/**
 * Local mavi activity log (this browser only).
 * Not a full chain indexer — just what this wallet did here.
 */

export type MaviActivityKind = "send" | "fund" | "receive_note";

export type MaviActivityItem = {
  id: string;
  kind: MaviActivityKind;
  /** Wallet address that owns this history row */
  wallet: string;
  hash?: string;
  to?: string;
  from?: string;
  amountEth?: string;
  at: string;
  note?: string;
};

const KEY = "mavi_activity_v1";
const MAX = 40;

function loadAll(): MaviActivityItem[] {
  if (typeof window === "undefined") return [];
  try {
    const raw = window.localStorage.getItem(KEY);
    if (!raw) return [];
    const parsed: unknown = JSON.parse(raw);
    if (!Array.isArray(parsed)) return [];
    return parsed.filter(isItem);
  } catch {
    return [];
  }
}

function isItem(v: unknown): v is MaviActivityItem {
  if (!v || typeof v !== "object") return false;
  const o = v as Record<string, unknown>;
  return (
    typeof o.id === "string" &&
    (o.kind === "send" || o.kind === "fund" || o.kind === "receive_note") &&
    typeof o.wallet === "string" &&
    typeof o.at === "string"
  );
}

function saveAll(items: MaviActivityItem[]) {
  try {
    window.localStorage.setItem(KEY, JSON.stringify(items.slice(0, MAX)));
  } catch {
    /* quota */
  }
}

export function readActivityForWallet(
  walletAddress: string,
  limit = 20,
): MaviActivityItem[] {
  const w = walletAddress.toLowerCase();
  return loadAll()
    .filter((i) => i.wallet.toLowerCase() === w)
    .slice(0, limit);
}

export function addActivity(
  item: Omit<MaviActivityItem, "id" | "at"> & { at?: string },
): MaviActivityItem {
  const full: MaviActivityItem = {
    ...item,
    id: `act_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`,
    at: item.at ?? new Date().toISOString(),
    wallet: item.wallet.toLowerCase(),
  };
  const next = [full, ...loadAll()];
  saveAll(next);
  return full;
}

export function clearActivityForWallet(walletAddress: string): void {
  const w = walletAddress.toLowerCase();
  saveAll(loadAll().filter((i) => i.wallet.toLowerCase() !== w));
}

export function formatActivityTime(iso: string): string {
  try {
    const d = new Date(iso);
    if (Number.isNaN(d.getTime())) return iso;
    return d.toLocaleString(undefined, {
      month: "short",
      day: "numeric",
      hour: "2-digit",
      minute: "2-digit",
    });
  } catch {
    return iso;
  }
}

export function shortHash(hash: string): string {
  if (hash.length < 14) return hash;
  return `${hash.slice(0, 8)}…${hash.slice(-6)}`;
}

/** Call after writing activity so open tabs / home refresh. */
export function notifyActivityChanged() {
  if (typeof window === "undefined") return;
  window.dispatchEvent(new Event("mavi-activity"));
}