OCR/frontend/src/hooks/useTaskValidation.ts

import { useEffect, useState } from 'react'
import { useQuery } from '@tanstack/react-query'
import { AxiosError } from 'axios'
import { useUploadStore } from '@/store/uploadStore'
import { useTaskStore } from '@/store/taskStore'
import { apiClientV2 } from '@/services/apiV2'
import type { TaskDetail } from '@/types/apiV2'

interface UseTaskValidationResult {
  taskId: string | null
  taskDetail: TaskDetail | undefined
  isLoading: boolean
  isNotFound: boolean
  clearAndReset: () => void
}

/**
 * Hook for validating task existence and handling deleted tasks gracefully.
 * Shows loading state first, then either returns task data or marks as not found.
 *
 * This hook integrates with both uploadStore (legacy) and taskStore (new).
 * The taskId is sourced from uploadStore.batchId for backward compatibility,
 * while task metadata is synced to taskStore for caching and state management.
 */
export function useTaskValidation(options?: {
  refetchInterval?: number | false | ((query: any) => number | false)
}): UseTaskValidationResult {
  // Legacy: Get taskId from uploadStore
  const { batchId, clearUpload } = useUploadStore()
  const taskId = batchId ? String(batchId) : null

  // New: Use taskStore for caching and state management
  const { updateTaskCache, removeFromCache, clearCurrentTask } = useTaskStore()

  const [isNotFound, setIsNotFound] = useState(false)

  // Reset isNotFound when taskId changes (new upload)
  useEffect(() => {
    setIsNotFound(false)
  }, [taskId])

  const { data: taskDetail, isLoading, error, isFetching } = useQuery({
    queryKey: ['taskDetail', taskId],
    queryFn: () => apiClientV2.getTask(taskId!),
    enabled: !!taskId && !isNotFound,
    retry: (failureCount, error: any) => {
      // Don't retry on 404
      if (error?.response?.status === 404) {
        return false
      }
      return failureCount < 2
    },
    refetchInterval: options?.refetchInterval ?? false,
    // Disable stale time to ensure we check fresh data
    staleTime: 0,
  })

  // Sync task details to taskStore cache when data changes
  useEffect(() => {
    if (taskDetail) {
      updateTaskCache(taskDetail)
    }
  }, [taskDetail, updateTaskCache])

  // Handle 404 error - mark as not found and clean up cache
  useEffect(() => {
    if (error && error instanceof AxiosError && error.response?.status === 404) {
      setIsNotFound(true)
      if (taskId) {
        removeFromCache(taskId)
      }
    }
  }, [error, taskId, removeFromCache])

  // Clear state and store
  const clearAndReset = () => {
    clearUpload()       // Legacy store
    clearCurrentTask()  // New store
    setIsNotFound(false)
  }

  return {
    taskId,
    taskDetail,
    // Show loading if we have a taskId and are still fetching (but not if already marked as not found)
    isLoading: !!taskId && !isNotFound && (isLoading || isFetching) && !taskDetail,
    isNotFound,
    clearAndReset,
  }
}