"""Secondary (non-INBOX) folder polling — multi-folder CONDSTORE sync (SPEC §6.3)."""

from __future__ import annotations

import uuid
from datetime import UTC, datetime
from email.message import EmailMessage

from sqlalchemy import delete, func, select
from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
from sqlalchemy.pool import NullPool

from app.config import get_settings
from app.db import session_scope
from app.identity.passwords import hash_password
from app.models import Account, Draft, Mailbox, Message, User
from app.providers.base import MailboxDelta, RemoteMessage
from app.sync import engine as sync_engine


def _raw(subject: str, mid: str) -> bytes:
    m = EmailMessage()
    m["Subject"] = subject
    m["From"] = "me@example.com"
    m["To"] = "bob@example.com"
    m["Message-ID"] = mid
    m["Date"] = "Mon, 09 Mar 2026 08:36:37 +0100"
    m.set_content("body")
    return m.as_bytes()


async def test_secondary_poll_syncs_special_folders_not_inbox(monkeypatch) -> None:  # type: ignore[no-untyped-def]
    engine = create_async_engine(get_settings().database_url, poolclass=NullPool)
    sm = async_sessionmaker(engine, expire_on_commit=False)
    session = sm()
    user = User(handle=f"sec{uuid.uuid4().hex[:8]}@test.local", password_hash=hash_password("pw"))
    session.add(user)
    await session.flush()
    account = Account(
        user_id=user.id,
        email="me@example.com",
        imap_config={},
        smtp_config={},
        secret_ct=b"",
        discovery_src="manual",
    )
    session.add(account)
    await session.flush()
    inbox = Mailbox(account_id=account.id, user_id=user.id, path="INBOX", special_use="inbox")
    sent = Mailbox(account_id=account.id, user_id=user.id, path="SENT", special_use="sent")
    custom = Mailbox(account_id=account.id, user_id=user.id, path="Notes", special_use=None)
    session.add_all([inbox, sent, custom])
    await session.commit()

    polled: list[str] = []

    class FakeProvider:
        async def poll(self, mailbox: str, *, last_seen_uid: int, highestmodseq: int | None):  # type: ignore[no-untyped-def]
            polled.append(mailbox)
            if mailbox == "SENT":
                return MailboxDelta(
                    [
                        RemoteMessage(
                            uid=5,
                            raw=_raw("Sent one", "<s1@x.com>"),
                            flags=frozenset({"\\Seen"}),
                            internal_date=datetime.now(UTC),
                        )
                    ],
                    [],
                    [],
                    None,
                    None,
                )
            return MailboxDelta([], [], [], None, None)

        async def close(self) -> None:
            return None

    monkeypatch.setattr(sync_engine, "build_provider", lambda _a: FakeProvider())

    try:
        await sync_engine._poll_secondary_once(account.id)

        # Only the non-INBOX special-use folder is polled (SENT); INBOX and the
        # custom folder (no special_use) are skipped.
        assert polled == ["SENT"]

        # The delta was applied: the sent message is now in the DB under SENT.
        session.expunge_all()
        n = await session.scalar(
            select(func.count()).select_from(Message).where(Message.mailbox_id == sent.id)
        )
        assert n == 1
    finally:
        async with session_scope() as cleanup:
            await cleanup.execute(delete(User).where(User.id == user.id))
        await session.close()
        await engine.dispose()


async def test_drafts_poll_reconciles_expunged_rows(monkeypatch) -> None:  # type: ignore[no-untyped-def]
    """A Drafts poll drops DB rows whose server copy was expunged (phantoms) and
    un-links a local draft whose mirrored copy vanished."""
    engine = create_async_engine(get_settings().database_url, poolclass=NullPool)
    sm = async_sessionmaker(engine, expire_on_commit=False)
    session = sm()
    user = User(handle=f"rec{uuid.uuid4().hex[:8]}@test.local", password_hash=hash_password("pw"))
    session.add(user)
    await session.flush()
    account = Account(
        user_id=user.id,
        email="me@example.com",
        imap_config={},
        smtp_config={},
        secret_ct=b"",
        discovery_src="manual",
    )
    session.add(account)
    await session.flush()
    drafts = Mailbox(account_id=account.id, user_id=user.id, path="DRAFTS", special_use="drafts")
    session.add(drafts)
    await session.flush()

    # uid 2 survives on the server; uids 1 and 3 were expunged (phantom DB rows).
    for uid in (1, 2, 3):
        session.add(
            Message(
                user_id=user.id,
                account_id=account.id,
                mailbox_id=drafts.id,
                uid=uid,
                internal_date=datetime.now(UTC),
                blob_sha256="",
            )
        )
    # A local draft still linking the vanished uid 3 must be un-linked (imap_uid -> NULL).
    linked = Draft(user_id=user.id, account_id=account.id, kind="new", payload={}, imap_uid=3)
    kept = Draft(user_id=user.id, account_id=account.id, kind="new", payload={}, imap_uid=2)
    session.add_all([linked, kept])
    await session.commit()

    class FakeProvider:
        async def poll(self, mailbox: str, *, last_seen_uid: int, highestmodseq: int | None):  # type: ignore[no-untyped-def]
            return MailboxDelta([], [], [], None, None)

        async def list_uids(self, mailbox: str) -> set[int]:
            return {2}  # only uid 2 remains on the server

        async def close(self) -> None:
            return None

    monkeypatch.setattr(sync_engine, "build_provider", lambda _a: FakeProvider())

    try:
        await sync_engine._poll_secondary_once(account.id)

        session.expunge_all()
        remaining = set(
            await session.scalars(select(Message.uid).where(Message.mailbox_id == drafts.id))
        )
        assert remaining == {2}  # phantoms 1 and 3 removed
        assert (await session.get(Draft, linked.id)).imap_uid is None  # un-linked
        assert (await session.get(Draft, kept.id)).imap_uid == 2  # untouched
    finally:
        async with session_scope() as cleanup:
            await cleanup.execute(delete(User).where(User.id == user.id))
        await session.close()
        await engine.dispose()