import { inferBloodPressureContext } from './health-observation-validate.mjs';
import { HEALTH_DRAFT_TTL_MS, createDraftKey } from './health-observation-draft-store.mjs';

function extractionToCommitBody(extracted = {}, { observedAt = Date.now(), source = 'photo', sourceRef = null } = {}) {
  const metricSet = extracted.metricSet ?? extracted.metric_set;
  if (metricSet === 'blood_pressure') {
    return {
      confirmed: true,
      metricSet: 'blood_pressure',
      systolic: extracted.values?.systolic ?? extracted.systolic,
      diastolic: extracted.values?.diastolic ?? extracted.diastolic,
      context: extracted.context ?? inferBloodPressureContext(observedAt),
      observedAt,
      source,
      sourceRef,
      qualityFlag: extracted.lowConfidence ? 'suspect' : 'ok',
      rawPayload: extracted.raw ?? extracted,
    };
  }
  if (metricSet === 'symptom') {
    return {
      confirmed: true,
      metricSet: 'symptom',
      symptomCode: extracted.symptomCode ?? extracted.code,
      severity: extracted.severity,
      observedAt,
      source,
      sourceRef,
    };
  }
  const valueNum =
    extracted.values?.valueNum
    ?? extracted.values?.hr
    ?? extracted.values?.weight
    ?? extracted.values?.spo2
    ?? extracted.values?.temperature
    ?? extracted.valueNum;
  return {
    confirmed: true,
    metricSet,
    valueNum,
    observedAt,
    source,
    sourceRef,
    context: 'any',
    qualityFlag: extracted.lowConfidence ? 'suspect' : 'ok',
    rawPayload: extracted.raw ?? extracted,
  };
}

export function createHealthObservationDraftService({ draftStore, observationService } = {}) {
  if (!draftStore || !observationService) {
    throw new Error('createHealthObservationDraftService requires draftStore and observationService');
  }

  return {
    draftStore,
    observationService,
    async saveExtractionDraft(userId, {
      extraction,
      channel = 'h5',
      sourceRef = null,
      now = Date.now(),
    } = {}) {
      if (!extraction?.ok) {
        const error = Object.assign(new Error('抽取结果无效，无法创建草稿'), { code: 'invalid_extraction' });
        throw error;
      }
      if (sourceRef) {
        const existing = await draftStore.findPendingBySourceRef(userId, sourceRef);
        if (existing) return existing;
      }
      const draftKey = createDraftKey({
        userId,
        sourceRef: sourceRef ?? `manual-${now}`,
        metricSet: extraction.metricSet,
        now,
      });
      return draftStore.insert(userId, {
        draftKey,
        metricSet: extraction.metricSet,
        sourceRef,
        channel,
        expiresAt: now + HEALTH_DRAFT_TTL_MS,
        extracted: {
          metricSet: extraction.metricSet,
          values: extraction.values,
          lowConfidence: extraction.lowConfidence ?? false,
          raw: extraction.raw ?? null,
          sourceRef,
        },
        validation: {
          requireConfirm: true,
          ok: true,
        },
      });
    },
    async getDraft(userId, draftKey) {
      const draft = await draftStore.findByKey(userId, draftKey);
      if (!draft) return null;
      if (draft.expiresAt <= Date.now()) return null;
      return draft;
    },
    async commitDraft(userId, draftKey, { source = 'photo' } = {}) {
      const draft = await this.getDraft(userId, draftKey);
      if (!draft) {
        const error = Object.assign(new Error('草稿不存在或已过期'), { code: 'draft_not_found' });
        throw error;
      }
      const body = extractionToCommitBody(draft.extracted, {
        observedAt: Date.now(),
        source,
        sourceRef: draft.sourceRef,
      });
      const result = await observationService.commit(userId, body);
      await draftStore.update(userId, draftKey, {
        status: 'committed',
        committedAt: Date.now(),
      });
      return { draft, ...result };
    },
    async discardDraft(userId, draftKey) {
      const draft = await draftStore.findByKey(userId, draftKey);
      if (!draft) return null;
      return draftStore.update(userId, draftKey, { status: 'discarded' });
    },
  };
}