import { existsSync, mkdirSync, readFileSync, writeFileSync } from 'node:fs'
import { dirname, resolve } from 'node:path'
import { spawnSync } from 'node:child_process'

const mode = process.argv[2] ?? 'check'
const rootDir = process.cwd()
const baselinePath = resolve(rootDir, 'client/typecheck-baseline.txt')

function runClientTypecheck() {
  const result = spawnSync('pnpm', ['--filter', 'client', 'exec', 'vue-tsc', '--build', '--pretty', 'false'], {
    cwd: rootDir,
    encoding: 'utf8',
  })

  if (result.error) {
    throw result.error
  }

  const combinedOutput = `${result.stdout ?? ''}\n${result.stderr ?? ''}`
  const diagnostics = parseDiagnostics(combinedOutput)
  return { result, combinedOutput, diagnostics }
}

function parseDiagnostics(output) {
  const regex = /^(.*\.(?:ts|tsx|vue)\(\d+,\d+\): error TS\d+: .*)$/gm
  const rows = []

  for (const match of output.matchAll(regex)) {
    const raw = String(match[1] ?? '').trim()
    rows.push(normalizeDiagnostic(raw))
  }

  return [...new Set(rows)].sort((a, b) => a.localeCompare(b))
}

function normalizeDiagnostic(row) {
  const rootPrefix = `${rootDir.replaceAll('\\', '/')}/`
  let normalized = row.replaceAll('\\', '/')
  normalized = normalized.split(`${rootPrefix}client/`).join('')
  normalized = normalized.split(rootPrefix).join('')
  if (normalized.startsWith('client/')) normalized = normalized.slice('client/'.length)
  return normalized
}

function readBaseline() {
  if (!existsSync(baselinePath)) return []
  return readFileSync(baselinePath, 'utf8')
    .split('\n')
    .map((line) => line.trim())
    .filter((line) => line.length > 0 && !line.startsWith('#'))
}

function writeBaseline(diagnostics) {
  mkdirSync(dirname(baselinePath), { recursive: true })
  const header = [
    '# Client typecheck baseline',
    '# Auto-generated by: pnpm run typecheck:client:baseline:update',
    '# One diagnostic per line. Do not edit manually unless necessary.',
    '',
  ]
  writeFileSync(baselinePath, `${header.join('\n')}${diagnostics.join('\n')}\n`, 'utf8')
}

if (mode === 'update') {
  const { result, combinedOutput, diagnostics } = runClientTypecheck()
  if (result.status !== 0 && diagnostics.length === 0) {
    console.error('Client typecheck failed without parsable diagnostics output.')
    console.error(combinedOutput)
    process.exit(1)
  }
  writeBaseline(diagnostics)
  console.log(`Updated ${baselinePath} with ${diagnostics.length} diagnostics.`)
  process.exit(0)
}

if (mode !== 'check') {
  console.error(`Unknown mode "${mode}". Use "check" or "update".`)
  process.exit(2)
}

const { result, combinedOutput, diagnostics } = runClientTypecheck()

if (result.status === 0) {
  console.log('Client typecheck is clean.')
  process.exit(0)
}

if (diagnostics.length === 0) {
  console.error('Client typecheck failed without parsable diagnostics output.')
  console.error(combinedOutput)
  process.exit(1)
}

const baseline = readBaseline()
if (baseline.length === 0) {
  console.error(`No baseline found at ${baselinePath}.`)
  console.error('Run: pnpm run typecheck:client:baseline:update')
  process.exit(1)
}

const baselineSet = new Set(baseline)
const newDiagnostics = diagnostics.filter((line) => !baselineSet.has(line))

if (newDiagnostics.length > 0) {
  console.error(`Found ${newDiagnostics.length} new client type errors not present in baseline:`)
  for (const line of newDiagnostics) {
    console.error(`- ${line}`)
  }
  console.error('If these are intentional and accepted, refresh baseline:')
  console.error('pnpm run typecheck:client:baseline:update')
  process.exit(1)
}

const resolvedCount = baseline.filter((line) => !diagnostics.includes(line)).length
console.log(`No new client type errors. Baseline size: ${baseline.length}. Current: ${diagnostics.length}. Resolved: ${resolvedCount}.`)
if (resolvedCount > 0) {
  console.log('You can refresh baseline to capture improvements:')
  console.log('pnpm run typecheck:client:baseline:update')
}
process.exit(0)