/**
 * AI 分鏡表 Composable
 * 統一處理錯誤，UI 只呼叫此 composable
 */

import { useAIProvider } from './useAIProvider'
import { buildStoryboardPrompt, type StoryboardInput } from '~/utils/ai/prompts'
import { getTextModel } from '~/utils/storage'
import { DEFAULT_TEXT_MODEL as DEFAULT_MODEL } from '~/utils/clients/gemini-models'

export function useAIStoryboard() {
  const isLoading = ref(false)
  const error = ref<string | null>(null)

  async function generate(input: StoryboardInput): Promise<string> {
    isLoading.value = true
    error.value = null

    try {
      // 根據選擇的模型自動選擇對應的 provider
      const modelName = getTextModel() || DEFAULT_MODEL
      const provider = useAIProvider(modelName)
      
      const prompt = buildStoryboardPrompt(input)
      const result = await provider.generateStoryboard(prompt)
      return result
    } catch (err) {
      const errorMessage = err instanceof Error ? err.message : '未知錯誤'
      error.value = errorMessage
      throw err
    } finally {
      isLoading.value = false
    }
  }

  return {
    generate,
    isLoading: readonly(isLoading),
    error: readonly(error)
  }
}