/**
 * useConversations — Conversation CRUD and history list management
 *
 * Manages the full array of all conversations. Persisted to storage.
 * Provides create, delete, update, and query operations.
 */

import type { Conversation, WorkflowId } from '@/types/index'
import { STORAGE_KEYS, generateId } from '@/constants/index'
import { useStorage } from './useStorage'

export function useConversations() {
  const { loadValue, saveValue } = useStorage()

  // All conversations loaded from persistence
  const conversations = ref<Conversation[]>(
    loadValue<Conversation[]>(STORAGE_KEYS.CONVERSATIONS, [])
  )

  /**
   * Persist the current conversations array to storage.
   */
  function persist(): void {
    saveValue(STORAGE_KEYS.CONVERSATIONS, conversations.value)
  }

  /**
   * Create a new empty conversation with the given workflow.
   */
  function createConversation(workflowId: WorkflowId, title?: string): Conversation {
    const now = Date.now()
    const conversation: Conversation = {
      id: generateId(),
      title: title ?? '新对话',
      workflowId: workflowId,
      messages: [],
      createdAt: now,
      updatedAt: now,
    }
    conversations.value.unshift(conversation)
    persist()
    return conversation
  }

  /**
   * Delete a conversation by ID.
   */
  function deleteConversation(id: string): void {
    conversations.value = conversations.value.filter((c) => c.id !== id)
    persist()
  }

  /**
   * Update a conversation's title.
   */
  function updateConversationTitle(id: string, title: string): void {
    const conv = conversations.value.find((c) => c.id === id)
    if (conv) {
      conv.title = title
      conv.updatedAt = Date.now()
      persist()
    }
  }

  /**
   * Get a conversation by ID.
   */
  function getConversation(id: string): Conversation | undefined {
    return conversations.value.find((c) => c.id === id)
  }

  /**
   * Update a conversation's messages and timestamp.
   * Used after adding/removing messages.
   */
  function saveConversation(conversation: Conversation): void {
    const index = conversations.value.findIndex((c) => c.id === conversation.id)
    if (index !== -1) {
      conversations.value[index] = conversation
      persist()
    }
  }

  return {
    conversations,
    createConversation,
    deleteConversation,
    updateConversationTitle,
    getConversation,
    saveConversation,
    persist,
  }
}