import { useEffect, useState } from 'react';
import { GetRowColors, SaveRowColors } from '../../wailsjs/go/main/App';
import { Checkbox } from '@/components/ui/checkbox';
import { useI18n } from '@/lib/i18n';
import { cn } from '@/lib/utils';
import type { RowColorSettings } from '@/lib/rowColors';

// A fixed palette plus a free picker. Muted values on purpose: they are
// composited at low opacity over a dark grid, where a saturated colour reads as
// an error state rather than a status.
const PALETTE = [
  '#16a34a', '#0ea5e9', '#f59e0b', '#a855f7',
  '#dc2626', '#14b8a6', '#eab308', '#ec4899',
  '#64748b', '#84cc16', '#6366f1', '#f97316',
];

// The rule ids the backend orders; the labels live here so a translation never
// travels through the settings row.
const LABELS: Record<string, string> = {
  confirmed_lotw: 'appr.confirmedLotw',
  confirmed_paper: 'appr.confirmedPaper',
  sent_waiting: 'appr.sentWaiting',
  to_send: 'appr.toSend',
};

export function AppearancePanel() {
  const { t } = useI18n();
  const [cfg, setCfg] = useState<RowColorSettings | null>(null);

  useEffect(() => {
    (async () => {
      try { setCfg((await GetRowColors()) as any); } catch { /* defaults on the backend */ }
    })();
  }, []);

  const save = (next: RowColorSettings) => {
    setCfg(next);
    SaveRowColors(next as any).catch(() => {});
  };
  const patchRule = (id: string, patch: Partial<{ color: string; enabled: boolean }>) => {
    if (!cfg) return;
    save({ ...cfg, rules: cfg.rules.map((r) => (r.id === id ? { ...r, ...patch } : r)) });
  };

  // The rule card shows the row exactly as the grid will draw it, so the choice
  // is made by looking rather than by imagining.
  const preview = (color: string): Record<string, string> => {
    const st = cfg?.style ?? 'bar';
    const pct = cfg?.intensity ?? 12;
    const out: Record<string, string> = {};
    if (st === 'tint' || st === 'both') out.backgroundColor = `color-mix(in srgb, ${color} ${pct}%, transparent)`;
    if (st === 'bar' || st === 'both') out.boxShadow = `inset 3px 0 0 ${color}`;
    return out;
  };

  if (!cfg) return <div className="p-1 text-sm text-muted-foreground">…</div>;

  return (
    <div className="space-y-4">
      <label className="flex items-start gap-2 text-sm cursor-pointer">
        <Checkbox checked={cfg.enabled} className="mt-0.5"
          onCheckedChange={(c) => save({ ...cfg, enabled: !!c })} />
        <span>{t('appr.enable')} <span className="text-xs text-muted-foreground">{t('appr.enableHint')}</span></span>
      </label>

      {cfg.enabled && (
        <div className="space-y-3">
          {/* Style first: it decides whether the colours below are a signal or a
              wallpaper, which matters more than which hue they are. */}
          <div className="flex items-center gap-3 flex-wrap">
            <span className="text-sm">{t('appr.style')}</span>
            <div className="inline-flex rounded-md border border-border overflow-hidden text-xs">
              {(['bar', 'tint', 'both'] as const).map((v) => (
                <button key={v} type="button" onClick={() => save({ ...cfg, style: v })}
                  className={cn('px-3 py-1.5 font-medium', (cfg.style ?? 'bar') === v ? 'bg-primary text-primary-foreground' : 'text-muted-foreground hover:bg-muted')}>
                  {t('appr.style' + v[0].toUpperCase() + v.slice(1))}
                </button>
              ))}
            </div>
            {(cfg.style ?? 'bar') !== 'bar' && (
              <label className="flex items-center gap-2 text-sm">
                {t('appr.intensity')}
                <input type="range" min={5} max={45} step={1} value={cfg.intensity ?? 12}
                  onChange={(e) => save({ ...cfg, intensity: parseInt(e.target.value, 10) })}
                  className="w-32 accent-[var(--primary)]" />
                <span className="font-mono text-xs text-muted-foreground w-8">{cfg.intensity ?? 12}%</span>
              </label>
            )}
          </div>
          {/* Order matters and is shown: a contact is usually several of these at
              once, and the first match wins. */}
          <p className="text-xs text-muted-foreground">{t('appr.orderHint')}</p>
          {cfg.rules.map((r, i) => (
            <div key={r.id} className="rounded-lg border border-border/60 p-2.5 space-y-2"
              style={r.enabled ? preview(r.color) : undefined}>
              <label className="flex items-center gap-2 text-sm cursor-pointer">
                <Checkbox checked={r.enabled} onCheckedChange={(c) => patchRule(r.id, { enabled: !!c })} />
                <span className="font-mono text-xs text-muted-foreground">{i + 1}.</span>
                <span className="font-medium">{t(LABELS[r.id] ?? r.id)}</span>
              </label>
              {r.enabled && (
                <div className="flex items-center gap-1.5 flex-wrap pl-6">
                  {PALETTE.map((c) => (
                    <button key={c} type="button" title={c}
                      onClick={() => patchRule(r.id, { color: c })}
                      className={cn('size-6 rounded-md border-2 transition-transform hover:scale-110',
                        r.color.toLowerCase() === c ? 'border-foreground' : 'border-transparent')}
                      style={{ backgroundColor: c }} />
                  ))}
                  <input type="color" value={r.color} title={t('appr.custom')}
                    onChange={(e) => patchRule(r.id, { color: e.target.value })}
                    className="size-6 rounded-md border border-border bg-transparent p-0 cursor-pointer" />
                </div>
              )}
            </div>
          ))}
        </div>
      )}
    </div>
  );
}