import { BadRequestException, ForbiddenException, Injectable, Logger, NotFoundException } from '@nestjs/common';
import { isPathAllowed } from '@basic-erp/sap-types';
import { AuditService } from '../audit/audit.service.js';
import type { AuthUser } from '../auth/auth.types.js';
import { AppConfigService } from '../config/app-config.service.js';
import { PermissionsService } from '../permissions/permissions.service.js';
import { SapDbService } from '../sapdb/sapdb.service.js';
import { HTML_REPORTS } from './html-reports.js';
import { createRenderer } from './html-render.js';
import { HtmlPdfService } from './html-pdf.service.js';
import type { HtmlReportDef, HtmlReportInfo, HtmlReportValues } from './html-reports.types.js';

/** Ruta de menú que permite ejecutar los reportes HTML. */
export const HTML_REPORTS_PATH = '/reportes-html/ejecutar';

const DATE = /^\d{4}-\d{2}-\d{2}$/;

/** Los valores de los parámetros: tipo comprobado, obligatorios exigidos, valor por defecto si está vacío y sin nombres de más. */
export function parseHtmlValues(def: HtmlReportDef, raw: Readonly<Record<string, unknown>>): HtmlReportValues {
  const known = new Set(def.params.map((p) => p.name));
  const extra = Object.keys(raw).filter((k) => !known.has(k));
  if (extra.length) throw new BadRequestException(`Parámetros desconocidos: ${extra.join(', ')}`);
  const out: Record<string, string> = {};
  const missing: string[] = [];
  for (const p of def.params) {
    const v = raw[p.name];
    // un parámetro de solo lectura vale siempre su valor por defecto, escriba lo que escriba el cliente
    let text = p.readOnly ? '' : typeof v === 'string' ? v.trim() : typeof v === 'number' ? String(v) : '';
    if (text === '') text = p.defaultValue ?? '';
    if (text === '') {
      if (p.required) missing.push(p.label);
      out[p.name] = '';
      continue;
    }
    if (text.length > 200) throw new BadRequestException(`El parámetro «${p.label}» es demasiado largo`);
    if (p.kind === 'number' && !Number.isFinite(Number(text))) throw new BadRequestException(`«${p.label}» debe ser un número`);
    if (p.kind === 'date' && !DATE.test(text)) throw new BadRequestException(`«${p.label}» debe ser una fecha yyyy-MM-dd`);
    if (p.kind === 'select' && p.options?.length && !p.options.some((o) => o.value === text)) throw new BadRequestException(`«${p.label}» no es una opción válida`);
    out[p.name] = text;
  }
  if (missing.length) throw new BadRequestException(`Falta indicar: ${missing.join(', ')}`);
  return out;
}

/**
 * Reportes HTML: plantillas Nunjucks que se rellenan con datos de la base de SAP y se imprimen desde el navegador. Lo que
 * hay lo define la rama de cada cliente (`html-reports.extensions.ts`); quien los ejecuta necesita el permiso de menú
 * «Reportes HTML».
 */
@Injectable()
export class HtmlReportsService {
  private readonly logger = new Logger(HtmlReportsService.name);
  private renderer?: ReturnType<typeof createRenderer>;

  constructor(
    private readonly config: AppConfigService,
    private readonly permissions: PermissionsService,
    private readonly audit: AuditService,
    private readonly sapdb: SapDbService,
    private readonly pdfService: HtmlPdfService,
  ) {}

  private async assertCanRun(user: AuthUser): Promise<void> {
    if (!isPathAllowed(await this.permissions.getPaths(user.webUser), HTML_REPORTS_PATH)) throw new ForbiddenException('No tiene permisos para ejecutar reportes HTML');
  }

  async list(user: AuthUser): Promise<HtmlReportInfo[]> {
    await this.assertCanRun(user);
    return [...HTML_REPORTS.values()]
      .map(({ code, title, category, description, params }) => ({ code, title, category, ...(description ? { description } : {}), enabled: true as const, params }))
      .sort((a, b) => a.category.localeCompare(b.category) || a.title.localeCompare(b.title));
  }

  /** El HTML del reporte con los valores indicados. */
  async render(user: AuthUser, code: string, raw: Readonly<Record<string, unknown>>, ip: string): Promise<string> {
    return this.run(user, code, raw, ip, 'html', (html) => html);
  }

  /** El PDF del reporte: el mismo HTML pasado por Chrome sin pantalla, con el papel y los márgenes de la plantilla. */
  async pdf(user: AuthUser, code: string, raw: Readonly<Record<string, unknown>>, ip: string): Promise<Buffer> {
    return this.run(user, code, raw, ip, 'pdf', (html) => this.pdfService.toPdf(html));
  }

  private async run<T>(user: AuthUser, code: string, raw: Readonly<Record<string, unknown>>, ip: string, format: 'html' | 'pdf', finish: (html: string) => T | Promise<T>): Promise<T> {
    await this.assertCanRun(user);
    const def = HTML_REPORTS.get(code);
    if (!def) throw new NotFoundException(`No existe el reporte ${code}`);
    const values = parseHtmlValues(def, raw);
    // solo los nombres de los parámetros: los valores pueden ser datos de clientes
    const detail = { format, params: def.params.map((p) => p.name) };
    try {
      const data = await def.data(values, { query: async (name, params) => (await this.sapdb.run(user, name, params ?? {}, ip)).rows });
      this.renderer ??= createRenderer(this.config.get('HTML_REPORTS_DIR'));
      const out = await finish(this.renderer.render(def.template, { ...data, params: values }));
      await this.audit.record({ action: 'html_report', webUser: user.webUser, ip, resource: code, detail });
      return out;
    } catch (e) {
      const message = e instanceof Error ? e.message : String(e);
      this.logger.error(`Reporte HTML ${code} (${format}) falló: ${message}`);
      await this.audit.record({ action: 'html_report', webUser: user.webUser, ip, resource: code, outcome: 'error', detail: { ...detail, error: message.slice(0, 300) } });
      throw e;
    }
  }
}