#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
router/main.py — Centaur Quant Architecture | Central Gateway (Python Router)

Role
----
Central TCP/IP gateway for the Universal Communication Bridge. The MQL5
Executor (CentaurQuant.mq5) streams SDP JSON frames into this process on
127.0.0.1:5555. This router:

  1. Accepts persistent client connections (one thread per connection).
  2. Reassembles frames terminated by '\n' or '\r\n' from raw TCP bytes.
  3. Parses each frame STRICTLY with the stdlib `json` module.
  4. Dispatches on the SDP "action_type" key:
       Heartbeat / Tick_Harvest -> lightweight console log
       Setup_Detected          -> LIVE LLM evaluation (MarketAnalyzer) + reply
       Trade_Opened / Closed   -> prominent log + SQLite telemetry persist
  5. Replies to Setup_Detected with the AI Advisory envelope:
       {"algorithmic_confidence_score": <float>}\n

The reply is advisory ONLY (Anti-Veto Principle): the MT5 side may still
execute regardless of the score. MarketAnalyzer returns a neutral 40.0 on
any LLM failure/timeout, which triggers the MT5 quarter-risk path.
Trade_Opened/Trade_Closed are persisted by TelemetryDB (Track B), closing
the score -> execution -> outcome feedback loop for future calibration.

Robustness
----------
- Per-connection threads are daemonized; the server never dies with a client.
- ConnectionResetError / BrokenPipeError / empty reads are handled as a
  clean disconnect; a reconnect is simply a new accept().
- Frames and the reassembly buffer are size-bounded to resist floods.

Standard library only: socket, threading, json, logging, argparse.
"""

import argparse
import json
import logging
import os
import socket
import sys
import threading
from typing import Any, Dict, List, Optional

# --- Track A: live LLM evaluation engine (Python/models/analyzer.py) -------
# Make the sibling packages importable whether run as a script or as a
# module:  python router/main.py   |   python -m router.main
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
from models.analyzer import MarketAnalyzer  # noqa: E402
from database.telemetry import TelemetryDB  # noqa: E402

# --------------------------------------------------------------------------
# Configuration
# --------------------------------------------------------------------------
HOST = "127.0.0.1"        # default listen address (MT5 side connects here)
PORT = 5555               # default listen port (matches CentaurQuant.mq5 input)
BACKLOG = 5               # pending-connection queue depth
RECV_BUFFER_SIZE = 4096   # bytes pulled per recv() call
MAX_FRAME_SIZE = 1_048_576  # 1 MB hard cap per logical frame (flood guard)
ENCODING = "utf-8"        # SDP frames are UTF-8 encoded

# --------------------------------------------------------------------------
# AI evaluation engine (Track A)
# Provider/model from env: PROVIDER=auto|openai|google, MODEL, *_API_KEY.
# Anti-Veto: analyze() returns 40.0 (quarter-risk trigger) on any failure.
# --------------------------------------------------------------------------
ANALYZER = MarketAnalyzer()

# --------------------------------------------------------------------------
# Telemetry persistence (Track B) — SQLite feedback-loop store.
# DB path overridable via env: CENTAUR_DB_PATH (default: ./centaur_telemetry.db)
# --------------------------------------------------------------------------
TELEMETRY = TelemetryDB(os.environ.get("CENTAUR_DB_PATH", "centaur_telemetry.db"))

# --------------------------------------------------------------------------
# Logging
# --------------------------------------------------------------------------
def configure_logging() -> None:
    """Console logging with timestamps; INFO shows the full SDP telemetry."""
    logging.basicConfig(
        level=logging.INFO,
        format="%(asctime)s | %(levelname)-8s | %(message)s",
        datefmt="%Y-%m-%d %H:%M:%S",
    )


# --------------------------------------------------------------------------
# Frame reassembly (newline / CRLF framed protocol)
# --------------------------------------------------------------------------
class FrameReader:
    """
    Incrementally reassembles '\n'-terminated text frames from raw bytes.

    The MT5 transport (CSocketClient) writes frames terminated by CRLF
    ("\r\n") and the receiver tolerates bare "\n" — so we split on "\n"
    and strip one trailing "\r" when present. Multiple frames may arrive
    inside a single recv(); the remainder is kept buffered across reads.
    """

    def __init__(self) -> None:
        self._buffer = b""

    def feed(self, data: bytes) -> List[str]:
        """Append raw bytes and return every COMPLETE frame they contain."""
        self._buffer += data
        frames: List[str] = []

        while True:
            idx = self._buffer.find(b"\n")
            if idx == -1:
                break  # no complete frame yet — keep buffering

            raw = self._buffer[:idx]            # frame body (terminator removed)
            self._buffer = self._buffer[idx + 1:]  # consume terminator too

            if raw.endswith(b"\r"):
                raw = raw[:-1]                  # CRLF tolerance

            if len(raw) > MAX_FRAME_SIZE:
                logging.warning("Frame exceeds %d bytes — dropped.", MAX_FRAME_SIZE)
                continue

            try:
                frames.append(raw.decode(ENCODING, errors="replace"))
            except UnicodeDecodeError as exc:  # pragma: no cover - defensive
                logging.warning("Undecodable frame dropped: %s", exc)

        # Flood guard: never let an unframed stream grow the buffer unbounded.
        if len(self._buffer) > MAX_FRAME_SIZE:
            logging.warning(
                "Reassembly buffer exceeded %d bytes without a terminator — cleared.",
                MAX_FRAME_SIZE,
            )
            self._buffer = b""

        return frames


# --------------------------------------------------------------------------
# Strict SDP parsing
# --------------------------------------------------------------------------
def parse_sdp_frame(frame: str) -> Optional[Dict[str, Any]]:
    """
    Strictly parse one SDP frame.

    Returns a dict only when the frame is valid JSON *and* an object *and*
    carries a string "action_type"; otherwise logs and returns None.
    """
    try:
        data = json.loads(frame)
    except json.JSONDecodeError as exc:
        logging.warning("Malformed JSON dropped: %s | frame=%.120r", exc, frame)
        return None

    if not isinstance(data, dict):
        logging.warning("Non-object JSON dropped: %r", data)
        return None

    if not isinstance(data.get("action_type"), str):
        logging.warning("Frame missing string 'action_type': %r", data)
        return None

    return data


# --------------------------------------------------------------------------
# Safe transport write (client may vanish between read and reply)
# --------------------------------------------------------------------------
def safe_send(conn: socket.socket, text: str) -> bool:
    """Best-effort frame write; never raises on a dead client."""
    try:
        conn.sendall(text.encode(ENCODING))
        return True
    except (ConnectionResetError, BrokenPipeError, OSError) as exc:
        logging.warning("Send failed (client gone?): %s", exc)
        return False


# --------------------------------------------------------------------------
# Action handlers
# --------------------------------------------------------------------------
def handle_heartbeat(msg: Dict[str, Any]) -> None:
    """Liveness signal — lightweight one-line log."""
    logging.info(
        "[Heartbeat] symbol=%s timeframe=%s",
        msg.get("symbol", "?"),
        msg.get("timeframe", "?"),
    )


def handle_tick_harvest(msg: Dict[str, Any]) -> None:
    """One harvested tick — compact telemetry line."""
    p = msg.get("payload") or {}
    logging.info(
        "[Tick_Harvest] %s %s bid=%s ask=%s spread_pts=%s tick_vol=%s",
        msg.get("symbol", "?"),
        msg.get("timeframe", "?"),
        p.get("bid", "?"),
        p.get("ask", "?"),
        p.get("spread_points", "?"),
        p.get("tick_volume", "?"),
    )


def handle_setup_detected(msg: Dict[str, Any], conn: socket.socket) -> None:
    """
    Setup proposal from the Executor.

    Extracts symbol / setup_type / historical_context, runs the LIVE LLM
    evaluation (MarketAnalyzer), and INSTANTLY replies with the AI Advisory
    envelope:
        {"algorithmic_confidence_score": <float>}\n
    """
    p = msg.get("payload") or {}
    symbol = msg.get("symbol", "?")
    setup_type = p.get("setup_type", "?")

    hist = msg.get("historical_context")
    swing_count = len(hist) if isinstance(hist, list) else 0

    logging.info(
        "[Setup_Detected] %s | setup=%s | entry=%s sl=%s tp=%s | ctx_swings=%d",
        symbol,
        setup_type,
        p.get("entry", "?"),
        p.get("sl", "?"),
        p.get("tp", "?"),
        swing_count,
    )

    # --- live LLM evaluation (Anti-Veto: neutral 40.0 on failure/timeout) ---
    result = ANALYZER.analyze(msg)
    score = result["score"]
    if result.get("used_fallback"):
        logging.warning("[AI_Advisory] %s | fallback score %.2f used — %s",
                        symbol, score, result.get("fallback_reason", ""))
    else:
        logging.info("[AI_Advisory] %s | score=%.2f | reason='%s' | provider=%s | %d ms",
                     symbol, score, result.get("reason", ""),
                     result.get("provider", "?"), result.get("latency_ms", 0))

    # --- AI Advisory envelope, newline-terminated (MT5 frames on '\n') ---
    reply = json.dumps({"algorithmic_confidence_score": score}) + "\n"
    if safe_send(conn, reply):
        logging.info("[AI_Advisory] %s | score=%.2f -> sent to MT5", symbol, score)
    else:
        logging.warning(
            "[AI_Advisory] %s | score=%.2f NOT delivered (client unreachable)",
            symbol,
            score,
        )


def handle_trade_opened(msg: Dict[str, Any]) -> None:
    """Position opened — prominent execution record + SQLite persist."""
    p = msg.get("payload") or {}
    logging.info(
        ">>> [Trade_Opened] %s %s | ticket=%s %s lot=%s entry=%s sl=%s tp=%s | ai_score=%s",
        msg.get("symbol", "?"),
        msg.get("timeframe", "?"),
        p.get("ticket", "?"),
        p.get("direction", "?"),
        p.get("lot", "?"),
        p.get("entry_price", "?"),
        p.get("sl", "?"),
        p.get("tp", "?"),
        msg.get("algorithmic_confidence_score", "?"),
    )
    # --- persist the execution record (Track B) ---
    TELEMETRY.log_trade_opened(msg)


def handle_trade_closed(msg: Dict[str, Any]) -> None:
    """Position closed — the feedback-loop training signal + SQLite update."""
    p = msg.get("payload") or {}
    logging.info(
        ">>> [Trade_Closed] %s | ticket=%s profit=%s r_multiple=%s initial_ai_score=%s",
        msg.get("symbol", "?"),
        p.get("ticket", "?"),
        p.get("profit", "?"),
        p.get("r_multiple", "?"),
        p.get("initial_ai_score", "?"),
    )
    # --- persist the closed outcome (Track B) ---
    TELEMETRY.log_trade_closed(msg)


# --------------------------------------------------------------------------
# Dispatcher
# --------------------------------------------------------------------------
# Setup_Detected is handled separately (it needs the socket to reply).
_ACTIONS: Dict[str, Any] = {
    "Heartbeat": handle_heartbeat,
    "Tick_Harvest": handle_tick_harvest,
    "Trade_Opened": handle_trade_opened,
    "Trade_Closed": handle_trade_closed,
}


def dispatch(msg: Dict[str, Any], conn: socket.socket) -> None:
    """Route one parsed SDP frame by its action_type."""
    action = msg.get("action_type")

    if action == "Setup_Detected":
        handle_setup_detected(msg, conn)
        return

    handler = _ACTIONS.get(action)
    if handler is None:
        logging.warning("[Router] unknown action_type=%r — frame ignored", action)
        return

    try:
        handler(msg)
    except Exception:  # a broken handler must never kill the connection thread
        logging.exception("[Router] handler '%s' raised — frame ignored", action)


# --------------------------------------------------------------------------
# Per-connection worker
# --------------------------------------------------------------------------
def handle_client(conn: socket.socket, addr: tuple) -> None:
    """
    Serve one persistent MT5 connection until it disconnects.

    Reads raw bytes, reassembles frames, parses and dispatches each one.
    A reconnect from the MT5 side simply spawns a fresh thread via accept().
    """
    host, port = addr[0], addr[1]
    logging.info("[Gateway] client connected: %s:%d", host, port)

    reader = FrameReader()
    try:
        while True:
            data = conn.recv(RECV_BUFFER_SIZE)
            if not data:
                # Peer performed an orderly close — empty byte read.
                logging.info("[Gateway] %s:%d closed connection (empty read)", host, port)
                break

            for frame in reader.feed(data):
                msg = parse_sdp_frame(frame)
                if msg is not None:
                    dispatch(msg, conn)

    except ConnectionResetError as exc:
        # MT5 terminal killed the socket (e.g., chart closed mid-session).
        logging.warning("[Gateway] %s:%d connection reset: %s", host, port, exc)
    except (BrokenPipeError, OSError) as exc:
        logging.warning("[Gateway] %s:%d socket error: %s", host, port, exc)
    except Exception:
        # Last-resort guard: log and drop the connection, keep the server up.
        logging.exception("[Gateway] %s:%d unexpected error — connection closed", host, port)
    finally:
        try:
            conn.shutdown(socket.SHUT_RDWR)
        except OSError:
            pass  # socket may already be closed by the peer
        conn.close()
        logging.info("[Gateway] %s:%d disconnected", host, port)


# --------------------------------------------------------------------------
# Server entry point
# --------------------------------------------------------------------------
def run_server(host: str, port: int) -> None:
    """Bind, listen, and accept client connections forever (Ctrl+C to stop)."""
    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)  # fast rebind
    server.bind((host, port))
    server.listen(BACKLOG)

    logging.info("=" * 72)
    logging.info("Centaur Gateway listening on %s:%d", host, port)
    logging.info("LLM backend: %s",
                 ANALYZER._backend.name if ANALYZER._backend else "NONE (fallback 40.0)")
    logging.info("Telemetry DB: %s", TELEMETRY.path)
    logging.info("Press Ctrl+C to stop.")
    logging.info("=" * 72)

    try:
        while True:
            conn, addr = server.accept()
            # daemon thread: dies with the process; never blocks shutdown
            thread = threading.Thread(target=handle_client, args=(conn, addr), daemon=True)
            thread.start()
    except KeyboardInterrupt:
        logging.info("[Gateway] Ctrl+C received — shutting down.")
    finally:
        server.close()
        TELEMETRY.close()
        logging.info("[Gateway] server socket closed, telemetry flushed. Bye.")


def main() -> None:
    parser = argparse.ArgumentParser(description="Centaur Quant — Central Gateway")
    parser.add_argument("--host", default=HOST, help="listen address (default: %(default)s)")
    parser.add_argument("--port", type=int, default=PORT, help="listen port (default: %(default)s)")
    args = parser.parse_args()

    configure_logging()
    run_server(args.host, args.port)


if __name__ == "__main__":
    main()