/**
 * @module tests/unit/test-suite-coverage-guard
 * @description Prevents a test file from silently falling outside EVERY vitest
 * config (so it never runs and gives false coverage confidence — the exact drift
 * that left ~27 test files un-run before 8.0). Every `*.test.ts` must either match
 * a gate config (`tests/unit/**`, `tests/integration/**`, `*.unit.test.ts`,
 * `*.integration.test.ts`) or be explicitly listed in MANUAL_ONLY below.
 */
import { describe, it, expect } from 'vitest'
import { readdirSync } from 'node:fs'
import { join, relative, dirname } from 'node:path'
import { fileURLToPath } from 'node:url'

const repoRoot = join(dirname(fileURLToPath(import.meta.url)), '../..')
const testsDir = join(repoRoot, 'tests')

function allTestFiles(dir: string, out: string[] = []): string[] {
  for (const e of readdirSync(dir, { withFileTypes: true })) {
    const p = join(dir, e.name)
    if (e.isDirectory()) allTestFiles(p, out)
    else if (e.isFile() && p.endsWith('.test.ts')) out.push(relative(repoRoot, p).split('\\').join('/'))
  }
  return out
}

/**
 * Test files INTENTIONALLY excluded from the unit/integration gate: benchmarks,
 * scale/perf measurements, package-size checks, and real-model-load checks. They
 * are run manually (slow / need real resources), not in CI. Every entry is a
 * conscious decision — a NEW orphan not listed here fails the guard below.
 */
const MANUAL_ONLY = new Set<string>([
  'tests/api/performance-benchmarks.test.ts',
  'tests/critical-neural-validation.test.ts',
  'tests/critical-performance-benchmark.test.ts',
  'tests/model-loading.test.ts',
  'tests/package-size-breakdown.test.ts',
  'tests/package-size-limit.test.ts',
  'tests/performance/graph-scale-performance.test.ts',
  'tests/performance/triple-intelligence-scale.test.ts',
  'tests/performance/typeAware.bench.test.ts'
])

function inGate(rel: string): boolean {
  return (
    rel.startsWith('tests/unit/') ||
    rel.startsWith('tests/integration/') ||
    rel.endsWith('.unit.test.ts') ||
    rel.endsWith('.integration.test.ts')
  )
}

describe('test-suite coverage guard', () => {
  it('every *.test.ts runs in a gate config or is explicitly allowlisted as manual', () => {
    const orphans = allTestFiles(testsDir).filter((f) => !inGate(f) && !MANUAL_ONLY.has(f))
    expect(
      orphans,
      'These test files match NO vitest config and are not in MANUAL_ONLY — rename to ' +
        '*.unit.test.ts / *.integration.test.ts (or move under tests/unit|integration), or add to ' +
        `MANUAL_ONLY if they are benchmarks:\n${orphans.join('\n')}`
    ).toEqual([])
  })

  it('the manual allowlist has no stale entries (every listed file still exists)', () => {
    const all = new Set(allTestFiles(testsDir))
    const stale = [...MANUAL_ONLY].filter((f) => !all.has(f))
    expect(stale, `MANUAL_ONLY lists files that no longer exist — remove them:\n${stale.join('\n')}`).toEqual([])
  })
})
