEBUG)
logging.getLogger('cryptofeed.connection').setLevel(logging.DEBUG)

# --- Global State and Lock ---
current_prices = defaultdict(list)
price_data_lock = asyncio.Lock()

# --- Async Functions ---

async def ticker_handler(ticker, receipt_timestamp):
    """Callback function to handle incoming Binance ticker data and update global state."""
    # Use CRITICAL level temporarily to ensure this message stands out if the handler is called
    # REMOVED ticker.last FROM THIS LOGGING LINE
    logger.critical(f"!!!!!! TICKER HANDLER ENTERED: {ticker.exchange} / {ticker.symbol} - BID: {ticker.bid} / ASK: {ticker.ask} !!!!!!")

    # Check if it's Binance (should always be true in this script)
    if ticker.exchange != EXCHANGE_INTERNAL_NAME:
        logger.warning(f"Received ticker from unexpected exchange: {ticker.exchange}. Skipping.")
        return

    # Binance tickers generally have bid/ask. Use bid price.
    price = ticker.bid

    if price is None:
        # Log if bid is missing, but don't rely on 'last' as a primary source for Binance tickers typically
        logger.debug(f"[{ticker.exchange}] Skipping {ticker.symbol}: Bid is None.")
        return

    # --- Process the price data ---
    symbol_parts = ticker.symbol.split('-')
    if len(symbol_parts) != 2:
        logger.warning(f"[{EXCHANGE_INTERNAL_NAME}] Skipping unexpected symbol format: {ticker.symbol}")
        return
    json_symbol_key = f"{symbol_parts[0]}/{symbol_parts[1]}"

    cex_name = EXCHANGE_DISPLAY_NAME # Use configured display name

    new_entry = { "price": float(price), "network": "CEX", "cex": cex_name }

    logger.debug(f"[{EXCHANGE_INTERNAL_NAME}_HANDLER] Acquiring lock for {json_symbol_key} - {cex_name} - Price: {price}")
    async with price_data_lock:
        logger.debug(f"[{EXCHANGE_INTERNAL_NAME}_HANDLER] Lock acquired. Updating {json_symbol_key} - {cex_name}")
        exchange_found = False
        for entry in current_prices[json_symbol_key]:
            if entry["cex"] == cex_name:
                entry["price"] = new_entry["price"]
                exchange_found = True
                logger.debug(f"[{EXCHANGE_INTERNAL_NAME}_HANDLER] Updated existing entry.")
                break
        if not exchange_found:
            current_prices[json_symbol_key].append(new_entry)
            logger.debug(f"[{EXCHANGE_INTERNAL_NAME}_HANDLER] Appended new entry.")


async def periodic_json_writer(filename, interval):
    """Periodically writes the current_prices dictionary to a JSON file."""
    # This function remains the same
    temp_filename = filename + ".tmp"; logged_write_error = False
    while True:
        try: await asyncio.sleep(interval); logged_write_error = False
        except asyncio.CancelledError: logger.info("JSON writer task cancelled."); break
        except Exception as e: logger.error(f"Error in JSON writer sleep: {e}"); await asyncio.sleep(interval * 2); continue

        logger.debug(f"Acquiring lock to write JSON...")
        try:
            async with price_data_lock:
                logger.debug(f"Lock acquired. Writing {len(current_prices)} symbols to {filename}...")
                data_to_write = dict(current_prices) # Create a copy for writing
            with open(temp_filename, 'w') as f: json.dump(data_to_write, f, indent=4)
            os.replace(temp_filename, filename)
            logger.debug(f"Successfully wrote data to {filename}")
        except IOError as e:
            if not logged_write_error: logger.error(f"Error writing JSON {filename}: {e}"); logged_write_error = True
        except Exception as e:
            if not logged_write_error: logger.error(f"Unexpected error during JSON write: {e}", exc_info=True); logged_write_error = True


# --- Synchronous Helper Functions ---

def read_tickers(filename):
    """Reads tickers from a file, expecting 'BASE/QUOTE' format."""
    # This function remains the same
    try:
        with open(filename, 'r') as f: raw_tickers = [line.strip() for line in f if line.strip() and not line.startswith('#')]
    except FileNotFoundError: logger.error(f"Ticker file '{filename}' not found."); sys.exit(1)
    if not raw_tickers: logger.error(f"No tickers found in '{filename}'."); sys.exit(1)
    desired_symbols, invalid = [], 0
    for t in raw_tickers:
        if '/' in t and len(t.split('/')) == 2:
            desired_symbols.append(t.replace('/', '-').upper())
        else:
            logger.warning(f"Skipping invalid format: '{t}'. Expected 'BASE/QUOTE'.")
            invalid += 1
    if not desired_symbols: logger.error(f"No valid format tickers found ('BASE/QUOTE')."); sys.exit(1)
    logger.info(f"Read {len(desired_symbols)} desired tickers (Cryptofeed fmt: BASE-QUOTE).")
    if invalid > 0: logger.warning(f"Skipped {invalid} invalid lines.")
    return desired_symbols

def get_validated_symbols_sync(exchange_class, exchange_name, desired_symbols):
    """Fetches supported symbols from the exchange and filters the desired list."""
    # This function remains the same, should work for Binance
    logger.info(f"[{exchange_name}] Fetching/retrieving supported symbols...")
    try:
        exchange_instance = exchange_class()
        supported_symbols = exchange_instance.symbols() # Assumed sync
        if not supported_symbols or not isinstance(supported_symbols, (list, set)):
             logger.error(f"[{exchange_name}] Invalid/empty symbol list received. Type: {type(supported_symbols)}.")
             return None
        supported_symbols_set = set(supported_symbols)
        logger.info(f"[{exchange_name}] Obtained {len(supported_symbols_set)} symbols via REST API.")
    except Exception as e:
        logger.error(f"[{exchange_name}] Error obtaining symbols: {e}.", exc_info=True)
        return None
    valid_symbols = []
    unsupported_count = 0
    for symbol in desired_symbols:
        if symbol in supported_symbols_set:
            valid_symbols.append(symbol)
        else:
            unsupported_count += 1
    if unsupported_count > 0:
        logger.info(f"[{exchange_name}] Filtered out {unsupported_count} unsupported symbols (not in REST API list).")
    if not valid_symbols:
        logger.warning(f"[{exchange_name}] No valid symbols found from the desired list.")
    else:
        logger.info(f"[{exchange_name}] Found {len(valid_symbols)} symbols from the list that are valid for WebSocket subscription.")
    return valid_symbols


# --- Main Execution Logic ---
if __name__ == "__main__":
    f = None
    writer_task = None
    total_subscribed_count = 0
    loop = asyncio.get_event_loop()

    try:
        desired_symbols = read_tickers(TICKER_FILE)
        f = FeedHandler()
        logger.info(f"--- Processing {EXCHANGE_DISPLAY_NAME} ---") # CHANGED

        symbols_to_subscribe = get_validated_symbols_sync(
            EXCHANGE_CLASS,              # CHANGED
            EXCHANGE_INTERNAL_NAME,      # CHANGED
            desired_symbols
        )

        if symbols_to_subscribe is not None:
            if len(symbols_to_subscribe) > 0:
                num_symbols = len(symbols_to_subscribe)
                num_connections = math.ceil(num_symbols / SYMBOL_LIMIT_PER_CONNECTION)
                logger.info(f"[{EXCHANGE_INTERNAL_NAME}] Validated {num_symbols} symbols. Limit/Conn: {SYMBOL_LIMIT_PER_CONNECTION}. Needs {num_connections} connection(s).") # CHANGED

                for i in range(num_connections):
                    start_index = i * SYMBOL_LIMIT_PER_CONNECTION
                    end_index = start_index + SYMBOL_LIMIT_PER_CONNECTION
                    symbol_chunk = symbols_to_subscribe[start_index:end_index]
                    if not symbol_chunk: continue

                    logger.info(f"[{EXCHANGE_INTERNAL_NAME} Conn {i+1}/{num_connections}] Adding feed for {len(symbol_chunk)} tickers...") # CHANGED
                    try:
                        f.add_feed(
                            EXCHANGE_CLASS(                # CHANGED
                                symbols=symbol_chunk,
                                channels=[TICKER],
                                callbacks={TICKER: TickerCallback(ticker_handler)}
                            )
                        )
                        logger.info(f"[{EXCHANGE_INTERNAL_NAME} Conn {i+1}/{num_connections}] Feed added successfully.") # CHANGED
                        total_subscribed_count += len(symbol_chunk)
                    except ValueError as ve:
                        logger.error(f"[{EXCHANGE_INTERNAL_NAME} Conn {i+1}/{num_connections}] Failed adding feed chunk: {ve}") # CHANGED
                    except Exception as e:
                        logger.error(f"[{EXCHANGE_INTERNAL_NAME} Conn {i+1}/{num_connections}] Unexpected error adding feed chunk: {e}", exc_info=True) # CHANGED

            else:
                logger.info(f"[{EXCHANGE_INTERNAL_NAME}] No valid symbols from '{TICKER_FILE}' to subscribe to.") # CHANGED
        else:
            logger.error(f"[{EXCHANGE_INTERNAL_NAME}] Skipping feed addition due to symbol validation failure.") # CHANGED

        if total_subscribed_count > 0:
            logger.info(f"\nSuccessfully configured {total_subscribed_count} {EXCHANGE_DISPLAY_NAME} symbols across {len(f.feeds)} connection(s).") # CHANGED
            logger.info(f"Creating background task for {JSON_FILENAME} (Interval: {WRITE_INTERVAL}s).")
            writer_task = loop.create_task(periodic_json_writer(JSON_FILENAME, WRITE_INTERVAL))

            logger.info(f"Starting feed handler...")
            logger.info("Press CTRL+C to stop.")
            f.run() # <--- THE CRITICAL CALL

        else:
            logger.error(f"\nNo {EXCHANGE_DISPLAY_NAME} symbols successfully configured for subscription. Exiting.") # CHANGED
            sys.exit(1)

    except KeyboardInterrupt:
        logger.info("\nShutdown requested via KeyboardInterrupt...")
    except SystemExit as e:
        logger.info(f"Exiting script (code {e.code}).")
    except Exception as e:
        logger.exception(f"\nCritical error in main execution: {e}")
    finally:
        if writer_task and not writer_task.done():
            logger.info("Cancelling JSON writer task...")
            writer_task.cancel()
        logger.info("Script finished.")