Structured Express API

/**
 * In-memory store. Swap this module for a database client (pg, Supabase, Prisma ...) —
 * the router only depends on these four functions.
 */
export type Note = { id: string; title: string; body: string; tags: string[]; createdAt: string; updatedAt: string };

const notes = new Map<string, Note>();
let counter = 1;

function seed() {
  const now = new Date().toISOString();
  const first: Note = { id: String(counter++), title: "Welcome", body: "This API keeps notes in memory. Restarting the server clears them.", tags: ["intro"], createdAt: now, updatedAt: now };
  notes.set(first.id, first);
}
seed();

export function listNotes(filter: { q?: string; tag?: string }) {
  return Array.from(notes.values()).filter((n) => {
    if (filter.tag && !n.tags.includes(filter.tag)) return false;
    if (filter.q) {
      const q = filter.q.toLowerCase();
      return n.title.toLowerCase().includes(q) || n.body.toLowerCase().includes(q);
    }
    return true;
  });
}
export function getNote(id: string) {
  return notes.get(id) ?? null;
}
export function saveNote(input: Omit<Note, "id" | "createdAt" | "updatedAt">, id?: string) {
  const now = new Date().toISOString();
  const existing = id ? notes.get(id) : undefined;
  const note: Note = { id: id ?? String(counter++), ...input, createdAt: existing?.createdAt ?? now, updatedAt: now };
  notes.set(note.id, note);
  return note;
}
export function deleteNote(id: string) {
  return notes.delete(id);
}