// Structural tests for the Insights MCP layer.
// We synthesise minimal Insights-style TSVs in a tmp dir, run the ingester
// + analytics handlers directly, and assert the shapes. The full e2e path
// (UnrealInsights.exe export) is not exercised here — that needs a real
// .utrace and an installed Insights binary.

import test from "node:test";
import assert from "node:assert/strict";
import fs from "node:fs";
import path from "node:path";
import os from "node:os";

import { dbAvailable, openDb, ingestRawDir, listTables, tableColumns, parseTabular } from "../src/insightsDb.js";

function mkTmp() {
  const dir = fs.mkdtempSync(path.join(os.tmpdir(), "insights-mcp-test-"));
  return dir;
}

function writeTsv(dir, name, header, rows) {
  const text = [header.join("\t"), ...rows.map((r) => r.join("\t"))].join("\n");
  fs.writeFileSync(path.join(dir, name), text);
}

test("parseTabular: TSV with mixed types", async () => {
  const dir = mkTmp();
  const raw = path.join(dir, "raw");
  fs.mkdirSync(raw);
  writeTsv(raw, "events.tsv",
    ["Name", "ThreadName", "StartTime", "Duration"],
    [
      ["UWorld::Tick", "GameThread", "0.0", "0.008"],
      ["BPP_Foo::Tick", "GameThread", "0.008", "0.003"],
      ["FrameTime", "GameThread", "0.0", "0.016"],
      ["FrameTime", "GameThread", "0.016", "0.052"], // a hitch
    ]
  );
  const parsed = await parseTabular(path.join(raw, "events.tsv"));
  assert.deepEqual(parsed.headers, ["Name", "ThreadName", "StartTime", "Duration"]);
  assert.equal(parsed.types[2], "REAL");
  assert.equal(parsed.rows.length, 4);
});

test("ingestRawDir: creates tables, picks indexes", async (t) => {
  if (!dbAvailable()) return t.skip("better-sqlite3 not installed yet (run npm install)");
  const dir = mkTmp();
  const raw = path.join(dir, "raw");
  fs.mkdirSync(raw);
  writeTsv(raw, "events.tsv",
    ["Name", "ThreadName", "StartTime", "Duration"],
    [
      ["UWorld::Tick", "GameThread", "0.0", "0.008"],
      ["FrameTime", "GameThread", "0.0", "0.016"],
      ["FrameTime", "GameThread", "0.016", "0.052"],
    ]
  );
  writeTsv(raw, "memtags.tsv",
    ["Name", "Peak", "Current"],
    [["Niagara", "180000000", "120000000"], ["Audio", "40000000", "30000000"]]
  );

  const db = openDb(dir);
  try {
    const summary = await ingestRawDir(db, raw);
    assert.ok(summary.find((s) => s.table === "events" && s.rows === 3));
    assert.ok(summary.find((s) => s.table === "memtags" && s.rows === 2));
    const tables = listTables(db);
    assert.ok(tables.includes("events"));
    assert.ok(tables.includes("memtags"));
    const cols = tableColumns(db, "events").map((c) => c.name);
    assert.deepEqual(cols, ["Name", "ThreadName", "StartTime", "Duration"]);
  } finally { db.close(); }
});

test("handleFrameStats: detects hitches over threshold", async (t) => {
  if (!dbAvailable()) return t.skip("better-sqlite3 not installed yet");
  const { handleOpenTrace, handleFrameStats } = await import("../src/insights.js");
  // We bypass open_trace's real-export by manually staging the cache
  // structure that open_trace would have produced.
  const projectDir = mkTmp();
  const traceId = "abcd1234deadbeef";
  const dir = path.join(projectDir, "Saved/InsightsMCP", traceId);
  fs.mkdirSync(path.join(dir, "raw"), { recursive: true });
  writeTsv(path.join(dir, "raw"), "events.tsv",
    ["Name", "ThreadName", "StartTime", "Duration"],
    [
      ["FrameTime", "GameThread", "0.000", "0.016"],
      ["FrameTime", "GameThread", "0.016", "0.017"],
      ["FrameTime", "GameThread", "0.033", "0.052"], // hitch
      ["FrameTime", "GameThread", "0.085", "0.018"],
      ["FrameTime", "GameThread", "0.103", "0.045"], // hitch
    ]
  );
  const db = openDb(dir);
  try { await ingestRawDir(db, path.join(dir, "raw")); } finally { db.close(); }
  // Write a minimal trace index entry.
  fs.writeFileSync(
    path.join(projectDir, "Saved/InsightsMCP/traces.json"),
    JSON.stringify({ [traceId]: { label: "synthetic", trace_path: "synthetic.utrace" } })
  );

  const res = await handleFrameStats({ trace_id: traceId, hitch_ms: 33, project_dir: projectDir });
  assert.equal(res.isError, undefined, res.content?.[0]?.text);
  const out = JSON.parse(res.content[0].text);
  assert.equal(out.frames, 5);
  assert.equal(out.hitch_count, 2);
  assert.ok(out.worst_hitches[0].ms >= 50);
});