import { ExpandedQuery } from './types.js';
const STOPWORDS = new Set([
'a',
'an',
'the',
'and',
'or',
'to',
'for',
'of',
'in',
'on',
'with',
'by',
'is',
'are',
'be',
'from',
'at',
'as',
'it',
'this',
'that',
'these',
'those',
'how',
'what',
'where',
'when',
'why',
]);
const SYNONYMS: Record<string, string[]> = {
auth: ['authentication', 'authorization'],
login: ['sign-in', 'signin'],
log: ['logging'],
config: ['configuration'],
cfg: ['configuration'],
db: ['database'],
repo: ['repository'],
svc: ['service'],
util: ['utility'],
api: ['endpoint'],
err: ['error'],
msg: ['message'],
};
function tokenize(input: string): string[] {
return input
.toLowerCase()
.split(/[^a-z0-9_]+/g)
.map(token => token.trim())
.filter(Boolean);
}
export function expandQuery(query: string, maxVariants: number = 4): ExpandedQuery[] {
const trimmed = query.trim();
if (!trimmed) {
return [];
}
const variants = new Map<string, ExpandedQuery>();
const addVariant = (value: string, source: ExpandedQuery['source'], weight: number) => {
const normalized = value.trim();
if (!normalized) {
return;
}
const key = normalized.toLowerCase();
if (variants.has(key)) {
return;
}
variants.set(key, {
query: normalized,
source,
weight,
index: variants.size,
});
};
addVariant(trimmed, 'original', 1);
if (maxVariants <= 1) {
return Array.from(variants.values());
}
if (/[`]/.test(trimmed) || trimmed.length > 200) {
return Array.from(variants.values());
}
const tokens = tokenize(trimmed);
if (tokens.length < 2) {
return Array.from(variants.values());
}
const coreTokens = tokens.filter(token => !STOPWORDS.has(token));
if (coreTokens.length < 2) {
return Array.from(variants.values());
}
addVariant(`where ${coreTokens.join(' ')} is handled`, 'expanded', 0.7);
addVariant(`implementation of ${coreTokens.join(' ')}`, 'expanded', 0.7);
for (let i = 0; i < coreTokens.length; i += 1) {
const token = coreTokens[i];
const replacements = SYNONYMS[token];
if (!replacements) {
continue;
}
for (const replacement of replacements) {
const clone = [...coreTokens];
clone[i] = replacement;
addVariant(clone.join(' '), 'expanded', 0.6);
if (variants.size >= maxVariants) {
return Array.from(variants.values()).slice(0, maxVariants);
}
}
}
return Array.from(variants.values()).slice(0, maxVariants);
}
