export const HEALTH_DRAFT_TTL_MS = 24 * 60 * 60 * 1000;

export function createDraftKey({ userId, sourceRef, metricSet, now = Date.now() } = {}) {
  const ref = String(sourceRef ?? 'manual').slice(0, 64);
  return `${String(userId)}:${metricSet}:${ref}:${now}`;
}

export function createInMemoryHealthObservationDraftStore() {
  const rowsByUser = new Map();
  let nextId = 1;

  return {
    async findByKey(userId, draftKey) {
      const rows = rowsByUser.get(String(userId)) ?? [];
      return rows.find((row) => row.draftKey === draftKey && row.status === 'pending') ?? null;
    },
    async findPendingBySourceRef(userId, sourceRef) {
      const rows = rowsByUser.get(String(userId)) ?? [];
      const now = Date.now();
      return (
        rows.find(
          (row) =>
            row.status === 'pending'
            && row.sourceRef === sourceRef
            && row.expiresAt > now,
        ) ?? null
      );
    },
    async insert(userId, draft) {
      const row = {
        id: nextId++,
        userId: String(userId),
        draftKey: draft.draftKey,
        metricSet: draft.metricSet,
        extracted: draft.extracted,
        validation: draft.validation,
        status: 'pending',
        channel: draft.channel ?? 'h5',
        sourceRef: draft.sourceRef ?? null,
        createdAt: draft.createdAt ?? Date.now(),
        expiresAt: draft.expiresAt ?? Date.now() + HEALTH_DRAFT_TTL_MS,
        committedAt: null,
      };
      const list = rowsByUser.get(row.userId) ?? [];
      list.unshift(row);
      rowsByUser.set(row.userId, list);
      return row;
    },
    async update(userId, draftKey, patch) {
      const rows = rowsByUser.get(String(userId)) ?? [];
      const index = rows.findIndex((row) => row.draftKey === draftKey);
      if (index < 0) return null;
      rows[index] = { ...rows[index], ...patch };
      return rows[index];
    },
  };
}