import { createPortal } from 'react-dom';
import { Palette, Check } from 'lucide-react';
import * as Dropdown from '@/components/ui/dropdown-menu';
import type { Theme } from '@/components/ui/ThemeProvider';
import { useTheme, useThemeKeys } from '@/components/ui/ThemeProvider';

const {
  DropdownMenu,
  DropdownMenuContent,
  DropdownMenuItem,
  DropdownMenuLabel,
  DropdownMenuSeparator,
  DropdownMenuTrigger,
} = Dropdown;

/**
 * Themes, out of the avatar menu and into the header.
 *
 * They were buried under an avatar next to "Sign out", which is where a preference goes when nobody has
 * decided it matters. With fourteen of them it is a thing you use, so it gets its own control.
 *
 * ── The overlay ──
 *
 * `ctrl+alt+space` opens a list in the middle of the screen; `j`/`k` move through it and `l` applies the
 * focused theme to the app BEHIND it. That is the whole idea, and it is why this is a portal over a
 * translucent backdrop rather than a modal dialog: you are meant to watch the application change while
 * you browse, so as little of it as possible should be covered.
 *
 * Ported from the owner's `vimazing`, keys and all.
 */
export const ThemeSwitcher = () => {
  const { theme, themeId, setTheme, themes } = useTheme();
  const { open, setOpen, focused, setFocused } = useThemeKeys();

  // Grouped by family, so `Duck Light`/`Duck Dark` and the two Catppuccins sit together. The registry is
  // readonly, so this builds mutable arrays rather than pushing into its own type.
  const families = themes.reduce<Record<string, Theme[]>>((acc, t) => {
    (acc[t.family] ??= []).push(t);
    return acc;
  }, {});

  return (
    <>
      <DropdownMenu>
        <DropdownMenuTrigger asChild>
          <button
            title={`Theme: ${theme.name}  ·  ctrl+alt+space for the list, ctrl+shift+h/l to cycle`}
            aria-label="Theme"
            className="flex h-8 w-8 items-center justify-center rounded-full transition-transform hover:scale-110 cursor-pointer"
            style={{ color: 'var(--header-fg)' }}
          >
            <Palette className="h-4 w-4" />
          </button>
        </DropdownMenuTrigger>
        <DropdownMenuContent align="end" className="z-50 max-h-[70vh] w-56 overflow-y-auto">
          <DropdownMenuLabel className="text-xs font-normal text-muted-foreground">
            ctrl+alt+space · ctrl+shift+h/l
          </DropdownMenuLabel>
          <DropdownMenuSeparator />
          {Object.entries(families).map(([family, entries]) => (
            <div key={family}>
              {entries.map((t) => (
                <DropdownMenuItem key={t.id} onClick={() => setTheme(t.id)} className="cursor-pointer">
                  <Check className={`mr-2 h-4 w-4 ${t.id === themeId ? 'opacity-100' : 'opacity-0'}`} />
                  {t.name}
                </DropdownMenuItem>
              ))}
            </div>
          ))}
        </DropdownMenuContent>
      </DropdownMenu>

      {open &&
        createPortal(
          <div
            className="fixed inset-0 z-[900] flex items-center justify-center"
            // Deliberately light: the point is to see the app change behind it.
            style={{ backgroundColor: 'color-mix(in srgb, var(--background) 55%, transparent)' }}
            onClick={() => setOpen(false)}
          >
            <div
              className="rounded-2xl border px-10 py-8 shadow-2xl"
              style={{
                backgroundColor: 'var(--popover)',
                borderColor: 'var(--border)',
                color: 'var(--popover-foreground)',
              }}
              onClick={(ev) => ev.stopPropagation()}
            >
              <ul className="flex flex-col gap-1">
                {themes.map((t) => {
                  const isFocused = t.id === focused;
                  return (
                    <li key={t.id}>
                      <button
                        onMouseEnter={() => setFocused(t.id)}
                        onClick={() => {
                          setTheme(t.id);
                          setOpen(false);
                        }}
                        className={`w-full rounded-md px-4 py-1 text-left transition-all cursor-pointer ${
                          isFocused ? 'text-2xl font-extrabold' : 'text-lg opacity-60 hover:opacity-100'
                        }`}
                      >
                        {t.name}
                        {t.id === themeId && <span className="ml-2 align-middle text-xs opacity-70">active</span>}
                      </button>
                    </li>
                  );
                })}
              </ul>
              <p className="mt-6 text-center text-xs opacity-60">
                j/k move · l preview · h reset · enter keep · esc cancel
              </p>
            </div>
          </div>,
          document.body,
        )}
    </>
  );
};