import type { Db } from "../db";
import { DEFAULTS, getSetting } from "../routes/settings";

export type LlmDeps = { db: Db; key: Buffer; fetchImpl?: typeof fetch };

export async function chatJSON(deps: LlmDeps, opts: { system: string; user: string }): Promise<unknown> {
  const f = deps.fetchImpl ?? fetch;
  const base = (await getSetting(deps.db, "llm_base_url", deps.key)) ?? DEFAULTS.llm_base_url;
  const model = (await getSetting(deps.db, "llm_model", deps.key)) ?? DEFAULTS.llm_model;
  const apiKey = await getSetting(deps.db, "llm_key", deps.key);

  const headers: Record<string, string> = { "content-type": "application/json" };
  if (apiKey) headers.authorization = `Bearer ${apiKey}`;

  const res = await f(`${base.replace(/\/$/, "")}/chat/completions`, {
    method: "POST",
    headers,
    body: JSON.stringify({
      model,
      response_format: { type: "json_object" },
      messages: [
        { role: "system", content: opts.system },
        { role: "user", content: opts.user },
      ],
    }),
  });
  if (!res.ok) throw new Error(`llm_error: provider returned ${res.status}`);

  const data = (await res.json()) as { choices?: { message?: { content?: string } }[] };
  const content = data.choices?.[0]?.message?.content;
  if (!content) throw new Error("llm_error: empty completion");
  const stripped = content.replace(/^\s*```(?:json)?\s*/i, "").replace(/\s*```\s*$/, "");
  try {
    return JSON.parse(stripped);
  } catch {
    throw new Error("llm_error: completion was not valid JSON");
  }
}