/**
 * Per-account dedupe of inbound QR strings from Baileys. Pure logic so the
 * pair-handler stays thin and the dedupe is unit-testable.
 *
 * Invariant: for a given accountId, identical QR payloads are dropped.
 * A different payload (or the first ever for that account) returns true,
 * meaning "yes, emit this one to the web".
 */
export function makeQrDedupe() {
  const last = new Map<string, string>();

  return {
    /** Returns true if this payload should be forwarded; false if it's a dup. */
    shouldEmit(accountId: string, payload: string): boolean {
      if (last.get(accountId) === payload) return false;
      last.set(accountId, payload);
      return true;
    },
    /** Forget the last payload — call when the session ends or pairing restarts. */
    reset(accountId: string): void {
      last.delete(accountId);
    },
    /** Test helper — current cache size. */
    size(): number {
      return last.size;
    },
  };
}

/**
 * Pure logic for the pair page's countdown bar. Given a remaining-seconds
 * value and the total window, return the rendering primitives. Extracted
 * so the visual behaviour is unit-testable.
 */
export interface CountdownRender {
  /** Width % for the progress bar [0..100]. */
  pct: number;
  /** True when the remaining time crosses the danger threshold — UI flips
   *  to destructive colours. Threshold scales with `total`: 10 s for short
   *  per-QR timers, 30 s for the multi-minute pairing window. */
  danger: boolean;
  /** True when the QR has expired (≤ 0). */
  expired: boolean;
}

export function countdownRender(seconds: number, total: number): CountdownRender {
  const safeTotal = total > 0 ? total : 1;
  const clamped = Math.max(0, Math.min(seconds, safeTotal));
  const pct = Math.round((clamped / safeTotal) * 100);
  // Short windows (≤60 s) use a 10 s warning; longer ones (the 5-minute
  // pairing window) use 30 s so it shows up while still actionable.
  const dangerThreshold = safeTotal <= 60 ? 10 : 30;
  return {
    pct,
    danger: clamped > 0 && clamped <= dangerThreshold,
    expired: clamped <= 0,
  };
}