// ─── Header Parsing ──────────────────────────────────────────────────────────

/**
 * Standard headers used by most providers (OpenAI, Fireworks, etc.)
 */
export const STANDARD_HEADERS = {
  limit: "x-ratelimit-limit-requests",
  remaining: "x-ratelimit-remaining-requests",
  reset: "x-ratelimit-reset-requests",
  limitTokens: "x-ratelimit-limit-tokens",
  remainingTokens: "x-ratelimit-remaining-tokens",
  resetTokens: "x-ratelimit-reset-tokens",
  retryAfter: "retry-after",
  overLimit: "x-ratelimit-over-limit",
};

/**
 * Anthropic uses custom headers
 */
export const ANTHROPIC_HEADERS = {
  limit: "anthropic-ratelimit-requests-limit",
  remaining: "anthropic-ratelimit-requests-remaining",
  reset: "anthropic-ratelimit-requests-reset",
  limitTokens: "anthropic-ratelimit-input-tokens-limit",
  remainingTokens: "anthropic-ratelimit-input-tokens-remaining",
  resetTokens: "anthropic-ratelimit-input-tokens-reset",
  retryAfter: "retry-after",
};

/**
 * Parse a reset time string into milliseconds.
 * Formats: "1s", "1m", "1h", "1ms", "60", ISO date, Unix timestamp
 */
export function parseResetTime(value) {
  if (!value) return null;

  // Duration strings: "1s", "500ms", "1m30s"
  const durationMatch = value.match(/^(?:(\d+)h)?(?:(\d+)m(?!s))?(?:(\d+)s)?(?:(\d+)ms)?$/);
  if (durationMatch) {
    const [, h, m, s, ms] = durationMatch;
    return (
      (parseInt(h || 0) * 3600 + parseInt(m || 0) * 60 + parseInt(s || 0)) * 1000 +
      parseInt(ms || 0)
    );
  }

  // Pure number: assume seconds
  const num = parseFloat(value);
  if (!isNaN(num) && num > 0) {
    // If it looks like a Unix timestamp (> year 2025)
    if (num > 1700000000) {
      return Math.max(0, num * 1000 - Date.now());
    }
    return num * 1000;
  }

  // ISO date string
  try {
    const date = new Date(value);
    if (!isNaN(date.getTime())) {
      return Math.max(0, date.getTime() - Date.now());
    }
  } catch {}

  return null;
}

export function toPlainHeaders(headers: unknown): Record<string, string> {
  if (!headers) return {};
  const plain: Record<string, string> = {};
  const obj = headers as Record<string, unknown>;
  if (typeof obj.forEach === "function") {
    try {
      (obj.forEach as (cb: (v: string, k: string) => void) => void)((v: string, k: string) => {
        plain[k.toLowerCase()] = v;
      });
      return plain;
    } catch {}
  }
  if (typeof obj.entries === "function") {
    try {
      for (const [k, v] of (obj.entries as () => Iterable<[string, string]>)()) {
        plain[k.toLowerCase()] = v;
      }
      return plain;
    } catch {}
  }
  try {
    for (const [k, v] of Object.entries(obj)) {
      plain[k.toLowerCase()] = v == null ? "" : String(v);
    }
  } catch {}
  return plain;
}