import { HttpStatus, Injectable, OnModuleInit } from '@nestjs/common';
import { AppException, ErrorCode } from '../../common/errors';
import { CatalogEntityKind } from '@prisma/client';
import { PrismaService } from '../../../prisma/prisma.service';
import {
  CatalogLabelService,
  CatalogLocale,
  normalizeCatalogLocale,
} from '../catalog/catalog-label.service';

export type ProsthesisTypeCatalogEntry = {
  code: string;
  sortOrder: number;
  label: string;
  category: string;
  subcategory: string;
  chartRegion: string;
  stackGroup: string;
};

type CatalogRow = {
  sortOrder: number;
  category: string;
  subcategory: string;
  chartRegion: string;
  stackGroup: string;
};

@Injectable()
export class ProsthesisCatalogService implements OnModuleInit {
  private loaded = false;
  private byCode = new Map<string, CatalogRow>();

  constructor(
    private readonly prisma: PrismaService,
    private readonly catalogLabels: CatalogLabelService,
  ) {}

  async onModuleInit() {
    await this.refresh();
  }

  async refresh(): Promise<void> {
    const rows = await this.prisma.prosthesisType.findMany({
      where: { isActive: true },
      orderBy: [{ sortOrder: 'asc' }, { code: 'asc' }],
      select: {
        code: true,
        sortOrder: true,
        category: true,
        subcategory: true,
        chartRegion: true,
        stackGroup: true,
      },
    });

    this.byCode = new Map(
      rows.map((row) => [
        row.code,
        {
          sortOrder: row.sortOrder,
          category: row.category,
          subcategory: row.subcategory,
          chartRegion: row.chartRegion,
          stackGroup: row.stackGroup,
        },
      ]),
    );
    this.loaded = true;
  }

  async list(
    localeInput?: string | null,
  ): Promise<ProsthesisTypeCatalogEntry[]> {
    await this.refresh();
    const locale = normalizeCatalogLocale(localeInput);
    const codes = [...this.byCode.keys()];
    const labels = await this.catalogLabels.resolveLabels(
      CatalogEntityKind.PROSTHESIS_TYPE,
      codes,
      locale,
    );

    return codes
      .map((code) => {
        const row = this.byCode.get(code)!;
        return {
          code,
          sortOrder: row.sortOrder,
          label: labels.get(code) ?? code,
          category: row.category,
          subcategory: row.subcategory,
          chartRegion: row.chartRegion,
          stackGroup: row.stackGroup,
        };
      })
      .sort(
        (a, b) => a.sortOrder - b.sortOrder || a.code.localeCompare(b.code),
      );
  }

  /** The 7 distinct category codes present in the active catalog, with labels in `locale`. */
  async listCategories(
    localeInput?: string | null,
  ): Promise<{ code: string; label: string }[]> {
    return this.listDistinct(
      (row) => row.category,
      CatalogEntityKind.PROSTHESIS_CATEGORY,
      localeInput,
    );
  }

  /** The 5 distinct subcategory codes (veneer, inlay, onlay, overlay, night_guard, …). */
  async listSubcategories(
    localeInput?: string | null,
  ): Promise<{ code: string; label: string }[]> {
    return this.listDistinct(
      (row) => row.subcategory,
      CatalogEntityKind.PROSTHESIS_SUBCATEGORY,
      localeInput,
    );
  }

  private async listDistinct(
    pick: (row: CatalogRow) => string,
    entityKind: CatalogEntityKind,
    localeInput?: string | null,
  ): Promise<{ code: string; label: string }[]> {
    await this.refresh();
    const locale = normalizeCatalogLocale(localeInput);
    const codes = [
      ...new Set([...this.byCode.values()].map(pick).filter(Boolean)),
    ].sort();
    const labels = await this.catalogLabels.resolveLabels(
      entityKind,
      codes,
      locale,
    );
    return codes.map((code) => ({ code, label: labels.get(code) ?? code }));
  }

  assertKnownProsthesisType(code: string): void {
    this.ensureLoaded();
    if (!this.byCode.has(code)) {
      throw new AppException(
        ErrorCode.CATALOG_UNKNOWN_PROSTHESIS_TYPE,
        HttpStatus.BAD_REQUEST,
      );
    }
  }

  async getStepCodesForProsthesisType(
    prosthesisTypeCode: string,
  ): Promise<string[]> {
    const type = await this.prisma.prosthesisType.findUnique({
      where: { code: prosthesisTypeCode },
      select: {
        steps: {
          orderBy: { stepOrder: 'asc' },
          select: { labWorkflowStep: { select: { code: true } } },
        },
      },
    });

    if (!type) {
      return [];
    }

    return type.steps.map((s) => s.labWorkflowStep.code);
  }

  async resolveStepLabels(
    stepCodes: string[],
    locale: CatalogLocale,
  ): Promise<Map<string, string>> {
    return this.catalogLabels.resolveLabels(
      CatalogEntityKind.LAB_WORKFLOW_STEP,
      stepCodes,
      locale,
    );
  }

  private ensureLoaded() {
    if (!this.loaded) {
      throw new Error('Prosthesis catalog is not loaded yet');
    }
  }
}