feat(core): add session form service (#34855)

packages/tui/src/util/question-form.ts

@@ -0,0 +1,30 @@
+import type { FormAnswer, FormFormInfo } from "@opencode-ai/sdk/v2"
+
+export type QuestionField = Extract<FormFormInfo["fields"][number], { type: "string" | "multiselect" }>
+export type QuestionForm = Omit<FormFormInfo, "fields"> & { fields: QuestionField[] }
+export type QuestionAnswer = string[]
+
+export function isQuestionForm(value: unknown): value is QuestionForm {
+  if (typeof value !== "object" || value === null) return false
+  const form = value as { mode?: unknown; metadata?: unknown; fields?: unknown }
+  if (form.mode !== "form") return false
+  if (typeof form.metadata !== "object" || form.metadata === null) return false
+  if ((form.metadata as { kind?: unknown }).kind !== "question") return false
+  return Array.isArray(form.fields) && form.fields.every(isQuestionField)
+}
+
+export function questionAnswer(fields: QuestionField[], answers: QuestionAnswer[]): FormAnswer {
+  const entries = fields.flatMap((field, index): Array<[string, string | string[]]> => {
+    const answer = answers[index] ?? []
+    if (answer.length === 0) return []
+    if (field.type === "multiselect") return [[field.key, answer]]
+    return [[field.key, answer[0] ?? ""]]
+  })
+  return Object.fromEntries(entries)
+}
+
+function isQuestionField(value: unknown): value is QuestionField {
+  if (typeof value !== "object" || value === null) return false
+  const field = value as { type?: unknown }
+  return field.type === "string" || field.type === "multiselect"
+}