"""
Joplin integration via the joppy ClientApi.

Actual notebook structure:
    Work > Timesheets > YYYY

Notes live directly inside the year notebook and are titled 'YYYY - WNN'.
"""

from datetime import date
from typing import Optional

from joppy.client_api import ClientApi


def _iso_week_label(d: date) -> str:
    """Return the note title for the week containing the given date, e.g. '2026 - W21'."""
    year, week, _ = d.isocalendar()
    return f"{year} - W{week:02d}"


def _find_notebook(
    api: ClientApi, title: str, parent_id: Optional[str] = None
) -> Optional[str]:
    """Return the ID of a notebook matching title (and optionally parent_id), or None."""
    for nb in api.get_all_notebooks():
        if nb.title == title:
            if parent_id is None or nb.parent_id == parent_id:
                return nb.id
    return None


def fetch_week_note(token: str, target_date: date) -> str:
    """
    Fetch the body of the weekly timesheet note from Joplin for the week
    containing target_date.

    Notebook path: Work > Timesheets > YYYY
    Note title:    YYYY - WNN

    Raises RuntimeError if any notebook or the note cannot be found.
    """
    api = ClientApi(token=token)
    week_label = _iso_week_label(target_date)
    year_str = str(target_date.year)

    work_id = _find_notebook(api, "Work")
    if work_id is None:
        raise RuntimeError("Joplin notebook 'Work' not found")

    timesheets_id = _find_notebook(api, "Timesheets", parent_id=work_id)
    if timesheets_id is None:
        raise RuntimeError("Joplin notebook 'Work > Timesheets' not found")

    year_id = _find_notebook(api, year_str, parent_id=timesheets_id)
    if year_id is None:
        raise RuntimeError(
            f"Joplin notebook 'Work > Timesheets > {year_str}' not found"
        )

    notes = api.get_all_notes(notebook_id=year_id, fields="id,title,body")
    for note in notes:
        if note.title == week_label:
            return note.body

    raise RuntimeError(
        f"Joplin note '{week_label}' not found in 'Work > Timesheets > {year_str}'"
    )