# -*- coding: utf-8 -*-
"""Small HTTP worker for running AniFileBERT training jobs on Google Colab.

Start this inside a Colab runtime:

    python colab_worker.py

The worker exposes a token-protected local HTTP API and, by default, starts a
Cloudflare Quick Tunnel so Codex on your local machine can submit jobs.
"""

from __future__ import annotations

import argparse
import json
import os
from pathlib import Path
import platform
import re
import secrets
import shutil
import signal
import subprocess
import sys
import threading
import time
import traceback
from http import HTTPStatus
from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
from typing import Any
from urllib.parse import parse_qs, urlparse
import urllib.request


TERMINAL_STATES = {"success", "failed", "cancelled"}
TUNNEL_URL_RE = re.compile(r"https://[-a-zA-Z0-9.]+\.trycloudflare\.com")


def utc_timestamp() -> str:
    return time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime())


def json_dumps(data: Any) -> str:
    return json.dumps(data, ensure_ascii=False, indent=2)


def read_tail(path: Path, lines: int) -> str:
    if not path.is_file():
        return ""
    if lines <= 0:
        return path.read_text(encoding="utf-8", errors="replace")

    chunk_size = 8192
    data = b""
    with path.open("rb") as f:
        f.seek(0, os.SEEK_END)
        pos = f.tell()
        while pos > 0 and data.count(b"\n") <= lines:
            read_size = min(chunk_size, pos)
            pos -= read_size
            f.seek(pos)
            data = f.read(read_size) + data
    return b"\n".join(data.splitlines()[-lines:]).decode("utf-8", errors="replace")


def download_cloudflared(path: Path) -> Path:
    if path.is_file():
        return path

    existing = shutil.which("cloudflared")
    if existing:
        return Path(existing)

    arch = platform.machine().lower()
    if arch in {"x86_64", "amd64"}:
        suffix = "linux-amd64"
    elif arch in {"aarch64", "arm64"}:
        suffix = "linux-arm64"
    else:
        raise RuntimeError(f"Unsupported CPU architecture for cloudflared: {arch}")

    url = f"https://github.com/cloudflare/cloudflared/releases/latest/download/cloudflared-{suffix}"
    print(f"Downloading cloudflared: {url}", flush=True)
    path.parent.mkdir(parents=True, exist_ok=True)
    urllib.request.urlretrieve(url, path)
    path.chmod(0o755)
    return path


class WorkerState:
    def __init__(self, repo_dir: Path, jobs_dir: Path):
        self.repo_dir = repo_dir
        self.jobs_dir = jobs_dir
        self.jobs_dir.mkdir(parents=True, exist_ok=True)
        self.jobs: dict[str, dict[str, Any]] = {}
        self.lock = threading.RLock()

    def list_jobs(self) -> list[dict[str, Any]]:
        with self.lock:
            return [self._public_job(job) for job in self.jobs.values()]

    def get_job(self, job_id: str) -> dict[str, Any] | None:
        with self.lock:
            job = self.jobs.get(job_id)
            return self._public_job(job) if job else None

    def get_job_internal(self, job_id: str) -> dict[str, Any] | None:
        with self.lock:
            return self.jobs.get(job_id)

    def active_job(self) -> dict[str, Any] | None:
        with self.lock:
            for job in self.jobs.values():
                if job["status"] not in TERMINAL_STATES:
                    return job
        return None

    def start_job(self, payload: dict[str, Any]) -> dict[str, Any]:
        with self.lock:
            active = self.active_job()
            if active is not None:
                raise RuntimeError(f"Job already running: {active['job_id']}")

            job_id = time.strftime("%Y%m%d-%H%M%S", time.gmtime()) + "-" + secrets.token_hex(3)
            job_dir = self.jobs_dir / job_id
            job_dir.mkdir(parents=True, exist_ok=True)
            log_path = job_dir / "worker.log"
            config_path: Path | None = None

            cmd = [sys.executable, "colab_train.py"]
            config = self._job_config(payload)
            config.setdefault("artifacts", {})
            config["artifacts"]["manifest"] = os.fspath(job_dir / "colab_run_manifest.json")
            config_path = job_dir / "config.json"
            config_path.write_text(json_dumps(config), encoding="utf-8")
            cmd.extend(["--config", os.fspath(config_path)])

            for arg in payload.get("args", []):
                cmd.append(str(arg))

            job = {
                "job_id": job_id,
                "status": "queued",
                "created_at": utc_timestamp(),
                "started_at": None,
                "finished_at": None,
                "returncode": None,
                "cmd": cmd,
                "cwd": os.fspath(self.repo_dir),
                "job_dir": os.fspath(job_dir),
                "log_path": os.fspath(log_path),
                "config_path": os.fspath(config_path) if config_path else None,
                "error": None,
                "process": None,
            }
            self.jobs[job_id] = job

        thread = threading.Thread(target=self._run_job, args=(job_id,), daemon=True)
        thread.start()
        return self._public_job(job)

    def _job_config(self, payload: dict[str, Any]) -> dict[str, Any]:
        if "config" in payload:
            return json.loads(json.dumps(payload["config"], ensure_ascii=False))

        profile = str(payload.get("profile", "dmhy_regex_finetune"))
        profile_path = self.repo_dir / "colab" / "configs" / f"{profile}.json"
        if not profile_path.is_file():
            raise FileNotFoundError(f"Profile not found: {profile_path}")
        return json.loads(profile_path.read_text(encoding="utf-8"))

    def cancel_job(self, job_id: str) -> dict[str, Any]:
        with self.lock:
            job = self.jobs.get(job_id)
            if job is None:
                raise KeyError(job_id)
            process: subprocess.Popen[str] | None = job.get("process")
            if job["status"] in TERMINAL_STATES:
                return self._public_job(job)
            job["status"] = "cancelled"
            job["finished_at"] = utc_timestamp()

        if process and process.poll() is None:
            try:
                os.killpg(os.getpgid(process.pid), signal.SIGTERM)
            except Exception:
                process.terminate()
        return self.get_job(job_id) or {}

    def _run_job(self, job_id: str) -> None:
        job = self.get_job_internal(job_id)
        if job is None:
            return
        log_path = Path(job["log_path"])
        try:
            with self.lock:
                job["status"] = "running"
                job["started_at"] = utc_timestamp()

            with log_path.open("w", encoding="utf-8", errors="replace") as log:
                log.write(f"job_id={job_id}\n")
                log.write(f"cwd={job['cwd']}\n")
                log.write("$ " + " ".join(job["cmd"]) + "\n\n")
                log.flush()

                process = subprocess.Popen(
                    job["cmd"],
                    cwd=job["cwd"],
                    stdout=subprocess.PIPE,
                    stderr=subprocess.STDOUT,
                    text=True,
                    encoding="utf-8",
                    errors="replace",
                    bufsize=1,
                    preexec_fn=os.setsid if hasattr(os, "setsid") else None,
                )
                with self.lock:
                    job["process"] = process

                assert process.stdout is not None
                for line in process.stdout:
                    log.write(line)
                    log.flush()
                    print(line, end="", flush=True)
                process.wait()

            with self.lock:
                job["returncode"] = process.returncode
                if job["status"] != "cancelled":
                    job["status"] = "success" if process.returncode == 0 else "failed"
                job["finished_at"] = utc_timestamp()
                job["process"] = None
        except Exception as exc:
            with log_path.open("a", encoding="utf-8", errors="replace") as log:
                traceback.print_exc(file=log)
            with self.lock:
                job["status"] = "failed"
                job["finished_at"] = utc_timestamp()
                job["error"] = f"{type(exc).__name__}: {exc}"
                job["process"] = None

    def _public_job(self, job: dict[str, Any]) -> dict[str, Any]:
        public = {key: value for key, value in job.items() if key != "process"}
        return public


def make_handler(state: WorkerState, token: str):
    class Handler(BaseHTTPRequestHandler):
        server_version = "AniFileBERTColabWorker/1.0"

        def log_message(self, fmt: str, *args: Any) -> None:
            print(f"[{utc_timestamp()}] {self.address_string()} {fmt % args}", flush=True)

        def do_GET(self) -> None:
            self._handle("GET")

        def do_POST(self) -> None:
            self._handle("POST")

        def _handle(self, method: str) -> None:
            parsed = urlparse(self.path)
            path = parsed.path.rstrip("/") or "/"
            parts = [part for part in path.split("/") if part]
            try:
                if not self._authorized():
                    self._send({"error": "unauthorized"}, HTTPStatus.UNAUTHORIZED)
                    return

                if method == "GET" and path == "/health":
                    self._send(
                        {
                            "ok": True,
                            "repo_dir": os.fspath(state.repo_dir),
                            "jobs_dir": os.fspath(state.jobs_dir),
                            "active_job": state.active_job()["job_id"] if state.active_job() else None,
                        }
                    )
                    return

                if method == "GET" and path == "/jobs":
                    self._send({"jobs": state.list_jobs()})
                    return

                if method == "POST" and path == "/jobs":
                    payload = self._read_json()
                    job = state.start_job(payload)
                    self._send(job, HTTPStatus.ACCEPTED)
                    return

                if len(parts) >= 2 and parts[0] == "jobs":
                    job_id = parts[1]
                    if method == "GET" and len(parts) == 2:
                        job = state.get_job(job_id)
                        if job is None:
                            self._send({"error": "job not found"}, HTTPStatus.NOT_FOUND)
                        else:
                            self._send(job)
                        return

                    if method == "GET" and len(parts) == 3 and parts[2] == "logs":
                        query = parse_qs(parsed.query)
                        tail = int(query.get("tail", ["200"])[0])
                        job = state.get_job_internal(job_id)
                        if job is None:
                            self._send({"error": "job not found"}, HTTPStatus.NOT_FOUND)
                        else:
                            self._send({"job_id": job_id, "log": read_tail(Path(job["log_path"]), tail)})
                        return

                    if method == "GET" and len(parts) == 3 and parts[2] == "manifest":
                        job = state.get_job_internal(job_id)
                        if job is None:
                            self._send({"error": "job not found"}, HTTPStatus.NOT_FOUND)
                        else:
                            manifest = self._find_manifest(job)
                            if manifest is None:
                                self._send({"error": "manifest not found"}, HTTPStatus.NOT_FOUND)
                            else:
                                self._send(json.loads(manifest.read_text(encoding="utf-8")))
                        return

                    if method == "POST" and len(parts) == 3 and parts[2] == "cancel":
                        try:
                            self._send(state.cancel_job(job_id))
                        except KeyError:
                            self._send({"error": "job not found"}, HTTPStatus.NOT_FOUND)
                        return

                self._send({"error": "not found"}, HTTPStatus.NOT_FOUND)
            except Exception as exc:
                traceback.print_exc()
                self._send({"error": f"{type(exc).__name__}: {exc}"}, HTTPStatus.INTERNAL_SERVER_ERROR)

        def _authorized(self) -> bool:
            header = self.headers.get("Authorization", "")
            if header == f"Bearer {token}":
                return True
            return self.headers.get("X-Colab-Token") == token

        def _read_json(self) -> dict[str, Any]:
            length = int(self.headers.get("Content-Length", "0"))
            if length == 0:
                return {}
            raw = self.rfile.read(length)
            return json.loads(raw.decode("utf-8"))

        def _find_manifest(self, job: dict[str, Any]) -> Path | None:
            config_path = job.get("config_path")
            if config_path and Path(config_path).is_file():
                config = json.loads(Path(config_path).read_text(encoding="utf-8"))
                training = config.get("training", {})
                save_dir = training.get("save_dir")
                if save_dir:
                    manifest = Path(save_dir) / "colab_run_manifest.json"
                    if manifest.is_file():
                        return manifest
            job_manifest = Path(job["job_dir"]) / "colab_run_manifest.json"
            return job_manifest if job_manifest.is_file() else None

        def _send(self, data: Any, status: HTTPStatus = HTTPStatus.OK) -> None:
            raw = json_dumps(data).encode("utf-8")
            self.send_response(status.value)
            self.send_header("Content-Type", "application/json; charset=utf-8")
            self.send_header("Content-Length", str(len(raw)))
            self.end_headers()
            self.wfile.write(raw)

    return Handler


def start_tunnel(port: int, binary_path: Path) -> subprocess.Popen[str]:
    cloudflared = download_cloudflared(binary_path)
    cmd = [
        os.fspath(cloudflared),
        "tunnel",
        "--url",
        f"http://127.0.0.1:{port}",
        "--no-autoupdate",
    ]
    proc = subprocess.Popen(
        cmd,
        stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT,
        text=True,
        encoding="utf-8",
        errors="replace",
        bufsize=1,
    )

    def pump() -> None:
        assert proc.stdout is not None
        for line in proc.stdout:
            print(line, end="", flush=True)
            match = TUNNEL_URL_RE.search(line)
            if match:
                print("\nCOLAB_WORKER_URL=" + match.group(0), flush=True)

    threading.Thread(target=pump, daemon=True).start()
    return proc


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Start the AniFileBERT Colab worker")
    parser.add_argument("--host", default="127.0.0.1", help="HTTP bind host")
    parser.add_argument("--port", type=int, default=7860, help="HTTP bind port")
    parser.add_argument("--repo-dir", default="/content/AniFileBERT", help="AniFileBERT checkout path in Colab")
    parser.add_argument("--jobs-dir", default="/content/drive/MyDrive/AniFileBERT/worker/jobs")
    parser.add_argument("--token", default=os.environ.get("ANIFILEBERT_COLAB_TOKEN"))
    parser.add_argument("--tunnel", choices=["cloudflare", "none"], default="cloudflare")
    parser.add_argument("--cloudflared-path", default="/tmp/anifilebert-cloudflared")
    return parser.parse_args()


def main() -> None:
    args = parse_args()
    token = args.token or secrets.token_urlsafe(24)
    repo_dir = Path(args.repo_dir)
    if not repo_dir.is_dir():
        raise RuntimeError(f"Repo directory does not exist: {repo_dir}")

    state = WorkerState(repo_dir=repo_dir, jobs_dir=Path(args.jobs_dir))
    server = ThreadingHTTPServer((args.host, args.port), make_handler(state, token))
    tunnel_proc: subprocess.Popen[str] | None = None

    print("=" * 72)
    print("AniFileBERT Colab worker is starting")
    print(f"Local URL: http://{args.host}:{args.port}")
    print(f"COLAB_WORKER_TOKEN={token}")
    print("Keep this Colab cell running while Codex uses the worker.")
    print("=" * 72, flush=True)

    if args.tunnel == "cloudflare":
        tunnel_proc = start_tunnel(args.port, Path(args.cloudflared_path))
    else:
        print("Tunnel disabled. Use the local URL from inside the Colab runtime.", flush=True)

    try:
        server.serve_forever()
    finally:
        server.server_close()
        if tunnel_proc and tunnel_proc.poll() is None:
            tunnel_proc.terminate()


if __name__ == "__main__":
    main()