import { baselineRowKey, serializeBaselineRow } from './health-baseline-serialize.mjs';

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

  return {
    async list(userId) {
      return [...(rowsByUser.get(String(userId)) ?? [])];
    },
    async upsertMany(userId, baselines = [], { computedAt = Date.now() } = {}) {
      const key = String(userId);
      const existing = rowsByUser.get(key) ?? [];
      const index = new Map(existing.map((row) => [baselineRowKey(row), row]));
      for (const base of baselines) {
        const serialized = serializeBaselineRow(base, computedAt);
        const rowKey = baselineRowKey(serialized);
        const prior = index.get(rowKey);
        if (prior) {
          index.set(rowKey, { ...prior, ...serialized });
        } else {
          index.set(rowKey, { id: nextId++, userId: key, ...serialized });
        }
      }
      const merged = [...index.values()];
      rowsByUser.set(key, merged);
      return merged;
    },
  };
}