basic-erp/apps/web/src/app/features/documents/document-form.page.ts

import { HttpErrorResponse, httpResource } from '@angular/common/http';
import { NgTemplateOutlet } from '@angular/common';
import { ChangeDetectionStrategy, Component, computed, inject, linkedSignal, signal } from '@angular/core';
import { toSignal } from '@angular/core/rxjs-interop';
import { ActivatedRoute, Router, RouterLink } from '@angular/router';
import type { SlListResponse } from '@basic-erp/sap-types';
import { map } from 'rxjs';
import { API_URL, apiErrorMessage } from '../../core/api';
import { formatNumber, todayIso } from '../../core/format';
import { CompanySettingsService } from '../../core/company/company-settings';
import { SlDocumentApi } from '../../core/sl/sl-document';
import { CheckboxField, CheckboxInput, DateField, LookupField, NumberField, NumberInput, SboField, SelectField, SelectInput, TextField, TextInput, TextareaField } from '../../shared/form';
import type { GridLine, GridMultiAdd } from '../../shared/grid/grid.types';
import { LinesGrid } from '../../shared/grid/lines-grid';
import type { VhLookup } from '../../shared/value-help/value-help.types';
import { Icon, MenuButton, type MenuItem, SboWindow, Toolbar, type StatusMessage, type WindowBadge } from '../../shared/window';
import { ValueHelp } from '../../shared/value-help/value-help';
import type { ListRow } from '../../shared/list/list.types';
import {
  type DocRecord,
  type NavTarget,
  computeTotals,
  EXPENSES_COLLECTION,
  type ExpenseRow,
  createPayload,
  expenseRowsOf,
  expensesChanged,
  expensesPayload,
  isBlankLine,
  isDocumentReadOnly,
  taxRateMap,
  updatePayload,
  validateExpenses,
  validateLayout,
} from './document-model';
import { SERVICE_DOC_TYPE } from './document-layouts';
import { type ComputedSource, type GroupCell, type HeaderField, PARTNER_COLUMNS, WAREHOUSE_LOOKUP, hasCurrency, hasExpenses, hasFolio, hasSeries, headerKeysOf, keysOfFields, requiredHeaderOf } from './document-layouts';
import { type CopyOrigin, copyFromDocument, copySources, copyTargets } from './document-copy';
import { DOCUMENT_SCREENS, type DocumentScreen, docNum, documentStatus, menuLabel } from './document-screens';
import { OBJECT_TYPES } from './document-objects';
import { detailHint, validateLineDetails } from './line-details';
import { ITEMS_MULTI_ADD, LINE_COLUMNS } from './line-columns';
import { RowsTable } from '../../shared/grid/rows-table';
import type { DetailColumn } from '../../shared/grid/grid.types';

const today = (): string => todayIso();
const DATE_KEYS = new Set(['DocDate', 'DocDueDate', 'RequriedDate', 'TaxDate', 'DueDate']);
/** SAP devuelve las fechas como `2026-01-05T00:00:00Z`; el campo de fecha y el guardado usan `2026-01-05`. */
const dateOnly = (v: unknown): string => (typeof v === 'string' ? v.slice(0, 10) : '');
const pickHeader = (doc: DocRecord | undefined, keys: readonly string[], blank: DocRecord): DocRecord => {
  if (!doc) return blank;
  return Object.fromEntries(
    keys.map((k) => [
      k,
      DATE_KEYS.has(k) ? dateOnly(doc[k]) : k === 'FolioNumber' ? text(doc[k]) : (doc[k] ?? (k === 'DiscountPercent' ? 0 : '')),
    ]),
  );
};
const text = (v: unknown): string => (v === null || v === undefined ? '' : String(v));
/** El folio se edita como texto; SAP lo espera como número. */
const folioAsNumber = (h: DocRecord): DocRecord => {
  const folio = h['FolioNumber'];
  if (typeof folio !== 'string') return h;
  return { ...h, FolioNumber: folio.trim() === '' ? null : Number(folio) };
};

/**
 * Formulario de un documento de ventas o compras: `nuevo` (vacío) o `:docEntry` (ver / editar).
 * Los cerrados y cancelados quedan en solo lectura. Al modificar se envía el `odata.etag` leído
 * (`If-Match`): si otro usuario cambió el documento, SAP responde 412 y se avisa sin pisarlo.
 */
@Component({
  selector: 'sbo-document-form-page',
  changeDetection: ChangeDetectionStrategy.OnPush,
  imports: [CheckboxField, CheckboxInput, DateField, Icon, LinesGrid, LookupField, MenuButton, NgTemplateOutlet, NumberField, NumberInput, RouterLink, RowsTable, SboField, SelectField, SelectInput, SboWindow, TextField, TextInput, TextareaField, Toolbar, ValueHelp],
  templateUrl: './document-form.page.html',
  styles: `
    h1 { margin: 0 0 6px; font-size: 18px; font-weight: 600; }
    p { margin: 0; color: var(--quiet); }
    a { color: var(--focus); }
    .totals { display: grid; gap: 2px; }
    .exp h3 { margin: 0 0 4px; font-size: 13px; font-weight: 600; }
    .exp .addrow { margin: 6px 0 0; }
    .ask { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin: 4px 0 6px; padding: 4px 8px; background: var(--warn-bg); border: 1px solid var(--line); border-radius: var(--radius); color: var(--ink); }
  `,
})
export class DocumentFormPage {
  private readonly route = inject(ActivatedRoute);
  private readonly router = inject(Router);
  private readonly api = inject(SlDocumentApi);
  /** La empresa usa redondeo (`OADM.RoundMthd`): solo entonces se ofrece la fila «Redondeo». */
  private readonly settings = inject(CompanySettingsService);
  protected readonly roundingEnabled = this.settings.roundingEnabled;

  protected readonly title = this.route.snapshot.data['title'] as string;
  protected readonly screen = this.route.snapshot.data['screen'] as DocumentScreen;
  protected readonly partner = this.screen.partner;
  /** Qué campos y columnas lleva este documento (lo declara su pantalla); el formulario solo lo dibuja. */
  protected readonly layout = this.screen.layout;
  private readonly lineSpec = this.layout.lines;
  /** Si el documento es de servicio, las columnas, los campos que se guardan y las reglas de las líneas son otras. */
  protected readonly serviceMode = computed(() => !!this.layout.service && this.header()['DocType'] === SERVICE_DOC_TYPE);
  private readonly spec = computed(() => (this.serviceMode() ? this.layout.service!.lines : this.lineSpec));
  private readonly headerKeys: readonly string[] = headerKeysOf(this.layout);
  private readonly hasFolio = hasFolio(this.layout);
  private readonly blankHeader: DocRecord = this.layout.newHeader();
  private readonly hasExpenses = hasExpenses(this.layout);
  private readonly hasCurrency = hasCurrency(this.layout);
  private pick(doc: DocRecord | undefined): DocRecord {
    return pickHeader(doc, this.headerKeys, this.blankHeader);
  }
  private docLines(doc: DocRecord | undefined): GridLine[] {
    return (doc?.[this.lineSpec.key] as GridLine[] | undefined) ?? [];
  }
  protected readonly docEntry = toSignal(
    this.route.paramMap.pipe(map((p) => (p.has('docEntry') ? Number(p.get('docEntry')) : null))),
    { initialValue: this.route.snapshot.paramMap.has('docEntry') ? Number(this.route.snapshot.paramMap.get('docEntry')) : null },
  );
  protected readonly isNew = computed(() => this.docEntry() === null);

  // --- datos ---------------------------------------------------------------------------------

  private readonly docResource = httpResource<DocRecord>(() => {
    const id = this.docEntry();
    return id === null ? undefined : `${API_URL}/sl/${this.screen.resource}/${id}`;
  });
  private readonly taxResource = httpResource<SlListResponse<DocRecord>>(() =>
    this.partner
      ? { url: `${API_URL}/sl/${this.partner.taxResource}`, params: { $select: 'Code,Rate', $top: 500 } }
      : undefined,
  );

  /** Gastos adicionales de SAP (flete, seguro…): sus nombres se muestran junto al código de cada fila. */
  private readonly expensesResource = httpResource<SlListResponse<DocRecord>>(() =>
    this.hasExpenses ? { url: `${API_URL}/sl/AdditionalExpenses`, params: { $select: 'ExpensCode,Name', $top: 200 } } : undefined,
  );
  private readonly expenseNames = computed(
    () => new Map((this.expensesResource.hasValue() ? this.expensesResource.value().value : []).map((e) => [String(e['ExpensCode']), text(e['Name'])])),
  );

  // --- moneda y tipo de cambio ---------------------------------------------------------------

  private readonly currenciesResource = httpResource<SlListResponse<DocRecord>>(() =>
    this.hasCurrency ? { url: `${API_URL}/sl/Currencies`, params: { $select: 'Code,Name', $top: 100 } } : undefined,
  );
  /** Moneda local primero («Moneda local») y después las demás. */
  protected readonly currencyOptions = computed(() => {
    const local = this.settings.localCurrency();
    const others = (this.currenciesResource.hasValue() ? this.currenciesResource.value().value : [])
      .filter((c) => text(c['Code']) !== local)
      .map((c) => ({ value: text(c['Code']), label: `${text(c['Code'])} · ${text(c['Name'])}` }));
    return [{ value: local, label: 'Moneda local' }, ...others];
  });
  protected readonly currencyValue = computed(() => text(this.header()['DocCurrency']) || this.settings.localCurrency());
  /** El documento está en la moneda local (o la empresa aún no informa cuál es): no lleva tipo de cambio. */
  protected readonly isLocalCurrency = computed(() => !text(this.header()['DocCurrency']) || this.currencyValue() === this.settings.localCurrency());

  protected onCurrency(code: string): void {
    this.header.update((h) => ({ ...h, DocCurrency: code, DocRate: '' }));
    this.message.set(null);
    if (code !== this.settings.localCurrency()) void this.fetchRate(code);
  }

  /** El tipo de cambio de la moneda en la fecha del documento; se puede corregir a mano. */
  private async fetchRate(currency: string): Promise<void> {
    try {
      const rate = await this.api.currencyRate(currency, text(this.header()['DocDate']) || today());
      if (text(this.header()['DocCurrency']) === currency) this.header.update((h) => ({ ...h, DocRate: rate }));
    } catch (e) {
      this.message.set({ kind: 'warn', text: `No se pudo obtener el tipo de cambio de ${currency}: ${apiErrorMessage(e)}` });
    }
  }

  /** Filas de gastos adicionales; se reinician al cargar o recargar el documento. */
  protected readonly expenses = linkedSignal<ExpenseRow[]>(() => expenseRowsOf(this.doc()));
  protected readonly expenseColumns: readonly DetailColumn[] = [
    {
      key: 'ExpenseCode',
      title: 'Gasto',
      type: 'lookup',
      required: true,
      width: '90px',
      lookup: {
        title: 'Gastos adicionales',
        resource: 'AdditionalExpenses',
        orderby: 'ExpensCode',
        valueKey: 'ExpensCode',
        valueType: 'number',
        columns: [
          { key: 'ExpensCode', title: 'Código', width: '90px', mono: true },
          { key: 'Name', title: 'Nombre' },
        ],
      },
    },
    { key: '_Name', title: 'Nombre', type: 'text', width: '170px', computed: (row) => this.expenseNames().get(String(row['ExpenseCode'] ?? '')) ?? '' },
    { key: 'LineTotal', title: 'Importe', type: 'number', decimals: 2, required: true, width: '110px' },
    {
      key: 'TaxCode',
      title: 'Impuesto',
      type: 'lookup',
      width: '100px',
      lookup: {
        ...(this.layout.columns.find((c) => c.key === 'TaxCode')?.lookup?.config ?? LINE_COLUMNS.tax.lookup!.config),
      },
    },
    { key: 'Remarks', title: 'Comentarios', type: 'text', width: '180px' },
  ];

  protected setExpenses(rows: ExpenseRow[]): void {
    this.expenses.set(rows);
    this.message.set(null);
  }

  protected addExpense(): void {
    this.setExpenses([...this.expenses(), {}]);
  }

  /** Series de numeración de este tipo de documento (acción `SeriesService_GetDocumentSeries` de SAP). */
  private readonly hasSeries = hasSeries(this.layout);
  private readonly objectType = OBJECT_TYPES[this.screen.path];
  private readonly seriesResource = httpResource<SlListResponse<DocRecord>>(() =>
    this.hasSeries && this.objectType
      ? {
          url: `${API_URL}/sl/SeriesService_GetDocumentSeries`,
          method: 'POST',
          body: { DocumentTypeParams: { Document: String(this.objectType) } },
        }
      : undefined,
  );
  protected readonly seriesValue = computed<number | null>(() => Number(this.header()['Series']) || null);

  /** Series elegibles: del subtipo de la pantalla y sin bloquear; la del documento abierto se incluye siempre. */
  protected readonly seriesOptions = computed(() => {
    const subType = this.layout.seriesSubType ?? '--';
    const rows = this.seriesResource.hasValue() ? this.seriesResource.value().value : [];
    const options = rows
      .filter((r) => r['DocumentSubType'] === subType && r['Locked'] !== 'tYES')
      .map((r) => ({ value: Number(r['Series']), label: text(r['Name']) || String(r['Series']) }));
    const current = Number(this.doc()?.['Series']);
    if (current && !options.some((o) => o.value === current)) {
      const known = rows.find((r) => Number(r['Series']) === current);
      options.unshift({ value: current, label: text(known?.['Name']) || `Serie ${current}` });
    }
    return options;
  });

  protected readonly doc = computed(() => (this.docResource.hasValue() ? this.docResource.value() : undefined));
  protected readonly loading = computed(() => this.docResource.isLoading());
  protected readonly loadError = computed(() => {
    const err = this.docResource.error();
    return err ? (err instanceof HttpErrorResponse && err.status === 404 ? 'El documento no existe.' : apiErrorMessage(err)) : '';
  });

  /** Valores editables; se reinician al cargar o recargar el documento. */
  protected readonly header = linkedSignal<DocRecord>(() => this.pick(this.doc()));
  protected readonly lines = linkedSignal<readonly GridLine[]>(() => this.docLines(this.doc()).map((l) => ({ ...l })));
  protected readonly partnerName = linkedSignal(() => text(this.doc()?.['CardName']));
  /** RUT del socio: lo completa SAP desde el maestro; aquí solo se muestra. */
  protected readonly partnerTaxId = linkedSignal(() => text(this.doc()?.['FederalTaxID']));

  // --- estado --------------------------------------------------------------------------------

  protected readonly readOnly = computed(() => isDocumentReadOnly(this.doc()) || (!!this.layout.immutable && !this.isNew()));
  protected readonly saving = signal(false);
  private readonly message = signal<StatusMessage | null>(
    ((): StatusMessage | null => {
      const created = (this.router.currentNavigation()?.extras.state as { created?: string } | undefined)?.created;
      return created ? { kind: 'ok', text: `Documento ${created} creado.` } : null;
    })(),
  );
  protected readonly conflict = signal(false);

  protected readonly status = computed<StatusMessage>(() => {
    if (this.loading()) return { kind: 'info', text: 'Cargando…' };
    if (this.loadError()) return { kind: 'err', text: this.loadError() };
    const message = this.message();
    if (message) return message;
    if (this.readOnly()) {
      const posted = this.layout.immutable && !isDocumentReadOnly(this.doc());
      return { kind: 'info', text: posted ? 'Documento contabilizado: solo lectura.' : 'Documento cerrado o cancelado: solo lectura.' };
    }
    if (this.isNew()) {
      return { kind: 'info', text: this.partner ? `Indique el ${this.partner.label.toLowerCase()} y las líneas.` : 'Complete la cabecera y las líneas.' };
    }
    return { kind: 'info', text: this.dirty() ? 'Hay cambios sin guardar.' : '' };
  });
  protected readonly badge = computed<WindowBadge | undefined>(() => {
    if (this.isNew()) return { label: 'Nueva', tone: 'info' };
    const d = this.doc();
    return d ? documentStatus(d) : undefined;
  });
  protected readonly windowTitle = computed(() => {
    const num = this.doc()?.['DocNum'];
    return num === undefined ? this.title : `${this.title} · ${text(num)}`;
  });

  protected readonly dirty = computed(() => {
    const d = this.doc();
    if (!d) return text(this.header()['CardCode']) !== '' || this.lines().some((l) => !isBlankLine(l, this.serviceMode())) || expensesPayload(this.expenses()).length > 0;
    const { body } = updatePayload(this.pick(d), this.header(), this.docLines(d), this.lines(), this.spec());
    return Object.keys(body).length > 0 || (this.hasExpenses && expensesChanged(d, this.expenses()));
  });

  // --- totales -------------------------------------------------------------------------------

  private readonly rates = computed(() =>
    taxRateMap(this.taxResource.hasValue() ? this.taxResource.value().value : []),
  );
  protected readonly totals = computed(() =>
    computeTotals(this.lines(), this.rates(), Number(this.header()['DiscountPercent'] ?? 0), this.expenses(), this.header()['Rounding'] === 'tYES' ? Number(this.header()['RoundingDiffAmount'] ?? 0) : 0),
  );
  protected readonly fmt = (n: number): string => formatNumber(n, 2);

  // --- copiar de / a ----------------------------------------------------------------------------

  private readonly copyOrigin = (this.router.currentNavigation()?.extras.state as { copyFrom?: CopyOrigin } | undefined)?.copyFrom;
  protected readonly copyListFor = signal<string | null>(null);

  /** "Copiar a": solo desde un documento guardado, abierto y sin cambios pendientes. */
  protected readonly copyToItems = computed<MenuItem[]>(() => {
    const blocked = this.isNew() || this.readOnly() || this.dirty();
    return copyTargets(this.screen.path).map((p) => ({ id: p, label: menuLabel(p), disabled: blocked }));
  });
  protected readonly copyFromItems = computed<MenuItem[]>(() =>
    copySources(this.screen.path).map((p) => ({ id: p, label: menuLabel(p), disabled: !this.isNew() })),
  );
  protected readonly copyListTitle = computed(() => menuLabel(this.copyListFor() ?? ''));
  protected readonly copyListScreen = computed(() => DOCUMENT_SCREENS.find((s) => s.path === this.copyListFor()));
  /** Documentos abiertos del origen elegido, del mismo socio si ya se indicó. */
  protected readonly copyListFilter = computed(() => {
    const card = text(this.header()['CardCode']);
    return [`DocumentStatus eq 'bost_Open'`, `Cancelled eq 'tNO'`, ...(card ? [`CardCode eq '${card.replace(/'/g, "''")}'`] : [])].join(' and ');
  });
  protected readonly copyListColumns = this.partner
    ? ([
        docNum,
        { key: 'CardCode', title: this.partner.label, width: '120px', mono: true },
        { key: 'CardName', title: 'Nombre' },
        { key: 'DocDate', title: 'Fecha', type: 'date', align: 'center', width: '105px' },
      ] as const)
    : ([
        docNum,
        { key: 'FromWarehouse', title: 'Almacén origen', width: '130px', mono: true },
        { key: 'ToWarehouse', title: 'Almacén destino', width: '130px', mono: true },
        { key: 'DocDate', title: 'Fecha', type: 'date', align: 'center', width: '105px' },
      ] as const);

  protected copyTo(path: string): void {
    const docEntry = this.docEntry();
    if (docEntry === null) return;
    const origin: CopyOrigin = { path: this.screen.path, docEntry };
    void this.router.navigateByUrl(`${path}/nuevo`, { state: { copyFrom: origin } });
  }

  protected copyFrom(path: string): void {
    this.copyListFor.set(path);
  }

  protected async copyPicked(rows: ListRow[]): Promise<void> {
    const path = this.copyListFor();
    this.copyListFor.set(null);
    const docEntry = rows[0]?.['DocEntry'];
    if (path && typeof docEntry === 'number') await this.loadCopy({ path, docEntry });
  }

  /** Trae el documento origen y vuelca sus datos y líneas abiertas en el formulario. */
  private async loadCopy(origin: CopyOrigin): Promise<void> {
    const source = DOCUMENT_SCREENS.find((s) => s.path === origin.path);
    if (!source) return;
    try {
      const doc = await this.api.get(source.resource, origin.docEntry);
      const copied = copyFromDocument(doc, origin.path, menuLabel(origin.path), source.layout.lines.key);
      const card = text(this.header()['CardCode']);
      if (card && card !== text(copied.header['CardCode'])) {
        this.message.set({ kind: 'warn', text: `El documento es de ${text(copied.header['CardCode'])}; este es de ${card}.` });
        return;
      }
      if (!copied.lines.length) {
        this.message.set({ kind: 'warn', text: 'El documento no tiene líneas abiertas para copiar.' });
        return;
      }
      // el tipo (artículo / servicio) del origen: si este documento ya tiene líneas de otro tipo no se mezclan
      const copiedType = text(copied.header['DocType']);
      if (this.layout.service && copiedType && copiedType !== text(this.header()['DocType'])) {
        if (this.lines().some((l) => !isBlankLine(l, this.serviceMode()))) {
          this.message.set({ kind: 'warn', text: `El documento es de ${copiedType === SERVICE_DOC_TYPE ? 'servicio' : 'artículos'} y este tiene líneas de otro tipo.` });
          return;
        }
        this.header.update((h) => ({ ...h, DocType: copiedType }));
      }
      if (!card) {
        this.header.update((h) => ({ ...h, ...copied.header }));
        this.partnerName.set(text(doc['CardName']));
        this.partnerTaxId.set(text(doc['FederalTaxID']));
      }
      this.lines.update((ls) => [...ls.filter((l) => !isBlankLine(l, this.serviceMode())), ...copied.lines]);
      this.message.set({
        kind: 'ok',
        text: `Copiado de ${menuLabel(origin.path).toLowerCase()} ${text(doc['DocNum'])}${copied.skipped ? ` (${copied.skipped} línea(s) cerradas no se copian)` : ''}. Revise y pulse Crear.`,
      });
    } catch (e) {
      this.message.set({ kind: 'err', text: apiErrorMessage(e) });
    }
  }

  // --- configuración de la vista --------------------------------------------------------------

  protected readonly columns = computed(() => (this.serviceMode() ? this.layout.service!.columns : this.layout.columns));
  private readonly itemColumn = this.layout.columns.find((c) => c.key === 'ItemCode') ?? this.layout.columns[0];
  protected readonly newLine = () => (this.serviceMode() ? this.layout.service!.newLine() : this.layout.newLine(this.header()));
  /** Recalcula la línea con la tasa de cada impuesto (precio con y sin impuesto, total). */
  protected readonly detailHint = detailHint;
  protected readonly recalc = computed(() =>
    !this.serviceMode() && this.layout.recalc ? (line: GridLine, key: string) => this.layout.recalc!(line, key, this.rates()) : undefined,
  );
  protected readonly multi: GridMultiAdd = {
    ...ITEMS_MULTI_ADD,
    lookup: this.itemColumn.lookup!.config,
    toLine: (item) => this.itemColumn.lookup!.apply(item, this.layout.newLine(this.header())),
  };
  protected readonly warehouseLookup: VhLookup = {
    ...WAREHOUSE_LOOKUP,
    columns: this.layout.lookups?.warehouse ?? WAREHOUSE_LOOKUP.columns,
  };
  protected readonly partnerLookup: VhLookup = {
    title: this.partner?.type === 'cSupplier' ? 'Proveedores' : 'Clientes',
    resource: 'BusinessPartners',
    baseFilter: `CardType eq '${this.partner?.type ?? 'cCustomer'}'`,
    orderby: 'CardCode',
    columns: this.layout.lookups?.partner ?? PARTNER_COLUMNS,
    extraFields: ['FederalTaxID', 'Currency'],
  };

  protected str = text;

  private readonly lockedKeys = new Set(this.layout.lockedKeys ?? []);
  /** El campo se ve pero no se edita (una extensión de cliente lo dejó de solo lectura). */
  protected locked(f: HeaderField): boolean {
    // la moneda de un documento ya creado no se cambia
    if (f.type === 'currency' && !this.isNew()) return true;
    // el tipo (artículo / servicio) no se cambia en un documento ya creado
    if (f.type === 'select' && f.key === 'DocType' && !this.isNew()) return true;
    return this.lockedKeys.size > 0 && (keysOfFields([f]).some((k) => this.lockedKeys.has(k)) || (f.type === 'computed' && this.lockedKeys.has(f.source)));
  }

  /** Valor de una fila de solo lectura (número del documento, datos del socio, totales). */
  protected computedValue(source: ComputedSource): string {
    switch (source) {
      case 'docNum':
        return text(this.doc()?.['DocNum']);
      case 'partnerName':
        return this.partnerName();
      case 'partnerTaxId':
        return this.partnerTaxId();
      case 'subtotal':
        return this.fmt(this.totals().subtotal);
      case 'expenses':
        return this.fmt(this.totals().expenses);
      case 'tax':
        return this.fmt(this.totals().tax);
      case 'downPayment':
        return this.fmt(Number(this.doc()?.['DownPaymentAmount'] ?? 0));
      case 'applied':
        return this.fmt(Number(this.doc()?.['PaidToDate'] ?? 0));
      case 'balance': {
        const d = this.doc();
        return this.fmt(d ? Number(d['DocTotal'] ?? 0) - Number(d['PaidToDate'] ?? 0) : 0);
      }
      case 'total':
        return this.fmt(this.totals().total);
    }
  }

  constructor() {
    if (this.copyOrigin) void this.loadCopy(this.copyOrigin);
  }

  protected setHeader(key: string, value: unknown): void {
    if (key === 'DocType' && this.layout.service) return this.onDocType(String(value));
    this.header.update((h) => ({ ...h, [key]: value }));
    this.message.set(null);
    // otra fecha del documento, otro tipo de cambio
    if (key === 'DocDate' && this.isNew() && !this.isLocalCurrency()) void this.fetchRate(this.currencyValue());
  }

  /** Tipo al que se quiere cambiar y que espera confirmación porque hay líneas escritas que se descartarían. */
  protected readonly pendingType = signal<string | null>(null);

  /** La celda de un grupo de campos (el indicador) cuya lista de valores está abierta. */
  protected readonly groupCell = signal<GroupCell | null>(null);

  protected groupPicked(rows: ListRow[]): void {
    const cell = this.groupCell();
    const row = rows[0];
    if (cell?.kind === 'lookup' && row) {
      this.setHeader(cell.key, row[cell.lookup.valueKey ?? cell.lookup.columns[0]?.key ?? ''] ?? '');
    }
    this.groupCell.set(null);
  }

  /** Cambiar entre artículo y servicio cambia las columnas de línea: las líneas escritas no sirven y se pide permiso para descartarlas. */
  private onDocType(type: string): void {
    if (type === text(this.header()['DocType'])) return;
    if (this.lines().some((l) => !isBlankLine(l, this.serviceMode()))) {
      this.pendingType.set(type);
      return;
    }
    this.applyDocType(type);
  }

  protected applyDocType(type: string): void {
    this.pendingType.set(null);
    this.header.update((h) => ({ ...h, DocType: type }));
    this.lines.set([]);
    this.message.set(null);
  }

  protected readonly pendingTypeLabel = computed(() => (this.pendingType() === SERVICE_DOC_TYPE ? 'Servicio' : 'Artículo'));
  protected readonly lineCount = computed(() => this.lines().filter((l) => !isBlankLine(l, this.serviceMode())).length);

  /** Al escribir otro código el nombre anterior ya no vale; se completa al salir del campo o al elegir de la lista. */
  protected onPartnerText(code: string): void {
    if (code === text(this.header()['CardCode'])) return;
    this.setHeader('CardCode', code);
    this.partnerName.set('');
    this.partnerTaxId.set('');
  }

  protected notify(textMessage: string): void {
    this.message.set({ kind: 'warn', text: textMessage });
  }

  protected onPartner(row: Record<string, unknown>): void {
    this.partnerName.set(text(row['CardName']));
    this.partnerTaxId.set(text(row['FederalTaxID']));
    // el documento toma la moneda del socio (si es una sola y no es la local), como en SAP
    const currency = text(row['Currency']);
    if (this.isNew() && this.hasCurrency && currency && currency !== '##' && currency !== this.currencyValue() && this.isLocalCurrency()) this.onCurrency(currency);
    // elegido el socio, el documento nuevo arranca con una línea lista para escribir
    if (this.isNew() && !this.readOnly() && this.lines().length === 0) this.lines.set([this.newLine()]);
  }

  protected setLines(lines: readonly GridLine[]): void {
    this.lines.set(lines);
    this.message.set(null);
  }

  // --- acciones ------------------------------------------------------------------------------

  protected async go(target: NavTarget): Promise<void> {
    try {
      const entry = await this.api.neighbour(this.screen.resource, target, this.docEntry(), this.screen.baseFilter);
      if (entry === null) {
        this.message.set({ kind: 'warn', text: 'No hay más documentos en esa dirección.' });
        return;
      }
      this.message.set(null);
      await this.router.navigate(['..', entry], { relativeTo: this.route });
    } catch (e) {
      this.message.set({ kind: 'err', text: apiErrorMessage(e) });
    }
  }

  protected async save(): Promise<void> {
    if (this.saving() || this.readOnly()) return;
    const errors = validateLayout(this.header(), this.lines(), requiredHeaderOf(this.layout), this.layout.requiredLine, this.serviceMode());
    if (this.layout.details?.length && !this.serviceMode()) errors.push(...validateLineDetails(this.lines()));
    if (this.hasFolio && !/^\d*$/.test(text(this.header()['FolioNumber']).trim())) errors.push('El número de folio debe ser numérico.');
    if (this.hasExpenses) errors.push(...validateExpenses(this.expenses()));
    if (errors.length) {
      this.message.set({ kind: 'err', text: errors[0] });
      return;
    }
    this.saving.set(true);
    this.conflict.set(false);
    try {
      const d = this.doc();
      if (!d) {
        const header = folioAsNumber(this.layout.beforeCreate?.(this.header()) ?? this.header());
        // en la moneda local no se envía moneda ni tipo de cambio: SAP usa los suyos
        if (this.isLocalCurrency()) {
          delete header['DocCurrency'];
          delete header['DocRate'];
        }
        // sin redondeo marcado no se envía nada: SAP calcula el suyo
        if (header['Rounding'] !== 'tYES') {
          delete header['Rounding'];
          delete header['RoundingDiffAmount'];
        }
        const body = createPayload(header, this.lines(), this.spec());
        if (this.hasExpenses && expensesPayload(this.expenses()).length) body[EXPENSES_COLLECTION] = expensesPayload(this.expenses());
        const created = await this.api.create(this.screen.resource, body);
        await this.router.navigate(['..', created['DocEntry']], {
          relativeTo: this.route,
          state: { created: text(created['DocNum']) },
        });
        return;
      }
      const update = updatePayload(this.pick(d), this.header(), this.docLines(d), this.lines(), this.spec());
      const body = folioAsNumber(update.body);
      let replaceLines = update.replaceLines;
      if (this.hasExpenses && expensesChanged(d, this.expenses())) {
        body[EXPENSES_COLLECTION] = expensesPayload(this.expenses());
        replaceLines = true; // SAP reemplaza la colección entera
      }
      if (!Object.keys(body).length) {
        this.message.set({ kind: 'info', text: 'No hay cambios que guardar.' });
        return;
      }
      await this.api.update(this.screen.resource, this.docEntry()!, body, text(d['odata.etag']) || undefined, replaceLines);
      this.message.set({ kind: 'ok', text: 'Documento actualizado.' });
      this.docResource.reload();
    } catch (e) {
      if (e instanceof HttpErrorResponse && e.status === 412) {
        this.conflict.set(true);
        this.message.set({
          kind: 'warn',
          text: 'Otro usuario modificó este documento. Recárguelo para ver sus cambios; los suyos no se guardaron.',
        });
      } else {
        this.message.set({ kind: 'err', text: apiErrorMessage(e) });
      }
    } finally {
      this.saving.set(false);
    }
  }

  protected reload(): void {
    this.conflict.set(false);
    this.message.set(null);
    this.docResource.reload();
  }
}