import { useEffect, useState } from 'react';
import { Link, useNavigate, useParams } from 'react-router-dom';
import {
  ArrowLeft, Mail, Phone, User, Globe, Pencil, Trash2, X, AlertTriangle, Plus, Lightbulb
} from 'lucide-react';
import { api, fmt } from '../api';
import { Card, Btn, Field, inputCls, Modal, Spinner, ErrorBox, Table, StatusBadge, Badge } from '../components/ui';
import { EngagementFormModal, TYPE_LABELS, ENG_STATUS_LABELS } from './Engagements';

const STATUS_LABELS = { lead: 'Lead', active: 'Actief', paused: 'Gepauzeerd', archived: 'Gearchiveerd' };
const INV_STATUS_LABELS = { draft: 'Concept', sent: 'Verzonden', paid: 'Betaald', overdue: 'Verlopen', cancelled: 'Geannuleerd' };

const EMPTY_FORM = {
  name: '', industry: '', website: '', contact_name: '', contact_email: '',
  contact_phone: '', status: 'lead', source: '', notes: ''
};

// Zelfde formulier als in Clients.jsx (bewerk-modus)
function ClientFormModal({ open, onClose, client, onSaved, onDelete }) {
  const [form, setForm] = useState(EMPTY_FORM);
  const [saving, setSaving] = useState(false);
  const [error, setError] = useState(null);

  useEffect(() => {
    if (!open) return;
    setError(null);
    setForm(client ? {
      name: client.name || '',
      industry: client.industry || '',
      website: client.website || '',
      contact_name: client.contact_name || '',
      contact_email: client.contact_email || '',
      contact_phone: client.contact_phone || '',
      status: client.status || 'lead',
      source: client.source || '',
      notes: client.notes || ''
    } : EMPTY_FORM);
  }, [open, client]);

  const set = (k) => (e) => setForm((f) => ({ ...f, [k]: e.target.value }));

  const submit = async (e) => {
    e.preventDefault();
    setSaving(true);
    setError(null);
    try {
      await api.put(`/clients/${client.id}`, form);
      onSaved();
    } catch (err) {
      setError(err);
    } finally {
      setSaving(false);
    }
  };

  return (
    <Modal open={open} onClose={onClose} title="Cliënt bewerken" wide>
      <form onSubmit={submit} className="space-y-3">
        <ErrorBox error={error} />
        <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
          <Field label="Bedrijfsnaam *" className="md:col-span-2">
            <input className={inputCls} value={form.name} onChange={set('name')} required autoFocus />
          </Field>
          <Field label="Branche">
            <input className={inputCls} value={form.industry} onChange={set('industry')} />
          </Field>
          <Field label="Website">
            <input className={inputCls} value={form.website} onChange={set('website')} placeholder="https://..." />
          </Field>
          <Field label="Contactpersoon">
            <input className={inputCls} value={form.contact_name} onChange={set('contact_name')} />
          </Field>
          <Field label="E-mail">
            <input type="email" className={inputCls} value={form.contact_email} onChange={set('contact_email')} />
          </Field>
          <Field label="Telefoon">
            <input className={inputCls} value={form.contact_phone} onChange={set('contact_phone')} />
          </Field>
          <Field label="Status">
            <select className={inputCls} value={form.status} onChange={set('status')}>
              {Object.entries(STATUS_LABELS).map(([k, v]) => <option key={k} value={k}>{v}</option>)}
            </select>
          </Field>
          <Field label="Bron" className="md:col-span-2">
            <input className={inputCls} value={form.source} onChange={set('source')} placeholder="Bijv. referral, website, netwerk" />
          </Field>
          <Field label="Notities" className="md:col-span-2">
            <textarea className={inputCls} rows={3} value={form.notes} onChange={set('notes')} />
          </Field>
        </div>
        <div className="flex items-center justify-between gap-2 pt-1">
          <Btn type="button" variant="danger" onClick={onDelete}>
            <Trash2 className="w-3.5 h-3.5" /> Verwijderen
          </Btn>
          <div className="flex gap-2">
            <Btn type="button" variant="secondary" onClick={onClose}>Annuleren</Btn>
            <Btn type="submit" loading={saving}>Opslaan</Btn>
          </div>
        </div>
      </form>
    </Modal>
  );
}

const ADVICE_COLORS = { critical: 'text-red', high: 'text-yellow', medium: 'text-blue', low: 'text-muted' };

export default function ClientDetail() {
  const { id } = useParams();
  const navigate = useNavigate();
  const [data, setData] = useState(null);
  const [error, setError] = useState(null);
  const [tab, setTab] = useState('overzicht');
  const [editOpen, setEditOpen] = useState(false);
  const [engModalOpen, setEngModalOpen] = useState(false);
  const [noteText, setNoteText] = useState('');
  const [noteSaving, setNoteSaving] = useState(false);
  const [noteError, setNoteError] = useState(null);

  const load = () => {
    setError(null);
    api.get(`/clients/${id}`).then(setData).catch(setError);
  };
  useEffect(load, [id]);

  if (!data) {
    return error ? <ErrorBox error={error} onRetry={load} /> : <Spinner />;
  }

  const { client, engagements, assessments, advice, diagrams, notes, timeEntries, invoices } = data;
  const totalHours = timeEntries.reduce((s, t) => s + (t.hours || 0), 0);
  const websiteHref = client.website
    ? (/^https?:\/\//i.test(client.website) ? client.website : `https://${client.website}`)
    : null;

  const dismissAdvice = async (adviceId) => {
    try {
      await api.post(`/clients/${id}/advice/${adviceId}/dismiss`);
      load();
    } catch (err) {
      setError(err);
    }
  };

  const addNote = async (e) => {
    e.preventDefault();
    if (!noteText.trim()) return;
    setNoteSaving(true);
    setNoteError(null);
    try {
      await api.post(`/clients/${id}/notes`, { content: noteText.trim() });
      setNoteText('');
      load();
    } catch (err) {
      setNoteError(err);
    } finally {
      setNoteSaving(false);
    }
  };

  const removeNote = async (noteId) => {
    if (!window.confirm('Deze notitie verwijderen?')) return;
    try {
      await api.del(`/clients/${id}/notes/${noteId}`);
      load();
    } catch (err) {
      setError(err);
    }
  };

  const removeClient = async () => {
    if (!window.confirm(`Cliënt "${client.name}" verwijderen? Dit kan niet ongedaan worden gemaakt.`)) return;
    try {
      await api.del(`/clients/${client.id}`);
      navigate('/clients');
    } catch (err) {
      setError(err);
      setEditOpen(false);
    }
  };

  const tabs = [
    { key: 'overzicht', label: 'Overzicht' },
    { key: 'engagements', label: `Engagements (${engagements.length})` },
    { key: 'notities', label: `Notities (${notes.length})` },
    { key: 'uren', label: `Uren (${timeEntries.length})` },
    { key: 'facturen', label: `Facturen (${invoices.length})` }
  ];

  return (
    <div className="space-y-4 fade-in">
      {error && <ErrorBox error={error} onRetry={load} />}

      {/* Header */}
      <div className="flex items-start justify-between gap-4 flex-wrap">
        <div className="min-w-0">
          <div className="flex items-center gap-3 flex-wrap">
            <h1 className="text-xl font-bold tracking-tight">{client.name}</h1>
            <StatusBadge status={client.status} labels={STATUS_LABELS} />
          </div>
          <div className="flex items-center gap-4 mt-1.5 text-[12px] text-muted flex-wrap">
            {client.industry && <span>{client.industry}</span>}
            {websiteHref && (
              <a href={websiteHref} target="_blank" rel="noreferrer" className="flex items-center gap-1 text-accent hover:underline">
                <Globe className="w-3.5 h-3.5" /> {client.website}
              </a>
            )}
          </div>
          <div className="flex items-center gap-4 mt-1 text-[12px] text-muted flex-wrap">
            {client.contact_name && <span className="flex items-center gap-1"><User className="w-3.5 h-3.5" /> {client.contact_name}</span>}
            {client.contact_email && <span className="flex items-center gap-1"><Mail className="w-3.5 h-3.5" /> {client.contact_email}</span>}
            {client.contact_phone && <span className="flex items-center gap-1"><Phone className="w-3.5 h-3.5" /> {client.contact_phone}</span>}
          </div>
        </div>
        <div className="flex gap-2 shrink-0">
          <Link
            to="/clients"
            className="inline-flex items-center gap-1.5 rounded-lg px-3.5 py-2 text-[13px] bg-card border border-border text-text hover:bg-card-hover transition-colors"
          >
            <ArrowLeft className="w-3.5 h-3.5" /> Terug
          </Link>
          <Btn variant="secondary" onClick={() => setEditOpen(true)}>
            <Pencil className="w-3.5 h-3.5" /> Bewerken
          </Btn>
        </div>
      </div>

      {/* Tabs */}
      <div className="flex gap-1 border-b border-border-soft overflow-x-auto">
        {tabs.map((t) => (
          <button
            key={t.key}
            onClick={() => setTab(t.key)}
            className={`px-3 py-2 text-[13px] whitespace-nowrap border-b-2 -mb-px transition-colors ${tab === t.key ? 'border-accent text-text font-medium' : 'border-transparent text-muted hover:text-text'}`}
          >
            {t.label}
          </button>
        ))}
      </div>

      {/* Tab: Overzicht */}
      {tab === 'overzicht' && (
        <div className="grid grid-cols-1 xl:grid-cols-2 gap-4">
          <Card title="Actief advies" subtitle="Automatisch gegenereerd" className="xl:col-span-2">
            {advice.length === 0 ? (
              <div className="text-muted text-[13px] py-4 text-center flex flex-col items-center gap-2">
                <Lightbulb className="w-5 h-5" /> Alles onder controle
              </div>
            ) : (
              <div className="space-y-2">
                {advice.map((a) => (
                  <div key={a.id} className="flex items-start gap-2.5 px-2.5 py-2 rounded-lg bg-bg-soft">
                    <AlertTriangle className={`w-4 h-4 mt-0.5 shrink-0 ${ADVICE_COLORS[a.priority] || 'text-blue'}`} />
                    <div className="min-w-0 flex-1">
                      <div className="text-[12px]">{a.advice_text}</div>
                      <div className="text-[11px] text-muted mt-0.5">{fmt.datetime(a.created_at)}</div>
                    </div>
                    <button
                      onClick={() => dismissAdvice(a.id)}
                      className="p-1 rounded text-muted hover:text-text shrink-0"
                      title="Advies afronden"
                    >
                      <X className="w-3.5 h-3.5" />
                    </button>
                  </div>
                ))}
              </div>
            )}
          </Card>

          <Card title="Notities">
            {client.notes
              ? <p className="text-[13px] whitespace-pre-wrap">{client.notes}</p>
              : <div className="text-muted text-[13px] py-2">Geen notities</div>}
          </Card>

          <Card title="Diagrammen" actions={<Link to="/diagrams" className="text-[12px] text-accent hover:underline">Alles</Link>}>
            {diagrams.length === 0 ? (
              <div className="text-muted text-[13px] py-2">Nog geen diagrammen</div>
            ) : (
              <div className="space-y-1.5">
                {diagrams.map((d) => (
                  <Link key={d.id} to="/diagrams" className="flex items-center justify-between gap-2 px-2.5 py-2 rounded-lg hover:bg-card-hover transition-colors">
                    <div className="min-w-0">
                      <div className="text-[13px] font-medium truncate">{d.name}</div>
                      <div className="text-[11px] text-muted">{d.diagram_type}</div>
                    </div>
                    <span className="text-[12px] text-muted shrink-0">{fmt.date(d.updated_at)}</span>
                  </Link>
                ))}
              </div>
            )}
          </Card>

          <Card title={`Assessments (${assessments.length})`} className="xl:col-span-2">
            {assessments.length === 0 ? (
              <div className="text-muted text-[13px] py-2">Nog geen assessments</div>
            ) : (
              <div className="space-y-1.5">
                {assessments.map((a) => (
                  <div key={a.id} className="flex items-center justify-between gap-2 px-2.5 py-2 rounded-lg hover:bg-card-hover transition-colors">
                    <span className="text-[13px] font-medium">Assessment #{a.id}</span>
                    <span className="text-[12px] text-muted">{fmt.datetime(a.created_at)}</span>
                  </div>
                ))}
              </div>
            )}
          </Card>
        </div>
      )}

      {/* Tab: Engagements */}
      {tab === 'engagements' && (
        <Card
          title="Engagements"
          actions={<Btn size="sm" onClick={() => setEngModalOpen(true)}><Plus className="w-3.5 h-3.5" /> Nieuw engagement</Btn>}
        >
          <Table
            columns={[
              {
                label: 'Titel',
                render: (e) => (
                  <Link to={`/engagements/${e.id}`} className="font-medium text-text hover:text-accent transition-colors">
                    {e.title}
                  </Link>
                )
              },
              { label: 'Type', render: (e) => TYPE_LABELS[e.type] || e.type },
              { label: 'Status', render: (e) => <StatusBadge status={e.status} labels={ENG_STATUS_LABELS} /> },
              { label: 'Start', render: (e) => <span className="text-muted">{fmt.date(e.start_date)}</span> }
            ]}
            rows={engagements}
            keyFn={(e) => e.id}
            empty={<div className="text-muted text-[13px] py-4 text-center">Nog geen engagements</div>}
          />
        </Card>
      )}

      {/* Tab: Notities */}
      {tab === 'notities' && (
        <Card title="Notities">
          <form onSubmit={addNote} className="mb-4 space-y-2">
            {noteError && <ErrorBox error={noteError} />}
            <div className="flex items-end gap-2">
              <textarea
                className={inputCls}
                rows={2}
                placeholder="Schrijf een notitie..."
                value={noteText}
                onChange={(e) => setNoteText(e.target.value)}
              />
              <Btn type="submit" loading={noteSaving} className="shrink-0">Toevoegen</Btn>
            </div>
          </form>
          {notes.length === 0 ? (
            <div className="text-muted text-[13px] py-4 text-center">Nog geen notities</div>
          ) : (
            <div className="space-y-1.5">
              {notes.map((n) => (
                <div key={n.id} className="flex items-start justify-between gap-2 px-2.5 py-2 rounded-lg hover:bg-card-hover transition-colors">
                  <div className="min-w-0">
                    <div className="text-[13px] whitespace-pre-wrap">{n.content}</div>
                    <div className="text-[11px] text-muted mt-0.5">{n.created_by} · {fmt.datetime(n.created_at)}</div>
                  </div>
                  <button
                    onClick={() => removeNote(n.id)}
                    className="p-1.5 rounded-md text-muted hover:text-red hover:bg-bg-soft shrink-0"
                    title="Verwijderen"
                  >
                    <Trash2 className="w-3.5 h-3.5" />
                  </button>
                </div>
              ))}
            </div>
          )}
        </Card>
      )}

      {/* Tab: Uren */}
      {tab === 'uren' && (
        <Card title="Urenregistratie" subtitle={`Totaal: ${fmt.hours(totalHours)}`}>
          <Table
            columns={[
              { label: 'Datum', render: (t) => fmt.date(t.date) },
              { label: 'Gebruiker', render: (t) => t.username || <span className="text-muted">-</span> },
              { label: 'Uren', render: (t) => fmt.hours(t.hours) },
              { label: 'Omschrijving', render: (t) => t.description || <span className="text-muted">-</span> },
              { label: 'Facturabel', render: (t) => <Badge color={t.billable ? 'green' : 'muted'}>{t.billable ? 'Ja' : 'Nee'}</Badge> },
              { label: 'Tarief', render: (t) => <span className="text-muted">{fmt.euro(t.hourly_rate)}</span> }
            ]}
            rows={timeEntries}
            keyFn={(t) => t.id}
            empty={<div className="text-muted text-[13px] py-4 text-center">Nog geen uren geregistreerd</div>}
          />
          {timeEntries.length > 0 && (
            <div className="text-right text-[13px] mt-3 pt-3 border-t border-border-soft">
              Totaal: <span className="font-semibold">{fmt.hours(totalHours)}</span>
            </div>
          )}
        </Card>
      )}

      {/* Tab: Facturen */}
      {tab === 'facturen' && (
        <Card title="Facturen">
          <Table
            columns={[
              {
                label: 'Nummer',
                render: (i) => (
                  <Link to={`/invoices/${i.id}`} className="font-medium text-text hover:text-accent transition-colors">
                    {i.number}
                  </Link>
                )
              },
              { label: 'Datum', render: (i) => <span className="text-muted">{fmt.date(i.date)}</span> },
              { label: 'Totaal', render: (i) => fmt.euro(i.total) },
              { label: 'Status', render: (i) => <StatusBadge status={i.status} labels={INV_STATUS_LABELS} /> }
            ]}
            rows={invoices}
            keyFn={(i) => i.id}
            empty={<div className="text-muted text-[13px] py-4 text-center">Nog geen facturen</div>}
          />
        </Card>
      )}

      <ClientFormModal
        open={editOpen}
        client={client}
        onClose={() => setEditOpen(false)}
        onSaved={() => { setEditOpen(false); load(); }}
        onDelete={removeClient}
      />
      <EngagementFormModal
        open={engModalOpen}
        onClose={() => setEngModalOpen(false)}
        clientId={client.id}
        onSaved={() => { setEngModalOpen(false); load(); }}
      />
    </div>
  );
}