import { Injectable } from '@nestjs/common'
import { isNil } from 'lodash'

import { AnthropometryRepository } from '../../repositories/anthropometry.repository'
import { Anthropometry, Patient } from '../../models'
import { RedisService } from '../redis/redis.service'
import { AnthropometriesFilter, PatientRepository } from '../../repositories'

export type CacheValue = Anthropometry[] & { error: string }[]

export const ERROR_NOT_FOUND = 'not-found'

@Injectable()
export class BioimpedanceService {
  constructor(
    private readonly anthropometryRepository: AnthropometryRepository,
    private readonly patientRepository: PatientRepository,
    private readonly redis: RedisService,
  ) {}

  async getPatientAnthropometriesCache(patient: Patient, filter: AnthropometriesFilter): Promise<Anthropometry[]> {
    const cache = await this.redis.get(patient.login + '-' + filter)
    const anthropometries: CacheValue = cache && JSON.parse(cache)

    if (isNil(anthropometries)) return null
    if (anthropometries?.[0]?.error === ERROR_NOT_FOUND) return null
    if (!Array.isArray(anthropometries)) return []

    return anthropometries
  }

  async createPatientAnthropometriesCache(patientId: string, filter: AnthropometriesFilter): Promise<void> {
    const patient = await this.patientRepository.get(patientId)
    const anthropometries = await this.findAnthropometriesForCache(patient, filter)

    await this.setCache(patient.login + '-' + filter, anthropometries)
  }

  private async findAnthropometriesForCache(
    patient: Patient,
    filter: AnthropometriesFilter,
  ): Promise<Partial<Anthropometry>[]> {
    const patientWithAnthropometries = await this.anthropometryRepository.findByPatientLogin(patient.login, filter)

    return this.buildAnthropometriesToCache(patientWithAnthropometries, patientWithAnthropometries?.anthropometries)
  }

  private async setCache(cacheKey: string, anthropometries: Partial<Anthropometry>[]): Promise<void> {
    await this.redis.set(cacheKey, JSON.stringify(anthropometries))
  }

  private buildAnthropometriesToCache = (
    patient: Patient,
    anthropometries: Anthropometry[],
  ): Partial<Anthropometry>[] =>
    anthropometries?.map((anthropometry: Anthropometry, index: number) => {
      const data = anthropometry.toPlain()
      const isLast = index === anthropometries.length - 1

      data.subscriber = patient.subscriber
      data.allow_bioimpedance = patient.subscriber || isLast

      return data
    }) || []
}