/**
 * Pure utility functions for the draft clock/timer system.
 * Extracted here to be independently testable and shared across
 * route handlers and UI components.
 *
 * Clock model (chess-clock / Fischer increment):
 *   - Draft start: every team receives `initialTime` as their bank.
 *   - While on the clock: the active team's bank counts down each second.
 *   - After a pick is made: the picker's bank += `incrementTime`.
 *   - Between turns: all other teams' banks are left untouched.
 */

/**
 * Formats a HH:MM time string as 12-hour time with AM/PM.
 * e.g. "23:00" → "11:00 PM", "07:30" → "7:30 AM"
 */
export function formatTime12h(t: string): string {
  const [h, m] = t.split(":").map(Number);
  const ap = (h || 0) >= 12 ? "PM" : "AM";
  return `${(h || 0) % 12 || 12}:${String(m || 0).padStart(2, "0")} ${ap}`;
}

/**
 * Formats a seconds value for display.
 *   undefined  → "--:--"
 *   < 3600 s   → "m:ss"
 *   >= 3600 s  → "h:mm:ss"
 */
export function formatClockTime(seconds: number | undefined): string {
  if (seconds === undefined) return "--:--";
  const clamped = Math.max(0, seconds); // guard against negative values from timer drift
  const h = Math.floor(clamped / 3600);
  const m = Math.floor((clamped % 3600) / 60);
  const s = clamped % 60;
  if (h > 0)
    return `${h}:${String(m).padStart(2, "0")}:${String(s).padStart(2, "0")}`;
  return `${m}:${String(s).padStart(2, "0")}`;
}

/**
 * Returns a team's new bank time after they complete a pick.
 * The increment is the post-pick reward (chess clock model).
 *
 * @param bankTime    Current remaining seconds in the team's bank
 * @param incrementTime  Bonus seconds awarded after each pick
 */
export function calculateTimeAfterPick(
  bankTime: number,
  incrementTime: number
): number {
  return bankTime + incrementTime;
}

/**
 * Converts a draftSpeed form value + timerMode into DB time fields.
 *
 * Standard mode: speed is raw seconds (the per-pick time); both fields equal it.
 * Chess clock mode: speed is a named preset that maps to (initial bank, increment).
 */
export function parseDraftSpeed(
  draftSpeed: string | null,
  draftTimerMode: "chess_clock" | "standard"
): { draftInitialTime: number; draftIncrementTime: number } {
  if (draftTimerMode === "standard") {
    const seconds = parseInt(draftSpeed ?? "", 10);
    const time = isNaN(seconds) ? 90 : seconds;
    return { draftInitialTime: time, draftIncrementTime: time };
  }

  if (draftSpeed?.startsWith("custom:")) {
    const [, bankStr, incrStr] = draftSpeed.split(":");
    const bank = parseInt(bankStr ?? "", 10);
    const incr = parseInt(incrStr ?? "", 10);
    if (!isNaN(bank) && !isNaN(incr)) return { draftInitialTime: bank, draftIncrementTime: incr };
  }
  switch (draftSpeed) {
    case "fast":
      return { draftInitialTime: 60, draftIncrementTime: 10 };
    case "slow":
      return { draftInitialTime: 28800, draftIncrementTime: 3600 };
    case "very-slow":
      return { draftInitialTime: 43200, draftIncrementTime: 3600 };
    default:
      return { draftInitialTime: 120, draftIncrementTime: 15 };
  }
}

/**
 * Returns the Tailwind colour class(es) for a timer value.
 *
 *   > 60 s   → green  (plenty of time)
 *   > 30 s   → amber  (getting tight)
 *   > 10 s   → coral  (urgent)
 *   ≤ 10 s   → coral + animate-pulse  (critical)
 *   undefined → muted (clock not running)
 */
export function getTimerColorClass(seconds: number | undefined): string {
  if (seconds === undefined) return "text-muted-foreground";
  if (seconds > 60) return "text-emerald-400";
  if (seconds > 30) return "text-amber-accent";
  if (seconds > 10) return "text-coral-accent";
  return "text-coral-accent animate-pulse";
}