import { defineConfig } from "vitest/config";
import { resolve } from "node:path";
import { cpus } from "node:os";

// Keep worker fan-out conservative by default. Over-subscribing threads can
// starve Vitest's worker RPC channel and trigger flaky "onTaskUpdate" timeouts
// under heavy SQLite test load.
const defaultMaxWorkers = Math.min(4, Math.max(1, cpus().length - 1));
const requestedMaxWorkers = Number.parseInt(process.env.VITEST_MAX_WORKERS ?? String(defaultMaxWorkers), 10);
const maxWorkers = Math.max(1, Number.isFinite(requestedMaxWorkers) ? requestedMaxWorkers : defaultMaxWorkers);
process.env.VITEST_MAX_WORKERS = String(maxWorkers);

export default defineConfig({
  resolve: {
    alias: {
      "@fusion/test-utils": resolve(__dirname, "./src/__test-utils__/workspace.ts"),
    },
  },
  test: {
    include: ["src/**/*.test.ts"],
    setupFiles: [
      "./src/__tests__/setup-test-isolation.ts",
      "./src/__test-utils__/vitest-setup.ts",
    ],
    globalSetup: ["./src/__test-utils__/vitest-teardown.ts"],
    maxWorkers,
    poolOptions: { threads: { minThreads: 1, maxThreads: maxWorkers }, forks: { minForks: 1, maxForks: maxWorkers } },
    fileParallelism: true,
    // Core runs a large SQLite-heavy suite while other workspace packages test concurrently.
    // Use a slightly higher timeout to reduce nondeterministic slow-machine flakes.
    testTimeout: 15_000,
    hookTimeout: 15_000,
    coverage: {
      enabled: false,
      reporter: ["text", "html", "json"],
      reportsDirectory: "./coverage",
      include: ["src/**/*.ts"],
      exclude: ["**/*.test.ts", "**/*.d.ts", "dist/**"],
    },
  },
});