import { ReportData } from "../../features/report";
import {
  mergeBucketPeriods,
  getAmount,
  PeriodKey,
} from "../report.helpers";
import { ChartDataPoint } from "./HistoryChart.models";

// ─── Tab → PeriodKey ─────────────────────────────────────────

const TAB_TO_KEY: Record<string, PeriodKey> = {
  Weekly: "weekly",
  Monthly: "monthly",
  Yearly: "yearly",
  "Financial Year": "fyly",
  "All Time": "full",
};

export function tabToKey(tab: string): PeriodKey {
  return TAB_TO_KEY[tab] ?? "full";
}

// ─── Comparison ──────────────────────────────────────────────

function attachComparison(
  points: ChartDataPoint[],
  key: PeriodKey
): ChartDataPoint[] {
  const getCompareIndex = (i: number) => {
    if (key === "weekly") return i - 4;
    if (key === "monthly") return i - 12;
    if (key === "yearly") return i - 1;
    if (key === "fyly") return i - 1;
    return -1;
  };

  return points.map((p, i) => {
    const ci = getCompareIndex(i);

    return {
      ...p,
      compare:
        ci >= 0 && points[ci]
          ? {
              id: points[ci].id,
              label: points[ci].label,
              amount: points[ci].amount,
            }
          : undefined,
    };
  });
}

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

export function buildChartData(
  reportData: ReportData,
  key: PeriodKey,
  mode: "expense" | "income",
  comparison: boolean
): ChartDataPoint[] {
  const merged = mergeBucketPeriods(reportData.buckets, key);

  let points: ChartDataPoint[] = merged.map((p) => ({
    id: p.id,
    label: p.label,
    amount: getAmount(p, mode),
  }));

  if (comparison) {
    points = attachComparison(points, key);
  }

  return points;
}