app.py

"""FastAPI control panel for the CERNenv trainer Space.

Endpoints:
    GET  /              → status page (HTML)
    GET  /status        → JSON status of the current training run
    GET  /metrics       → JSON snapshot of reward / success rate
    GET  /logs          → tail of the training log
    POST /train         → start (or restart) a training run
    GET  /health        → liveness probe

Designed to run on a Hugging Face Space with `sdk: docker`. Heavy training
work runs in a background thread so the HTTP server stays responsive.
"""

from __future__ import annotations

import json
import logging
import os
import subprocess
import sys
import threading
import time
from datetime import datetime, timezone
from pathlib import Path
from typing import Any, Dict, Optional

from fastapi import FastAPI, HTTPException
from fastapi.responses import FileResponse, HTMLResponse, JSONResponse, PlainTextResponse
from fastapi.staticfiles import StaticFiles


logging.basicConfig(level=logging.INFO, format="%(asctime)s [%(levelname)s] %(message)s")
logger = logging.getLogger(__name__)


def _resolve_repo_root() -> Path:
    env_root = os.environ.get("CERNENV_ROOT")
    candidates = []
    if env_root:
        candidates.append(Path(env_root))
    candidates.extend([
        Path("/home/user/app"),
        Path(__file__).resolve().parent.parent.parent,
    ])
    for p in candidates:
        try:
            if p.exists():
                return p.resolve()
        except OSError:
            continue
    return candidates[-1].resolve()


REPO_ROOT = _resolve_repo_root()
LOG_DIR = REPO_ROOT / "training" / "runs"
try:
    LOG_DIR.mkdir(parents=True, exist_ok=True)
except OSError as exc:  # pragma: no cover - read-only filesystem fallback
    logger.warning("could not create %s (%s); using /tmp", LOG_DIR, exc)
    LOG_DIR = Path("/tmp/cernenv-runs")
    LOG_DIR.mkdir(parents=True, exist_ok=True)
LOG_FILE = LOG_DIR / "training.log"
EVIDENCE_DIR = REPO_ROOT / "evidence"
try:
    EVIDENCE_DIR.mkdir(parents=True, exist_ok=True)
except OSError:  # pragma: no cover
    EVIDENCE_DIR = Path("/tmp/cernenv-evidence")
    EVIDENCE_DIR.mkdir(parents=True, exist_ok=True)
METRICS_FILE = EVIDENCE_DIR / "before_after_metrics.json"


def _env(name: str, default: str) -> str:
    return os.environ.get(name, default)


def _detect_gpus() -> int:
    try:
        import torch  # type: ignore
        if torch.cuda.is_available():
            return torch.cuda.device_count()
    except Exception:
        pass
    try:
        out = subprocess.run(
            ["nvidia-smi", "--query-gpu=name", "--format=csv,noheader"],
            capture_output=True, text=True, timeout=5,
        )
        return len([l for l in out.stdout.splitlines() if l.strip()])
    except Exception:
        return 0


_NUM_GPUS = _detect_gpus()


CONFIG = {
    "model_name":       _env("MODEL_NAME", "unsloth/Qwen2.5-3B-Instruct"),
    "difficulty":       _env("DIFFICULTY", "easy"),
    "curriculum":       _env("CURRICULUM", "1") == "1",
    "curriculum_promote": float(_env("CURRICULUM_PROMOTE", "0.55")),
    "curriculum_demote":  float(_env("CURRICULUM_DEMOTE", "0.10")),
    "total_episodes":   int(_env("TOTAL_EPISODES", "1500")),
    "max_steps":        int(_env("MAX_STEPS", "18")),
    "num_generations":  int(_env("NUM_GENERATIONS", "8")),
    "checkpoint_eval_steps":    int(_env("CHECKPOINT_EVAL_STEPS", "25")),
    "checkpoint_eval_episodes": int(_env("CHECKPOINT_EVAL_EPISODES", "8")),
    "eval_episodes":    int(_env("EVAL_EPISODES", "32")),
    "output_dir":       _env("OUTPUT_DIR", "runs/unsloth-grpo"),
    "evidence_dir":     _env("EVIDENCE_DIR", "evidence"),
    "num_gpus":         int(_env("NUM_GPUS", str(_NUM_GPUS or 1))),
    "hf_username":      _env("HF_USERNAME", "anugrah55"),
    "push_repo":        _env(
        "PUSH_REPO",
        f"{_env('HF_USERNAME', 'anugrah55')}/cernenv-grpo-qwen2.5-3b",
    ),
    "autostart":        _env("AUTOSTART", "0") == "1",
}


# ── Run state ────────────────────────────────────────────────────────────


class RunState:
    def __init__(self) -> None:
        self.lock = threading.Lock()
        self.thread: Optional[threading.Thread] = None
        self.process: Optional[subprocess.Popen] = None
        self.status: str = "idle"  # idle | running | finished | failed
        self.started_at: Optional[str] = None
        self.finished_at: Optional[str] = None
        self.last_error: Optional[str] = None
        self.last_config: Dict[str, Any] = {}

    def to_dict(self) -> Dict[str, Any]:
        with self.lock:
            return {
                "status": self.status,
                "started_at": self.started_at,
                "finished_at": self.finished_at,
                "last_error": self.last_error,
                "last_config": self.last_config,
            }


STATE = RunState()


# ── Training pipeline ────────────────────────────────────────────────────


def _stream_subprocess(cmd: list[str], log_handle) -> int:
    log_handle.write(f"\n$ {' '.join(cmd)}\n")
    log_handle.flush()
    proc = subprocess.Popen(
        cmd,
        cwd=str(REPO_ROOT),
        stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT,
        bufsize=1,
        universal_newlines=True,
        env={**os.environ, "PYTHONPATH": str(REPO_ROOT)},
    )
    STATE.process = proc
    assert proc.stdout is not None
    for line in proc.stdout:
        log_handle.write(line)
        log_handle.flush()
    rc = proc.wait()
    log_handle.write(f"[exit code {rc}]\n")
    log_handle.flush()
    STATE.process = None
    return rc


def _build_training_cmd(config: Dict[str, Any]) -> list[str]:
    """Compose the training launcher (single-GPU python or multi-GPU accelerate)."""
    base = [
        "-m", "training.training_unsloth",
        "--model_name", config["model_name"],
        "--difficulty", config["difficulty"],
        "--total_episodes", str(config["total_episodes"]),
        "--max_steps", str(config["max_steps"]),
        "--num_generations", str(config["num_generations"]),
        "--checkpoint_eval_steps", str(config["checkpoint_eval_steps"]),
        "--checkpoint_eval_episodes", str(config["checkpoint_eval_episodes"]),
        "--output_dir", config["output_dir"],
        "--evidence_dir", config["evidence_dir"],
    ]
    if config.get("curriculum"):
        base.extend([
            "--curriculum",
            "--curriculum_promote", str(config["curriculum_promote"]),
            "--curriculum_demote",  str(config["curriculum_demote"]),
        ])
    n = max(int(config.get("num_gpus", 1)), 1)
    if n > 1:
        return ["accelerate", "launch", "--num_processes", str(n), "--mixed_precision", "bf16"] + base
    return [sys.executable] + base


def _push_evidence_to_hub(*, evidence_dir: Path, repo_id: str, log) -> None:
    """Upload the entire evidence/ directory to the model repo."""
    token = os.environ.get("HF_TOKEN")
    if not token:
        log.write("\n[skip] HF_TOKEN not set — evidence not pushed\n")
        log.flush()
        return
    try:
        from huggingface_hub import HfApi
        api = HfApi(token=token)
        api.upload_folder(
            folder_path=str(evidence_dir),
            repo_id=repo_id,
            repo_type="model",
            path_in_repo="evidence",
            commit_message="Upload CERNenv training evidence (curves, evals, plots)",
        )
        log.write(f"\n[ok] uploaded evidence/ → https://huggingface.co/{repo_id}/tree/main/evidence\n")
        log.flush()
    except Exception as exc:
        log.write(f"\n[warn] evidence push failed: {exc}\n")
        log.flush()


def _training_pipeline(config: Dict[str, Any]) -> None:
    started = datetime.now(timezone.utc).isoformat()
    with STATE.lock:
        STATE.status = "running"
        STATE.started_at = started
        STATE.finished_at = None
        STATE.last_error = None
        STATE.last_config = dict(config)

    evidence_dir = Path(config["evidence_dir"]).resolve()
    evidence_dir.mkdir(parents=True, exist_ok=True)

    LOG_FILE.parent.mkdir(parents=True, exist_ok=True)
    with open(LOG_FILE, "a") as log:
        log.write(f"\n=== Training started {started} ===\n")
        log.write(json.dumps(config, indent=2) + "\n")
        log.flush()
        try:
            output_dir = config["output_dir"]
            difficulty = config["difficulty"]
            max_steps = str(config["max_steps"])
            eval_episodes = str(config["eval_episodes"])
            model_name = config["model_name"]
            push_repo = config["push_repo"]
            evidence_str = config["evidence_dir"]
            pre_jsonl = f"{evidence_str}/pre_eval.jsonl"
            post_jsonl = f"{evidence_str}/post_eval.jsonl"

            log.write("\n--- baseline sanity check (random / heuristic / oracle) ---\n")
            log.flush()
            for agent in ("random", "heuristic", "oracle"):
                _stream_subprocess(
                    [
                        sys.executable, "-m", "scripts.run_agent",
                        "--agent", agent, "--difficulty", difficulty,
                        "--episodes", "3", "--quiet",
                    ],
                    log,
                )

            log.write(f"\n--- pre-train evaluation ({eval_episodes} eps) ---\n")
            log.flush()
            rc = _stream_subprocess(
                [
                    sys.executable, "-m", "training.evaluate",
                    "--model_name", model_name,
                    "--difficulty", difficulty,
                    "--episodes", eval_episodes,
                    "--max_steps", max_steps,
                    "--tag", "pre_train",
                    "--out", pre_jsonl,
                ],
                log,
            )
            if rc != 0:
                # don't abort — we still want training + post-eval evidence.
                log.write(f"\n[warn] pre-train eval failed (rc={rc}); continuing without baseline\n")
                log.flush()

            log.write(f"\n--- GRPO training ({config['num_gpus']} GPU process(es)) ---\n")
            log.flush()
            rc = _stream_subprocess(_build_training_cmd(config), log)
            if rc != 0:
                raise RuntimeError(f"training failed (rc={rc})")

            # ── LoRA save-and-reload smoke test ─────────────────────
            # Hackathon FAQ Q9: "Do not upcast a 4-bit model to 16-bit
            # and then merge the LoRA weights naively" — the canonical
            # cause of a broken push. Before we burn time on the full
            # post-train evaluation (32 eps), do a 2-episode cold-load
            # rollout against the saved adapters. If that fails, abort
            # immediately so we surface a save problem, not a 30-min
            # eval timeout.
            log.write(
                f"\n--- adapter save/reload smoke test "
                f"(loading {output_dir} cold-start, 2 eps) ---\n"
            )
            log.flush()
            rc = _stream_subprocess(
                [
                    sys.executable, "-m", "training.evaluate",
                    "--model_name", model_name,
                    "--adapter_dir", output_dir,
                    "--difficulty", difficulty,
                    "--episodes", "2",
                    "--max_steps", max_steps,
                    "--tag", "smoke",
                    "--out", f"{evidence_str}/smoke_eval.jsonl",
                ],
                log,
            )
            if rc != 0:
                raise RuntimeError(
                    f"adapter smoke test failed (rc={rc}); refusing to push "
                    f"unloadable adapters to the Hub. Inspect {output_dir} and "
                    "verify adapter_config.json + adapter_model.safetensors exist."
                )

            log.write(f"\n--- post-train evaluation ({eval_episodes} eps) ---\n")
            log.flush()
            rc = _stream_subprocess(
                [
                    sys.executable, "-m", "training.evaluate",
                    "--model_name", model_name,
                    "--adapter_dir", output_dir,
                    "--difficulty", difficulty,
                    "--episodes", eval_episodes,
                    "--max_steps", max_steps,
                    "--tag", "post_train",
                    "--out", post_jsonl,
                ],
                log,
            )
            if rc != 0:
                log.write(f"\n[warn] post-train eval failed (rc={rc}); evidence will be partial\n")
                log.flush()

            log.write("\n--- evidence: before/after summary, distribution, trajectories ---\n")
            log.flush()
            try:
                from training.evidence import (
                    EvidencePaths,
                    render_before_after,
                    render_sample_trajectories,
                    render_training_curve,
                    render_reward_components,
                    render_checkpoint_progression,
                )
                paths = EvidencePaths(root=Path(evidence_str))
                paths.ensure()
                metrics = render_before_after(
                    pre_jsonl=Path(pre_jsonl),
                    post_jsonl=Path(post_jsonl),
                    summary_png=paths.before_after_summary_png,
                    distribution_png=paths.reward_distribution_png,
                    metrics_json=paths.before_after_metrics_json,
                )
                render_sample_trajectories(
                    pre_jsonl=Path(pre_jsonl),
                    post_jsonl=Path(post_jsonl),
                    md_path=paths.sample_trajectories_md,
                )
                render_training_curve(paths.training_log_csv, paths.training_curve_png)
                render_reward_components(
                    paths.reward_components_csv, paths.reward_components_png,
                )
                render_checkpoint_progression(
                    paths.checkpoint_evals_csv, paths.checkpoint_progression_png,
                )
                log.write(json.dumps(metrics, indent=2) + "\n")
                log.flush()
            except Exception as exc:
                log.write(f"[warn] evidence rendering failed: {exc}\n")
                log.flush()

            if os.environ.get("HF_TOKEN"):
                log.write("\n--- push adapters to Hub ---\n")
                log.flush()
                _stream_subprocess(
                    [
                        sys.executable, "-m", "scripts.push_to_hub", "model",
                        "--adapter_dir", output_dir,
                        "--repo_id", push_repo,
                        "--base_model", model_name,
                    ],
                    log,
                )
                _push_evidence_to_hub(
                    evidence_dir=evidence_dir,
                    repo_id=push_repo,
                    log=log,
                )
            else:
                log.write("\n[skip] HF_TOKEN not set — not pushing to Hub\n")
                log.flush()

            with STATE.lock:
                STATE.status = "finished"
        except Exception as exc:
            logger.exception("training pipeline failed")
            with STATE.lock:
                STATE.status = "failed"
                STATE.last_error = str(exc)
        finally:
            finished = datetime.now(timezone.utc).isoformat()
            log.write(f"\n=== Training ended {finished} ===\n")
            log.flush()
            with STATE.lock:
                STATE.finished_at = finished


def _start_training(config: Dict[str, Any]) -> None:
    with STATE.lock:
        if STATE.status == "running":
            raise RuntimeError("a training run is already in progress")
        STATE.thread = threading.Thread(
            target=_training_pipeline,
            args=(config,),
            name="cernenv-trainer",
            daemon=True,
        )
        STATE.thread.start()


# ── FastAPI app ──────────────────────────────────────────────────────────


app = FastAPI(title="CERNenv Trainer", version="0.1.0")


_HTML = """\
<!doctype html>
<html lang=en>
<head>
  <meta charset=utf-8>
  <title>CERNenv Trainer</title>
  <style>
    body { font-family: ui-sans-serif, system-ui, sans-serif; margin: 2rem auto;
           max-width: 1000px; color:#111; padding: 0 1rem; line-height:1.5 }
    h1 { margin-bottom: 0 }
    h2 { margin-top: 2rem; border-bottom:1px solid #eee; padding-bottom:.25rem }
    .muted { color:#666 }
    pre { background:#0e1116; color:#e6edf3; padding:1rem; border-radius:6px;
          overflow-x:auto; max-height:40vh; font-size:.85em }
    button { font-size:1rem; padding:.6rem 1rem; border-radius:6px; border:1px solid #888;
             background:#fff; cursor:pointer; margin-right:.4rem }
    .pill { display:inline-block; padding:.1rem .55rem; border-radius:999px;
            background:#eef; color:#225; font-size:.85em }
    .ok { background:#dfd; color:#272 }
    .fail { background:#fdd; color:#822 }
    .run { background:#fdf6d8; color:#774 }
    table { border-collapse:collapse; margin:.5rem 0 }
    td, th { padding:.25rem .8rem .25rem 0; vertical-align: top; text-align:left }
    th { color:#444; font-weight:600 }
    .grid { display:grid; grid-template-columns:1fr 1fr; gap:1rem }
    .card { border:1px solid #e5e7eb; border-radius:8px; padding:.75rem; background:#fafafa }
    .card img { max-width:100%; border-radius:4px }
    .delta-pos { color:#15803d; font-weight:600 }
    .delta-neg { color:#b91c1c; font-weight:600 }
    code { background:#f4f4f4; padding:.05rem .35rem; border-radius:4px }
    a { color:#1d4ed8 }
  </style>
</head>
<body>
  <h1>⚛️ CERNenv Trainer</h1>
  <p class=muted>GRPO + Unsloth + LoRA on the CERNenv LHC discovery environment. Multi-GPU on Hugging Face Spaces.</p>

  <h2>Run status</h2>
  <p>Status: <span id=status class=pill>?</span></p>
  <table id=meta></table>
  <p>
    <button onclick="startRun()">▶ Start training</button>
    <button onclick="refresh()">↻ Refresh</button>
    <a href="/evidence" target=_blank><button>📁 Evidence index</button></a>
    <a href="/docs" target=_blank><button>🛠 API</button></a>
  </p>

  <h2>Training-progress evidence</h2>
  <p class=muted>Auto-updated as training runs. All artifacts are also saved to <code>evidence/</code> and pushed to the model repo on the Hub.</p>
  <div class=grid>
    <div class=card><b>Per-step training curve</b><br>
      <img id=curve src="/evidence/training_curve.png" onerror="this.style.display='none'">
      <div id=curve_missing class=muted style="display:none">(not yet — waiting for first GRPO step)</div>
    </div>
    <div class=card><b>Reward components (terminal vs shaping)</b><br>
      <img id=components src="/evidence/reward_components.png" onerror="this.style.display='none'">
      <div id=components_missing class=muted style="display:none">(populated after a few rollouts — watches verifier hacks)</div>
    </div>
    <div class=card><b>Mid-training checkpoint progression</b><br>
      <img id=ckpt src="/evidence/checkpoint_progression.png" onerror="this.style.display='none'">
      <div id=ckpt_missing class=muted style="display:none">(not yet — waiting for first checkpoint eval)</div>
    </div>
    <div class=card><b>Before vs after summary</b><br>
      <img id=summary src="/evidence/before_after_summary.png" onerror="this.style.display='none'">
      <div id=summary_missing class=muted style="display:none">(generated after post-train eval)</div>
    </div>
    <div class=card><b>Reward distribution: pre vs post</b><br>
      <img id=dist src="/evidence/reward_distribution.png" onerror="this.style.display='none'">
      <div id=dist_missing class=muted style="display:none">(generated after post-train eval)</div>
    </div>
  </div>

  <h2>Before / after metrics</h2>
  <table id=metrics_table>
    <tr><th>metric</th><th>pre</th><th>post</th><th>Δ</th></tr>
  </table>

  <h2>Live logs (tail)</h2>
  <pre id=logs>loading…</pre>

<script>
function fmt(v) {
  if (v == null) return '–';
  if (typeof v === 'number') return v.toFixed(3);
  return v;
}
function fmtDelta(d) {
  if (d == null || isNaN(d)) return '–';
  const sign = d >= 0 ? '+' : '';
  const cls = d >= 0 ? 'delta-pos' : 'delta-neg';
  return `<span class="${cls}">${sign}${d.toFixed(3)}</span>`;
}

async function refresh() {
  // status
  const s = await fetch('/status').then(r => r.json());
  const pill = document.getElementById('status');
  pill.textContent = s.status;
  pill.className = 'pill ' + ({idle:'',running:'run',finished:'ok',failed:'fail'}[s.status] || '');

  const meta = document.getElementById('meta');
  meta.innerHTML = '';
  const obj = {
    started_at: s.started_at, finished_at: s.finished_at, error: s.last_error,
    ...(s.last_config || {}),
  };
  for (const [k, v] of Object.entries(obj)) {
    if (v == null || v === '') continue;
    const tr = document.createElement('tr');
    tr.innerHTML = `<td><b>${k}</b></td><td><code>${v}</code></td>`;
    meta.appendChild(tr);
  }

  // metrics
  const m = await fetch('/metrics').then(r => r.json()).catch(() => ({pre:null, post:null}));
  const tbody = document.getElementById('metrics_table');
  tbody.innerHTML = '<tr><th>metric</th><th>pre</th><th>post</th><th>Δ</th></tr>';
  const fields = ['mean_reward', 'success_rate', 'mass_acc', 'channel_acc', 'median_reward'];
  for (const f of fields) {
    const pre = m.pre && m.pre[f];
    const post = m.post && m.post[f];
    const delta = m.delta && m.delta[f];
    const tr = document.createElement('tr');
    tr.innerHTML = `<td><code>${f}</code></td><td>${fmt(pre)}</td><td>${fmt(post)}</td><td>${fmtDelta(delta)}</td>`;
    tbody.appendChild(tr);
  }

  // bust caches on plots
  const bust = '?t=' + Date.now();
  for (const [imgId, missingId] of [
    ['curve', 'curve_missing'],
    ['components', 'components_missing'],
    ['ckpt', 'ckpt_missing'],
    ['summary', 'summary_missing'],
    ['dist', 'dist_missing'],
  ]) {
    const img = document.getElementById(imgId);
    const miss = document.getElementById(missingId);
    const baseSrc = img.getAttribute('src').split('?')[0];
    const probe = new Image();
    probe.onload  = () => { img.src = baseSrc + bust; img.style.display=''; miss.style.display='none'; };
    probe.onerror = () => { img.style.display='none'; miss.style.display=''; };
    probe.src = baseSrc + bust;
  }

  const logs = await fetch('/logs?tail=200').then(r => r.text());
  document.getElementById('logs').textContent = logs || '(no logs yet)';
}
async function startRun() {
  const r = await fetch('/train', {method:'POST'});
  if (!r.ok) alert((await r.json()).detail || 'failed');
  setTimeout(refresh, 500);
}
refresh();
setInterval(refresh, 5000);
</script>
</body>
</html>
"""


@app.get("/", response_class=HTMLResponse)
def index() -> HTMLResponse:
    return HTMLResponse(_HTML)


@app.get("/health")
def health() -> Dict[str, str]:
    return {"status": "ok"}


@app.get("/status")
def status() -> JSONResponse:
    return JSONResponse(STATE.to_dict())


@app.get("/metrics")
def metrics() -> JSONResponse:
    if METRICS_FILE.exists():
        try:
            return JSONResponse(json.loads(METRICS_FILE.read_text()))
        except Exception:
            return JSONResponse({"error": "metrics file unreadable"}, status_code=500)
    return JSONResponse({"pre": None, "post": None, "delta": None})


@app.get("/evidence")
def evidence_index() -> JSONResponse:
    """List every evidence artifact currently on disk."""
    files = []
    if EVIDENCE_DIR.exists():
        for p in sorted(EVIDENCE_DIR.iterdir()):
            if p.is_file():
                files.append({
                    "name": p.name,
                    "size": p.stat().st_size,
                    "url": f"/evidence/{p.name}",
                })
    return JSONResponse({"dir": str(EVIDENCE_DIR), "files": files})


@app.get("/evidence/{name}")
def evidence_file(name: str):
    """Serve a single evidence artifact (PNG/CSV/JSON/MD) by filename."""
    if "/" in name or ".." in name:
        raise HTTPException(status_code=400, detail="invalid name")
    target = EVIDENCE_DIR / name
    if not target.exists() or not target.is_file():
        raise HTTPException(status_code=404, detail=f"{name} not found")
    return FileResponse(target)


@app.get("/logs", response_class=PlainTextResponse)
def logs(tail: int = 400) -> PlainTextResponse:
    if not LOG_FILE.exists():
        return PlainTextResponse("")
    text = LOG_FILE.read_text()
    lines = text.splitlines()
    return PlainTextResponse("\n".join(lines[-max(tail, 1):]))


@app.post("/train")
def train() -> JSONResponse:
    try:
        _start_training(dict(CONFIG))
    except RuntimeError as exc:
        raise HTTPException(status_code=409, detail=str(exc))
    return JSONResponse({"status": "started", "config": CONFIG})


@app.on_event("startup")
def _maybe_autostart() -> None:
    if CONFIG["autostart"]:
        try:
            _start_training(dict(CONFIG))
            logger.info("autostarted training run")
        except RuntimeError as exc:
            logger.warning("autostart skipped: %s", exc)