import type { TableMetadata } from "@tailor-platform/app-shell";

const DATE_ONLY_RE = /^\d{4}-\d{2}-\d{2}$/;
// Only `datetime` / `time` need expansion to RFC3339 — true `Date` fields
// already match the GraphQL Date scalar's YYYY-MM-DD format the date filter
// emits. Including "date" here corrupts Date filters
// (e.g. receiptDate on the GR list, invoiceDate on the PI list).
const DATETIME_FIELD_TYPES = new Set(["datetime", "time"]);

/**
 * Normalize datetime filter values emitted by DataTable.Filters.
 *
 * The date filter editors DataTable.Filters uses emit bare "YYYY-MM-DD"
 * strings, but TailorDB's DateTime scalar requires a full RFC3339 datetime, so filters
 * on datetime fields silently match nothing. For each known datetime field in
 * the table metadata, rewrite bare date strings to ISO datetimes:
 *
 * - `eq: "YYYY-MM-DD"` → `gte: startOfDayLocal, lt: startOfNextDayLocal`
 *   so "equals <date>" covers the whole day in the user's local timezone.
 * - `gt`/`gte`/`lt`/`lte` expand to start-of-day UTC (lower) or end-of-day
 *   UTC (upper) as before.
 */
export function normalizeCollectionQuery(
  query: Record<string, Record<string, unknown>> | undefined,
  tableMetadata: TableMetadata,
): Record<string, Record<string, unknown>> | undefined {
  if (!query) return query;

  const datetimeFields = new Set(
    tableMetadata.fields.filter((f) => DATETIME_FIELD_TYPES.has(f.type)).map((f) => f.name),
  );

  const next: Record<string, Record<string, unknown>> = {};
  for (const [field, ops] of Object.entries(query)) {
    if (!datetimeFields.has(field)) {
      next[field] = ops;
      continue;
    }
    next[field] = normalizeOps(ops);
  }
  return next;
}

function normalizeOps(ops: Record<string, unknown>): Record<string, unknown> {
  const out: Record<string, unknown> = {};
  for (const [op, value] of Object.entries(ops)) {
    // `eq` on a datetime field with a bare date string means "on this day".
    // Expand to a gte/lt range spanning the full day in the user's local timezone.
    if (op === "eq" && typeof value === "string" && DATE_ONLY_RE.test(value)) {
      const [year, month, day] = value.split("-").map(Number);
      out.gte = new Date(year, month - 1, day, 0, 0, 0, 0).toISOString();
      out.lt = new Date(year, month - 1, day + 1, 0, 0, 0, 0).toISOString();
    } else {
      out[op] = normalizeValue(op, value);
    }
  }
  return out;
}

function normalizeValue(op: string, value: unknown): unknown {
  if (Array.isArray(value)) {
    return value.map((v) => toIsoIfBareDate(op, v));
  }
  return toIsoIfBareDate(op, value);
}

function toIsoIfBareDate(op: string, value: unknown): unknown {
  if (typeof value !== "string" || !DATE_ONLY_RE.test(value)) return value;
  // Upper-bound operators expand to end-of-day so the selected date is inclusive.
  const isUpperBound = op === "lt" || op === "lte";
  return isUpperBound ? `${value}T23:59:59.999Z` : `${value}T00:00:00.000Z`;
}