import { ReportData, Transaction } from "../../features/report";
import {
  mergeBucketPeriods,
  periodIdToKey,
  formatCurrency,
} from "../report.helpers";
import { LatestItem } from "./LatestItems.models";

// ─── Transaction extraction ─────────────────────────────────

function extractTransactions(
  reportData: ReportData,
  selectedPeriodId: string | null,
  mode: "expense" | "income"
): Transaction[] {
  if (selectedPeriodId) {
    const key = periodIdToKey(selectedPeriodId);
    const periods = mergeBucketPeriods(reportData.buckets, key);
    const selected = periods.find((p) => p.id === selectedPeriodId);

    if (!selected) return [];

    return mode === "expense"
      ? (selected.expenses.transactions || [])
      : (selected.incomes.transactions || []);
  }

  const periods = mergeBucketPeriods(reportData.buckets, "full");

  if (!periods.length) return [];

  const full = periods[0];

  return mode === "expense"
    ? (full.expenses.transactions || [])
    : (full.incomes.transactions || []);
}

// ─── Main adapter ────────────────────────────────────────────

export function buildLatestItems(
  reportData: ReportData,
  selectedPeriodId: string | null,
  mode: "expense" | "income"
): LatestItem[] {
  const txns = extractTransactions(reportData, selectedPeriodId, mode);

  return txns
    .filter((t) => (mode === "expense" ? t.amount < 0 : t.amount >= 0))
    .sort(
      (a, b) =>
        new Date(b.occurred_at).getTime() -
        new Date(a.occurred_at).getTime()
    )
    .map((t, index) => ({
      id: index + 1,
      title: t.payee.name,
      subtitle: t.tags.map((tag) => tag.name).join(", "),
      amount: formatCurrency(t.amount),
      timeAgo: new Date(t.occurred_at).toLocaleDateString("en-IN"),
    }));
}