import { useEffect, useMemo, useState } from 'react';
import type { FormEvent } from 'react';
import { Link, useNavigate, useSearchParams } from 'react-router';
import { Alert, LoadingBlock, errorMessage } from '../components/Feedback';
import { Icon } from '../components/Icon';
import { getAsset } from '../lib/api';
import {
  createInventoryStructure,
  getInventoryFamilyFindings,
  getInventoryStructureOptions,
  listInventoryStructureParents,
} from '../lib/inventoryStructureApi';
import type {
  InventoryFamily,
  InventoryFamilyFindings,
  InventoryStructureKind,
  InventoryStructureOptions,
  InventoryStructureParent,
} from '../lib/inventoryStructureApi';

const KINDS: Array<{ kind: InventoryStructureKind; label: string }> = [
  { kind: 'DEPARTAMENTO', label: 'Departamento' },
  { kind: 'AREA', label: 'Área' },
  { kind: 'YACIMIENTO', label: 'Yacimiento' },
  { kind: 'INSTALACION', label: 'Instalación' },
  { kind: 'SUBINSTALACION', label: 'Subinstalación' },
  { kind: 'EMPRESA', label: 'Empresa' },
];
const childKindByParentType: Record<string, InventoryStructureKind | undefined> = {
  departamento: 'AREA', area: 'YACIMIENTO', yacimiento: 'INSTALACION', instalacion: 'SUBINSTALACION',
};
const parentLabelByKind: Partial<Record<InventoryStructureKind,string>> = {
  AREA:'Departamento', YACIMIENTO:'Área', INSTALACION:'Yacimiento', SUBINSTALACION:'Instalación',
};
function kindLabel(kind: InventoryStructureKind) { return KINDS.find((item) => item.kind===kind)?.label ?? kind; }

export function InventoryCreatePage() {
  const navigate = useNavigate();
  const [searchParams] = useSearchParams();
  const contextParentId = searchParams.get('parentId');
  const [options, setOptions] = useState<InventoryStructureOptions | null>(null);
  const [kind, setKind] = useState<InventoryStructureKind>('DEPARTAMENTO');
  const [parents, setParents] = useState<InventoryStructureParent[]>([]);
  const [parentSearch, setParentSearch] = useState('');
  const [parentId, setParentId] = useState('');
  const [familyId, setFamilyId] = useState('');
  const [operatorCompanyId, setOperatorCompanyId] = useState('');
  const [concessionTypeId, setConcessionTypeId] = useState('');
  const [familyFindings, setFamilyFindings] = useState<InventoryFamilyFindings | null>(null);
  const [name, setName] = useState('');
  const [code, setCode] = useState('');
  const [commonName, setCommonName] = useState('');
  const [description, setDescription] = useState('');
  const [loading, setLoading] = useState(true);
  const [saving, setSaving] = useState(false);
  const [error, setError] = useState('');

  useEffect(() => {
    getInventoryStructureOptions().then(async (loaded) => {
      setOptions(loaded);
      if (contextParentId) {
        const parent = await getAsset(contextParentId);
        const inferred = childKindByParentType[parent.type.code.toLowerCase()];
        if (inferred) { setKind(inferred); setParentId(parent.id); }
      }
    }).catch((requestError) => setError(errorMessage(requestError))).finally(() => setLoading(false));
  }, [contextParentId]);

  const requiresParent = Boolean(parentLabelByKind[kind]);
  const requiresFamily = kind === 'INSTALACION' || kind === 'SUBINSTALACION';
  const requiresYacimientoContext = kind === 'YACIMIENTO';
  const parentLabel = parentLabelByKind[kind] ?? '';

  useEffect(() => {
    if (!requiresParent) { setParents([]); setParentId(''); return; }
    const timer = window.setTimeout(() => {
      listInventoryStructureParents(kind,parentSearch).then((loaded) => {
        setParents(loaded);
        if (contextParentId && loaded.some((item) => item.id===contextParentId)) setParentId(contextParentId);
      }).catch((requestError) => setError(errorMessage(requestError)));
    },150);
    return () => window.clearTimeout(timer);
  }, [kind,parentSearch,contextParentId,requiresParent]);

  const selectedParent = parents.find((item) => item.id===parentId) ?? null;
  const families = useMemo(() => {
    if (!options) return [] as InventoryFamily[];
    if (kind==='INSTALACION') return options.installationFamilies;
    if (kind==='SUBINSTALACION') {
      const parentFamilyId=selectedParent?.inventoryFamily?.id;
      return parentFamilyId ? options.subinstallationFamilies.filter((item)=>item.parentFamilyIds.includes(parentFamilyId)) : [];
    }
    return [];
  },[options,kind,selectedParent]);
  const selectedFamily=families.find((item)=>item.id===familyId) ?? null;

  useEffect(() => {
    if (!familyId) { setFamilyFindings(null); return; }
    getInventoryFamilyFindings(familyId).then(setFamilyFindings).catch((requestError)=>setError(errorMessage(requestError)));
  },[familyId]);
  useEffect(() => {
    if (!requiresFamily) setFamilyId('');
    if (kind==='SUBINSTALACION' && familyId && !families.some((item)=>item.id===familyId)) setFamilyId('');
  },[kind,requiresFamily,families,familyId]);
  useEffect(() => {
    if (!requiresYacimientoContext) { setOperatorCompanyId(''); setConcessionTypeId(''); }
  },[requiresYacimientoContext]);

  const changeKind=(next:InventoryStructureKind) => {
    setKind(next); setParentId(''); setParentSearch(''); setFamilyId(''); setFamilyFindings(null);
    setOperatorCompanyId(''); setConcessionTypeId(''); setError('');
  };
  const save=async(event:FormEvent) => {
    event.preventDefault();
    if (requiresParent && !parentId) { setError(`Seleccioná ${parentLabel}.`); return; }
    if (requiresYacimientoContext && !operatorCompanyId) { setError('Seleccioná la Empresa relacionada del Yacimiento.'); return; }
    if (requiresYacimientoContext && !concessionTypeId) { setError('Seleccioná el Tipo de concesión del Yacimiento.'); return; }
    if (requiresFamily && !familyId) { setError(`Seleccioná el tipo de ${kindLabel(kind).toLowerCase()}.`); return; }
    setSaving(true); setError('');
    try {
      const created=await createInventoryStructure({
        kind,name:name.trim(),parentId:parentId || null,familyId:familyId || null,
        operatorCompanyId:operatorCompanyId || null,concessionTypeId:concessionTypeId || null,
        code:code.trim() || null,commonName:commonName.trim() || null,description:description.trim() || null,
      });
      navigate(`/inventarios/${created.id}`,{replace:true});
    } catch(requestError) { setError(errorMessage(requestError)); }
    finally { setSaving(false); }
  };

  if (loading) return <LoadingBlock label="Preparando alta…" />;
  return <section className="narrow-section asset-detail-page">
    <nav className="breadcrumb asset-detail-breadcrumb" aria-label="Ruta del Inventario"><Link to="/inventarios">Inventarios</Link><span>›</span><strong>Nuevo registro</strong></nav>
    <div className="page-heading asset-editor-heading"><div><span className="eyebrow">CARGA MANUAL</span><h1>Nuevo registro</h1><p>Modelo fijo: Departamento → Área → Yacimiento → Instalación → Subinstalación. La Empresa y el Tipo de concesión pertenecen al Yacimiento.</p></div></div>
    {error && <Alert>{error}</Alert>}
    <form className="panel form-panel" onSubmit={save}>
      <div className="form-section"><div><h2>1. ¿Qué querés crear?</h2><p className="section-copy">Área sólo depende de Departamento. Yacimiento define Área, Empresa relacionada y Tipo de concesión.</p></div><label className="field"><span>Tipo</span><select value={kind} onChange={(event)=>changeKind(event.target.value as InventoryStructureKind)}>{KINDS.map((item)=><option key={item.kind} value={item.kind}>{item.label}</option>)}</select></label></div>
      {requiresParent && <div className="form-section"><div><h2>2. Ubicación</h2><p className="section-copy">Elegí el {parentLabel.toLowerCase()} concreto.</p></div><label className="field"><span>Buscar {parentLabel.toLowerCase()}</span><input value={parentSearch} onChange={(event)=>setParentSearch(event.target.value)} placeholder={`Buscar ${parentLabel.toLowerCase()}…`} /></label><label className="field"><span>{parentLabel} <em>obligatorio</em></span><select value={parentId} onChange={(event)=>{setParentId(event.target.value);setFamilyId('');}} required><option value="">Seleccionar…</option>{parents.map((parent)=><option key={parent.id} value={parent.id}>{parent.name} · {parent.code}</option>)}</select></label></div>}
      {requiresYacimientoContext && <div className="form-section"><div><h2>3. Contexto del Yacimiento</h2><p className="section-copy">Estas relaciones pertenecen directamente al Yacimiento y no al Área.</p></div><div className="form-grid"><label className="field"><span>Empresa relacionada <em>obligatorio</em></span><select value={operatorCompanyId} onChange={(event)=>setOperatorCompanyId(event.target.value)} required><option value="">Seleccionar…</option>{options?.companies.map((company)=><option key={company.id} value={company.id}>{company.name}</option>)}</select></label><label className="field"><span>Tipo de concesión <em>obligatorio</em></span><select value={concessionTypeId} onChange={(event)=>setConcessionTypeId(event.target.value)} required><option value="">Seleccionar…</option>{options?.concessionTypes.map((type)=><option key={type.id} value={type.id}>{type.name}</option>)}</select></label></div></div>}
      {requiresFamily && <div className="form-section"><div><h2>3. Clasificación técnica</h2><p className="section-copy">Define los datos técnicos y Hallazgos aplicables. En Subinstalaciones sólo aparecen clasificaciones compatibles con la Instalación elegida.</p></div>{kind==='SUBINSTALACION' && !selectedParent?.inventoryFamily ? <Alert>La Instalación elegida todavía no tiene clasificación técnica.</Alert> : <label className="field"><span>Tipo de {kindLabel(kind).toLowerCase()} <em>obligatorio</em></span><select value={familyId} onChange={(event)=>setFamilyId(event.target.value)} required><option value="">Seleccionar…</option>{families.map((family)=><option key={family.id} value={family.id}>{family.name}</option>)}</select></label>}{kind==='SUBINSTALACION' && selectedParent?.inventoryFamily && families.length===0 && <Alert>No hay tipos de Subinstalación compatibles con {selectedParent.inventoryFamily.name}.</Alert>}{selectedFamily && <div className="context-create-banner"><Icon name="alert" /><div><strong>{selectedFamily.name}</strong><span>{familyFindings ? `${familyFindings.count} Hallazgo${familyFindings.count===1?'':'s'} asociado${familyFindings.count===1?'':'s'}` : 'Cargando Hallazgos asociados…'}</span>{familyFindings && familyFindings.items.length>0 && <ul style={{margin:'8px 0 0',paddingLeft:18}}>{familyFindings.items.slice(0,6).map((item)=><li key={item.id}>{item.title}</li>)}{familyFindings.items.length>6 && <li>+ {familyFindings.items.length-6} más</li>}</ul>}</div></div>}</div>}
      <div className="form-section"><div><h2>{requiresYacimientoContext ? '4' : requiresFamily ? '4' : requiresParent ? '3' : '2'}. Nombre</h2><p className="section-copy">El nombre es el dato propio principal de este nivel. Los datos técnicos se completan después, cuando corresponda.</p></div><label className="field"><span>Nombre <em>obligatorio</em></span><input autoFocus value={name} onChange={(event)=>setName(event.target.value)} required maxLength={200} placeholder={`Nombre de ${kindLabel(kind).toLowerCase()}`} /></label><details style={{marginTop:12}}><summary style={{cursor:'pointer',fontWeight:700}}>Datos opcionales</summary><div style={{marginTop:14}}><div className="form-grid"><label className="field"><span>Código DH</span><input value={code} onChange={(event)=>setCode(event.target.value.toUpperCase())} maxLength={120} pattern="[A-Z0-9][A-Z0-9._/-]*" placeholder="Dejalo vacío para generar automáticamente" /></label><label className="field"><span>Nombre habitual</span><input value={commonName} onChange={(event)=>setCommonName(event.target.value)} maxLength={200} /></label></div><label className="field"><span>Descripción</span><textarea value={description} onChange={(event)=>setDescription(event.target.value)} rows={2} maxLength={4000} /></label></div></details></div>
      <div className="form-actions"><Link className="button secondary" to="/inventarios">Cancelar</Link><button className="button primary" disabled={saving || !name.trim() || (requiresParent && !parentId) || (requiresYacimientoContext && (!operatorCompanyId || !concessionTypeId)) || (requiresFamily && !familyId)}><Icon name="check" />{saving?'Creando…':`Crear ${kindLabel(kind)}`}</button></div>
    </form>
  </section>;
}