import type { MonthViewModel } from "../domain/views.ts";

export type MonthPieMode = "spending" | "allocation";
export interface MonthPieSlice {
  id: string;
  label: string;
  amount: number;
}

/** Chart data comes from the same folded figures as the month table. */
export function monthPieData(view: MonthViewModel, mode: MonthPieMode) {
  const items: MonthPieSlice[] = view.rows.map(({ post, figures }) => ({
    id: post.id,
    label: post.name,
    amount: mode === "spending" ? figures.charges : figures.allocation,
  }));
  if (mode === "spending" && view.looseCharges !== 0) {
    items.push({ id: "unassigned", label: "Unassigned", amount: view.looseCharges });
  }
  const byAmount = (a: MonthPieSlice, b: MonthPieSlice) => b.amount - a.amount || a.label.localeCompare(b.label);
  const positive = items.filter((item) => item.amount > 0).sort(byAmount);
  const adjustments = items.filter((item) => item.amount < 0).sort((a, b) => a.amount - b.amount);
  return {
    positive,
    adjustments,
    positiveTotal: positive.reduce((sum, item) => sum + item.amount, 0),
    netTotal: mode === "spending" ? view.totalCharges : view.totalAllocation,
  };
}