import assert from "node:assert/strict";
import { test } from "node:test";
import { fetchStats, parseStats, type UsageStats } from "../src/lib/stats";

test("parseStats extracts totals and gen p95", () => {
  const stats = parseStats({
    total_requests: 1985,
    total_input_tokens: 312327705,
    total_output_tokens: 932710,
    total_cache_tokens: 308144640,
    gen_histogram: { p50: 341, p95: 378.86, p99: 392 },
  });
  assert.deepEqual(stats, { totalRequests: 1985, totalInputTokens: 312327705, totalOutputTokens: 932710, genP95: 378.86 });
});

test("parseStats defaults missing fields and rejects malformed input", () => {
  assert.deepEqual(parseStats({}), { totalRequests: 0, totalInputTokens: 0, totalOutputTokens: 0, genP95: 0 });
  assert.equal(parseStats({ total_requests: "nope" })!.totalRequests, 0);
  assert.equal(parseStats(null), null);
  assert.equal(parseStats("x"), null);
});

test("fetchStats calls /api/metrics/stats with a model query", async () => {
  const calls: string[] = [];
  const orig = globalThis.fetch;
  globalThis.fetch = (async (url: RequestInfo | URL) => {
    calls.push(String(url));
    return { ok: true, json: async () => ({ total_requests: 7 }) } as unknown as Response;
  }) as typeof fetch;
  try {
    await fetchStats({ baseUrl: "http://x" }, "DeepSeek-V4-Flash-0731");
    assert.equal(calls[0], "http://x/api/metrics/stats?model=DeepSeek-V4-Flash-0731");
  } finally {
    globalThis.fetch = orig;
  }
});

test("fetchStats omits the model query for 'all' and returns null on HTTP error", async () => {
  const calls: string[] = [];
  const orig = globalThis.fetch;
  globalThis.fetch = (async (url: RequestInfo | URL) => {
    calls.push(String(url));
    return { ok: false, status: 500 } as unknown as Response;
  }) as typeof fetch;
  try {
    const stats = await fetchStats({ baseUrl: "http://x" }, "all");
    assert.equal(stats, null);
    assert.equal(calls[0], "http://x/api/metrics/stats");
  } finally {
    globalThis.fetch = orig;
  }
});