"""
Gradio 5 UI for the ARB-MAX trainer Space.

Responsibilities:
  - Read env vars (ASSET, MODEL_VARIANT, N_TRIALS, N_FOLDS, AUTO_START, HF_TOKEN).
  - Set up DATA_DIR/logs/cache/output.
  - On boot: start background worker that waits for the dataset to be ready on
    `commanderzee/15m-crypto` (poll every 5 min), then calls train.run_training.
  - UI: status, tail of logs (filtered), disk usage, refresh, manual Start button.
"""

from __future__ import annotations

import logging
import os
import shutil
import threading
import time
import traceback
from pathlib import Path
from typing import Optional

import gradio as gr
from huggingface_hub import HfApi
from huggingface_hub.utils import HfHubHTTPError

# ---------------------------------------------------------------------------
# Config
# ---------------------------------------------------------------------------
ASSET = os.environ.get("ASSET", "btc").strip().lower()
MODEL_VARIANT = os.environ.get("MODEL_VARIANT", "v1_arb").strip()
N_TRIALS = int(os.environ.get("N_TRIALS", "150"))
N_FOLDS = int(os.environ.get("N_FOLDS", "5"))
AUTO_START = os.environ.get("AUTO_START", "1").strip() == "1"
HF_TOKEN = os.environ.get("HF_TOKEN", "")

DATASET_REPO = "commanderzee/15m-crypto"

DATA_DIR = Path("/data") if Path("/data").exists() else Path("/tmp")
LOG_DIR = DATA_DIR / "logs"
CACHE_DIR = DATA_DIR / "cache"
OUTPUT_DIR = DATA_DIR / "output"
LOG_FILE = LOG_DIR / "train.log"

for d in (LOG_DIR, CACHE_DIR, OUTPUT_DIR):
    d.mkdir(parents=True, exist_ok=True)


# ---------------------------------------------------------------------------
# Logger
# ---------------------------------------------------------------------------
def _build_logger() -> logging.Logger:
    logger = logging.getLogger("arbmax_trainer")
    logger.setLevel(logging.INFO)
    # avoid duplicate handlers on reload
    for h in list(logger.handlers):
        logger.removeHandler(h)
    fmt = logging.Formatter("%(asctime)s %(levelname)s %(message)s")
    fh = logging.FileHandler(LOG_FILE, mode="a", encoding="utf-8")
    fh.setFormatter(fmt)
    logger.addHandler(fh)
    sh = logging.StreamHandler()
    sh.setFormatter(fmt)
    logger.addHandler(sh)
    logger.propagate = False
    return logger


_logger = _build_logger()


def _log(msg: str) -> None:
    try:
        _logger.info(msg)
    except Exception:
        # last-ditch fallback
        try:
            with LOG_FILE.open("a", encoding="utf-8") as f:
                f.write(msg + "\n")
        except Exception:
            pass


# ---------------------------------------------------------------------------
# Worker state
# ---------------------------------------------------------------------------
_worker_lock = threading.Lock()
_worker_state = {
    "thread": None,          # type: Optional[threading.Thread]
    "status": "idle",        # idle | waiting_for_data | training | done | error
    "detail": "",
    "started_at": None,
    "finished_at": None,
}


# ---------------------------------------------------------------------------
# Dataset readiness check
# ---------------------------------------------------------------------------
def _dataset_files_ready(hf_token: str, asset: str) -> bool:
    """Both book_snapshot_5/{asset}.parquet and ohlcv_1s/{asset}.parquet present."""
    api = HfApi(token=hf_token)
    try:
        info = api.repo_info(repo_id=DATASET_REPO, repo_type="dataset", token=hf_token)
    except HfHubHTTPError:
        return False
    except Exception:
        return False
    siblings = getattr(info, "siblings", []) or []
    names = {getattr(s, "rfilename", None) for s in siblings}
    needed = {f"book_snapshot_5/{asset}.parquet", f"ohlcv_1s/{asset}.parquet"}
    return needed.issubset(names)


# ---------------------------------------------------------------------------
# Worker body
# ---------------------------------------------------------------------------
def _worker_body() -> None:
    # Deferred import so app boots fast even if heavy libs are slow.
    try:
        from train import run_training
    except Exception as e:  # noqa: BLE001
        _worker_state["status"] = "error"
        _worker_state["detail"] = f"import error: {e!r}"
        _log(f"[worker] import error: {e!r}")
        _log(traceback.format_exc())
        return

    _worker_state["status"] = "waiting_for_data"
    _worker_state["detail"] = f"waiting for {ASSET} parquet files on {DATASET_REPO}"
    _worker_state["started_at"] = time.time()
    _log(f"[worker] waiting for {ASSET} parquet files on {DATASET_REPO}")

    while True:
        try:
            ready = _dataset_files_ready(HF_TOKEN, ASSET)
        except Exception as e:  # noqa: BLE001
            _log(f"[worker] readiness check error: {e!r}")
            ready = False
        if ready:
            break
        time.sleep(300)  # 5 min

    _worker_state["status"] = "training"
    _worker_state["detail"] = "calling run_training"
    _log(f"[worker] dataset ready, starting training for {ASSET} ({MODEL_VARIANT})")

    try:
        result = run_training(
            asset=ASSET,
            hf_token=HF_TOKEN,
            variant=MODEL_VARIANT,
            n_trials=N_TRIALS,
            n_folds=N_FOLDS,
            log=_log,
            cache_dir=str(CACHE_DIR),
            output_dir=str(OUTPUT_DIR),
        )
        _worker_state["status"] = "done"
        _worker_state["detail"] = f"training completed: {result}"
        _worker_state["finished_at"] = time.time()
        _log(f"[worker] done: {result}")
    except Exception as e:  # noqa: BLE001
        _worker_state["status"] = "error"
        _worker_state["detail"] = f"training error: {e!r}"
        _worker_state["finished_at"] = time.time()
        _log(f"[worker] training error: {e!r}")
        _log(traceback.format_exc())


def _start_worker_idempotent() -> str:
    with _worker_lock:
        t: Optional[threading.Thread] = _worker_state.get("thread")  # type: ignore[assignment]
        if t is not None and t.is_alive():
            return f"Worker already running (status={_worker_state['status']})"
        new_t = threading.Thread(target=_worker_body, daemon=True, name="arbmax-worker")
        _worker_state["thread"] = new_t
        new_t.start()
        return "Worker started"


# ---------------------------------------------------------------------------
# Log tailing (filtered)
# ---------------------------------------------------------------------------
_LOG_NOISE_FRAGMENTS = (
    "HTTP Request:",
    "/gradio_api/",
    "/_app/",
    "/assets/",
    "/?logs=",
    "/?__theme=",
)


def _tail_log(max_bytes: int = 500 * 1024) -> str:
    try:
        if not LOG_FILE.exists():
            return "(log empty)"
        size = LOG_FILE.stat().st_size
        read_from = max(0, size - max_bytes)
        with LOG_FILE.open("rb") as f:
            f.seek(read_from)
            raw = f.read().decode("utf-8", errors="replace")
        lines = raw.splitlines()
        filtered = [l for l in lines if not any(frag in l for frag in _LOG_NOISE_FRAGMENTS)]
        return "\n".join(filtered[-2000:]) or "(log empty)"
    except Exception as e:  # noqa: BLE001
        return f"(log read error: {e!r})"


def _disk_usage() -> str:
    try:
        usage = shutil.disk_usage(str(DATA_DIR))
        gb = 1024 ** 3
        return (
            f"DATA_DIR={DATA_DIR}  "
            f"total={usage.total / gb:.2f} GB  "
            f"used={usage.used / gb:.2f} GB  "
            f"free={usage.free / gb:.2f} GB"
        )
    except Exception as e:  # noqa: BLE001
        return f"(disk usage error: {e!r})"


def _status_text() -> str:
    s = _worker_state
    started = s.get("started_at")
    finished = s.get("finished_at")
    started_str = time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime(started)) if started else "-"
    finished_str = time.strftime("%Y-%m-%d %H:%M:%S", time.gmtime(finished)) if finished else "-"
    return (
        f"asset={ASSET}  variant={MODEL_VARIANT}  trials={N_TRIALS}  folds={N_FOLDS}\n"
        f"status={s['status']}\n"
        f"detail={s['detail']}\n"
        f"started_at_utc={started_str}\n"
        f"finished_at_utc={finished_str}"
    )


def _refresh_all():
    return _status_text(), _tail_log(), _disk_usage()


def _on_start_click():
    msg = _start_worker_idempotent()
    _log(f"[ui] start click: {msg}")
    return _status_text(), _tail_log(), _disk_usage()


# ---------------------------------------------------------------------------
# Build Gradio app
# ---------------------------------------------------------------------------
def build_app() -> gr.Blocks:
    with gr.Blocks(title=f"ARB-MAX Trainer — {ASSET}/{MODEL_VARIANT}") as demo:
        gr.Markdown(
            f"# ARB-MAX Trainer\n"
            f"**asset** = `{ASSET}`  ·  **variant** = `{MODEL_VARIANT}`  ·  "
            f"**trials** = `{N_TRIALS}`  ·  **folds** = `{N_FOLDS}`  ·  "
            f"**auto_start** = `{AUTO_START}`"
        )
        with gr.Row():
            with gr.Column(scale=1):
                status_box = gr.Textbox(
                    label="Status",
                    value=_status_text(),
                    lines=5,
                    interactive=False,
                )
                disk_box = gr.Textbox(
                    label="Disk",
                    value=_disk_usage(),
                    lines=2,
                    interactive=False,
                )
                with gr.Row():
                    refresh_btn = gr.Button("Refresh")
                    start_btn = gr.Button("Start worker", variant="primary")
            with gr.Column(scale=2):
                log_box = gr.Code(
                    label="Training log (tail, filtered)",
                    value=_tail_log(),
                    language=None,
                    lines=28,
                )

        refresh_btn.click(_refresh_all, outputs=[status_box, log_box, disk_box])
        start_btn.click(_on_start_click, outputs=[status_box, log_box, disk_box])

        # 5s auto-refresh
        timer = gr.Timer(5.0, active=True)
        timer.tick(_refresh_all, outputs=[status_box, log_box, disk_box])

    return demo


# ---------------------------------------------------------------------------
# Entry point
# ---------------------------------------------------------------------------
if AUTO_START:
    try:
        _start_worker_idempotent()
    except Exception as e:  # noqa: BLE001
        _log(f"[boot] auto-start error: {e!r}")

demo = build_app()

if __name__ == "__main__":
    demo.queue().launch(server_name="0.0.0.0", server_port=7860)