frontend/src/lib/interactiveChatSession.ts

export type ChatMsg = { role: 'user' | 'agent'; text: string }

export type ChatSession = {
  messages: ChatMsg[]
  input: string
  progress: number
  /** True when no valid stored session existed (brand-new conversation). */
  isFresh: boolean
}

/** Bump when the opening question / flow changes so stale stored sessions are discarded. */
const SESSION_VERSION = 2

export const ADVISOR_CHAT_STORAGE_KEY = 'advisor_chat_v1'
export const PERSONA_CHAT_STORAGE_KEY = 'persona_chat_v1'

export const ADVISOR_CHAT_INITIAL_MESSAGE =
  "Let's design your advisor panel — we'll walk through the workshop form in order. First, what would you like to name this advisor panel?"

export const PERSONA_CHAT_INITIAL_MESSAGE =
  "Hi! I'm here to help you describe an AI advisor persona for your CCAI project. We'll go through the form in order. First, what would you like to name this persona (the label shown in the app)?"

/** Load synchronously on first render so a save effect cannot wipe stored session first. */
export function loadChatSession(storageKey: string, initialAgentMessage: string): ChatSession {
  try {
    const raw = localStorage.getItem(storageKey)
    if (raw) {
      const j = JSON.parse(raw) as Partial<ChatSession> & { version?: number }
      if (
        j.version === SESSION_VERSION &&
        Array.isArray(j.messages) &&
        j.messages.length > 0
      ) {
        return {
          messages: j.messages as ChatMsg[],
          input: typeof j.input === 'string' ? j.input : '',
          progress: typeof j.progress === 'number' ? j.progress : 0,
          isFresh: false,
        }
      }
    }
  } catch {
    /* ignore */
  }
  return {
    messages: [{ role: 'agent', text: initialAgentMessage }],
    input: '',
    progress: 0,
    isFresh: true,
  }
}

export function saveChatSession(
  storageKey: string,
  session: { messages: ChatMsg[]; input: string; progress: number },
) {
  localStorage.setItem(
    storageKey,
    JSON.stringify({ version: SESSION_VERSION, ...session }),
  )
}

export function clearChatSession(storageKey: string) {
  localStorage.removeItem(storageKey)
}