import { HttpErrorResponse, httpResource } from '@angular/common/http';
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 { map } from 'rxjs';
import { API_URL, apiErrorMessage } from '../../core/api';
import { SlMasterApi } from '../../core/sl/sl-master';
import { RowsTable } from '../../shared/grid/rows-table';
import { Icon, SboWindow, Tab, Tabs, Toolbar, type StatusMessage, type WindowBadge } from '../../shared/window';
import { updatePayload, type DocRecord } from '../documents/document-model';
import type { HeaderField } from '../documents/document-layouts';
import { displayCode } from './finanzas/chart-tree.model';
import { ChartTreePanel } from './finanzas/chart-tree.panel';
import { MasterField } from './master-field';
import {
  type CollectionRow,
  type MasterNavTarget,
  collectionPayload,
  collectionRowsOf,
  collectionsCreatePayload,
  createMasterPayload,
  masterCollectionsOf,
  masterKeysOf,
  masterRequiredOf,
  pickMaster,
  validateMaster,
} from './master-model';
import type { MasterCollection, MasterScreen } from './master-types';

const text = (v: unknown): string => (v === null || v === undefined ? '' : String(v));

/**
 * Formulario de un maestro (cliente, proveedor, artículo): `nuevo` (vacío) o `:clave` (ver / editar).
 * Los campos y pestañas los declara la pantalla (`MasterLayout`); aquí solo se cargan, se editan y se
 * guardan. Al modificar se envía el `odata.etag` leído (`If-Match`): si otro usuario cambió el registro,
 * SAP responde 412 y se avisa sin pisarlo.
 */
@Component({
  selector: 'sbo-master-form-page',
  changeDetection: ChangeDetectionStrategy.OnPush,
  imports: [ChartTreePanel, Icon, MasterField, RouterLink, RowsTable, SboWindow, Tab, Tabs, Toolbar],
  templateUrl: './master-form.page.html',
  styles: `
    .addrow { margin: 6px 0 0; }
    .split.two { display: grid; grid-template-columns: minmax(380px, 460px) minmax(0, 1fr); gap: 16px; align-items: start; }
    .split.two .sbo-hdr { grid-template-columns: minmax(0, 1fr); gap: 4px; }
    .left { min-width: 0; }
  `,
})
export class MasterFormPage {
  private readonly route = inject(ActivatedRoute);
  private readonly router = inject(Router);
  private readonly api = inject(SlMasterApi);

  protected readonly title = this.route.snapshot.data['title'] as string;
  protected readonly screen = this.route.snapshot.data['screen'] as MasterScreen;
  protected readonly layout = this.screen.layout;
  private readonly keys = masterKeysOf(this.layout);
  private readonly required = masterRequiredOf(this.layout);
  private readonly collections = masterCollectionsOf(this.layout);

  protected readonly key = toSignal(this.route.paramMap.pipe(map((p) => p.get('key'))), {
    initialValue: this.route.snapshot.paramMap.get('key'),
  });
  protected readonly isNew = computed(() => this.key() === null);
  /** SAP no crea este registro desde aquí (los lotes): sin botón «Nuevo» y `/nuevo` vuelve a la lista. */
  protected readonly creatable = this.screen.creatable !== false;

  constructor() {
    if (!this.creatable && this.isNew()) void this.router.navigate(['..'], { relativeTo: this.route });
  }

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

  private readonly resource = httpResource<DocRecord>(() => {
    const key = this.key();
    return key === null ? undefined : `${API_URL}/sl/${this.screen.resource}/${encodeURIComponent(key)}`;
  });
  protected readonly doc = computed(() => (this.resource.hasValue() ? this.resource.value() : undefined));
  protected readonly loading = computed(() => this.resource.isLoading());
  protected readonly loadError = computed(() => {
    const err = this.resource.error();
    return err ? (err instanceof HttpErrorResponse && err.status === 404 ? 'El registro no existe.' : apiErrorMessage(err)) : '';
  });

  /** Valores editables; se reinician al cargar o recargar el registro. */
  protected readonly header = linkedSignal<DocRecord>(() => this.pick(this.doc()));
  private pick(doc: DocRecord | undefined): DocRecord {
    return pickMaster(doc, this.keys, this.layout.newHeader());
  }

  /** Filas de las tablas (direcciones, contactos, precios…); se reinician al cargar o recargar el registro. */
  protected readonly tables = linkedSignal<Record<string, CollectionRow[]>>(() =>
    Object.fromEntries(this.collections.map((c) => [c.key, collectionRowsOf(this.doc(), c)])),
  );

  /** Lo que cambió en cada tabla (colección → filas a enviar). */
  private tableChanges(): Record<string, CollectionRow[]> {
    const d = this.doc();
    return Object.fromEntries(
      this.collections.flatMap((c) => {
        const changed = collectionPayload(c, collectionRowsOf(d, c), this.tables()[c.key] ?? []);
        return changed ? [[c.key, changed] as const] : [];
      }),
    );
  }

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

  protected readonly saving = signal(false);
  protected readonly conflict = 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: `${this.screen.singular} ${created} creado.` } : null;
    })(),
  );

  protected readonly dirty = computed(() => {
    const d = this.doc();
    if (!d) return false;
    return Object.keys(updatePayload(this.pick(d), this.header(), [], []).body).length > 0 || Object.keys(this.tableChanges()).length > 0;
  });

  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.isNew()) return { kind: 'info', text: 'Indique el código y el nombre.' };
    return { kind: 'info', text: this.dirty() ? 'Hay cambios sin guardar.' : '' };
  });
  protected readonly badge = computed<WindowBadge | undefined>(() => {
    if (this.isNew()) return { label: 'Nuevo', tone: 'info' };
    const d = this.doc();
    if (!d) return undefined;
    if (this.screen.badge) return this.screen.badge(d);
    return d['Frozen'] === 'tYES' ? { label: 'Inactivo', tone: 'muted' } : { label: 'Activo', tone: 'ok' };
  });
  protected readonly windowTitle = computed(() => {
    const d = this.doc();
    if (this.screen.titleField && d) return `${this.screen.singular} · ${text(d[this.screen.titleField])}`;
    const code = this.screen.displayField && d ? displayCode({ Code: text(d[this.screen.keyField]), FormatCode: text(d[this.screen.displayField]) }) : d?.[this.screen.keyField];
    return code === undefined ? this.screen.singular : `${this.screen.singular} · ${text(code)}`;
  });

  // --- edición -------------------------------------------------------------------------------

  protected setValue(key: string, value: string | number): void {
    this.header.update((h) => ({ ...h, [key]: value }));
    this.message.set(null);
  }

  /** Clave de SAP de un campo del formulario (los de un maestro siempre la tienen). */
  protected keyOf(f: HeaderField): string {
    return 'key' in f ? f.key : '';
  }

  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(key: string): boolean {
    return this.lockedKeys.has(key);
  }

  protected rowsOf(c: MasterCollection): CollectionRow[] {
    return this.tables()[c.key] ?? [];
  }

  protected setRows(c: MasterCollection, rows: CollectionRow[]): void {
    this.tables.update((t) => ({ ...t, [c.key]: rows }));
    this.message.set(null);
  }

  protected addRow(c: MasterCollection): void {
    this.setRows(c, [...this.rowsOf(c), { ...(c.newRow?.() ?? {}) }]);
  }

  /** La tabla permite añadir y quitar filas. */
  protected growable(c: MasterCollection): boolean {
    return !c.readonly && c.mode === 'replace' && c.growable !== false;
  }

  /** Cuenta que se resalta en el árbol del plan de cuentas: la abierta o, si es nueva, su cuenta padre (que fija el grupo). */
  protected groupCode(): string {
    return this.key() ?? text(this.header()['FatherAccountKey']);
  }

  protected value(key: string): unknown {
    // el código de una cuenta ya creada se ve con su formato (el `_SYS…` interno no es lo que el usuario conoce)
    if (this.screen.displayField && key === this.screen.keyField && !this.isNew()) {
      const d = this.doc();
      return displayCode({ Code: text(d?.[this.screen.keyField]), FormatCode: text(d?.[this.screen.displayField]) });
    }
    return this.header()[key];
  }

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

  protected async save(): Promise<void> {
    if (this.saving()) return;
    const errors = validateMaster(this.header(), this.required);
    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 body = { ...createMasterPayload(this.header(), this.layout.fixed), ...collectionsCreatePayload(this.layout, this.tables()) };
        const created = await this.api.create(this.screen.resource, body);
        const key = text(created[this.screen.keyField]);
        await this.router.navigate(['..', key], { relativeTo: this.route, state: { created: key } });
        return;
      }
      const { body } = updatePayload(this.pick(d), this.header(), [], []);
      const changes = this.tableChanges();
      Object.assign(body, changes);
      if (!Object.keys(body).length) {
        this.message.set({ kind: 'info', text: 'No hay cambios que guardar.' });
        return;
      }
      // Reemplazar la colección solo cuando se manda completa (direcciones, contactos), nunca en las que van por filas.
      const replace = this.collections.some((c) => c.mode === 'replace' && c.key in changes);
      await this.api.update(this.screen.resource, this.key()!, body, text(d['odata.etag']) || undefined, replace);
      this.message.set({ kind: 'ok', text: `${this.screen.singular} actualizado.` });
      this.resource.reload();
    } catch (e) {
      if (e instanceof HttpErrorResponse && e.status === 412) {
        this.conflict.set(true);
        this.message.set({ kind: 'warn', text: 'Otro usuario modificó este registro. 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.resource.reload();
  }
}