"""Drill-down: from a report line to its underlying journal items.

Given an account_id and a Period, fetches the matching account.move.line
records and returns them in a flat list. Used by the OWL drill-down
dialog and the engine's drill_down() public API."""

from dataclasses import dataclass
from datetime import date


@dataclass
class DrillDownRow:
    move_line_id: int
    move_id: int
    move_name: str
    date: date
    account_code: str
    account_name: str
    partner_name: str | None
    label: str
    debit: float
    credit: float
    balance: float

    def to_dict(self):
        return {
            'move_line_id': self.move_line_id,
            'move_id': self.move_id,
            'move_name': self.move_name,
            'date': str(self.date),
            'account_code': self.account_code,
            'account_name': self.account_name,
            'partner_name': self.partner_name or '',
            'label': self.label,
            'debit': self.debit,
            'credit': self.credit,
            'balance': self.balance,
        }


def fetch_drill_down(
    env,
    *,
    account_id: int,
    date_from: date,
    date_to: date,
    company_id: int | None = None,
    limit: int = 500,
) -> list[dict]:
    """Fetch journal items for an account within a date range.

    Returns flat list of dicts ready for the drill-down OWL table."""
    Line = env['account.move.line'].sudo()
    domain = [
        ('account_id', '=', account_id),
        ('date', '>=', date_from),
        ('date', '<=', date_to),
        ('parent_state', '=', 'posted'),
    ]
    if company_id:
        domain.append(('company_id', '=', company_id))

    move_lines = Line.search(domain, limit=limit, order='date asc, id asc')
    rows = []
    for ml in move_lines:
        rows.append(
            DrillDownRow(
                move_line_id=ml.id,
                move_id=ml.move_id.id,
                move_name=ml.move_id.name or '',
                date=ml.date,
                account_code=ml.account_id.code,
                account_name=ml.account_id.name,
                partner_name=ml.partner_id.name if ml.partner_id else None,
                label=ml.name or '',
                debit=ml.debit,
                credit=ml.credit,
                balance=ml.balance,
            ).to_dict()
        )
    return rows