/**
 * Structural conformance gate.
 *
 * Counts production-source code-smells and compares against committed baselines.
 * Nonzero exit code = a baseline was violated.  The script does NOT alter
 * files; it only audits and reports.
 *
 * Usage: node scripts/check-structural.js [--fix-baseline]
 */

import { readFileSync, writeFileSync } from 'fs'
import { fileURLToPath } from 'url'
import glob from 'glob'
import path from 'path'

const __dirname = path.dirname(fileURLToPath(import.meta.url))
const ROOT = path.resolve(__dirname, '..')
const BASELINE_PATH = path.join(ROOT, 'scripts', '.structural-baseline.json')

const PACKAGE_DIRS = glob.sync('packages/*', { cwd: ROOT, absolute: true })
  .filter(d => !d.match(/(imhotep-fixtures|imhotep-bench|imhotep-cli)$/))

function srcFiles(pkgDir) {
  return glob.sync('src/**/*.ts', { cwd: pkgDir, absolute: true })
    .filter(f => !f.endsWith('.test.ts') && !f.endsWith('.d.ts'))
}

function countPattern(files, pattern, excludeComment = false) {
  let count = 0
  const locations = []
  for (const f of files) {
    const lines = readFileSync(f, 'utf8').split('\n')
    for (let i = 0; i < lines.length; i++) {
      const line = lines[i]
      if (excludeComment && line.trim().startsWith('//')) continue
      const matches = line.match(pattern)
      if (matches) {
        count += matches.length
        locations.push(`${path.relative(ROOT, f)}:${i + 1}`)
      }
    }
  }
  return { count, locations }
}

const allFiles = PACKAGE_DIRS.flatMap(d => srcFiles(d))
const pkgNames = PACKAGE_DIRS.map(d => path.basename(d))

const violations = {
  asAny: countPattern(allFiles, /\bas any\b/g, true),
  emptyCatch: countPattern(allFiles, /\bcatch\s*\{/),
  nullishZero: countPattern(allFiles, /\?\?\s*0(?![.\d])/, true),
}

const baseline = (() => {
  try { return JSON.parse(readFileSync(BASELINE_PATH, 'utf8')) }
  catch { return {} }
})()

const results = {
  timestamp: new Date().toISOString(),
  packages: pkgNames,
  violations,
  baseline,
}

const errors = []

for (const [key, current] of Object.entries(violations)) {
  const allowed = baseline[key] ?? 0
  const delta = current.count - allowed
  const status = delta <= 0 ? 'PASS' : 'FAIL'
  const msg = `  ${key.padEnd(18)} current=${String(current.count).padStart(3)}  baseline=${String(allowed).padStart(3)}  delta=${String(delta).padStart(4)}  ${status}`
  console.log(msg)
  if (status === 'FAIL') {
    errors.push(`${key} (${current.count} > baseline ${allowed})`)
    console.log(`    New locations:`)
    for (const loc of current.locations.slice(0, 10)) {
      console.log(`      ${loc}`)
    }
    if (current.locations.length > 10) {
      console.log(`      ... and ${current.locations.length - 10} more`)
    }
  }
}

const fixBaseline = process.argv.includes('--fix-baseline')
if (fixBaseline) {
  const newBaseline = {}
  for (const [key, v] of Object.entries(violations)) {
    newBaseline[key] = v.count
  }
  writeFileSync(BASELINE_PATH, JSON.stringify(newBaseline, null, 2) + '\n')
  console.log(`\n  Baseline written to ${path.relative(ROOT, BASELINE_PATH)}`)
  console.log('Structural gate PASSED (baseline updated)')
  process.exit(0)
}

writeFileSync(BASELINE_PATH, JSON.stringify(baseline, null, 2) + '\n')

if (errors.length > 0) {
  console.error(`\nStructural gate FAILED (${errors.length} violation(s)):`)
  for (const e of errors) console.error(`  - ${e}`)
  console.error(`\nIf these are legitimate, update the baseline with:`)
  console.error(`  node scripts/check-structural.js --fix-baseline`)
  process.exit(1)
} else {
  console.log('\nStructural gate PASSED')
}