"""IMAP operations (flags, delete, move, folders) for the Mail plugin.

Extracted from services.py as part of the God-object split (BUG-018 pilot).
Re-exported by ``app.plugins.builtins.mail.services``.
"""

from __future__ import annotations

import logging
import uuid

import aioimaplib
from sqlalchemy import and_, select
from sqlalchemy.ext.asyncio import AsyncSession

from app.plugins.builtins.mail.imap_sync import (
    _parse_imap_list_response,
    get_account_password,
)
from app.plugins.builtins.mail.models import (
    Mail,
    MailAccount,
    MailFolder,
)

logger = logging.getLogger(__name__)


async def imap_sync_mail_flags(
    db: AsyncSession,
    mail_id: uuid.UUID,
    tenant_id: uuid.UUID,
) -> None:
    """Sync is_seen/is_flagged flags from DB to IMAP server.

    Connects to the IMAP server, selects the mail's folder,
    and uses UID STORE to set/remove \\Seen and \\Flagged flags.
    Non-critical: logs warnings on failure but does not raise.
    """
    import logging

    logger = logging.getLogger(__name__)

    # Load the mail with its folder and account
    mail = (
        await db.execute(
            select(Mail).where(
                and_(Mail.id == mail_id, Mail.tenant_id == tenant_id)
            )
        )
    ).scalar_one_or_none()
    if not mail:
        logger.warning("imap_sync_mail_flags: mail %s not found", mail_id)
        return

    folder = (
        await db.execute(
            select(MailFolder).where(
                and_(MailFolder.id == mail.folder_id, MailFolder.tenant_id == tenant_id)
            )
        )
    ).scalar_one_or_none()
    if not folder:
        logger.warning("imap_sync_mail_flags: folder %s not found for mail %s", mail.folder_id, mail_id)
        return

    account = (
        await db.execute(
            select(MailAccount).where(
                and_(MailAccount.id == folder.account_id, MailAccount.tenant_id == tenant_id)
            )
        )
    ).scalar_one_or_none()
    if not account:
        logger.warning("imap_sync_mail_flags: account not found for mail %s", mail_id)
        return

    if not mail.message_id:
        logger.warning("imap_sync_mail_flags: mail %s has no message_id, cannot sync", mail_id)
        return

    password = await get_account_password(account)
    client = None

    try:
        client = aioimaplib.IMAP4_SSL(host=account.imap_host, port=account.imap_port)
        await client.wait_hello_from_server()
        await client.login(account.username, password)

        # Select the folder
        select_resp = await client.select(folder.imap_name)
        if select_resp.result != 'OK':
            logger.warning("imap_sync_mail_flags: cannot select folder %s", folder.imap_name)
            return

        # Find the UID by searching for the Message-ID header
        search_resp = await client.uid_search(f'HEADER Message-ID "{mail.message_id}"')
        uids_raw = search_resp[1][0] if search_resp[1] and search_resp[1][0] else b''
        if isinstance(uids_raw, (bytes, bytearray)):
            uids = uids_raw.split()
        else:
            uids = []

        if not uids:
            logger.warning("imap_sync_mail_flags: no UID found for Message-ID %s", mail.message_id)
            return

        uid_str = uids[0].decode() if isinstance(uids[0], bytes) else str(uids[0])

        # Sync \Seen flag
        if mail.is_seen:
            await client.uid('store', uid_str, '+FLAGS (\\Seen)')
        else:
            await client.uid('store', uid_str, '-FLAGS (\\Seen)')

        # Sync \Flagged flag
        if mail.is_flagged:
            await client.uid('store', uid_str, '+FLAGS (\\Flagged)')
        else:
            await client.uid('store', uid_str, '-FLAGS (\\Flagged)')

        logger.info("imap_sync_mail_flags: synced flags for mail %s (UID %s)", mail_id, uid_str)

    except Exception as exc:
        logger.warning("imap_sync_mail_flags: failed for mail %s: %s", mail_id, exc)
    finally:
        if client is not None:
            try:
                await client.logout()
            except Exception:
                logger.debug("Ignored exception in mail service", exc_info=True)


# ─── IMAP Delete ───


async def _find_trash_folder_name(
    db: AsyncSession, account: MailAccount, tenant_id: uuid.UUID
) -> str | None:
    """Find the IMAP Trash folder name for an account.

    Checks account.trash_folder_imap_name, then DB folders with 'trash' in imap_name,
    then queries the IMAP server LIST for common Trash folder names.
    """
    # 1) Explicit mapping on account
    if account.trash_folder_imap_name:
        return account.trash_folder_imap_name

    # 2) DB folder with 'trash' in imap_name
    db_folders = (
        await db.execute(
            select(MailFolder).where(
                and_(MailFolder.account_id == account.id, MailFolder.tenant_id == tenant_id)
            )
        )
    ).scalars().all()
    for f in db_folders:
        if 'trash' in f.imap_name.lower():
            return f.imap_name

    # 3) Query IMAP server for common Trash folder names
    password = await get_account_password(account)
    client = None
    try:
        client = aioimaplib.IMAP4_SSL(host=account.imap_host, port=account.imap_port)
        await client.wait_hello_from_server()
        await client.login(account.username, password)
        list_resp = await client.list('""', '"*"')
        imap_folders, _ = _parse_imap_list_response(list_resp)
        trash_candidates = ['Trash', 'INBOX.Trash', 'INBOX.Trash', 'Deleted', 'Deleted Items', 'Papierkorb']
        for _, name in imap_folders:
            if name in trash_candidates or 'trash' in name.lower():
                return name
    except Exception:
        logger.debug("Ignored exception in mail service", exc_info=True)
    finally:
        if client:
            try:
                await client.logout()
            except Exception:
                logger.debug("Ignored exception in mail service", exc_info=True)

    return None


async def imap_delete_mail(
    db: AsyncSession, mail_id: uuid.UUID, tenant_id: uuid.UUID, *, permanent: bool = False
) -> None:
    """Delete mail from IMAP server.

    If permanent=False (default): MOVE mail to IMAP Trash folder (like real mail clients).
    If permanent=True: STORE \\Deleted + EXPUNGE (permanent delete from server).
    Uses UID MOVE if supported, otherwise COPY + STORE \\Deleted + EXPUNGE.
    Raises exceptions on failure so caller can queue for retry.
    """
    import logging

    logger = logging.getLogger(__name__)

    mail = (
        await db.execute(
            select(Mail).where(
                and_(Mail.id == mail_id, Mail.tenant_id == tenant_id)
            )
        )
    ).scalar_one_or_none()
    if not mail:
        logger.warning("imap_delete_mail: mail %s not found", mail_id)
        return

    folder = (
        await db.execute(
            select(MailFolder).where(
                and_(MailFolder.id == mail.folder_id, MailFolder.tenant_id == tenant_id)
            )
        )
    ).scalar_one_or_none()
    if not folder:
        logger.warning("imap_delete_mail: folder %s not found for mail %s", mail.folder_id, mail_id)
        return

    account = (
        await db.execute(
            select(MailAccount).where(
                and_(MailAccount.id == folder.account_id, MailAccount.tenant_id == tenant_id)
            )
        )
    ).scalar_one_or_none()
    if not account:
        logger.warning("imap_delete_mail: account not found for mail %s", mail_id)
        return

    if not mail.imap_uid and not mail.message_id:
        logger.warning("imap_delete_mail: mail %s has no imap_uid or message_id, cannot sync", mail_id)
        return

    # Lifecycle hook: mail.before_delete
    from app.core.hooks import do_action
    await do_action("mail.before_delete", mail_id=str(mail.id), tenant_id=str(tenant_id), permanent=permanent, db=db)

    # Find Trash folder on IMAP server (only needed for non-permanent delete)
    trash_folder_name = None
    if not permanent:
        trash_folder_name = await _find_trash_folder_name(db, account, tenant_id)
        if not trash_folder_name:
            logger.warning("imap_delete_mail: no Trash folder found for account %s, will permanent delete", account.id)

    password = await get_account_password(account)
    client = None

    try:
        client = aioimaplib.IMAP4_SSL(host=account.imap_host, port=account.imap_port)
        await client.wait_hello_from_server()
        await client.login(account.username, password)

        select_resp = await client.select(folder.imap_name)
        if select_resp.result != 'OK':
            raise RuntimeError(f"cannot select folder {folder.imap_name}")

        # Use stored imap_uid directly; fall back to Message-ID search
        if mail.imap_uid:
            uid_str = mail.imap_uid
        else:
            search_resp = await client.uid_search(f'HEADER Message-ID "{mail.message_id}"')
            uids_raw = search_resp[1][0] if search_resp[1] and search_resp[1][0] else b''
            if isinstance(uids_raw, (bytes, bytearray)):
                uids = uids_raw.split()
            else:
                uids = []
            if not uids:
                raise RuntimeError(f"no UID found for Message-ID {mail.message_id}")
            uid_str = uids[0].decode() if isinstance(uids[0], bytes) else str(uids[0])

        if permanent or not trash_folder_name:
            # Permanent delete: STORE \Deleted + EXPUNGE
            await client.uid('store', uid_str, r'+FLAGS (\\Deleted)')
            await client.expunge()
            logger.info("imap_delete_mail: permanent deleted mail %s (UID %s)", mail_id, uid_str)
            return

        # Non-permanent: MOVE to Trash folder (like Thunderbird, Outlook, etc.)
        # Don't move if already in Trash
        if folder.imap_name.lower() == trash_folder_name.lower():
            # Already in Trash — permanent delete
            await client.uid('store', uid_str, r'+FLAGS (\\Deleted)')
            await client.expunge()
            logger.info("imap_delete_mail: permanent deleted mail %s (already in Trash, UID %s)", mail_id, uid_str)
            return

        # Try UID MOVE first
        try:
            move_resp = await client.uid('move', uid_str, trash_folder_name)
            if move_resp.result == 'OK':
                logger.info("imap_delete_mail: moved mail %s (UID %s) to Trash %s", mail_id, uid_str, trash_folder_name)
                return
        except Exception as move_exc:
            logger.info("imap_delete_mail: UID MOVE not supported, falling back: %s", move_exc)

        # Fallback: COPY to Trash + STORE \Deleted + EXPUNGE
        copy_resp = await client.uid('copy', uid_str, trash_folder_name)
        if copy_resp.result != 'OK':
            raise RuntimeError(f"COPY to Trash failed for mail {mail_id}")
        await client.uid('store', uid_str, r'+FLAGS (\\Deleted)')
        await client.expunge()
        logger.info("imap_delete_mail: moved mail %s (UID %s) to Trash via COPY+DELETE", mail_id, uid_str)

        # Lifecycle hook: mail.after_delete
        from app.core.hooks import do_action
        await do_action("mail.after_delete", mail_id=str(mail.id), tenant_id=str(tenant_id), permanent=permanent, db=db)

    except Exception as exc:
        logger.warning("imap_delete_mail: failed for mail %s: %s", mail_id, exc)
        raise
    finally:
        if client is not None:
            try:
                await client.logout()
            except Exception:
                logger.debug("Ignored exception in mail service", exc_info=True)


# ─── IMAP Move ───


async def imap_move_mail(
    db: AsyncSession,
    mail_id: uuid.UUID,
    target_folder_id: uuid.UUID,
    tenant_id: uuid.UUID,
) -> None:
    """Move mail to another folder on IMAP server.

    Uses stored imap_uid directly; falls back to Message-ID search if missing.
    Uses UID MOVE if supported, otherwise COPY + STORE \\Deleted + EXPUNGE.
    Raises exceptions on failure so caller can queue for retry.
    """
    import logging

    logger = logging.getLogger(__name__)

    mail = (
        await db.execute(
            select(Mail).where(
                and_(Mail.id == mail_id, Mail.tenant_id == tenant_id)
            )
        )
    ).scalar_one_or_none()
    if not mail:
        logger.warning("imap_move_mail: mail %s not found", mail_id)
        return

    source_folder = (
        await db.execute(
            select(MailFolder).where(
                and_(MailFolder.id == mail.folder_id, MailFolder.tenant_id == tenant_id)
            )
        )
    ).scalar_one_or_none()
    if not source_folder:
        logger.warning("imap_move_mail: source folder not found for mail %s", mail_id)
        return

    target_folder = (
        await db.execute(
            select(MailFolder).where(
                and_(MailFolder.id == target_folder_id, MailFolder.tenant_id == tenant_id)
            )
        )
    ).scalar_one_or_none()
    if not target_folder:
        logger.warning("imap_move_mail: target folder %s not found", target_folder_id)
        return

    account = (
        await db.execute(
            select(MailAccount).where(
                and_(MailAccount.id == source_folder.account_id, MailAccount.tenant_id == tenant_id)
            )
        )
    ).scalar_one_or_none()
    if not account:
        logger.warning("imap_move_mail: account not found for mail %s", mail_id)
        return

    if not mail.imap_uid and not mail.message_id:
        logger.warning("imap_move_mail: mail %s has no imap_uid or message_id, cannot sync", mail_id)
        return

    # Lifecycle hook: mail.before_move
    from app.core.hooks import do_action
    await do_action("mail.before_move", mail_id=str(mail.id), tenant_id=str(tenant_id), source_folder_id=str(source_folder.id), target_folder_id=str(target_folder.id), db=db)

    password = await get_account_password(account)
    client = None

    try:
        client = aioimaplib.IMAP4_SSL(host=account.imap_host, port=account.imap_port)
        await client.wait_hello_from_server()
        await client.login(account.username, password)

        select_resp = await client.select(source_folder.imap_name)
        if select_resp.result != 'OK':
            raise RuntimeError(f"cannot select folder {source_folder.imap_name}")

        # Use stored imap_uid directly; fall back to Message-ID search
        if mail.imap_uid:
            uid_str = mail.imap_uid
        else:
            search_resp = await client.uid_search(f'HEADER Message-ID "{mail.message_id}"')
            uids_raw = search_resp[1][0] if search_resp[1] and search_resp[1][0] else b''
            if isinstance(uids_raw, (bytes, bytearray)):
                uids = uids_raw.split()
            else:
                uids = []
            if not uids:
                raise RuntimeError(f"no UID found for Message-ID {mail.message_id}")
            uid_str = uids[0].decode() if isinstance(uids[0], bytes) else str(uids[0])

        # Try UID MOVE first; fall back to COPY + STORE \\Deleted + EXPUNGE
        try:
            move_resp = await client.uid('move', uid_str, target_folder.imap_name)
            if move_resp.result == 'OK':
                logger.info("imap_move_mail: moved mail %s (UID %s) via UID MOVE", mail_id, uid_str)
                return
        except Exception as move_exc:
            logger.info("imap_move_mail: UID MOVE not supported, falling back: %s", move_exc)

        # Fallback: COPY + STORE \\Deleted + EXPUNGE
        copy_resp = await client.uid('copy', uid_str, target_folder.imap_name)
        if copy_resp.result != 'OK':
            raise RuntimeError(f"COPY failed for mail {mail_id}")

        await client.uid('store', uid_str, r'+FLAGS (\\Deleted)')
        await client.expunge()

        logger.info("imap_move_mail: moved mail %s (UID %s) via COPY+DELETE", mail_id, uid_str)

        # Lifecycle hook: mail.after_move
        from app.core.hooks import do_action
        await do_action("mail.after_move", mail_id=str(mail.id), tenant_id=str(tenant_id), source_folder_id=str(source_folder.id), target_folder_id=str(target_folder.id), db=db)

    except Exception as exc:
        logger.warning("imap_move_mail: failed for mail %s: %s", mail_id, exc)
        raise
    finally:
        if client is not None:
            try:
                await client.logout()
            except Exception:
                logger.debug("Ignored exception in mail service", exc_info=True)