import React, { useMemo, useState } from 'react';
import { Badge, BudgetBar, Card, EmptyState, ErrorBox, Segmented, Spinner, inputClass } from '../ui/controls';
import { Icon } from '../ui/Icon';
import { CountUp, ProgressChart } from '../ui/charts';
import { ReportTable } from './ReportTable';
import { ExportMenu } from './ExportMenu';
import { useAuth } from '../../lib/auth';
import { projectsApi, qs, reportsApi, type ProjectDetail } from '../../lib/api';
import { useLoader } from '../../lib/hooks';
import { formatDate, formatEuro, formatHours, formatNumber, mondayOf, todayIso } from '../../lib/format';
import { useRouter } from '../../lib/router';
import { TYPE_TONE } from '../projects/Projects';
import { PROJECT_TYPE_LABELS } from '../../types';

export const ProjectReport: React.FC<{ id: number | null }> = ({ id }) => {
  const { navigate } = useRouter();
  const projects = useLoader(() => projectsApi.list(), []);
  const report = useLoader(() => (id ? reportsApi.project(id) : Promise.resolve(null)), [id]);

  const options = useMemo(() => [...(projects.data ?? [])].sort((a, b) => a.display_name.localeCompare(b.display_name, 'de')), [projects.data]);

  return (
    <div className="space-y-4">
      <div className="flex flex-wrap items-center gap-2">
        <select className={`${inputClass} !w-auto min-w-[260px] max-w-full`} value={id ?? ''} onChange={(e) => navigate(e.target.value ? `reports/projekt/${e.target.value}` : 'reports/projekt')}>
          <option value="">Projekt wählen…</option>
          {options.map((p) => (
            <option key={p.id} value={p.id}>
              {p.display_name} · {p.code}
            </option>
          ))}
        </select>
      </div>
      {!id ? (
        <EmptyState icon="folder" title="Projekt auswählen" text="Verlauf, Budget, Tasks, Team und Budgettöpfe eines Projekts." />
      ) : report.error ? (
        <ErrorBox message={report.error} onRetry={report.reload} />
      ) : !report.data ? (
        <Spinner label="Lade Projektreport…" />
      ) : (
        <ProjectReportBody key={id} detail={report.data} />
      )}
    </div>
  );
};

export const ProjectReportBody: React.FC<{ detail: ProjectDetail; compact?: boolean }> = ({ detail, compact }) => {
  const { settings } = useAuth();
  const { navigate } = useRouter();
  const [chart, setChart] = useState<'progress' | 'weekly'>('progress');
  const [tab, setTab] = useState<'tasks' | 'team' | 'pots'>('tasks');
  const [showNotes, setShowNotes] = useState(false);
  const p = detail.project;
  const t = detail.totals;
  const budgetHours = p.budget_hours;
  const remaining = budgetHours != null ? Math.max(0, budgetHours - p.budget_used_minutes / 60) : null;
  const remainingPct = budgetHours ? Math.round(((remaining ?? 0) / budgetHours) * 100) : null;
  const thisWeek = mondayOf(todayIso());
  const virtualRate = p.type === 'fixed' && p.used_minutes ? (p.budget_value ?? 0) / (p.used_minutes / 60) : null;
  const month = todayIso().slice(0, 7);

  const exportOptions = [
    { label: 'PDF – Stundennachweis (Monat)', hint: 'Alle Mitarbeiter, aktueller Monat', path: `/exports/timesheet${qs({ month, format: 'pdf', user_id: 'all', project_id: p.id })}`, filename: `${p.code}.pdf` },
    { label: 'Excel – Stundennachweis (Monat)', path: `/exports/timesheet${qs({ month, format: 'xlsx', user_id: 'all', project_id: p.id, amounts: 1 })}`, filename: `${p.code}.xlsx` },
    { label: 'CSV – alle Buchungen', path: `/exports/report${qs({ from: p.start_date, to: todayIso(), project_id: p.id, group: 'detail', format: 'csv', include_fixed: 1 })}`, filename: `${p.code}.csv` },
    { label: 'PDF – Tasks gesamt', path: `/exports/report${qs({ from: p.start_date, to: todayIso(), project_id: p.id, group: 'tasks', format: 'pdf', include_fixed: 1 })}`, filename: `${p.code}-tasks.pdf` },
  ];

  return (
    <div className="space-y-4">
      {!compact && (
        <div className="animate-rise">
          <button onClick={() => navigate(`reports/kunde/${p.customer_id}`)} className="text-sm font-bold text-ink-500 hover:text-brand-700">
            {p.customer.name}
          </button>
          <div className="flex flex-wrap items-start justify-between gap-3">
            <h2 className="text-2xl leading-tight text-ink-900 sm:text-3xl">
              <span className="tabular text-ink-400">[{p.code}]</span> {p.display_name}
            </h2>
            <div className="flex gap-2">
              <button onClick={() => navigate(`projekte/${p.id}`)} className="flex items-center gap-1.5 rounded-xl border border-ink-200 px-3 py-1.5 text-xs font-bold text-ink-600 hover:border-brand-300 hover:text-brand-700">
                <Icon name="edit" className="h-3.5 w-3.5" /> Projekt öffnen
              </button>
              <ExportMenu options={exportOptions} label="Aktionen" />
            </div>
          </div>
          <div className="mt-2 flex flex-wrap items-center gap-2 text-sm text-ink-500">
            <Badge tone={TYPE_TONE[p.type]}>{PROJECT_TYPE_LABELS[p.type]}</Badge>
            <span className="flex items-center gap-1">
              <Icon name="calendar" className="h-4 w-4" />
              Start: {formatDate(p.start_date)}
              {p.end_date && ` · Ende: ${formatDate(p.end_date)}`}
            </span>
          </div>
          {p.notes && (
            <div className="mt-2 max-w-3xl text-sm text-ink-500">
              <p className={showNotes ? 'whitespace-pre-line' : 'line-clamp-2'}>{p.notes}</p>
              <button onClick={() => setShowNotes(!showNotes)} className="text-xs font-bold text-sky-700 underline">
                {showNotes ? 'Weniger' : 'Mehr anzeigen'}
              </button>
            </div>
          )}
        </div>
      )}

      <Card className="animate-rise p-4 sm:p-5" style={{ '--i': 1 } as React.CSSProperties}>
        <div className="mb-3 flex flex-wrap items-center justify-between gap-2">
          <Segmented
            size="sm"
            value={chart}
            onChange={setChart}
            options={[
              { value: 'progress', label: 'Projektverlauf' },
              { value: 'weekly', label: 'Stunden pro Woche' },
            ]}
          />
          <span className="text-xs text-ink-400">Stunden · Start {formatDate(p.start_date)}</span>
        </div>
        <ProgressChart
          mode={chart}
          budget={budgetHours}
          format={(v) => `${formatNumber(v, 0)} h`}
          points={detail.weekly.map((w) => ({
            label: w.label,
            value: w.cumulative_minutes == null ? null : w.cumulative_minutes / 60,
            bar: w.billable_minutes / 60,
            barB: (w.minutes - w.billable_minutes) / 60,
            current: w.week_start === thisWeek,
          }))}
        />
      </Card>

      <div className="grid gap-3 sm:grid-cols-2 xl:grid-cols-5">
        <Kpi index={2} title="Gesamtstunden">
          <CountUp value={t.minutes / 60} format={(v) => formatNumber(v, 2)} className="text-3xl font-extrabold text-ink-900" />
          <Row label="Billable" value={formatHours(t.billable_minutes)} />
          <Row label="Non-billable" value={formatHours(t.non_billable_minutes)} />
        </Kpi>
        <Kpi index={3} title={`Budget verbleibend${remainingPct != null ? ` (${remainingPct} %)` : ''}`}>
          <p className="tabular text-3xl font-extrabold text-ink-900">{remaining == null ? '∞' : formatNumber(remaining, 2)}</p>
          <Row label="Gesamtbudget" value={budgetHours == null ? 'unbegrenzt' : `${formatNumber(budgetHours, 2)} h`} />
          <BudgetBar className="mt-2" percent={budgetHours ? (p.budget_used_minutes / 60 / budgetHours) * 100 : null} warnAt={settings.budget_warn_percent} />
        </Kpi>
        <Kpi
          index={4}
          title={p.type === 'fixed' ? 'Virtueller Stundensatz' : p.type === 'abruf' ? (p.billing_unit === 'day' ? 'Tagessatz' : 'Stundensatz') : 'Budget in Tagen'}
        >
          {p.type === 'fixed' ? (
            <>
              <p className="tabular text-3xl font-extrabold text-ink-900">{virtualRate ? formatEuro(virtualRate, 2) : 'n/a'}</p>
              <Row label="Festpreis ÷ Stunden" value="nur intern" />
            </>
          ) : p.type === 'abruf' ? (
            <>
              <p className="tabular text-3xl font-extrabold text-ink-900">{formatEuro(p.rate, 2)}</p>
              <Row label="Abrechnung" value="nach Aufwand, ohne Budget" />
            </>
          ) : (
            <>
              <p className="tabular text-3xl font-extrabold text-ink-900">{remaining == null ? '∞' : formatNumber(remaining / settings.hours_per_day, 1)}</p>
              <Row label="Tage frei von" value={budgetHours == null ? '–' : formatNumber(budgetHours / settings.hours_per_day, 1)} />
            </>
          )}
        </Kpi>
        <Kpi index={5} title="Umsatz erbracht">
          <CountUp value={p.earned ?? 0} format={(v) => formatEuro(v, 2)} className="text-3xl font-extrabold text-ink-900" />
          <Row label="Budget gesamt" value={formatEuro(p.budget_value, 2)} />
        </Kpi>
        <Kpi index={6} title="Umsatz offen">
          <CountUp value={p.open ?? 0} format={(v) => formatEuro(v, 2)} className="text-3xl font-extrabold text-ink-900" />
          <Row label="Töpfe aktiv" value={`${p.pots.filter((x) => x.status === 'active').length} von ${p.pots.length}`} />
        </Kpi>
      </div>

      <Card className="animate-rise overflow-hidden" style={{ '--i': 7 } as React.CSSProperties}>
        <div className="flex gap-1 border-b border-ink-100 px-4 pt-1">
          {(
            [
              ['tasks', 'Tasks'],
              ['team', 'Team'],
              ['pots', 'Budgettöpfe'],
            ] as const
          ).map(([key, label]) => (
            <button key={key} onClick={() => setTab(key)} className={`relative px-3 py-3 text-sm font-bold ${tab === key ? 'text-ink-900' : 'text-ink-400 hover:text-ink-700'}`}>
              {label}
              {tab === key && <span className="absolute inset-x-2 bottom-0 h-0.5 rounded-full bg-[var(--color-brand-accent)]" />}
            </button>
          ))}
        </div>
        {tab === 'tasks' && <ReportTable rows={detail.tasks} kind="tasks" label="Task" />}
        {tab === 'team' && <ReportTable rows={detail.team} kind="team" label="Name" />}
        {tab === 'pots' && <PotsBreakdown detail={detail} />}
      </Card>
    </div>
  );
};

/** Gesamtuebersicht aller Toepfe und darunter jeder Topf einzeln. */
const PotsBreakdown: React.FC<{ detail: ProjectDetail }> = ({ detail }) => {
  const { settings } = useAuth();
  const p = detail.project;
  const totalBudget = p.pots.reduce((s, x) => s + (x.budget_hours ?? 0), 0);
  return (
    <div className="space-y-4 p-4">
      <div className="rounded-2xl bg-ink-50 p-4">
        <p className="text-[11px] font-extrabold uppercase tracking-wider text-ink-400">Gesamt · {p.pots.length} Töpfe</p>
        <div className="tabular mt-1 grid grid-cols-2 gap-3 text-sm sm:grid-cols-4">
          <Row label="Gebucht" value={`${formatHours(p.used_minutes)} h`} />
          <Row label="Budget" value={totalBudget ? `${formatNumber(totalBudget, 2)} h` : 'unbegrenzt'} />
          <Row label="Erbracht" value={formatEuro(p.earned, 2)} />
          <Row label="Offen" value={formatEuro(p.open, 2)} />
        </div>
        <BudgetBar className="mt-3" percent={totalBudget ? (p.budget_used_minutes / 60 / totalBudget) * 100 : null} warnAt={settings.budget_warn_percent} />
      </div>
      {detail.pots.map((pot, i) => (
        <div key={pot.id} className="animate-rise rounded-2xl border border-ink-200" style={{ '--i': i } as React.CSSProperties}>
          <div className="flex flex-wrap items-center justify-between gap-2 p-4">
            <div>
              <p className="font-extrabold text-ink-900">{pot.label}</p>
              <p className="text-xs text-ink-400">
                {formatDate(pot.valid_from)} – {formatDate(pot.valid_to)} · {pot.status === 'active' ? 'aktiv' : pot.status === 'expired' ? 'abgelaufen' : pot.status === 'exhausted' ? 'aufgebraucht' : 'geplant'}
              </p>
            </div>
            <div className="tabular flex flex-wrap gap-4 text-xs">
              <Row label="Gebucht" value={`${formatHours(pot.used_minutes)} h`} />
              <Row label="Frei" value={pot.remaining_hours == null ? '∞' : `${formatNumber(pot.remaining_hours, 2)} h`} />
              <Row label="Erbracht" value={formatEuro(pot.earned, 2)} />
              <Row label="Offen" value={formatEuro(pot.open, 2)} />
            </div>
          </div>
          <BudgetBar className="mx-4 mb-3" percent={pot.percent_used} warnAt={settings.budget_warn_percent} muted={pot.status === 'expired'} />
          <div className="grid border-t border-ink-100 lg:grid-cols-2">
            <ReportTable rows={pot.tasks} kind="tasks" label="Task" totals={false} />
            <ReportTable rows={pot.team} kind="team" label="Team" totals={false} />
          </div>
        </div>
      ))}
    </div>
  );
};

const Kpi: React.FC<{ title: string; index: number; children: React.ReactNode }> = ({ title, index, children }) => (
  <Card className="animate-rise p-4" style={{ '--i': index } as React.CSSProperties}>
    <p className="mb-1 text-sm font-semibold text-ink-500">{title}</p>
    {children}
  </Card>
);

const Row: React.FC<{ label: string; value: string }> = ({ label, value }) => (
  <p className="tabular mt-1 flex items-center justify-between gap-3 text-sm">
    <span className="text-ink-500">{label}</span>
    <b className="text-ink-900">{value}</b>
  </p>
);

export { Row as ReportRow, Kpi as ReportKpi };