import { healthEventFingerprint, mapHealthEventToPgPayload } from './health-event-serialize.mjs';

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

  return {
    async list(userId, { status = 'open', limit = 100 } = {}) {
      const rows = rowsByUser.get(String(userId)) ?? [];
      return rows
        .filter((row) => !status || row.status === status)
        .slice(0, limit);
    },
    async listUnreadAlerts(userId, { limit = 20 } = {}) {
      const rows = rowsByUser.get(String(userId)) ?? [];
      return rows
        .filter((row) => row.status === 'open' && (row.severity === 'watch' || row.severity === 'alert'))
        .slice(0, limit);
    },
    async acknowledge(userId, eventId) {
      const rows = rowsByUser.get(String(userId)) ?? [];
      const index = rows.findIndex((row) => Number(row.id) === Number(eventId));
      if (index < 0) return null;
      rows[index] = { ...rows[index], status: 'acknowledged', acknowledgedAt: Date.now() };
      return rows[index];
    },
    async acknowledgeAll(userId) {
      const rows = rowsByUser.get(String(userId)) ?? [];
      let count = 0;
      for (let i = 0; i < rows.length; i += 1) {
        if (rows[i].status === 'open' && (rows[i].severity === 'watch' || rows[i].severity === 'alert')) {
          rows[i] = { ...rows[i], status: 'acknowledged', acknowledgedAt: Date.now() };
          count += 1;
        }
      }
      return count;
    },
    async insertIfNew(userId, event, { now = Date.now() } = {}) {
      const key = String(userId);
      const rows = rowsByUser.get(key) ?? [];
      const fingerprint = healthEventFingerprint(event);
      const duplicate = rows.find(
        (row) => row.status === 'open' && healthEventFingerprint(row) === fingerprint,
      );
      if (duplicate) return { row: duplicate, created: false };
      const payload = mapHealthEventToPgPayload(event, now);
      const row = {
        id: nextId++,
        userId: key,
        eventType: payload.event_type,
        severity: payload.severity,
        detectedAt: now,
        ruleId: payload.rule_id,
        metricsInvolved: JSON.parse(payload.metrics_involved),
        evidenceObservationIds: [],
        agentSummary: payload.agent_summary,
        status: 'open',
        message: payload.agent_summary,
        metricType: event.metricType ?? null,
        symptomCode: event.symptomCode ?? null,
        createdAt: now,
      };
      rows.unshift(row);
      rowsByUser.set(key, rows);
      return { row, created: true };
    },
  };
}