import { getNodeText, getChildByField } from '../tree-sitter-helpers';

import type { LanguageExtractor } from '../tree-sitter-types';

import { luaExtractor } from './lua';

// Luau (https://luau.org) is a gradually-typed superset of Lua. The

// tree-sitter-luau grammar reuses the same node names as the vendored Lua

// grammar (function_declaration, variable_declaration, function_call,

// dot/method_index_expression, …), so the Luau extractor extends the Lua one

// and adds the type-system pieces Luau introduces:

// - `type X = ...` / `export type X = ...` → type_definition (type_alias)

// - typed parameters and return types → richer signatures

//

// require detection, receiver-splitting (t.f / t:m → methods), and local

// variable extraction are inherited unchanged from luaExtractor. The shared

// `extractVariable` core branch is gated on `lua` || `luau`.

export const luauExtractor: LanguageExtractor = {

...luaExtractor,

// `type X = ...` and `export type X = ...`

typeAliasTypes: ['type_definition'],

// Only Luau `export type` is exported; the keyword leads the node.

isExported: (node, source) => source.slice(node.startIndex, node.startIndex + 7) === 'export ',

// Params + Luau return type (the named child after `parameters`, before the body).

getSignature: (node, source) => {

const params = getChildByField(node, 'parameters');

if (!params) return undefined;

let sig = getNodeText(params, source);

const kids = node.namedChildren;

const idx = kids.findIndex((c) => c.startIndex === params.startIndex);

const ret = idx >= 0 ? kids[idx + 1] : null;

if (ret && ret.type !== 'block') sig += `: ${getNodeText(ret, source)}`;

return sig;

},

};