import { useEffect, useState } from 'react';
import { Link, useSearchParams } from 'react-router';
import { useAuth } from '../../auth/AuthContext';
import { Alert, EmptyState, LoadingBlock, errorMessage } from '../../components/Feedback';
import { Icon } from '../../components/Icon';
import { getAssetLineage } from '../../lib/api';
import type { AssetLineageItem } from '../../lib/api';
import {
  listInventoryAreas,
  listInventoryChildren,
} from '../../lib/inventoryBrowserApi';
import type {
  InventoryBrowserArea,
  InventoryBrowserItem,
  InventoryQuery,
} from '../../lib/inventoryBrowserApi';
import { assetOperationalStatusLabel, assetStatusClass, assetStatusLabel } from './assetPresentation';

function navigationHref(base: URLSearchParams, parentId?: string) {
  const params = new URLSearchParams(base);
  params.delete('view');
  params.delete('page');
  params.delete('section');
  params.delete('companyId');
  parentId ? params.set('parentId', parentId) : params.delete('parentId');
  return `/inventarios${params.size ? `?${params}` : ''}`;
}

function AreaCard({ area, href }: { area: InventoryBrowserArea; href: string }) {
  return <Link className="asset-browser-item" to={href}>
    <span className="asset-browser-item-icon"><Icon name="map" size={17} /></span>
    <span className="asset-browser-item-main">
      <strong>{area.name}</strong>
      <small>
        {area.code} · {area.yacimientoCount} yacimiento{area.yacimientoCount === 1 ? '' : 's'}
        {area.currentOperator ? ` · Operadora vigente: ${area.currentOperator.name}` : ' · Sin operadora vigente'}
      </small>
    </span>
    <span className="asset-browser-item-status">
      <strong>{area.inventoryCount}</strong>
      <small>instancia{area.inventoryCount === 1 ? '' : 's'} real{area.inventoryCount === 1 ? '' : 'es'}</small>
    </span>
    <Icon name="chevron" size={16} />
  </Link>;
}

function InventoryCard({ item, href }: { item: InventoryBrowserItem; href: string }) {
  const structural = !item.isInventoryInstance;
  return <Link className="asset-browser-item" to={href}>
    <span className="asset-browser-item-icon"><Icon name={structural ? 'map' : 'layers'} size={17} /></span>
    <span className="asset-browser-item-main">
      <strong>{item.name}</strong>
      <small>
        {item.code} · {item.type.name}
        {item.inventoryFamily ? ` · ${item.inventoryFamily.name}` : ''}
        {item.commonName ? ` · ${item.commonName}` : ''}
      </small>
    </span>
    <span className="asset-browser-item-status">
      {structural
        ? <><span className="tag">Contexto</span><small>{item.childrenCount} nivel{item.childrenCount === 1 ? '' : 'es'} inferior{item.childrenCount === 1 ? '' : 'es'}</small></>
        : <><span className={`status-badge ${assetStatusClass(item.informationStatus)}`}>{assetStatusLabel(item.informationStatus)}</span><small>{assetOperationalStatusLabel(item.operationalStatus)}</small></>}
    </span>
    <Icon name="chevron" size={16} />
  </Link>;
}

function nextLevelLabel(typeCode: string | undefined) {
  switch (typeCode?.toLowerCase()) {
    case 'area': return 'Yacimientos';
    case 'yacimiento': return 'Instalaciones';
    case 'instalacion': return 'Subinstalaciones';
    default: return 'Niveles inferiores';
  }
}

export function AssetHierarchyView({ filters }: { filters: InventoryQuery }) {
  const { hasPermission } = useAuth();
  const canCreate = hasPermission('assets.create');
  const [searchParams] = useSearchParams();
  const parentId = searchParams.get('parentId') ?? '';
  const [areas, setAreas] = useState<InventoryBrowserArea[]>([]);
  const [children, setChildren] = useState<InventoryBrowserItem[]>([]);
  const [lineage, setLineage] = useState<AssetLineageItem[]>([]);
  const [hasMore, setHasMore] = useState(false);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState('');

  useEffect(() => {
    let active = true;
    setLoading(true);
    setError('');
    setAreas([]);
    setChildren([]);
    setLineage([]);
    setHasMore(false);

    const run = async () => {
      if (!parentId) {
        const response = await listInventoryAreas({
          search: filters.search,
          operationalAreaId: filters.operationalAreaId,
          operatorCompanyId: filters.operatorCompanyId,
        });
        if (active) setAreas(response.data);
        return;
      }

      const [loadedLineage, response] = await Promise.all([
        getAssetLineage(parentId),
        listInventoryChildren(parentId, { search: filters.search }),
      ]);
      if (!active) return;
      setLineage(loadedLineage.filter((item) => ['area','yacimiento','instalacion','subinstalacion'].includes(item.type.code.toLowerCase())));
      setChildren(response.data);
      setHasMore(response.meta.hasMore);
    };

    run()
      .catch((requestError) => active && setError(errorMessage(requestError)))
      .finally(() => active && setLoading(false));
    return () => { active = false; };
  }, [parentId, filters.search, filters.operationalAreaId, filters.operatorCompanyId]);

  if (loading) return <LoadingBlock label="Cargando inventarios…" />;

  if (!parentId) {
    const realTotal = areas.reduce((sum, area) => sum + Number(area.inventoryCount ?? 0), 0);
    return <div className="asset-browser-panel">
      {error && <Alert>{error}</Alert>}
      <div className="asset-browser-section-heading">
        <div>
          <span className="eyebrow">ESTRUCTURA TERRITORIAL</span>
          <h2>Áreas</h2>
          <p>Las Áreas y Yacimientos son contexto de navegación. El Inventario real comienza en las Instalaciones/Subinstalaciones efectivamente registradas.</p>
        </div>
        <div className="asset-browser-current-actions">
          <span className="count-pill">{realTotal} Inventario real</span>
          <span className="count-pill">{areas.length} Áreas</span>
        </div>
      </div>
      {areas.length === 0
        ? <EmptyState title="No hay Áreas para mostrar" text="Probá con otra búsqueda o revisá el contexto seleccionado." />
        : <div className="asset-browser-list">{areas.map((area) => <AreaCard key={area.id} area={area} href={navigationHref(searchParams, area.id)} />)}</div>}
      <div className="asset-browser-levels" aria-label="Estructura de Inventarios">
        <div><span>1</span><strong>Área</strong><small>Ancla territorial</small></div><i>›</i>
        <div><span>2</span><strong>Yacimiento</strong><small>Contexto dentro del Área</small></div><i>›</i>
        <div><span>3</span><strong>Instalación</strong><small>Inventario real</small></div><i>›</i>
        <div><span>4</span><strong>Subinstalación</strong><small>Inventario real</small></div>
      </div>
    </div>;
  }

  const current = lineage.at(-1) ?? null;
  const breadcrumb = <nav className="asset-browser-breadcrumb" aria-label="Ruta del Inventario">
    <Link to="/inventarios">Inventarios</Link>
    {lineage.map((item,index) => {
      const isLast=index===lineage.length-1;
      return <span className="asset-browser-crumb-part" key={item.id}>
        <span>›</span>
        {isLast ? <strong>{item.name}</strong> : <Link to={navigationHref(searchParams,item.id)}>{item.name}</Link>}
      </span>;
    })}
  </nav>;

  return <div className="asset-browser-panel">
    {breadcrumb}
    {error && <Alert>{error}</Alert>}
    {hasMore && <Alert type="info">Este nivel tiene más de 200 registros. Usá la búsqueda para acotar el resultado.</Alert>}
    <div className="asset-browser-current-heading">
      <div>
        <span className="eyebrow">{current?.type.name ?? 'INVENTARIO'}</span>
        <h2>{current?.name ?? 'Nivel de Inventario'}</h2>
        <p>{current?.code ?? ''}</p>
      </div>
      <div className="asset-browser-current-actions">
        {current && <Link className="button secondary" to={`/inventarios/${current.id}`}>Ver ficha</Link>}
        {canCreate && current?.type.code.toLowerCase() !== 'subinstalacion' && <Link className="button primary" to={`/inventarios/nuevo?parentId=${parentId}`}><Icon name="plus" />Agregar aquí</Link>}
      </div>
    </div>

    <section className="asset-browser-group">
      <div className="asset-browser-group-heading">
        <div><h3>{nextLevelLabel(current?.type.code)}</h3><p>La jerarquía permitida es Área → Yacimiento → Instalación → Subinstalación.</p></div>
        <span>{children.length}</span>
      </div>
      {children.length === 0
        ? <EmptyState
            title={current?.type.code.toLowerCase() === 'subinstalacion' ? 'Fin de la jerarquía' : 'No hay registros en este nivel'}
            text={current?.type.code.toLowerCase() === 'yacimiento'
              ? 'Todavía no hay Instalaciones reales registradas en este Yacimiento.'
              : current?.type.code.toLowerCase() === 'instalacion'
                ? 'Todavía no hay Subinstalaciones registradas en esta Instalación.'
                : 'No hay registros que coincidan con la búsqueda actual.'}
          />
        : <div className="asset-browser-list">{children.map((item) => <InventoryCard key={item.id} item={item} href={navigationHref(searchParams,item.id)} />)}</div>}
    </section>
  </div>;
}