import type { SearchBackend } from "./backends";

import { classifySearchConfidence } from "./search";

type SearchRequestBody = {

embedding?: unknown;

topK?: unknown;

modelId?: unknown;

};

type SearchBackends = Record<string, SearchBackend>;

function json(data: unknown, init?: ResponseInit): Response {

return new Response(JSON.stringify(data, null, 2), {

...init,

headers: {

"content-type": "application/json; charset=utf-8",

...init?.headers,

},

});

}

function parseEmbedding(value: unknown): number[] | null {

if (!Array.isArray(value)) {

return null;

}

const embedding = value.map(Number);

if (embedding.some((item) => !Number.isFinite(item))) {

return null;

}

return embedding;

}

export async function handleSearchRequest(

request: Request,

backends: SearchBackends,

): Promise<Response> {

if (request.method !== "POST") {

return json({ error: "POST 요청만 지원합니다." }, { status: 405 });

}

let body: SearchRequestBody;

try {

body = (await request.json()) as SearchRequestBody;

} catch {

return json({ error: "JSON 본문을 읽을 수 없습니다." }, { status: 400 });

}

const embedding = parseEmbedding(body.embedding);

if (!embedding) {

return json({ error: "embedding 배열이 필요합니다." }, { status: 400 });

}

const requestedTopK = typeof body.topK === "number" ? body.topK : 5;

const topK = Math.min(Math.max(Math.trunc(requestedTopK), 1), 20);

const modelId = typeof body.modelId === "string" ? body.modelId : "tiny-sample-v1";

const backend = backends[modelId];

if (!backend) {

return json({ error: `지원하지 않는 modelId입니다: ${modelId}` }, { status: 400 });

}

try {

const results = await backend.search(embedding, topK);

return json({

topK,

modelId,

backend: backend.name,

confidence: classifySearchConfidence(results),

results,

});

} catch (error) {

return json(

{ error: error instanceof Error ? error.message : "검색 중 오류가 발생했습니다." },

{ status: 400 },

);

}

}