import { Injectable } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';

import { DocumentType } from '../catalog/documentType.entity';
import { CatalogService } from '../catalog/catalog.service';
import {
  DocumentCriticality,
  StoreDocumentStatus,
} from '../common/enum/document.enum';
import {
  daysBetween,
  resolveStatus,
  todayKey,
} from '../common/utils/status.util';
import { StoreDocument } from '../document/storeDocument.entity';
import {
  ComplianceSummaryResponseDto,
  UpcomingExpirationDto,
} from './dto/response/compliance.dto';
import { LeadTimeService } from './leadTime.service';

/** Peso da criticidade no score — o mesmo do painel. */
const CRITICALITY_WEIGHT: Record<DocumentCriticality, number> = {
  [DocumentCriticality.Interdicao]: 3,
  [DocumentCriticality.Multa]: 2,
  [DocumentCriticality.Administrativa]: 1,
};

interface IObligation {
  type: DocumentType;
  status: StoreDocumentStatus;
  document?: StoreDocument;
}

@Injectable()
export class ComplianceService {
  constructor(
    @InjectRepository(StoreDocument)
    private readonly documentRepository: Repository<StoreDocument>,
    private readonly catalogService: CatalogService,
    private readonly leadTimeService: LeadTimeService,
  ) {}

  /**
   * Score ponderado por criticidade — a MESMA régua do painel
   * (`mapping/Mapping.tsx#buildComplianceSummary`), agora com o backend como
   * fonte da verdade: interdição pesa 3, multa 2, administrativa 1; "vence em
   * breve" ainda vale meio peso e "em renovação" 0,75 (protocolado no prazo
   * mantém o posto operante).
   */
  async getSummary(params: {
    programId: string;
    storeId: string;
  }): Promise<ComplianceSummaryResponseDto> {
    const obligations = await this.getObligations(params);

    const totals = {
      valid: 0,
      expiringSoon: 0,
      inRenewal: 0,
      expired: 0,
      missing: 0,
    };

    let earnedWeight = 0;
    let totalWeight = 0;
    let criticalPending = 0;

    obligations.forEach(({ type, status }) => {
      const weight = CRITICALITY_WEIGHT[type.criticality] ?? 1;
      totalWeight += weight;

      switch (status) {
        case StoreDocumentStatus.Valid:
          totals.valid += 1;
          earnedWeight += weight;
          break;
        case StoreDocumentStatus.ExpiringSoon:
          totals.expiringSoon += 1;
          earnedWeight += weight / 2;
          break;
        case StoreDocumentStatus.InRenewal:
          totals.inRenewal += 1;
          earnedWeight += weight * 0.75;
          break;
        case StoreDocumentStatus.Expired:
          totals.expired += 1;
          break;
        case StoreDocumentStatus.Missing:
        default:
          totals.missing += 1;
          break;
      }

      const isPending =
        status === StoreDocumentStatus.Expired ||
        status === StoreDocumentStatus.Missing;
      if (isPending && type.criticality === DocumentCriticality.Interdicao) {
        criticalPending += 1;
      }
    });

    return {
      storeId: params.storeId,
      score: totalWeight
        ? Math.round((earnedWeight / totalWeight) * 100)
        : 100,
      totals,
      criticalPending,
    };
  }

  /**
   * Vencimentos na janela, ordenados — a matéria-prima dos alertas.
   *
   * Cada item carrega o prazo dinâmico (`effectiveLeadDays`): o catálogo é
   * piso, e a mediana observada do órgão na carteira o estica quando o órgão
   * está mais lento que o prazo legal supõe.
   */
  async getUpcoming(params: {
    programId: string;
    storeId: string;
    days: number;
  }): Promise<UpcomingExpirationDto[]> {
    const [obligations, leadIndex] = await Promise.all([
      this.getObligations(params),
      this.leadTimeService.getIndex(params.programId),
    ]);
    const today = todayKey();

    return obligations
      .filter(({ document }) => !!document?.expiryDate)
      .map(({ type, status, document }) => {
        const lead = this.leadTimeService.effectiveLeadFor(type, leadIndex);
        return {
          typeCode: type.code,
          typeName: type.name,
          criticality: type.criticality,
          status,
          expiryDate: document!.expiryDate!,
          daysToExpiry: daysBetween(today, document!.expiryDate!),
          renewalLeadDays: type.renewalLeadDays,
          effectiveLeadDays: lead.effectiveLeadDays,
          observed: lead.observed,
        };
      })
      .filter(item => item.daysToExpiry <= params.days)
      .sort((a, b) => a.daysToExpiry - b.daysToExpiry);
  }

  /**
   * Uma linha por obrigação do catálogo — obrigação sem documento entra como
   * `missing`. É o cruzamento que o painel fazia no client, agora no dono do
   * dado.
   */
  async getObligations(params: {
    programId: string;
    storeId: string;
  }): Promise<IObligation[]> {
    const [types, documents] = await Promise.all([
      this.catalogService.getActiveTypes(),
      this.documentRepository.find({
        where: { programId: params.programId, storeId: params.storeId },
      }),
    ]);

    const today = todayKey();

    return types.map(type => {
      const document = documents.find(item => item.typeCode === type.code);
      if (!document) {
        return { type, status: StoreDocumentStatus.Missing };
      }
      return {
        type,
        document,
        status: resolveStatus(
          {
            expiryDate: document.expiryDate,
            hasRenewalProtocol: !!document.renewalProtocolNumber,
            renewalLeadDays: type.renewalLeadDays,
          },
          today,
        ),
      };
    });
  }
}