"""
Bundle store — SQLite-backed storage for GEK bundles and keypair bundles.

GEK bundles: ECIES-wrapped GEK targeted at a specific user's X25519 key.
Keypair bundles: AES-GCM encrypted (Ed25519 + X25519) private keys, encrypted
with the user's password-derived bundle_key. Opaque to the node.

Both are stored and served over the P2P DataChannel during MNP handshake.
"""

import logging
from pathlib import Path

import aiosqlite

log = logging.getLogger(__name__)

_SCHEMA_GEK = """\
CREATE TABLE IF NOT EXISTS gek_bundles (
    group_id    TEXT NOT NULL,
    user_id     TEXT NOT NULL,
    pk_eph_b64  TEXT NOT NULL,
    nonce_b64   TEXT NOT NULL,
    wrapped_b64 TEXT NOT NULL,
    stored_at   TEXT NOT NULL DEFAULT (datetime('now')),
    PRIMARY KEY (group_id, user_id)
);
"""

_SCHEMA_KEYPAIR = """\
CREATE TABLE IF NOT EXISTS keypair_bundles (
    user_id     TEXT PRIMARY KEY,
    bundle_enc  TEXT NOT NULL,
    stored_at   TEXT NOT NULL DEFAULT (datetime('now'))
);
"""


class BundleStore:
    def __init__(self, db_path: Path):
        self._db_path = db_path
        self._db: aiosqlite.Connection | None = None

    async def open(self) -> None:
        self._db_path.parent.mkdir(parents=True, exist_ok=True)
        self._db = await aiosqlite.connect(str(self._db_path))
        await self._db.execute(_SCHEMA_GEK)
        await self._db.execute(_SCHEMA_KEYPAIR)
        await self._db.commit()

    async def store(
        self,
        group_id: str,
        user_id: str,
        pk_eph_b64: str,
        nonce_b64: str,
        wrapped_b64: str,
    ) -> None:
        assert self._db
        await self._db.execute(
            "INSERT OR REPLACE INTO gek_bundles "
            "(group_id, user_id, pk_eph_b64, nonce_b64, wrapped_b64, stored_at) "
            "VALUES (?, ?, ?, ?, ?, datetime('now'))",
            (group_id, user_id, pk_eph_b64, nonce_b64, wrapped_b64),
        )
        await self._db.commit()

    async def fetch(self, group_id: str, user_id: str) -> dict | None:
        assert self._db
        async with self._db.execute(
            "SELECT pk_eph_b64, nonce_b64, wrapped_b64 FROM gek_bundles "
            "WHERE group_id = ? AND user_id = ?",
            (group_id, user_id),
        ) as cursor:
            row = await cursor.fetchone()
            if not row:
                return None
            return {
                "pk_eph_b64": row[0],
                "nonce_b64": row[1],
                "wrapped_b64": row[2],
            }

    async def store_keypair(self, user_id: str, bundle_enc: str) -> None:
        assert self._db
        await self._db.execute(
            "INSERT OR REPLACE INTO keypair_bundles "
            "(user_id, bundle_enc, stored_at) VALUES (?, ?, datetime('now'))",
            (user_id, bundle_enc),
        )
        await self._db.commit()

    async def fetch_keypair(self, user_id: str) -> str | None:
        assert self._db
        async with self._db.execute(
            "SELECT bundle_enc FROM keypair_bundles WHERE user_id = ?",
            (user_id,),
        ) as cursor:
            row = await cursor.fetchone()
            return row[0] if row else None

    async def delete_keypair(self, user_id: str) -> bool:
        """
        Drop someone's keypair bundle at their own request.

        Backing keys up here is what lets a second browser recover them with the
        password — and it is also what puts a PBKDF2-protected blob on every node
        whose group they join (finding C4). Someone who does not need the first
        should be able to withdraw the second, and not merely stop adding to it.
        """
        assert self._db
        cur = await self._db.execute(
            "DELETE FROM keypair_bundles WHERE user_id = ?", (user_id,))
        await self._db.commit()
        return cur.rowcount > 0

    async def close(self) -> None:
        if self._db:
            await self._db.close()
            self._db = None