/** In-memory interpretation of the public bounded collection filter contract. */
export function matchesRecordWhere(data: Record<string, unknown>, where: unknown): boolean {
  if (!where || typeof where !== "object") return true;
  return Object.entries(where).every(([key, condition]) => {
    const value = data[key];
    if (condition === null || typeof condition !== "object") return value === condition;
    return Object.entries(condition).every(([operator, expected]) => {
      if (operator === "eq") return value === expected;
      if (operator === "contains")
        return (
          typeof value === "string" &&
          typeof expected === "string" &&
          value.toLowerCase().includes(expected.toLowerCase())
        );
      if (
        typeof value !== typeof expected ||
        (typeof value !== "string" && typeof value !== "number")
      )
        return false;
      const comparison =
        typeof value === "number"
          ? value - Number(expected)
          : value.localeCompare(String(expected));
      if (operator === "gt") return comparison > 0;
      if (operator === "gte") return comparison >= 0;
      if (operator === "lt") return comparison < 0;
      if (operator === "lte") return comparison <= 0;
      return false;
    });
  });
}

/** Numeric fields sort by value; mixed scalar types keep numbers together. */
export function compareRecordValues(a: unknown, b: unknown): number {
  if (typeof a === "number" && typeof b === "number") return a - b;
  if (typeof a === "number") return -1;
  if (typeof b === "number") return 1;
  const left = String(a ?? ""),
    right = String(b ?? "");
  // PostgreSQL's C collation follows Unicode code points for valid UTF-8.
  // JavaScript's default comparison instead sorts surrogate code units.
  let i = 0,
    j = 0;
  while (i < left.length && j < right.length) {
    const leftPoint = left.codePointAt(i)!,
      rightPoint = right.codePointAt(j)!;
    if (leftPoint !== rightPoint) return leftPoint - rightPoint;
    i += leftPoint > 0xffff ? 2 : 1;
    j += rightPoint > 0xffff ? 2 : 1;
  }
  return left.length - right.length;
}