Add the autofix engine

packages/steiger/src/cli.ts

@@ -11,6 +11,7 @@ import { cosmiconfig } from 'cosmiconfig'
 
 import { linter } from './app'
 import { setConfig, schema as configSchema } from './models/config'
+import { applyAutofixes } from './features/autofix'
 
 const yargsProgram = yargs(hideBin(process.argv))
   .scriptName('steiger')
@@ -21,6 +22,11 @@ const yargsProgram = yargs(hideBin(process.argv))
     describe: 'watch filesystem changes',
     type: 'boolean',
   })
+  .option('fix', {
+    demandOption: false,
+    describe: 'apply auto-fixes',
+    type: 'boolean',
+  })
   .string('_')
   .check((argv) => {
     const filePaths = argv._
@@ -58,11 +64,19 @@ if (consoleArgs.watch) {
   const unsubscribe = diagnosticsChanged.watch((state) => {
     console.clear()
     reportPretty(state)
+    if (consoleArgs.fix) {
+      applyAutofixes(state)
+    }
   })
   prexit(() => {
     stopWatching()
     unsubscribe()
   })
 } else {
-  await linter.run(resolve(consoleArgs._[0])).then(reportPretty)
+  const diagnostics = await linter.run(resolve(consoleArgs._[0]))
+
+  reportPretty(diagnostics)
+  if (consoleArgs.fix) {
+    applyAutofixes(diagnostics)
+  }
 }

packages/steiger/src/features/autofix.ts

@@ -0,0 +1,27 @@
+import { dirname, join } from 'node:path'
+import { rename, open, mkdir, rm } from 'node:fs/promises'
+import type { Diagnostic } from '@feature-sliced/steiger-plugin'
+
+export async function applyAutofixes(diagnostics: Array<Diagnostic>) {
+  return Promise.all(
+    diagnostics
+      .flatMap((diagnostic) => diagnostic.fixes ?? [])
+      .map((fix) => {
+        switch (fix.type) {
+          case 'rename':
+            return rename(fix.path, join(dirname(fix.path), fix.newName))
+          case 'create-file':
+            return open(fix.path, 'w').then((file) => file.close())
+          case 'create-folder':
+            return mkdir(fix.path, { recursive: true })
+          case 'delete':
+            return rm(fix.path, { recursive: true })
+          case 'modify-file':
+            return open(fix.path, 'w').then(async (file) => {
+              await file.write(fix.content)
+              return file.close()
+            })
+        }
+      }),
+  )
+}