/** Client-side humanizers for audit codes, user agents and dates. No secrets, no side effects. */

const ACTION_LABELS: Record<string, string> = {
  login: "Signed in",
  logout: "Signed out",
  "account.created": "Account created",
  "account.deleted": "Account deleted",
  "account.export": "Account exported",
  "email.verified": "Email verified",
  "email.change_requested": "Email change requested",
  "email.changed": "Email changed",
  "password.reset_requested": "Password reset requested",
  "password.reset": "Password reset",
  "password.changed": "Password changed",
  "session.revoked": "Session revoked",
  "sessions.revoked": "All sessions revoked",
  "provider.key_added": "API key added",
  "provider.key_replaced": "API key replaced",
  "provider.key_removed": "API key removed",
  "provider.key_validated": "API key validated",
  "provider.key_invalid": "API key rejected",
  "onboarding.completed": "Onboarding completed",
};

export function humanizeAction(code: string): string {
  if (ACTION_LABELS[code]) return ACTION_LABELS[code];
  // "provider.key_added" → "Provider key added"
  const words = code.replace(/[._-]+/g, " ").trim();
  return words.charAt(0).toUpperCase() + words.slice(1);
}

export function actionTone(code: string): "default" | "success" | "warning" | "danger" | "info" {
  if (/deleted|invalid|revoked|rejected/.test(code)) return "danger";
  if (/reset|change_requested/.test(code)) return "warning";
  if (/added|validated|verified|created|changed/.test(code)) return "success";
  if (/login|export/.test(code)) return "info";
  return "default";
}

export interface UaSummary {
  browser: string;
  os: string;
  device: "desktop" | "mobile" | "tablet" | "unknown";
  label: string;
}

/** Best-effort user-agent summary — good enough for a sessions list, never authoritative. */
export function describeUserAgent(ua: string | null | undefined): UaSummary {
  if (!ua) return { browser: "Unknown browser", os: "Unknown OS", device: "unknown", label: "Unknown device" };
  const s = ua;
  let browser = "Browser";
  if (/Edg\//.test(s)) browser = "Edge";
  else if (/OPR\/|Opera/.test(s)) browser = "Opera";
  else if (/Arc\//.test(s)) browser = "Arc";
  else if (/Firefox\//.test(s)) browser = "Firefox";
  else if (/Chrome\//.test(s) && !/Chromium/.test(s)) browser = "Chrome";
  else if (/Chromium/.test(s)) browser = "Chromium";
  else if (/Safari\//.test(s) && /Version\//.test(s)) browser = "Safari";
  else if (/curl|node|python|okhttp|Go-http/i.test(s)) browser = "API client";

  let os = "Unknown OS";
  if (/iPhone|iPad|iPod/.test(s)) os = "iOS";
  else if (/Android/.test(s)) os = "Android";
  else if (/Mac OS X|Macintosh/.test(s)) os = "macOS";
  else if (/Windows/.test(s)) os = "Windows";
  else if (/CrOS/.test(s)) os = "ChromeOS";
  else if (/Linux/.test(s)) os = "Linux";

  let device: UaSummary["device"] = "desktop";
  if (/iPad|Tablet/.test(s)) device = "tablet";
  else if (/Mobi|iPhone|Android.*Mobile/.test(s)) device = "mobile";

  return { browser, os, device, label: `${browser} on ${os}` };
}

export function formatDateTime(date: string | Date | null | undefined, opts: Intl.DateTimeFormatOptions = {}): string {
  if (!date) return "—";
  const d = typeof date === "string" ? new Date(date) : date;
  if (Number.isNaN(d.getTime())) return "—";
  return d.toLocaleString("en-US", { month: "short", day: "numeric", hour: "numeric", minute: "2-digit", ...opts });
}

export function formatDate(date: string | Date | null | undefined): string {
  if (!date) return "—";
  const d = typeof date === "string" ? new Date(date) : date;
  if (Number.isNaN(d.getTime())) return "—";
  return d.toLocaleDateString("en-US", { month: "long", day: "numeric", year: "numeric" });
}

/** formatRelative that also accepts Date objects returned by the auth client. */
export function formatRelativeSafe(date: string | Date | null | undefined): string {
  if (!date) return "—";
  const d = typeof date === "string" ? new Date(date) : date;
  if (Number.isNaN(d.getTime())) return "—";
  const s = Math.round((Date.now() - d.getTime()) / 1000);
  if (s < 45) return "just now";
  const m = Math.round(s / 60);
  if (m < 60) return `${m} min ago`;
  const h = Math.round(m / 60);
  if (h < 24) return `${h} h ago`;
  const days = Math.round(h / 24);
  if (days < 7) return `${days} d ago`;
  return d.toLocaleDateString("en-US", { month: "short", day: "numeric" });
}

export function formatPercent(n: number | null | undefined, digits = 1): string {
  if (n === null || n === undefined || Number.isNaN(n)) return "—";
  return `${(n * 100).toFixed(digits)}%`;
}

/** Turn an API error (ClientApiError, Error, Better Auth {error}) into a short user-facing string. */
export function errorMessage(e: unknown, fallback = "Something went wrong"): string {
  if (!e) return fallback;
  if (typeof e === "string") return e;
  if (typeof e === "object") {
    const o = e as { message?: unknown; error?: { message?: unknown } };
    if (typeof o.message === "string" && o.message) return o.message;
    if (o.error && typeof o.error.message === "string") return o.error.message;
  }
  return fallback;
}