import React from "react";
import { SmithersError } from "../utils/errors";

export type TimerProps = {
  id: string;
  /**
   * Relative duration (examples: "500ms", "1s", "30m", "1h", "7d").
   */
  duration?: string;
  /**
   * Absolute fire time (ISO timestamp or Date).
   */
  until?: string | Date;
  /**
   * Recurring timer syntax is reserved for phase 2 and is not supported yet.
   */
  every?: string;
  skipIf?: boolean;
  dependsOn?: string[];
  needs?: Record<string, string>;
  label?: string;
  meta?: Record<string, unknown>;
  key?: string;
};

export function Timer(props: TimerProps) {
  if (props.skipIf) return null;

  const hasDuration = typeof props.duration === "string" && props.duration.trim().length > 0;
  const hasUntil = props.until !== undefined && props.until !== null && String(props.until).trim().length > 0;
  if ((hasDuration ? 1 : 0) + (hasUntil ? 1 : 0) !== 1) {
    throw new SmithersError(
      "INVALID_INPUT",
      `<Timer id="${props.id}"> requires exactly one of "duration" or "until".`,
    );
  }
  if (props.every !== undefined) {
    throw new SmithersError(
      "INVALID_INPUT",
      `<Timer id="${props.id}"> does not support "every" yet. Recurring timers ship in phase 2.`,
    );
  }

  const untilIso =
    props.until instanceof Date
      ? props.until.toISOString()
      : typeof props.until === "string"
        ? props.until
        : undefined;

  const timerMeta = {
    timer: true,
    ...(hasDuration ? { duration: props.duration } : {}),
    ...(hasUntil ? { until: untilIso } : {}),
    ...props.meta,
  };

  return React.createElement("smithers:timer", {
    id: props.id,
    key: props.key,
    duration: props.duration,
    until: untilIso,
    dependsOn: props.dependsOn,
    needs: props.needs,
    label: props.label ?? `timer:${props.id}`,
    meta: Object.keys(timerMeta).length > 0 ? timerMeta : undefined,
    __smithersTimerDuration: props.duration,
    __smithersTimerUntil: untilIso,
  });
}