// Which loaded module an offset is into: the game's own executable (the
// usual case, and the default) or one of the libraries it loads. Shows
// nothing at all when the game has only the one, so most people never see it.

import { useEffect, useState } from 'react';
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
import { loadedModules } from '../lib/locations.ts';
import type { Location } from '../lib/locations.ts';
import { useWorkbench } from './workbench.tsx';

// Radix selects cannot hold an empty value, so the executable gets a stand-in.
const MAIN = ':main';

type InModule = Extract<Location, { kind: 'module' | 'pointer' }>;

/** For a location editor: the same location with the module set, or cleared for the executable. */
export function ModuleChoice(props: { loc: InModule; onChange: (loc: Location) => void }) {
  const { ctx } = useWorkbench();
  const value = props.loc.module;
  const pick = (module: string | undefined) => {
    const { module: _old, ...rest } = props.loc;
    props.onChange(module === undefined ? rest : { ...rest, module });
  };
  const [names, setNames] = useState<string[]>([]);

  useEffect(() => {
    let canceled = false;
    loadedModules(ctx)
      .then((list) => !canceled && setNames(list.map((m) => m.module).filter((n): n is string => n !== undefined)))
      .catch(() => {});
    return () => {
      canceled = true;
    };
  }, [ctx]);

  // A module the cheat names but the game has not loaded (yet) must stay selectable, or opening the editor would silently change it.
  const all = value !== undefined && !names.includes(value) ? [...names, value] : names;
  if (all.length === 0) return null;

  return (
    <div className="flex items-center gap-2 text-sm text-muted-foreground">
      <span className="shrink-0">Inside</span>
      <Select value={value ?? MAIN} onValueChange={(v) => pick(v === MAIN ? undefined : v)}>
        <SelectTrigger className="min-w-0 flex-1 text-foreground" aria-label="Which module the offset is into">
          <SelectValue />
        </SelectTrigger>
        <SelectContent>
          <SelectItem value={MAIN}>The game itself (main executable)</SelectItem>
          {all.map((name) => (
            <SelectItem key={name} value={name}>
              {name}
              {names.includes(name) ? '' : ' (not loaded right now)'}
            </SelectItem>
          ))}
        </SelectContent>
      </Select>
    </div>
  );
}