#!/usr/bin/env python3
"""WebDAV server backed by Hugging Face Hub (dataset storage).

Windows-compatible: includes all required DAV headers, proper PROPFIND
responses, parent-directory auto-creation, and safe delete logic.
"""

import os
import io
import logging
import stat
from datetime import datetime, timezone
from typing import Optional

from wsgidav.wsgidav_app import WsgiDAVApp
from wsgidav.dav_provider import DAVProvider, DAVCollection, DAVNonCollection

from huggingface_hub import HfFileSystem, hf_hub_download

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# ── Configuration ──────────────────────────────────────────────
HF_REPO_ID = os.environ.get("HF_REPO_ID", "e2dew32/cloud-drive")
HF_REPO_TYPE = "dataset"

fs = HfFileSystem()
REPO_ROOT = f"{HF_REPO_TYPE}s/{HF_REPO_ID}"


def _norm(path: str) -> str:
    """Normalise a WebDAV path to an HF path."""
    path = path.strip("/")
    return f"{REPO_ROOT}/{path}" if path else REPO_ROOT


def _stat(path: str) -> dict:
    """Return info dict for a file or directory."""
    try:
        info = fs.info(path)
        return info
    except Exception:
        return {}


def _ensure_parent(hf_path: str):
    """Create parent directories on HF Hub if they don't exist."""
    parent = "/".join(hf_path.split("/")[:-1])
    if not parent or parent == REPO_ROOT:
        return
    try:
        if not fs.isdir(parent):
            fs.mkdir(parent, exist_ok=True, parents=True)
            logger.info(f"Created parent dir: {parent}")
    except Exception as e:
        logger.warning(f"ensure_parent failed for {parent}: {e}")


# ── DAV Provider ───────────────────────────────────────────────
class HFDAVProvider(DAVProvider):
    """Expose HF Hub storage as a WebDAV tree."""

    def __init__(self):
        super().__init__()

    def get_resource_inst(self, path, environ):
        norm = _norm(path)
        info = _stat(norm)
        if not info:
            return None

        if info.get("type") == "directory":
            return HFDavCollection(path, environ, info)
        return HFDavNonCollection(path, environ, info)

    def is_collection(self, path):
        info = _stat(_norm(path))
        return info.get("type") == "directory"


class HFDavCollection(DAVCollection):
    def __init__(self, path, environ, info):
        super().__init__(path, environ)
        self._info = info

    def get_display_name(self):
        return self.path.rstrip("/").split("/")[-1] or "/"

    def get_member_names(self):
        norm = _norm(self.path)
        try:
            entries = fs.ls(norm, detail=False)
        except Exception:
            return []
        names = []
        for e in entries:
            name = e.rsplit("/", 1)[-1]
            # Filter out . and .. to prevent Windows infinite loops
            if name not in (".", "..", ""):
                names.append(name)
        return names

    def get_member(self, name):
        child_path = self.path.rstrip("/") + "/" + name
        return self.provider.get_resource_inst(child_path, self.environ)

    def create_empty_resource(self, name):
        """Called when client does PUT with no body first."""
        child_path = self.path.rstrip("/") + "/" + name
        norm = _norm(child_path)
        _ensure_parent(norm)
        return HFDavNonCollection(
            child_path, self.environ, {"type": "file", "size": 0, "name": name}
        )

    def create_collection(self, name):
        """MKCOL – create a directory."""
        new_path = self.path.rstrip("/") + "/" + name
        norm = _norm(new_path)
        try:
            fs.mkdir(norm, exist_ok=True, parents=True)
            logger.info(f"MKCOL: {norm}")
        except Exception as e:
            logger.error(f"mkdir failed: {e}")

    def get_creation_date(self):
        return datetime.now(timezone.utc)

    def get_modified_date(self):
        return datetime.now(timezone.utc)

    def get_content_length(self):
        return 0

    def get_content_type(self):
        return "httpd/unix-directory"

    def is_collection(self):
        return True

    def support_etag(self):
        return 0

    def get_etag(self):
        return None

    def is_property_locked(self, name):
        return False

    def get_property_names(self, is_allprop):
        return []

    def get_property_value(self, name):
        return None

    def support_recursive_delete(self, path):
        return True

    def delete(self):
        norm = _norm(self.path)
        # Safety: never delete the repo root
        if norm == REPO_ROOT:
            logger.warning("Blocked attempt to delete repo root")
            return
        try:
            entries = fs.ls(norm, detail=False)
            for e in entries:
                try:
                    if fs.isdir(e):
                        fs.rm(e, recursive=True)
                    else:
                        fs.rm(e)
                except Exception as inner:
                    logger.warning(f"delete entry {e}: {inner}")
            fs.rmdir(norm)
            logger.info(f"Deleted collection: {norm}")
        except Exception as e:
            logger.error(f"delete collection failed: {e}")


class HFDavNonCollection(DAVNonCollection):
    def __init__(self, path, environ, info):
        super().__init__(path, environ)
        self._info = info

    def get_display_name(self):
        return self.path.rstrip("/").split("/")[-1]

    def get_content_length(self):
        return self._info.get("size", 0)

    def get_content_type(self):
        name = self.get_display_name()
        if "." in name:
            ext = name.rsplit(".", 1)[-1].lower()
            types = {
                "txt": "text/plain",
                "md": "text/markdown",
                "json": "application/json",
                "html": "text/html",
                "css": "text/css",
                "js": "application/javascript",
                "xml": "application/xml",
                "csv": "text/csv",
                "jpg": "image/jpeg",
                "jpeg": "image/jpeg",
                "png": "image/png",
                "gif": "image/gif",
                "svg": "image/svg+xml",
                "pdf": "application/pdf",
                "zip": "application/zip",
                "mp3": "audio/mpeg",
                "mp4": "video/mp4",
            }
            return types.get(ext, "application/octet-stream")
        return "application/octet-stream"

    def get_creation_date(self):
        return datetime.now(timezone.utc)

    def get_modified_date(self):
        lc = self._info.get("last_commit") or {}
        mtime = lc.get("date")
        if mtime:
            try:
                return datetime.fromisoformat(mtime.replace("Z", "+00:00"))
            except Exception:
                pass
        return datetime.now(timezone.utc)

    def get_content(self):
        norm = _norm(self.path)
        try:
            with fs.open(norm, "rb") as f:
                return io.BytesIO(f.read())
        except Exception as e:
            logger.error(f"read failed: {e}")
            return io.BytesIO(b"")

    def begin_write(self, content_type=None):
        norm = _norm(self.path)
        _ensure_parent(norm)
        logger.info(f"begin_write: {norm}")
        return HFWriteBuffer(norm)

    def is_property_locked(self, name):
        return False

    def get_property_names(self, is_allprop):
        return []

    def get_property_value(self, name):
        return None

    def delete(self):
        norm = _norm(self.path)
        try:
            fs.rm(norm)
            logger.info(f"Deleted file: {norm}")
        except Exception as e:
            logger.error(f"delete file failed: {e}")

    def support_etag(self):
        return 0

    def get_etag(self):
        return None

    def move_dest(self, dest_provider, dest_path, recursive, dry_run, environ):
        """Handle MOVE (rename)."""
        src_norm = _norm(self.path)
        dst_norm = _norm(dest_path)
        logger.info(f"MOVE {src_norm} -> {dst_norm}")
        try:
            _ensure_parent(dst_norm)
            data = fs.cat(src_norm)
            fs.pipe(dst_norm, data)
            fs.rm(src_norm)
        except Exception as e:
            logger.error(f"move failed: {e}")

    def copy(self, dest_provider, dest_path, environ, depth="infinity", dry_run=False):
        """Handle COPY."""
        src_norm = _norm(self.path)
        dst_norm = _norm(dest_path)
        logger.info(f"COPY {src_norm} -> {dst_norm}")
        try:
            _ensure_parent(dst_norm)
            data = fs.cat(src_norm)
            fs.pipe(dst_norm, data)
        except Exception as e:
            logger.error(f"copy failed: {e}")


class HFWriteBuffer(io.BytesIO):
    """Buffer for writing file content to HF Hub."""

    def __init__(self, path):
        super().__init__()
        self.path = path

    def close(self):
        data = self.getvalue()
        try:
            fs.pipe(self.path, data)
            logger.info(f"Written {len(data)} bytes to {self.path}")
        except Exception as e:
            logger.error(f"Write failed: {e}")
        super().close()


# ── Windows Compatibility Middleware ───────────────────────────
class WindowsCompatMiddleware:
    """Add headers required by Windows WebClient and fix OPTIONS response."""

    def __init__(self, app):
        self.app = app

    def __call__(self, environ, start_response):
        if environ.get("REQUEST_METHOD") == "OPTIONS":
            # Windows requires these headers in OPTIONS response
            headers = [
                ("DAV", "1, 2"),
                ("Allow", "OPTIONS, GET, HEAD, POST, PUT, DELETE, PROPFIND, PROPPATCH, MKCOL, COPY, MOVE, LOCK, UNLOCK"),
                ("Content-Length", "0"),
                ("MS-Author-Via", "DAV"),
                ("Content-Type", "httpd/unix-directory"),
            ]
            start_response("200 OK", headers)
            return [b""]

        def custom_start_response(status, response_headers, exc_info=None):
            # Ensure every response has Windows-required headers
            header_names = {k.lower() for k, _ in response_headers}
            if "ms-author-via" not in header_names:
                response_headers.append(("MS-Author-Via", "DAV"))
            if "dav" not in header_names:
                response_headers.append(("DAV", "1, 2"))
            if "access-control-allow-origin" not in header_names:
                response_headers.append(("Access-Control-Allow-Origin", "*"))
            return start_response(status, response_headers, exc_info)

        return self.app(environ, custom_start_response)


# ── WsgiDAVApp setup ──────────────────────────────────────────
def create_app():
    user = os.environ.get("WEBDAV_USER", "user")
    passwd = os.environ.get("WEBDAV_PASS", "pass")

    app = WsgiDAVApp(
        {
            "host": "0.0.0.0",
            "port": 7860,
            "provider_mapping": {"/": HFDAVProvider()},
            "simple_dc": {
                "user_mapping": {"*": {user: {"password": passwd, "roles": ["admin"]}}}
            },
            "http_authenticator": {
                "DAV_auth_type": "basic",
            },
            "verbose": 1,
            "dir_browser": {"enable": False},  # Disable browser UI, pure WebDAV
        }
    )
    # Wrap with Windows compatibility middleware
    return WindowsCompatMiddleware(app)


if __name__ == "__main__":
    from cheroot.wsgi import Server

    app = create_app()
    server = Server(("0.0.0.0", 7860), app)
    logger.info("Starting WebDAV server on :7860")
    try:
        server.start()
    except KeyboardInterrupt:
        server.stop()