import { createServer } from "node:http";

const port = Number(process.env.PORT ?? 18091);

const json = (response, status, body) => {
  response.writeHead(status, { "content-type": "application/json" });
  response.end(JSON.stringify(body));
};

const server = createServer(async (request, response) => {
  if (request.method === "GET" && request.url === "/health") {
    json(response, 200, { ok: true });
    return;
  }
  if (request.method !== "POST" || request.url !== "/api/v1/chat/completions") {
    json(response, 404, { error: { message: "Not found" } });
    return;
  }
  if (request.headers.authorization !== "Bearer workshop-test-openrouter-key") {
    json(response, 401, { error: { message: "Invalid upstream credentials" } });
    return;
  }

  const chunks = [];
  for await (const chunk of request) chunks.push(chunk);
  const body = JSON.parse(Buffer.concat(chunks).toString("utf8"));
  if (body.model !== "~deepseek/deepseek-v4-flash-latest") {
    json(response, 400, { error: { message: "Unexpected upstream model" } });
    return;
  }

  const completion = {
    id: "gen-workshop-test",
    object: "chat.completion",
    model: body.model,
    choices: [{ index: 0, message: { role: "assistant", content: "Hello from the Homarr provider" }, finish_reason: "stop" }],
    usage: { prompt_tokens: 12, completion_tokens: 7, total_tokens: 19, cost: 0.00041 },
  };
  if (!body.stream) {
    json(response, 200, completion);
    return;
  }

  response.writeHead(200, {
    "content-type": "text/event-stream",
    "cache-control": "no-cache",
    "x-request-id": "mock-openrouter-request",
  });
  response.write(
    `data: ${JSON.stringify({
      id: completion.id,
      object: "chat.completion.chunk",
      model: body.model,
      choices: [{ index: 0, delta: { role: "assistant", content: "Hello from " }, finish_reason: null }],
    })}\n\n`,
  );
  setTimeout(() => {
    response.write(
      `data: ${JSON.stringify({
        id: completion.id,
        object: "chat.completion.chunk",
        model: body.model,
        choices: [{ index: 0, delta: { content: "the Homarr provider" }, finish_reason: "stop" }],
        usage: completion.usage,
      })}\n\n`,
    );
    response.end("data: [DONE]\n\n");
  }, 150);
});

server.listen(port, "0.0.0.0");