import { readdir, readFile, writeFile } from 'node:fs/promises'
import { join } from 'node:path'

const homeDirectory = process.env.HOME
if (!homeDirectory) throw new Error('HOME is required.')

const profileDirectory = process.env.DSH_PROFILE_DIRECTORY || join(homeDirectory, '.dsh', 'profiles', 'web')
const extensionsDirectory = process.env.DSH_EDITOR_EXTENSIONS_DIRECTORY || join(homeDirectory, '.dsh', 'touched-git', 'editor', 'extensions')

async function replaceKnownText(filePath, oldText, newText) {
  const content = await readFile(filePath, 'utf8')
  if (content.includes(newText)) return false
  if (!content.includes(oldText)) throw new Error(`Unsupported package contents: ${filePath}`)
  await writeFile(filePath, content.replace(oldText, newText))
  return true
}

async function exposeDiffViewer() {
  const packageDirectory = join(profileDirectory, 'node_modules', '@dsh-external', 'dsh-diff-viewer')
  await replaceKnownText(
    join(packageDirectory, 'src', 'client', 'index.tsx'),
    "import { MutationRow } from './mutation-row.tsx'",
    "import { MutationRow } from './mutation-row.tsx'\nexport { DiffViewer } from './DiffViewer.tsx'\nexport type { DiffHunk, DiffViewerLabels, DiffViewMode } from './DiffViewer.tsx'",
  )
  await replaceKnownText(
    join(packageDirectory, 'lib', 'client.js'),
    '\t\texports.apply = apply;\n\t\texports.inject = inject;',
    '\t\texports.DiffViewer = DiffViewer;\n\t\texports.apply = apply;\n\t\texports.inject = inject;',
  )
}

async function patchLegacyBranchCompare() {
  let entries
  try {
    entries = await readdir(extensionsDirectory, { withFileTypes: true })
  } catch (error) {
    if (error.code === 'ENOENT') return
    throw error
  }

  for (const entry of entries) {
    if (!entry.isDirectory() || !entry.name.startsWith('codexdebayan.branch-compare-')) continue
    await replaceKnownText(
      join(extensionsDirectory, entry.name, 'dist', 'git', 'GitService.js'),
      "this.execGit(['diff', '--name-status', baseBranch, targetBranch])",
      "this.execGit(['diff', '--name-status', baseBranch, targetBranch, '--'])",
    )
  }
}

await exposeDiffViewer()
await patchLegacyBranchCompare()