import { useRef, useState } from 'react';
import { useGameStore } from '@/store';
import { ConfirmModal } from '@/components/common/ConfirmModal';
import { getTokenPayload, isRegistered, isAdmin } from '@/lib/api';

export function SettingsPage() {
  const settings = useGameStore((s) => s.meta.settings);
  const companyName = useGameStore((s) => s.meta.companyName);
  const updateState = useGameStore((s) => s.updateState);
  const addNotification = useGameStore((s) => s.addNotification);
  const fileInputRef = useRef<HTMLInputElement>(null);
  const [showResetConfirm, setShowResetConfirm] = useState(false);
  const [importData, setImportData] = useState<{ data: unknown; name: string } | null>(null);

  const toggleSound = () => {
    updateState({ meta: { ...useGameStore.getState().meta, settings: { ...settings, soundEnabled: !settings.soundEnabled } } });
  };

  const setMusicVolume = (v: number) => {
    updateState({ meta: { ...useGameStore.getState().meta, settings: { ...settings, musicVolume: v } } });
  };

  const handleReset = () => {
    localStorage.removeItem('token-empire-save');
    window.location.reload();
  };

  const handleExport = () => {
    const state = useGameStore.getState();
    const { activePage, notifications, ...gameState } = state;
    const blob = new Blob([JSON.stringify(gameState)], { type: 'application/json' });
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = `token-empire-${companyName.replace(/\s+/g, '-').toLowerCase()}.json`;
    a.click();
    URL.revokeObjectURL(url);
  };

  const handleImport = (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0];
    if (!file) return;

    const reader = new FileReader();
    reader.onload = (event) => {
      try {
        const data = JSON.parse(event.target?.result as string);
        if (!data.meta?.companyName) {
          addNotification({ title: 'Import Failed', message: 'Invalid save file: missing company data.', type: 'danger', tick: useGameStore.getState().meta.tickCount });
          return;
        }
        setImportData({ data, name: data.meta.companyName });
      } catch {
        addNotification({ title: 'Import Failed', message: 'Could not read save file. Make sure it is a valid Token Empire export.', type: 'danger', tick: useGameStore.getState().meta.tickCount });
      }
    };
    reader.readAsText(file);
    if (fileInputRef.current) fileInputRef.current.value = '';
  };

  const confirmImport = () => {
    if (!importData) return;
    localStorage.setItem('token-empire-save', JSON.stringify({ state: importData.data }));
    window.location.reload();
  };

  const payload = getTokenPayload();
  const registered = isRegistered();
  const admin = isAdmin();

  return (
    <div className="space-y-6 max-w-2xl">
      <h2 className="text-2xl font-bold">Settings</h2>

      <div className="bg-surface-900 border border-surface-700 rounded-xl p-4 space-y-4">
        <h3 className="font-semibold">Account</h3>
        {registered ? (
          <div className="space-y-2">
            {payload?.email && (
              <div className="flex items-center justify-between">
                <div>
                  <div className="text-sm">Email</div>
                  <div className="text-xs text-surface-400">{payload.email}</div>
                </div>
              </div>
            )}
            {payload?.username && (
              <div className="flex items-center justify-between">
                <div>
                  <div className="text-sm">Username</div>
                  <div className="text-xs text-surface-400">{payload.username}</div>
                </div>
              </div>
            )}
            {admin && (
              <div className="flex items-center gap-2">
                <span className="text-xs px-2 py-0.5 rounded-full bg-accent/20 text-accent font-medium">Admin</span>
              </div>
            )}
          </div>
        ) : (
          <div className="text-sm text-surface-400">Playing as guest.</div>
        )}
      </div>

      <div className="bg-surface-900 border border-surface-700 rounded-xl p-4 space-y-4">
        <h3 className="font-semibold">Game</h3>

        <div className="flex items-center justify-between">
          <div>
            <div className="text-sm">Sound Effects</div>
            <div className="text-xs text-surface-400">Play UI sounds and notifications</div>
          </div>
          <ToggleSwitch checked={settings.soundEnabled} onChange={toggleSound} />
        </div>

        <div className="flex items-center justify-between">
          <div>
            <div className="text-sm">Music Volume</div>
            <div className="text-xs text-surface-400">Background music level</div>
          </div>
          <div className="flex items-center gap-2">
            <input
              type="range"
              min={0}
              max={100}
              value={settings.musicVolume * 100}
              onChange={(e) => setMusicVolume(Number(e.target.value) / 100)}
              className="w-32 accent-accent"
            />
            <span className="text-sm font-mono text-surface-400 w-8 text-right">{Math.round(settings.musicVolume * 100)}%</span>
          </div>
        </div>
      </div>

      <div className="bg-surface-900 border border-surface-700 rounded-xl p-4 space-y-4">
        <h3 className="font-semibold">Save Data</h3>
        <div className="flex gap-3">
          <button
            onClick={handleExport}
            className="px-4 py-2 rounded bg-surface-800 hover:bg-surface-700 border border-surface-600 text-sm"
          >
            Export Save
          </button>
          <button
            onClick={() => fileInputRef.current?.click()}
            className="px-4 py-2 rounded bg-surface-800 hover:bg-surface-700 border border-surface-600 text-sm"
          >
            Import Save
          </button>
          <input
            ref={fileInputRef}
            type="file"
            accept=".json"
            onChange={handleImport}
            className="hidden"
          />
          <button
            onClick={() => setShowResetConfirm(true)}
            className="px-4 py-2 rounded bg-danger/20 hover:bg-danger/30 border border-danger/50 text-danger text-sm"
          >
            Reset Progress
          </button>
        </div>
      </div>

      {showResetConfirm && (
        <ConfirmModal
          title="Reset All Progress"
          message="This will permanently delete your save data and start a new game. This cannot be undone."
          confirmLabel="Reset Everything"
          danger
          onConfirm={handleReset}
          onCancel={() => setShowResetConfirm(false)}
        />
      )}

      {importData && (
        <ConfirmModal
          title="Import Save"
          message={`Import save for "${importData.name}"? This will replace your current game.`}
          confirmLabel="Import"
          onConfirm={confirmImport}
          onCancel={() => setImportData(null)}
        />
      )}
    </div>
  );
}

function ToggleSwitch({ checked, onChange }: { checked: boolean; onChange: () => void }) {
  return (
    <button
      onClick={onChange}
      className={`w-10 h-6 rounded-full transition-colors ${checked ? 'bg-accent' : 'bg-surface-600'}`}
    >
      <div className={`w-4 h-4 bg-white rounded-full transition-transform mx-1 mt-1 ${checked ? 'translate-x-4' : ''}`} />
    </button>
  );
}