"""
Reconciliation of the month-end close.

Internal identity (always holds and proves nothing was silently dropped):
    uploaded_total = receivable_orders + paid_orders + transfers_total

Closing receivable:
    final_receivable_usd = Σ_marketplace ROUND(reserve + additional_sales) x fx
                           + manual_adjustments

Status is "Reconciled" when |identity difference| and |vs-expected difference|
are within the rounding tolerance (default USD 0.01).
"""
from __future__ import annotations

from dataclasses import dataclass, field

from .settlements import AggregationResult, Classification, RECEIVABLE_ACCOUNT_TYPES
from .receivable import ReceivableResult

DEFAULT_TOLERANCE = 0.01


@dataclass
class Reconciliation:
    uploaded_total: float = 0.0
    receivable_orders: float = 0.0     # Σ order_total over receivable settlements (all accts)
    paid_orders: float = 0.0           # Σ order_total over paid settlements
    transfers_total: float = 0.0       # Σ total over transfer rows
    reserve_total: float = 0.0
    manual_adjustments: float = 0.0
    final_receivable_usd: float = 0.0
    identity_difference: float = 0.0
    expected_receivable: float | None = None
    expected_difference: float | None = None
    tolerance: float = DEFAULT_TOLERANCE
    status: str = "Reconciled"
    notes: list[str] = field(default_factory=list)

    @property
    def reconciled(self) -> bool:
        return self.status == "Reconciled"


def reconcile(
    agg: AggregationResult,
    cls: Classification,
    receivable: ReceivableResult,
    manual_adjustments: float = 0.0,
    expected_receivable: float | None = None,
    tolerance: float = DEFAULT_TOLERANCE,
) -> Reconciliation:
    r = Reconciliation(tolerance=tolerance, manual_adjustments=manual_adjustments,
                       expected_receivable=expected_receivable)
    r.uploaded_total = agg.uploaded_total
    for key, st in agg.settlements.items():
        if st.status == "receivable":
            r.receivable_orders += st.order_total
        else:
            r.paid_orders += st.order_total
        r.transfers_total += st.transfer_total
    r.reserve_total = sum(m.reserve for m in receivable.marketplaces.values())
    r.final_receivable_usd = receivable.total_usd + manual_adjustments

    reconstructed = r.receivable_orders + r.paid_orders + r.transfers_total
    r.identity_difference = r.uploaded_total - reconstructed
    if abs(r.identity_difference) > tolerance:
        r.status = "Unreconciled"
        r.notes.append(
            f"Uploaded total {r.uploaded_total:,.2f} != "
            f"receivable+paid+transfers {reconstructed:,.2f} "
            f"(diff {r.identity_difference:,.2f})."
        )
    if expected_receivable is not None:
        r.expected_difference = r.final_receivable_usd - expected_receivable
        if abs(r.expected_difference) > tolerance:
            r.status = "Unreconciled"
            r.notes.append(
                f"Computed receivable {r.final_receivable_usd:,.2f} vs expected "
                f"{expected_receivable:,.2f} (diff {r.expected_difference:,.2f})."
            )
    return r