Show confirmation when submitting certain commands

https://3.basecamp.com/2914079/buckets/37331921/todos/8617430347

app/javascript/controllers/terminal_controller.js

@@ -1,8 +1,9 @@
 import { Controller } from "@hotwired/stimulus"
+import { HttpStatus } from "helpers/http_helpers"
 
 export default class extends Controller {
-  static targets = [ "input" ]
-  static classes = [ "error" ]
+  static targets = [ "input", "form", "confirmation" ]
+  static classes = [ "error", "confirmation" ]
 
   // Actions
 
@@ -10,17 +11,70 @@ export default class extends Controller {
     this.inputTarget.focus()
   }
 
-  handleSubmit(event) {
+  executeCommand(event) {
     if (event.detail.success) {
-      event.target.reset()
+      this.#reset()
     } else {
-      this.#handleErrorResponse(event.detail.fetchResponse.response.status)
+      const response = event.detail.fetchResponse.response
+      this.#handleErrorResponse(response)
     }
   }
 
-  #handleErrorResponse(code) {
-    if (code == 422) {
-      this.element.classList.add(this.errorClass)
+  async #handleErrorResponse(response) {
+    const status = response.status
+    const message = await response.text()
+
+    if (status === HttpStatus.UNPROCESSABLE) {
+      this.#showError()
+    } else if (status === HttpStatus.CONFLICT) {
+      this.#requestConfirmation(message)
     }
   }
+
+  #reset(inputValue = "") {
+    this.formTarget.reset()
+    this.inputTarget.value = inputValue
+    this.confirmationTarget.value = ""
+
+    this.element.classList.remove(this.errorClass)
+    this.element.classList.remove(this.confirmationClass)
+  }
+
+  #showError() {
+    this.element.classList.add(this.errorClass)
+  }
+
+  async #requestConfirmation(message) {
+    const originalInputValue = this.inputTarget.value
+    this.element.classList.add(this.confirmationClass)
+    this.inputTarget.value = `${message}? [Y/n] `
+
+    try {
+      await this.#waitForConfirmation()
+      this.#submitWithConfirmation(originalInputValue)
+    } catch {
+      this.#reset(originalInputValue)
+    }
+  }
+
+  #waitForConfirmation() {
+    return new Promise((resolve, reject) => {
+      this.inputTarget.addEventListener("keydown", (event) => {
+        event.preventDefault()
+        const key = event.key.toLowerCase()
+
+        if (key === "enter" || key === "y") {
+          resolve()
+        } else {
+          reject()
+        }
+      }, { once: true })
+    })
+  }
+
+  #submitWithConfirmation(inputValue) {
+    this.inputTarget.value = inputValue
+    this.confirmationTarget.value = "confirmed"
+    this.formTarget.requestSubmit()
+  }
 }