"""
trovedb.py — Concrete implementation of Trove protocols backed by Sqlite3Trove.

Implements BlobNote, TreeNote, and Trove protocols defined in trove.py.
Depends on db.py (Sqlite3Trove) for storage.
"""

from typing import Optional, Iterator, override
from pathlib import Path
import datetime as dt
import uuid

from .db import Sqlite3Trove, NOTE_ROOT_ID

from . import trove as tr

from .trove import Note, Trove, TreeEntry, NoteNotFound, ObjectId


class NoteImpl(Note):
    """Concrete note implementation."""

    def __init__(self, parent: 'TroveImpl', object_id: ObjectId):
        if not isinstance(object_id, uuid.UUID):
            object_id = uuid.UUID(str(object_id))
        assert isinstance(object_id, uuid.UUID)

        self._parent = parent
        self._db = parent.db
        self._object_id: uuid.UUID = object_id

    @staticmethod
    def get_impl_id(note: Note) -> uuid.UUID:
        if not isinstance(note.object_id, uuid.UUID):
            raise TypeError("Note not compatible with NoteImpl")
        return note.object_id

    # Note protocol
    @property
    def object_id(self) -> ObjectId:
        return self._object_id

    @property
    def readonly(self) -> bool:
        return False

    @property
    def mtime(self) -> dt.datetime:
        """Return modification time as UTC datetime."""
        mtime = self._db.get_mtime(self._object_id)
        return mtime if mtime is not None else dt.datetime.now(tz=dt.timezone.utc)

    @property
    def mime(self) -> str:
        """Return MIME type from the objects table."""
        info = self._db.get_info(self._object_id)
        return info.type if info else "application/octet-stream"

    def get_raw_metadata(self, key: str) -> Optional[bytes]:
        return self._db.read_metadata(self._object_id, key)

    def set_raw_metadata(self, key: str, value: bytes) -> None:
        self._db.write_metadata(self._object_id, key, value)

    def read_content(self) -> bytes:
        data = self._db.read_object(self._object_id)
        return data if data is not None else b""

    def write_content(self, data: bytes) -> None:
        self._db.write_content(self._object_id, data)

    def children(self) -> Iterator[TreeEntry]:
        """Get all children of this note."""
        for name, object_id in self._db.list_tree(self._object_id).items():
            yield TreeEntry(name, object_id)

    def new_child(self, name: str, mime: str, content: bytes | None, executable: bool, hidden: bool) -> Note:
        """Create a new child note."""
        content = content if content is not None else b""
        object_id = self._db.write_blob(data=content, object_id=None, dtype=mime, executable=executable, hidden=hidden)
        self._db.link(self._object_id, name, object_id)
        return NoteImpl(self._parent, object_id)

    def child(self, name: str) -> Note:
        """Retrieve a child note by name."""
        entries = self._db.list_tree(self._object_id)
        if name not in entries:
            raise tr.ErrorNotFound(name)
        child_id = entries[name]
        value = self._parent.get_raw_note(child_id)
        if value is None:
            raise tr.ErrorNotFound("dangling child link") # FIXME: better errors
        return value

    def rm_child(self, name: str, recurse: bool) -> None:
        """Remove a child note."""
        note = self.child(name)
        if note.has_children() and not recurse:
            raise tr.ErrorNotEmpty(name)
        self._db.unlink(self._object_id, name)


# ---------------------------------------------------------------------------
# Trove
# ---------------------------------------------------------------------------

class TroveImpl(Trove):
    """
    Concrete Trove: top-level API backed by a Sqlite3Trove database.

    Use TroveImpl.open() to get an instance.
    """

    def __init__(self, db: Sqlite3Trove):
        self._db = db

    @classmethod
    def open(cls, path: str | Path, create: bool = False) -> "TroveImpl":
        db = Sqlite3Trove.open(path, create=create)
        return cls(db)

    @property
    def db(self) -> Sqlite3Trove:
        return self._db

    def close(self) -> None:
        self._db.close()

    def __enter__(self):
        return self

    def __exit__(self, *_):
        self.close()

    # Trove protocol
    def get_raw_note(self, note_id: ObjectId) -> Note:
        """Return a BlobNote or TreeNote for the given id, or None if not found."""
        if not isinstance(note_id, uuid.UUID):
            note_id = uuid.UUID(str(note_id))
        info = self._db.get_info(note_id)
        if info is None:
            raise NoteNotFound(note_id)
        return NoteImpl(self, note_id)

    @override
    def move(self, src_parent: Note, src_name: str, dst_parent: Note, dst_name: str, overwrite: bool):
        """Move a child note to a new location."""
        src_note = src_parent.child(src_name)
        if not isinstance(src_note, NoteImpl):
            raise tr.ErrorBadType("not a valid DB note")
        if not isinstance(dst_parent, NoteImpl):
            raise tr.ErrorBadType("not a valid DB note")
        self._db.link(dst_parent.object_id, dst_name, src_note.object_id)
        self._db.unlink(src_parent.object_id, src_name)

    def create_blob(self, data: bytes | None = None,
                    dtype: str = "application/octet-stream") -> Note:
        """Create a new blob object and return a BlobNote for it."""
        obj_id = self._db.write_blob(data or b"", dtype=dtype)
        return NoteImpl(self, obj_id)

    def get_root(self) -> Note:
        """Return the root TreeNote (always id=NOTE_ROOT_ID)."""
        return NoteImpl(self, NOTE_ROOT_ID)


def open_db_trove(path: str | Path, create: bool = False, **kwargs: tr.OpenArguments) -> Trove:
    return TroveImpl.open(path, create=create)