"""Shared IMAP operations used by mailcat sorters."""

from __future__ import annotations

import email
import email.header
from email.message import Message

from imap_utils import quote_mailbox
from mail_routes import PREFIX, quarter_folder, route_from_subject


HEADER_FETCH = "(BODY.PEEK[HEADER.FIELDS (FROM SUBJECT DATE)])"


def decode_header_value(value) -> str:
    """Decode an RFC 2047 header value into display text."""
    if not value:
        return ""
    try:
        parts = email.header.decode_header(value)
        out = []
        for raw, charset in parts:
            if isinstance(raw, bytes):
                out.append(raw.decode(charset or "utf-8", errors="replace"))
            else:
                out.append(str(raw))
        return " ".join(out).strip()
    except Exception:
        return str(value or "")


def fetch_body(data) -> bytes | None:
    """Return the first bytes payload from an IMAP FETCH response."""
    if not data:
        return None
    for item in data:
        if isinstance(item, tuple) and len(item) >= 2 and isinstance(item[1], bytes):
            return item[1]
    return None


def parse_header(raw_header: bytes) -> Message:
    """Parse an IMAP header payload into an email Message."""
    return email.message_from_bytes(raw_header)


def destination_from_header(raw_header: bytes) -> str | None:
    """Return the full IMAP destination folder for a fetched header."""
    msg = parse_header(raw_header)
    from_raw = decode_header_value(msg.get("From", ""))
    subject = decode_header_value(msg.get("Subject", ""))
    date_str = msg.get("Date", "")

    destination = route_from_subject(from_raw, subject)
    if destination == "__FACTUUR_DATE__":
        destination = quarter_folder(date_str)
    if destination:
        return PREFIX + destination
    return None


def ensure_mailbox(mail, folder: str) -> bool:
    """Create a mailbox and its parents if they do not already exist."""
    parts = folder.split(".")
    for index in range(1, len(parts) + 1):
        parent = ".".join(parts[:index])
        status, _ = mail.create(quote_mailbox(parent))
        if status not in {"OK", "NO"}:
            return False
    return True


def move_message(mail, uid: bytes, src: str, dst: str):
    """Copy a message to dst and mark it deleted in src."""
    select_status, select_data = mail.select(quote_mailbox(src))
    if select_status != "OK":
        return False, ("select_source", select_status, select_data)

    copy_status, copy_data = mail.uid("COPY", uid, quote_mailbox(dst))
    if copy_status != "OK":
        return False, ("copy", copy_status, copy_data)

    store_status, store_data = mail.uid("STORE", uid, "+FLAGS", "\\Deleted")
    if store_status != "OK":
        return False, ("store_deleted", store_status, store_data)

    return True, None