#!/usr/bin/env node
// AZ-485 / F4 — STC-ARCH-01: no cross-component deep imports.
//
// Every component under src/<component>/ exposes its Public API via a barrel
// (src/<component>/index.ts). Cross-component imports MUST go through the
// barrel; reaching into another component's internal files is a layering
// violation.
//
// Single source of truth — scripts/run-tests.sh delegates here, and the
// architecture unit test calls this script with a synthetic fixture to verify
// the check fails on a deep import (AC-4) and passes on the migrated codebase
// (AC-5). Mirrors the scripts/check-banned-deps.mjs pattern (AZ-482).
//
// Usage:
//   node scripts/check-arch-imports.mjs [--root=<repo-root>]
//
// Exit code 0 on PASS (no offending deep imports); non-zero on FAIL with the
// hit list on stderr.

import { readFileSync, statSync, readdirSync } from 'node:fs'
import { join, dirname, resolve, relative } from 'node:path'
import { fileURLToPath } from 'node:url'

const __filename = fileURLToPath(import.meta.url)
const __dirname = dirname(__filename)

function parseArgs(argv) {
  const out = { root: resolve(__dirname, '..') }
  for (const a of argv.slice(2)) {
    if (a.startsWith('--root=')) out.root = resolve(a.slice('--root='.length))
    else if (a === '-h' || a === '--help') {
      process.stderr.write('Usage: check-arch-imports.mjs [--root=<repo-root>]\n')
      process.exit(0)
    }
  }
  return out
}

const SCAN_ROOTS = ['src', 'tests', 'e2e']
const IGNORED_DIRS = new Set([
  'node_modules', 'dist', 'build', 'test-output', 'test-results',
  'coverage', '.git', '.cache', 'playwright-report', 'blob-report',
])
const SOURCE_EXT = new Set(['.ts', '.tsx'])

// Cross-component deep-import pattern: `from '<up>/<src>?/<component>/<File>'`
//   - one or more `..` segments
//   - optional `src/` prefix (used by tests/ and e2e/ imports)
//   - a known component directory
//   - a path segment starting with a letter (i.e. NOT the barrel `index`)
//
// Allowed by construction:
//   - barrel:           from '../api'          (no further /<File>)
//   - intra-component:  from './sse'           (starts with ./, not ../)
const COMPONENT_DIRS = 'api|auth|components|features/[a-z-]+|hooks|i18n'
const DEEP_IMPORT_RE = new RegExp(
  String.raw`from\s+['"](?:\.\./)+(?:src/)?(?:${COMPONENT_DIRS})/[A-Za-z]`,
)

// F3-pending exemptions:
//   - `features/annotations/classColors` — classColors is logically owned by
//     11_class-colors but physically lives under 06_annotations. Re-exporting
//     it through the 06_annotations barrel creates a circular import:
//        AnnotationsPage -> DetectionClasses -> 06_annotations barrel
//        -> AnnotationsPage
//     so consumers (DetectionClasses, tests/detection_classes.test.tsx)
//     import the file directly. F3 will move the file and remove this
//     exemption.
const EXEMPT_RE = /features\/annotations\/classColors/

function* walkSourceFiles(rootDir) {
  let entries
  try {
    entries = readdirSync(rootDir, { withFileTypes: true })
  } catch {
    return
  }
  for (const entry of entries) {
    const full = join(rootDir, entry.name)
    if (entry.isDirectory()) {
      if (IGNORED_DIRS.has(entry.name)) continue
      yield* walkSourceFiles(full)
    } else if (entry.isFile()) {
      const dot = entry.name.lastIndexOf('.')
      if (dot < 0) continue
      const ext = entry.name.slice(dot)
      if (!SOURCE_EXT.has(ext)) continue
      yield full
    }
  }
}

function scanFile(file, root) {
  const hits = []
  let text
  try {
    text = readFileSync(file, 'utf8')
  } catch {
    return hits
  }
  const rel = relative(root, file).replaceAll('\\', '/')
  const lines = text.split('\n')
  for (let i = 0; i < lines.length; i++) {
    const line = lines[i]
    if (/^\s*\/\//.test(line)) continue
    if (!DEEP_IMPORT_RE.test(line)) continue
    if (EXEMPT_RE.test(line)) continue
    hits.push(`${rel}:${i + 1}: ${line.trim().slice(0, 200)}`)
  }
  return hits
}

function main() {
  const { root } = parseArgs(process.argv)
  const hits = []
  for (const sub of SCAN_ROOTS) {
    const full = join(root, sub)
    try { statSync(full) } catch { continue }
    for (const file of walkSourceFiles(full)) {
      hits.push(...scanFile(file, root))
    }
  }
  if (hits.length) {
    process.stderr.write(
      'STC-ARCH-01 — cross-component deep imports detected ' +
      '(must go through component barrel, see module-layout.md):\n',
    )
    for (const h of hits) process.stderr.write(`  ${h}\n`)
    process.exit(1)
  }
  process.exit(0)
}

main()