#!/usr/bin/env python3
"""HuggingMes Hermes state backup via Hugging Face Datasets."""

import hashlib
import json
import logging
import os
import shutil
import signal
import sys
import tempfile
import threading
import time
from pathlib import Path

os.environ.setdefault("HF_HUB_DISABLE_PROGRESS_BARS", "1")
os.environ.setdefault("HF_HUB_VERBOSITY", "error")

from huggingface_hub import HfApi, snapshot_download, upload_folder
from huggingface_hub.errors import HfHubHTTPError, RepositoryNotFoundError

logging.getLogger("huggingface_hub").setLevel(logging.ERROR)

HERMES_HOME = Path(os.environ.get("HERMES_HOME", "/opt/data"))
STATUS_FILE = Path("/tmp/huggingmes-sync-status.json")
INTERVAL = int(os.environ.get("SYNC_INTERVAL", "600"))
INITIAL_DELAY = int(os.environ.get("SYNC_START_DELAY", "10"))
HF_TOKEN = os.environ.get("HF_TOKEN", "").strip()
HF_USERNAME = os.environ.get("HF_USERNAME", "").strip()
SPACE_AUTHOR_NAME = os.environ.get("SPACE_AUTHOR_NAME", "").strip()
BACKUP_DATASET_NAME = os.environ.get("BACKUP_DATASET_NAME", "huggingmes-backup").strip()
INCLUDE_ENV = os.environ.get("SYNC_INCLUDE_ENV", "").strip().lower() in {"1", "true", "yes"}
MAX_FILE_SIZE_BYTES = int(os.environ.get("SYNC_MAX_FILE_BYTES", str(50 * 1024 * 1024)))

EXCLUDED_DIRS = {
    ".cache",
    ".git",
    ".npm",
    ".venv",
    "__pycache__",
    "node_modules",
    "venv",
}
EXCLUDED_TOP_LEVEL = {"logs"}
if not INCLUDE_ENV:
    EXCLUDED_TOP_LEVEL.add(".env")

HF_API = HfApi(token=HF_TOKEN) if HF_TOKEN else None
STOP_EVENT = threading.Event()
_REPO_ID_CACHE: str | None = None


def write_status(status: str, message: str) -> None:
    payload = {
        "status": status,
        "message": message,
        "timestamp": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()),
    }
    tmp_path = STATUS_FILE.with_suffix(".tmp")
    tmp_path.write_text(json.dumps(payload), encoding="utf-8")
    tmp_path.replace(STATUS_FILE)


def resolve_backup_repo() -> str:
    global _REPO_ID_CACHE
    if _REPO_ID_CACHE:
        return _REPO_ID_CACHE

    namespace = HF_USERNAME or SPACE_AUTHOR_NAME
    if not namespace and HF_API is not None:
        whoami = HF_API.whoami()
        namespace = whoami.get("name") or whoami.get("user") or ""

    namespace = str(namespace).strip()
    if not namespace:
        raise RuntimeError("Could not determine HF username. Set HF_USERNAME or use an account HF_TOKEN.")

    _REPO_ID_CACHE = f"{namespace}/{BACKUP_DATASET_NAME}"
    return _REPO_ID_CACHE


def ensure_repo_exists() -> str:
    repo_id = resolve_backup_repo()
    try:
        HF_API.repo_info(repo_id=repo_id, repo_type="dataset")
    except RepositoryNotFoundError:
        HF_API.create_repo(repo_id=repo_id, repo_type="dataset", private=True)
    return repo_id


def should_exclude(rel_posix: str, path: Path) -> bool:
    parts = Path(rel_posix).parts
    if not parts:
        return False
    if parts[0] in EXCLUDED_TOP_LEVEL:
        return True
    if any(part in EXCLUDED_DIRS for part in parts):
        return True
    # Exclude SQLite temporary files (shm, wal, journal)
    if path.is_file():
        name_lower = path.name.lower()
        if name_lower.endswith((".db-shm", ".db-wal", ".db-journal")):
            return True
        try:
            return path.stat().st_size > MAX_FILE_SIZE_BYTES
        except OSError:
            return True
    return False


def metadata_marker(root: Path) -> tuple[int, int, int]:
    if not root.exists():
        return (0, 0, 0)
    file_count = 0
    total_size = 0
    newest_mtime = 0
    for path in root.rglob("*"):
        if not path.is_file():
            continue
        rel = path.relative_to(root).as_posix()
        if should_exclude(rel, path):
            continue
        try:
            stat = path.stat()
        except OSError:
            continue
        file_count += 1
        total_size += int(stat.st_size)
        newest_mtime = max(newest_mtime, int(stat.st_mtime_ns))
    return (file_count, total_size, newest_mtime)


def fingerprint_dir(root: Path) -> str:
    hasher = hashlib.sha256()
    if not root.exists():
        return hasher.hexdigest()
    for path in sorted(p for p in root.rglob("*") if p.is_file()):
        rel = path.relative_to(root).as_posix()
        if should_exclude(rel, path):
            continue
        hasher.update(rel.encode("utf-8"))
        with path.open("rb") as handle:
            for chunk in iter(lambda: handle.read(1024 * 1024), b""):
                hasher.update(chunk)
    return hasher.hexdigest()


def create_snapshot_dir(source_root: Path) -> Path:
    staging_root = Path(tempfile.mkdtemp(prefix="huggingmes-sync-"))
    for path in sorted(source_root.rglob("*")):
        rel = path.relative_to(source_root)
        rel_posix = rel.as_posix()
        if should_exclude(rel_posix, path):
            continue
        target = staging_root / rel
        if path.is_dir():
            target.mkdir(parents=True, exist_ok=True)
            continue
        target.parent.mkdir(parents=True, exist_ok=True)
        try:
            shutil.copy2(path, target)
        except OSError:
            # File may have been deleted by the application since enumeration
            continue
    return staging_root


def restore() -> bool:
    if not HF_TOKEN:
        write_status("disabled", "HF_TOKEN is not configured.")
        return False

    repo_id = resolve_backup_repo()
    write_status("restoring", f"Restoring Hermes state from {repo_id}")
    try:
        with tempfile.TemporaryDirectory() as tmpdir:
            snapshot_download(repo_id=repo_id, repo_type="dataset", token=HF_TOKEN, local_dir=tmpdir)
            tmp_path = Path(tmpdir)
            if not any(tmp_path.iterdir()):
                write_status("fresh", "Backup dataset is empty. Starting fresh.")
                return True

            HERMES_HOME.mkdir(parents=True, exist_ok=True)
            for child in tmp_path.iterdir():
                if should_exclude(child.name, child):
                    continue
                target = HERMES_HOME / child.name
                if target.is_dir():
                    shutil.rmtree(target, ignore_errors=True)
                elif target.exists():
                    target.unlink()
                if child.is_dir():
                    shutil.copytree(child, target)
                else:
                    shutil.copy2(child, target)

        write_status("restored", f"Restored Hermes state from {repo_id}")
        return True
    except RepositoryNotFoundError:
        write_status("fresh", f"Backup dataset {repo_id} does not exist yet.")
        return True
    except HfHubHTTPError as exc:
        if exc.response is not None and exc.response.status_code == 404:
            write_status("fresh", f"Backup dataset {repo_id} does not exist yet.")
            return True
        write_status("error", f"Restore failed: {exc}")
        print(f"Restore failed: {exc}", file=sys.stderr)
        return False
    except Exception as exc:
        write_status("error", f"Restore failed: {exc}")
        print(f"Restore failed: {exc}", file=sys.stderr)
        return False


def sync_once(last_fingerprint: str | None = None, last_marker: tuple[int, int, int] | None = None):
    if not HF_TOKEN:
        write_status("disabled", "HF_TOKEN is not configured.")
        return (last_fingerprint or "", last_marker or (0, 0, 0))

    repo_id = ensure_repo_exists()
    current_marker = metadata_marker(HERMES_HOME)
    if last_marker is not None and current_marker == last_marker:
        write_status("synced", "No Hermes state changes detected.")
        return (last_fingerprint or "", current_marker)

    current_fingerprint = fingerprint_dir(HERMES_HOME)
    if last_fingerprint is not None and current_fingerprint == last_fingerprint:
        write_status("synced", "No Hermes state changes detected.")
        return (last_fingerprint, current_marker)

    write_status("syncing", f"Uploading Hermes state to {repo_id}")
    snapshot_dir = create_snapshot_dir(HERMES_HOME)
    try:
        try:
            HF_API.upload_large_folder(
                repo_id=repo_id,
                repo_type="dataset",
                folder_path=str(snapshot_dir),
                num_workers=2,
                print_report=False,
            )
        except AttributeError:
            upload_folder(
                folder_path=str(snapshot_dir),
                repo_id=repo_id,
                repo_type="dataset",
                token=HF_TOKEN,
                commit_message=f"HuggingMes sync {time.strftime('%Y-%m-%dT%H:%M:%SZ', time.gmtime())}",
                ignore_patterns=[".git/*", ".git"],
            )
    finally:
        shutil.rmtree(snapshot_dir, ignore_errors=True)

    write_status("success", f"Uploaded Hermes state to {repo_id}")
    return (current_fingerprint, current_marker)


def handle_signal(_sig, _frame) -> None:
    STOP_EVENT.set()


def loop() -> int:
    signal.signal(signal.SIGTERM, handle_signal)
    signal.signal(signal.SIGINT, handle_signal)
    try:
        repo_id = resolve_backup_repo()
        write_status("configured", f"Backup loop active for {repo_id} with {INTERVAL}s interval.")
    except Exception as exc:
        write_status("error", str(exc))
        print(f"Hermes sync error: {exc}")
        return 1

    last_fingerprint = fingerprint_dir(HERMES_HOME)
    last_marker = metadata_marker(HERMES_HOME)
    time.sleep(INITIAL_DELAY)
    print(f"Hermes state sync started: every {INTERVAL}s -> {repo_id}")

    while not STOP_EVENT.is_set():
        try:
            last_fingerprint, last_marker = sync_once(last_fingerprint, last_marker)
        except Exception as exc:
            write_status("error", f"Sync failed: {exc}")
            print(f"Hermes sync failed: {exc}")
        if STOP_EVENT.wait(INTERVAL):
            break
    return 0


def main() -> int:
    HERMES_HOME.mkdir(parents=True, exist_ok=True)
    if len(sys.argv) < 2:
        return loop()
    command = sys.argv[1]
    if command == "restore":
        return 0 if restore() else 1
    if command == "sync-once":
        try:
            sync_once()
            return 0
        except Exception as exc:
            write_status("error", f"Shutdown sync failed: {exc}")
            print(f"Hermes sync: shutdown sync failed: {exc}")
            return 1
    if command == "loop":
        return loop()
    print(f"Unknown command: {command}", file=sys.stderr)
    return 1


if __name__ == "__main__":
    raise SystemExit(main())