Frontend API structure.

frontend/app/hooks/useApi.test.ts

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+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
+import { renderHook, act, waitFor } from '@testing-library/react'
+import { useApi, useApiForm, useApiCache } from './useApi'
+
+// Mock API function for testing
+const mockApiFunction = vi.fn()
+const mockFormSubmitFunction = vi.fn()
+const mockCacheFunction = vi.fn()
+
+describe('useApi', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  afterEach(() => {
+    vi.restoreAllMocks()
+  })
+
+  it('should initialize with default state', () => {
+    const { result } = renderHook(() => useApi(mockApiFunction))
+
+    expect(result.current.data).toBeNull()
+    expect(result.current.loading).toBe(false)
+    expect(result.current.error).toBeNull()
+  })
+
+  it('should execute API function successfully', async () => {
+    const mockData = { id: 1, name: 'Test' }
+    mockApiFunction.mockResolvedValueOnce(mockData)
+
+    const { result } = renderHook(() => useApi(mockApiFunction))
+
+    let executeResult: unknown
+
+    await act(async () => {
+      executeResult = await result.current.execute('test-arg')
+    })
+
+    expect(result.current.data).toEqual(mockData)
+    expect(result.current.loading).toBe(false)
+    expect(result.current.error).toBeNull()
+    expect(executeResult).toEqual(mockData)
+    expect(mockApiFunction).toHaveBeenCalledWith('test-arg')
+  })
+
+  it('should handle API function errors', async () => {
+    const errorMessage = 'API Error'
+    mockApiFunction.mockRejectedValueOnce({ message: errorMessage })
+
+    const { result } = renderHook(() => useApi(mockApiFunction))
+
+    let executeResult: unknown
+
+    await act(async () => {
+      executeResult = await result.current.execute()
+    })
+
+    expect(result.current.data).toBeNull()
+    expect(result.current.loading).toBe(false)
+    expect(result.current.error).toBe(errorMessage)
+    expect(executeResult).toBeNull()
+  })
+
+  it('should call onSuccess callback', async () => {
+    const mockData = { id: 1 }
+    const onSuccess = vi.fn()
+    mockApiFunction.mockResolvedValueOnce(mockData)
+
+    const { result } = renderHook(() => useApi(mockApiFunction, { onSuccess }))
+
+    await act(async () => {
+      await result.current.execute()
+    })
+
+    expect(onSuccess).toHaveBeenCalledWith(mockData)
+  })
+
+  it('should call onError callback', async () => {
+    const errorMessage = 'Test Error'
+    const onError = vi.fn()
+    mockApiFunction.mockRejectedValueOnce({ message: errorMessage })
+
+    const { result } = renderHook(() => useApi(mockApiFunction, { onError }))
+
+    await act(async () => {
+      await result.current.execute()
+    })
+
+    expect(onError).toHaveBeenCalledWith(errorMessage)
+  })
+
+  it('should execute immediately when immediate option is true', async () => {
+    const mockData = { id: 1 }
+    mockApiFunction.mockResolvedValueOnce(mockData)
+
+    renderHook(() => useApi(mockApiFunction, { immediate: true }))
+
+    await waitFor(() => {
+      expect(mockApiFunction).toHaveBeenCalled()
+    })
+  })
+
+  it('should reset state', async () => {
+    const mockData = { id: 1 }
+    mockApiFunction.mockResolvedValueOnce(mockData)
+
+    const { result } = renderHook(() => useApi(mockApiFunction))
+
+    await act(async () => {
+      await result.current.execute()
+    })
+
+    expect(result.current.data).toEqual(mockData)
+
+    act(() => {
+      result.current.reset()
+    })
+
+    expect(result.current.data).toBeNull()
+    expect(result.current.loading).toBe(false)
+    expect(result.current.error).toBeNull()
+  })
+
+  it('should clear error', async () => {
+    mockApiFunction.mockRejectedValueOnce({ message: 'Test Error' })
+
+    const { result } = renderHook(() => useApi(mockApiFunction))
+
+    await act(async () => {
+      await result.current.execute()
+    })
+
+    expect(result.current.error).toBeTruthy()
+
+    act(() => {
+      result.current.clearError()
+    })
+
+    expect(result.current.error).toBeNull()
+  })
+
+  it('should cancel previous requests', async () => {
+    let resolveFirst: (value: unknown) => void
+    let resolveSecond: (value: unknown) => void
+
+    const firstPromise = new Promise(resolve => {
+      resolveFirst = resolve
+    })
+    const secondPromise = new Promise(resolve => {
+      resolveSecond = resolve
+    })
+
+    mockApiFunction
+      .mockReturnValueOnce(firstPromise)
+      .mockReturnValueOnce(secondPromise)
+
+    const { result } = renderHook(() => useApi(mockApiFunction))
+
+    // Start first request
+    act(() => {
+      result.current.execute('first')
+    })
+
+    // Start second request before first completes
+    act(() => {
+      result.current.execute('second')
+    })
+
+    // Resolve first request (should be cancelled)
+    await act(async () => {
+      resolveFirst({ data: 'first' })
+      await new Promise(resolve => setTimeout(resolve, 0))
+    })
+
+    // Resolve second request
+    await act(async () => {
+      resolveSecond({ data: 'second' })
+      await new Promise(resolve => setTimeout(resolve, 0))
+    })
+
+    expect(result.current.data).toEqual({ data: 'second' })
+  })
+})
+
+describe('useApiForm', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('should handle form submission', async () => {
+    const formData = { name: 'Test' }
+    const responseData = { id: 1, name: 'Test' }
+    mockFormSubmitFunction.mockResolvedValueOnce(responseData)
+
+    const { result } = renderHook(() => useApiForm(mockFormSubmitFunction))
+
+    let submitResult: unknown
+
+    await act(async () => {
+      submitResult = await result.current.handleSubmit(formData)
+    })
+
+    expect(submitResult).toEqual(responseData)
+    expect(mockFormSubmitFunction).toHaveBeenCalledWith(formData)
+    expect(result.current.data).toEqual(responseData)
+  })
+
+  it('should reset on success when option is enabled', async () => {
+    const formData = { name: 'Test' }
+    const responseData = { id: 1, name: 'Test' }
+    mockFormSubmitFunction.mockResolvedValueOnce(responseData)
+
+    const { result } = renderHook(() =>
+      useApiForm(mockFormSubmitFunction, { resetOnSuccess: true })
+    )
+
+    await act(async () => {
+      await result.current.handleSubmit(formData)
+    })
+
+    expect(result.current.data).toBeNull()
+  })
+})
+
+describe('useApiCache', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    vi.useFakeTimers()
+  })
+
+  afterEach(() => {
+    vi.useRealTimers()
+  })
+
+  it('should fetch and cache data', async () => {
+    const mockData = { id: 1, name: 'Test' }
+    mockCacheFunction.mockResolvedValueOnce(mockData)
+
+    const { result } = renderHook(() =>
+      useApiCache('test-key', mockCacheFunction)
+    )
+
+    let fetchResult: unknown
+
+    await act(async () => {
+      fetchResult = await result.current.fetchData()
+    })
+
+    expect(fetchResult).toEqual(mockData)
+    expect(result.current.data).toEqual(mockData)
+    expect(mockCacheFunction).toHaveBeenCalledTimes(1)
+  })
+
+  it('should return cached data when fresh', async () => {
+    const mockData = { id: 1, name: 'Test' }
+    mockCacheFunction.mockResolvedValueOnce(mockData)
+
+    const { result } = renderHook(() =>
+      useApiCache('test-key', mockCacheFunction, { staleTime: 60000 })
+    )
+
+    // First fetch
+    await act(async () => {
+      await result.current.fetchData()
+    })
+
+    // Second fetch should return cached data
+    let secondResult: unknown
+
+    await act(async () => {
+      secondResult = await result.current.fetchData()
+    })
+
+    expect(secondResult).toEqual(mockData)
+    expect(mockCacheFunction).toHaveBeenCalledTimes(1) // Should not call API again
+  })
+
+  it('should fetch fresh data when stale', async () => {
+    const mockData1 = { id: 1, name: 'Test 1' }
+    const mockData2 = { id: 2, name: 'Test 2' }
+
+    mockCacheFunction
+      .mockResolvedValueOnce(mockData1)
+      .mockResolvedValueOnce(mockData2)
+
+    const { result } = renderHook(() =>
+      useApiCache('test-key', mockCacheFunction, { staleTime: 1000 })
+    )
+
+    // First fetch
+    await act(async () => {
+      await result.current.fetchData()
+    })
+
+    expect(result.current.data).toEqual(mockData1)
+
+    // Advance time past stale time
+    act(() => {
+      vi.advanceTimersByTime(2000)
+    })
+
+    // Second fetch should get fresh data
+    await act(async () => {
+      await result.current.fetchData()
+    })
+
+    expect(result.current.data).toEqual(mockData2)
+    expect(mockCacheFunction).toHaveBeenCalledTimes(2)
+  })
+
+  it('should clear cache', async () => {
+    const mockData = { id: 1, name: 'Test' }
+    mockCacheFunction.mockResolvedValueOnce(mockData)
+
+    const { result } = renderHook(() =>
+      useApiCache('test-key', mockCacheFunction)
+    )
+
+    await act(async () => {
+      await result.current.fetchData()
+    })
+
+    expect(result.current.data).toEqual(mockData)
+
+    await act(async () => {
+      result.current.clearCache()
+    })
+
+    expect(result.current.data).toBeNull()
+  })
+
+  it('should indicate stale status', async () => {
+    const mockData = { id: 1, name: 'Test' }
+    mockCacheFunction.mockResolvedValueOnce(mockData)
+
+    const { result } = renderHook(() =>
+      useApiCache('test-key', mockCacheFunction, { staleTime: 1000 })
+    )
+
+    // Initially stale (no data)
+    expect(result.current.isStale).toBe(true)
+
+    // Fetch data
+    await act(async () => {
+      await result.current.fetchData()
+    })
+
+    // Should be fresh
+    expect(result.current.isStale).toBe(false)
+
+    // Advance time past stale time
+    act(() => {
+      vi.advanceTimersByTime(2000)
+    })
+
+    // Should be stale again
+    expect(result.current.isStale).toBe(true)
+  })
+})

frontend/app/hooks/useApi.ts

@@ -0,0 +1,227 @@
+import { useState, useCallback, useRef, useEffect } from 'react'
+import { ApiError } from '~/types/task'
+
+interface UseApiState<T> {
+  data: T | null
+  loading: boolean
+  error: string | null
+}
+
+interface UseApiActions<T> {
+  execute: (...args: unknown[]) => Promise<T | null>
+  reset: () => void
+  clearError: () => void
+}
+
+interface UseApiOptions {
+  immediate?: boolean
+  onSuccess?: (data: unknown) => void
+  onError?: (error: string) => void
+}
+
+export function useApi<T>(
+  apiFunction: (...args: unknown[]) => Promise<T>,
+  options: UseApiOptions = {}
+): UseApiState<T> & UseApiActions<T> {
+  const { immediate = false, onSuccess, onError } = options
+
+  const [state, setState] = useState<UseApiState<T>>({
+    data: null,
+    loading: false,
+    error: null,
+  })
+
+  const mountedRef = useRef(true)
+  const abortControllerRef = useRef<AbortController | null>(null)
+
+  useEffect(() => {
+    return () => {
+      mountedRef.current = false
+      if (abortControllerRef.current) {
+        abortControllerRef.current.abort()
+      }
+    }
+  }, [])
+
+  const reset = useCallback(() => {
+    setState({
+      data: null,
+      loading: false,
+      error: null,
+    })
+  }, [])
+
+  const clearError = useCallback(() => {
+    setState(prev => ({ ...prev, error: null }))
+  }, [])
+
+  const execute = useCallback(
+    async (...args: unknown[]): Promise<T | null> => {
+      // Cancel previous request if still pending
+      if (abortControllerRef.current) {
+        abortControllerRef.current.abort()
+      }
+
+      abortControllerRef.current = new AbortController()
+
+      setState(prev => ({ ...prev, loading: true, error: null }))
+
+      try {
+        const result = await apiFunction(...args)
+
+        if (!mountedRef.current) return null
+
+        setState(prev => ({
+          ...prev,
+          data: result,
+          loading: false,
+        }))
+
+        if (onSuccess) {
+          onSuccess(result)
+        }
+
+        return result
+      } catch (error) {
+        if (!mountedRef.current) return null
+
+        const apiError = error as ApiError
+        const errorMessage = apiError.message || 'An unknown error occurred'
+
+        setState(prev => ({
+          ...prev,
+          loading: false,
+          error: errorMessage,
+        }))
+
+        if (onError) {
+          onError(errorMessage)
+        }
+
+        return null
+      } finally {
+        abortControllerRef.current = null
+      }
+    },
+    [apiFunction, onSuccess, onError]
+  )
+
+  // Execute immediately if requested
+  useEffect(() => {
+    if (immediate) {
+      execute()
+    }
+  }, [immediate, execute])
+
+  return {
+    ...state,
+    execute,
+    reset,
+    clearError,
+  }
+}
+
+// Utility hook for handling form submissions
+export function useApiForm<T>(
+  submitFunction: (data: unknown) => Promise<T>,
+  options: UseApiOptions & { resetOnSuccess?: boolean } = {}
+) {
+  const { resetOnSuccess = false, ...apiOptions } = options
+
+  const api = useApi(submitFunction, apiOptions)
+
+  const handleSubmit = useCallback(
+    async (data: unknown) => {
+      const result = await api.execute(data)
+
+      if (result && resetOnSuccess) {
+        api.reset()
+      }
+
+      return result
+    },
+    [api, resetOnSuccess]
+  )
+
+  return {
+    ...api,
+    handleSubmit,
+  }
+}
+
+// Utility hook for data caching and synchronization
+export function useApiCache<T>(
+  key: string,
+  fetchFunction: () => Promise<T>,
+  options: { cacheTime?: number; staleTime?: number } = {}
+) {
+  const { cacheTime = 5 * 60 * 1000, staleTime = 30 * 1000 } = options // 5min cache, 30s stale
+
+  const [cacheData, setCacheData] = useState<{
+    data: T | null
+    timestamp: number
+  } | null>(null)
+
+  const api = useApi(fetchFunction)
+
+  const getCachedData = useCallback((): T | null => {
+    if (!cacheData) return null
+
+    const now = Date.now()
+    const age = now - cacheData.timestamp
+
+    if (age > cacheTime) {
+      setCacheData(null)
+      return null
+    }
+
+    return cacheData.data
+  }, [cacheData, cacheTime])
+
+  const isStale = useCallback((): boolean => {
+    if (!cacheData) return true
+
+    const now = Date.now()
+    const age = now - cacheData.timestamp
+
+    return age > staleTime
+  }, [cacheData, staleTime])
+
+  const fetchData = useCallback(
+    async (force = false): Promise<T | null> => {
+      // Return cached data if fresh and not forced
+      if (!force && !isStale()) {
+        const cached = getCachedData()
+        if (cached) return cached
+      }
+
+      const result = await api.execute()
+
+      if (result) {
+        setCacheData({
+          data: result,
+          timestamp: Date.now(),
+        })
+      }
+
+      return result
+    },
+    [api, isStale, getCachedData]
+  )
+
+  const clearCache = useCallback(() => {
+    setCacheData(null)
+    api.reset()
+  }, [api])
+
+  return {
+    data: api.data || getCachedData(),
+    loading: api.loading,
+    error: api.error,
+    fetchData,
+    clearCache,
+    get isStale() {
+      return isStale()
+    },
+  }
+}

frontend/app/hooks/useTask.test.ts

@@ -0,0 +1,210 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
+import { renderHook, act, waitFor } from '@testing-library/react'
+import { useTask } from './useTask'
+import { Task, TaskStatus, UpdateTaskRequest } from '~/types/task'
+import { apiClient } from '~/services/api'
+
+// Mock the API client
+vi.mock('~/services/api', () => ({
+  apiClient: {
+    getTask: vi.fn(),
+    updateTask: vi.fn(),
+    deleteTask: vi.fn(),
+  },
+}))
+
+const mockApiClient = apiClient as {
+  getTask: ReturnType<typeof vi.fn>
+  updateTask: ReturnType<typeof vi.fn>
+  deleteTask: ReturnType<typeof vi.fn>
+}
+
+// Sample task data
+const mockTask: Task = {
+  id: '550e8400-e29b-41d4-a716-446655440000',
+  title: 'Test Task',
+  description: 'Test Description',
+  status: TaskStatus.Todo,
+  created_at: '2023-01-01T00:00:00Z',
+  updated_at: '2023-01-01T00:00:00Z',
+  completed_at: null,
+}
+
+describe('useTask', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  afterEach(() => {
+    vi.restoreAllMocks()
+  })
+
+  it('should initialize with default state', () => {
+    const { result } = renderHook(() => useTask())
+
+    expect(result.current.task).toBeNull()
+    expect(result.current.loading).toBe(false)
+    expect(result.current.error).toBeNull()
+  })
+
+  describe('getTask', () => {
+    it('should fetch task successfully', async () => {
+      mockApiClient.getTask.mockResolvedValueOnce(mockTask)
+
+      const { result } = renderHook(() => useTask())
+
+      act(() => {
+        result.current.getTask(mockTask.id)
+      })
+
+      expect(result.current.loading).toBe(true)
+
+      await waitFor(() => {
+        expect(result.current.loading).toBe(false)
+      })
+
+      expect(result.current.task).toEqual(mockTask)
+      expect(result.current.error).toBeNull()
+      expect(mockApiClient.getTask).toHaveBeenCalledWith(mockTask.id)
+    })
+
+    it('should handle fetch errors', async () => {
+      const errorMessage = 'Task not found'
+      mockApiClient.getTask.mockRejectedValueOnce({ message: errorMessage })
+
+      const { result } = renderHook(() => useTask())
+
+      act(() => {
+        result.current.getTask(mockTask.id)
+      })
+
+      await waitFor(() => {
+        expect(result.current.loading).toBe(false)
+      })
+
+      expect(result.current.task).toBeNull()
+      expect(result.current.error).toBe(errorMessage)
+    })
+  })
+
+  describe('updateTask', () => {
+    it('should update task with optimistic update', async () => {
+      const updateData: UpdateTaskRequest = {
+        title: 'Updated Task',
+        status: TaskStatus.Done,
+      }
+      const updatedTask = { ...mockTask, ...updateData }
+
+      mockApiClient.getTask.mockResolvedValueOnce(mockTask)
+      mockApiClient.updateTask.mockResolvedValueOnce(updatedTask)
+
+      const { result } = renderHook(() => useTask())
+
+      // Set initial task
+      await act(async () => {
+        await result.current.getTask(mockTask.id)
+      })
+
+      let updateResult: Task | null = null
+
+      await act(async () => {
+        updateResult = await result.current.updateTask(mockTask.id, updateData)
+      })
+
+      expect(updateResult).toEqual(updatedTask)
+      expect(mockApiClient.updateTask).toHaveBeenCalledWith(
+        mockTask.id,
+        updateData
+      )
+    })
+
+    it('should handle update errors and revert optimistic update', async () => {
+      const updateData: UpdateTaskRequest = { status: TaskStatus.Done }
+      const errorMessage = 'Update failed'
+
+      // Setup initial task
+      mockApiClient.getTask.mockResolvedValueOnce(mockTask)
+
+      const { result } = renderHook(() => useTask())
+
+      // Set initial task state
+      await act(async () => {
+        await result.current.getTask(mockTask.id)
+      })
+
+      expect(result.current.task).toEqual(mockTask)
+
+      // Mock update failure and revert call
+      mockApiClient.updateTask.mockRejectedValueOnce({ message: errorMessage })
+      mockApiClient.getTask.mockResolvedValueOnce(mockTask)
+
+      let updateResult: Task | null = null
+
+      await act(async () => {
+        updateResult = await result.current.updateTask(mockTask.id, updateData)
+      })
+
+      expect(updateResult).toBeNull()
+      expect(result.current.error).toBe(errorMessage)
+      expect(result.current.loading).toBe(false)
+    })
+  })
+
+  describe('deleteTask', () => {
+    it('should delete task successfully', async () => {
+      mockApiClient.deleteTask.mockResolvedValueOnce(undefined)
+
+      const { result } = renderHook(() => useTask())
+
+      // Set initial task
+      await act(async () => {
+        mockApiClient.getTask.mockResolvedValueOnce(mockTask)
+        await result.current.getTask(mockTask.id)
+      })
+
+      await act(async () => {
+        await result.current.deleteTask(mockTask.id)
+      })
+
+      expect(result.current.task).toBeNull()
+      expect(result.current.error).toBeNull()
+      expect(mockApiClient.deleteTask).toHaveBeenCalledWith(mockTask.id)
+    })
+
+    it('should handle delete errors', async () => {
+      const errorMessage = 'Delete failed'
+      mockApiClient.deleteTask.mockRejectedValueOnce({ message: errorMessage })
+
+      const { result } = renderHook(() => useTask())
+
+      await act(async () => {
+        await result.current.deleteTask(mockTask.id)
+      })
+
+      expect(result.current.error).toBe(errorMessage)
+      expect(result.current.loading).toBe(false)
+    })
+  })
+
+  describe('clearError', () => {
+    it('should clear error state', async () => {
+      mockApiClient.getTask.mockRejectedValueOnce({ message: 'Test error' })
+
+      const { result } = renderHook(() => useTask())
+
+      // Trigger an error
+      await act(async () => {
+        await result.current.getTask(mockTask.id)
+      })
+
+      expect(result.current.error).toBeTruthy()
+
+      // Clear the error
+      act(() => {
+        result.current.clearError()
+      })
+
+      expect(result.current.error).toBeNull()
+    })
+  })
+})

frontend/app/hooks/useTask.ts

@@ -0,0 +1,114 @@
+import { useState, useCallback } from 'react'
+import { Task, UpdateTaskRequest, ApiError } from '~/types/task'
+import { apiClient } from '~/services/api'
+
+interface UseTaskState {
+  task: Task | null
+  loading: boolean
+  error: string | null
+}
+
+interface UseTaskActions {
+  getTask: (id: string) => Promise<void>
+  updateTask: (id: string, data: UpdateTaskRequest) => Promise<Task | null>
+  deleteTask: (id: string) => Promise<void>
+  clearError: () => void
+}
+
+export function useTask(): UseTaskState & UseTaskActions {
+  const [state, setState] = useState<UseTaskState>({
+    task: null,
+    loading: false,
+    error: null,
+  })
+
+  const clearError = useCallback(() => {
+    setState(prev => ({ ...prev, error: null }))
+  }, [])
+
+  const getTask = useCallback(async (id: string) => {
+    setState(prev => ({ ...prev, loading: true, error: null }))
+
+    try {
+      const task = await apiClient.getTask(id)
+      setState(prev => ({ ...prev, task, loading: false }))
+    } catch (error) {
+      const apiError = error as ApiError
+      setState(prev => ({
+        ...prev,
+        loading: false,
+        error: apiError.message,
+      }))
+    }
+  }, [])
+
+  const updateTask = useCallback(
+    async (id: string, data: UpdateTaskRequest): Promise<Task | null> => {
+      setState(prev => ({ ...prev, loading: true, error: null }))
+
+      try {
+        // Optimistic update
+        if (state.task && state.task.id === id) {
+          const optimisticTask: Task = {
+            ...state.task,
+            ...data,
+            updated_at: new Date().toISOString(),
+          }
+          setState(prev => ({ ...prev, task: optimisticTask }))
+        }
+
+        const updatedTask = await apiClient.updateTask(id, data)
+        setState(prev => ({ ...prev, task: updatedTask, loading: false }))
+        return updatedTask
+      } catch (error) {
+        const apiError = error as ApiError
+        setState(prev => ({
+          ...prev,
+          loading: false,
+          error: apiError.message,
+        }))
+
+        // Revert optimistic update on error
+        if (state.task && state.task.id === id) {
+          try {
+            const originalTask = await apiClient.getTask(id)
+            setState(prev => ({ ...prev, task: originalTask }))
+          } catch {
+            // If we can't revert, just keep the optimistic state
+          }
+        }
+
+        return null
+      }
+    },
+    [state.task]
+  )
+
+  const deleteTask = useCallback(async (id: string) => {
+    setState(prev => ({ ...prev, loading: true, error: null }))
+
+    try {
+      await apiClient.deleteTask(id)
+      setState(prev => ({
+        ...prev,
+        task: prev.task?.id === id ? null : prev.task,
+        loading: false,
+      }))
+    } catch (error) {
+      const apiError = error as ApiError
+      setState(prev => ({
+        ...prev,
+        loading: false,
+        error: apiError.message,
+      }))
+    }
+  }, [])
+
+  return {
+    ...state,
+    getTask,
+    updateTask,
+    deleteTask,
+    clearError,
+  }
+}

frontend/app/hooks/useTasks.test.ts

@@ -0,0 +1,317 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
+import { renderHook, act, waitFor } from '@testing-library/react'
+import { useTasks } from './useTasks'
+import { Task, TaskStatus, CreateTaskRequest } from '~/types/task'
+import { apiClient } from '~/services/api'
+
+// Mock the API client
+vi.mock('~/services/api', () => ({
+  apiClient: {
+    listTasks: vi.fn(),
+    createTask: vi.fn(),
+  },
+}))
+
+const mockApiClient = apiClient as {
+  listTasks: ReturnType<typeof vi.fn>
+  createTask: ReturnType<typeof vi.fn>
+}
+
+// Sample task data
+const mockTasks: Task[] = [
+  {
+    id: '550e8400-e29b-41d4-a716-446655440000',
+    title: 'Test Task 1',
+    description: 'Test Description 1',
+    status: TaskStatus.Todo,
+    created_at: '2023-01-01T00:00:00Z',
+    updated_at: '2023-01-01T00:00:00Z',
+    completed_at: null,
+  },
+  {
+    id: '550e8400-e29b-41d4-a716-446655440001',
+    title: 'Test Task 2',
+    description: 'Test Description 2',
+    status: TaskStatus.Done,
+    created_at: '2023-01-01T01:00:00Z',
+    updated_at: '2023-01-01T01:00:00Z',
+    completed_at: '2023-01-01T02:00:00Z',
+  },
+  {
+    id: '550e8400-e29b-41d4-a716-446655440002',
+    title: 'Test Task 3',
+    description: null,
+    status: TaskStatus.Backlog,
+    created_at: '2023-01-01T02:00:00Z',
+    updated_at: '2023-01-01T02:00:00Z',
+    completed_at: null,
+  },
+]
+
+describe('useTasks', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  afterEach(() => {
+    vi.restoreAllMocks()
+  })
+
+  it('should initialize with default state', () => {
+    const { result } = renderHook(() => useTasks({ autoFetch: false }))
+
+    expect(result.current.tasks).toEqual([])
+    expect(result.current.loading).toBe(false)
+    expect(result.current.error).toBeNull()
+    expect(result.current.lastFetch).toBeNull()
+  })
+
+  it('should auto-fetch tasks on mount by default', async () => {
+    mockApiClient.listTasks.mockResolvedValueOnce(mockTasks)
+
+    renderHook(() => useTasks())
+
+    await waitFor(() => {
+      expect(mockApiClient.listTasks).toHaveBeenCalledTimes(1)
+    })
+  })
+
+  it('should not auto-fetch when disabled', () => {
+    renderHook(() => useTasks({ autoFetch: false }))
+
+    expect(mockApiClient.listTasks).not.toHaveBeenCalled()
+  })
+
+  describe('fetchTasks', () => {
+    it('should fetch tasks successfully', async () => {
+      mockApiClient.listTasks.mockResolvedValueOnce(mockTasks)
+
+      const { result } = renderHook(() => useTasks({ autoFetch: false }))
+
+      await act(async () => {
+        await result.current.fetchTasks()
+      })
+
+      expect(result.current.tasks).toEqual(mockTasks)
+      expect(result.current.loading).toBe(false)
+      expect(result.current.error).toBeNull()
+      expect(result.current.lastFetch).toBeInstanceOf(Date)
+    })
+
+    it('should handle fetch errors', async () => {
+      const errorMessage = 'Fetch failed'
+      mockApiClient.listTasks.mockRejectedValueOnce({ message: errorMessage })
+
+      const { result } = renderHook(() => useTasks({ autoFetch: false }))
+
+      await act(async () => {
+        await result.current.fetchTasks()
+      })
+
+      expect(result.current.tasks).toEqual([])
+      expect(result.current.loading).toBe(false)
+      expect(result.current.error).toBe(errorMessage)
+    })
+  })
+
+  describe('createTask', () => {
+    it('should create task successfully', async () => {
+      const newTaskData: CreateTaskRequest = {
+        title: 'New Task',
+        description: 'New Description',
+      }
+      const newTask: Task = {
+        id: 'new-task-id',
+        title: newTaskData.title,
+        description: newTaskData.description || null,
+        status: TaskStatus.Todo,
+        created_at: '2023-01-01T03:00:00Z',
+        updated_at: '2023-01-01T03:00:00Z',
+        completed_at: null,
+      }
+
+      mockApiClient.createTask.mockResolvedValueOnce(newTask)
+
+      const { result } = renderHook(() => useTasks({ autoFetch: false }))
+
+      // Set initial tasks
+      await act(async () => {
+        mockApiClient.listTasks.mockResolvedValueOnce(mockTasks)
+        await result.current.fetchTasks()
+      })
+
+      let createResult: Task | null = null
+
+      await act(async () => {
+        createResult = await result.current.createTask(newTaskData)
+      })
+
+      expect(createResult).toEqual(newTask)
+      expect(result.current.tasks[0]).toEqual(newTask) // Should be first in list
+      expect(result.current.tasks).toHaveLength(mockTasks.length + 1)
+      expect(mockApiClient.createTask).toHaveBeenCalledWith(newTaskData)
+    })
+
+    it('should handle create errors', async () => {
+      const newTaskData: CreateTaskRequest = { title: '' }
+      const errorMessage = 'Title must not be empty'
+
+      mockApiClient.createTask.mockRejectedValueOnce({ message: errorMessage })
+
+      const { result } = renderHook(() => useTasks({ autoFetch: false }))
+
+      let createResult: Task | null = null
+
+      await act(async () => {
+        createResult = await result.current.createTask(newTaskData)
+      })
+
+      expect(createResult).toBeNull()
+      expect(result.current.error).toBe(errorMessage)
+      expect(result.current.loading).toBe(false)
+    })
+  })
+
+  describe('refreshTasks', () => {
+    it('should refresh tasks without loading state when tasks exist', async () => {
+      const { result } = renderHook(() => useTasks({ autoFetch: false }))
+
+      // Set initial tasks
+      await act(async () => {
+        mockApiClient.listTasks.mockResolvedValueOnce(mockTasks)
+        await result.current.fetchTasks()
+      })
+
+      // Refresh with updated tasks
+      const updatedTasks = [...mockTasks, { ...mockTasks[0], id: 'new-id' }]
+      mockApiClient.listTasks.mockResolvedValueOnce(updatedTasks)
+
+      await act(async () => {
+        await result.current.refreshTasks()
+      })
+
+      expect(result.current.tasks).toEqual(updatedTasks)
+    })
+
+    it('should show loading state when no tasks exist', async () => {
+      mockApiClient.listTasks.mockResolvedValueOnce(mockTasks)
+
+      const { result } = renderHook(() => useTasks({ autoFetch: false }))
+
+      act(() => {
+        result.current.refreshTasks()
+      })
+
+      expect(result.current.loading).toBe(true)
+
+      await waitFor(() => {
+        expect(result.current.loading).toBe(false)
+      })
+    })
+  })
+
+  describe('utility functions', () => {
+    beforeEach(async () => {
+      mockApiClient.listTasks.mockResolvedValueOnce(mockTasks)
+    })
+
+    it('should get task by ID', async () => {
+      const { result } = renderHook(() => useTasks())
+
+      await waitFor(() => {
+        expect(result.current.tasks).toHaveLength(mockTasks.length)
+      })
+
+      const foundTask = result.current.getTaskById(mockTasks[0].id)
+      expect(foundTask).toEqual(mockTasks[0])
+
+      const notFoundTask = result.current.getTaskById('nonexistent-id')
+      expect(notFoundTask).toBeUndefined()
+    })
+
+    it('should filter tasks by status', async () => {
+      const { result } = renderHook(() => useTasks())
+
+      await waitFor(() => {
+        expect(result.current.tasks).toHaveLength(mockTasks.length)
+      })
+
+      const todoTasks = result.current.filterTasksByStatus(TaskStatus.Todo)
+      expect(todoTasks).toHaveLength(1)
+      expect(todoTasks[0].status).toBe(TaskStatus.Todo)
+
+      const doneTasks = result.current.filterTasksByStatus(TaskStatus.Done)
+      expect(doneTasks).toHaveLength(1)
+      expect(doneTasks[0].status).toBe(TaskStatus.Done)
+
+      const backlogTasks = result.current.filterTasksByStatus(
+        TaskStatus.Backlog
+      )
+      expect(backlogTasks).toHaveLength(1)
+      expect(backlogTasks[0].status).toBe(TaskStatus.Backlog)
+    })
+  })
+
+  describe('clearError', () => {
+    it('should clear error state', async () => {
+      mockApiClient.listTasks.mockRejectedValueOnce({ message: 'Test error' })
+
+      const { result } = renderHook(() => useTasks({ autoFetch: false }))
+
+      // Trigger an error
+      await act(async () => {
+        await result.current.fetchTasks()
+      })
+
+      expect(result.current.error).toBeTruthy()
+
+      // Clear the error
+      act(() => {
+        result.current.clearError()
+      })
+
+      expect(result.current.error).toBeNull()
+    })
+  })
+
+  describe('refresh interval', () => {
+    it('should set up refresh interval', async () => {
+      vi.useFakeTimers()
+
+      const updatedTasks = [...mockTasks, { ...mockTasks[0], id: 'new-id' }]
+
+      mockApiClient.listTasks
+        .mockResolvedValueOnce(mockTasks)
+        .mockResolvedValueOnce(updatedTasks)
+        .mockResolvedValue(updatedTasks) // Handle any extra calls
+
+      const { result, unmount } = renderHook(() =>
+        useTasks({ refreshInterval: 1000, autoFetch: false })
+      )
+
+      // Manual initial fetch
+      await act(async () => {
+        await result.current.fetchTasks()
+      })
+
+      expect(result.current.tasks).toHaveLength(mockTasks.length)
+
+      const initialCallCount = mockApiClient.listTasks.mock.calls.length
+
+      // Advance timer to trigger refresh
+      await act(async () => {
+        vi.advanceTimersByTime(1000)
+        await vi.runOnlyPendingTimersAsync()
+      })
+
+      // Should have made at least one more call
+      expect(mockApiClient.listTasks.mock.calls.length).toBeGreaterThan(
+        initialCallCount
+      )
+      expect(result.current.tasks).toHaveLength(updatedTasks.length)
+
+      unmount()
+      vi.useRealTimers()
+    }, 10000)
+  })
+})

frontend/app/hooks/useTasks.ts

@@ -0,0 +1,160 @@
+import { useState, useCallback, useEffect } from 'react'
+import { Task, CreateTaskRequest, TaskStatus, ApiError } from '~/types/task'
+import { apiClient } from '~/services/api'
+
+interface UseTasksState {
+  tasks: Task[]
+  loading: boolean
+  error: string | null
+  lastFetch: Date | null
+}
+
+interface UseTasksActions {
+  fetchTasks: () => Promise<void>
+  createTask: (data: CreateTaskRequest) => Promise<Task | null>
+  refreshTasks: () => Promise<void>
+  clearError: () => void
+  getTaskById: (id: string) => Task | undefined
+  filterTasksByStatus: (status: TaskStatus) => Task[]
+}
+
+interface UseTasksOptions {
+  autoFetch?: boolean
+  refreshInterval?: number
+}
+
+export function useTasks(
+  options: UseTasksOptions = {}
+): UseTasksState & UseTasksActions {
+  const { autoFetch = true, refreshInterval } = options
+
+  const [state, setState] = useState<UseTasksState>({
+    tasks: [],
+    loading: false,
+    error: null,
+    lastFetch: null,
+  })
+
+  const clearError = useCallback(() => {
+    setState(prev => ({ ...prev, error: null }))
+  }, [])
+
+  const fetchTasks = useCallback(async () => {
+    setState(prev => ({ ...prev, loading: true, error: null }))
+
+    try {
+      const tasks = await apiClient.listTasks()
+      setState(prev => ({
+        ...prev,
+        tasks,
+        loading: false,
+        lastFetch: new Date(),
+      }))
+    } catch (error) {
+      const apiError = error as ApiError
+      setState(prev => ({
+        ...prev,
+        loading: false,
+        error: apiError.message,
+      }))
+    }
+  }, [])
+
+  const createTask = useCallback(
+    async (data: CreateTaskRequest): Promise<Task | null> => {
+      setState(prev => ({ ...prev, loading: true, error: null }))
+
+      try {
+        const newTask = await apiClient.createTask(data)
+
+        // Add the new task to the beginning of the list (most recent first)
+        setState(prev => ({
+          ...prev,
+          tasks: [newTask, ...prev.tasks],
+          loading: false,
+        }))
+
+        return newTask
+      } catch (error) {
+        const apiError = error as ApiError
+        setState(prev => ({
+          ...prev,
+          loading: false,
+          error: apiError.message,
+        }))
+        return null
+      }
+    },
+    []
+  )
+
+  const refreshTasks = useCallback(async () => {
+    // Force refresh without showing loading state if tasks already exist
+    const showLoading = state.tasks.length === 0
+
+    if (showLoading) {
+      setState(prev => ({ ...prev, loading: true, error: null }))
+    } else {
+      setState(prev => ({ ...prev, error: null }))
+    }
+
+    try {
+      const tasks = await apiClient.listTasks()
+      setState(prev => ({
+        ...prev,
+        tasks,
+        loading: false,
+        lastFetch: new Date(),
+      }))
+    } catch (error) {
+      const apiError = error as ApiError
+      setState(prev => ({
+        ...prev,
+        loading: false,
+        error: apiError.message,
+      }))
+    }
+  }, [state.tasks])
+
+  const getTaskById = useCallback(
+    (id: string): Task | undefined => {
+      return state.tasks.find(task => task.id === id)
+    },
+    [state.tasks]
+  )
+
+  const filterTasksByStatus = useCallback(
+    (status: TaskStatus): Task[] => {
+      return state.tasks.filter(task => task.status === status)
+    },
+    [state.tasks]
+  )
+
+  // Auto-fetch tasks on mount
+  useEffect(() => {
+    if (autoFetch) {
+      fetchTasks()
+    }
+  }, [autoFetch, fetchTasks])
+
+  // Set up refresh interval if specified
+  useEffect(() => {
+    if (!refreshInterval) return
+
+    const interval = setInterval(() => {
+      refreshTasks()
+    }, refreshInterval)
+
+    return () => clearInterval(interval)
+  }, [refreshInterval, refreshTasks])
+
+  return {
+    ...state,
+    fetchTasks,
+    createTask,
+    refreshTasks,
+    clearError,
+    getTaskById,
+    filterTasksByStatus,
+  }
+}

frontend/app/services/api.test.ts

@@ -0,0 +1,271 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
+import { apiClient } from './api'
+import {
+  Task,
+  TaskStatus,
+  CreateTaskRequest,
+  UpdateTaskRequest,
+} from '~/types/task'
+
+// Mock fetch globally
+const mockFetch = vi.fn()
+global.fetch = mockFetch
+
+// Sample task data for testing
+const mockTask: Task = {
+  id: '550e8400-e29b-41d4-a716-446655440000',
+  title: 'Test Task',
+  description: 'Test Description',
+  status: TaskStatus.Todo,
+  created_at: '2023-01-01T00:00:00Z',
+  updated_at: '2023-01-01T00:00:00Z',
+  completed_at: null,
+}
+
+const mockTasks: Task[] = [
+  mockTask,
+  {
+    ...mockTask,
+    id: '550e8400-e29b-41d4-a716-446655440001',
+    title: 'Another Task',
+    status: TaskStatus.Done,
+    completed_at: '2023-01-01T01:00:00Z',
+  },
+]
+
+describe('API Client', () => {
+  beforeEach(() => {
+    mockFetch.mockClear()
+    // Silence console.log during tests
+    vi.spyOn(console, 'log').mockImplementation(() => {})
+    vi.spyOn(console, 'error').mockImplementation(() => {})
+  })
+
+  afterEach(() => {
+    vi.restoreAllMocks()
+  })
+
+  describe('listTasks', () => {
+    it('should fetch all tasks successfully', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        status: 200,
+        statusText: 'OK',
+        json: () => Promise.resolve(mockTasks),
+      })
+
+      const result = await apiClient.listTasks()
+
+      expect(mockFetch).toHaveBeenCalledWith('/api/tasks', {
+        headers: { 'Content-Type': 'application/json' },
+      })
+      expect(result).toEqual(mockTasks)
+    })
+
+    it('should handle empty task list', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        status: 200,
+        statusText: 'OK',
+        json: () => Promise.resolve([]),
+      })
+
+      const result = await apiClient.listTasks()
+
+      expect(result).toEqual([])
+    })
+
+    it('should throw error on failed request', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: false,
+        status: 500,
+        statusText: 'Internal Server Error',
+        json: () => Promise.resolve({ message: 'Server error' }),
+      })
+
+      await expect(apiClient.listTasks()).rejects.toThrow('Server error')
+    })
+  })
+
+  describe('getTask', () => {
+    it('should fetch single task successfully', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        status: 200,
+        statusText: 'OK',
+        json: () => Promise.resolve(mockTask),
+      })
+
+      const result = await apiClient.getTask(mockTask.id)
+
+      expect(mockFetch).toHaveBeenCalledWith(`/api/tasks/${mockTask.id}`, {
+        headers: { 'Content-Type': 'application/json' },
+      })
+      expect(result).toEqual(mockTask)
+    })
+
+    it('should handle task not found', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: false,
+        status: 404,
+        statusText: 'Not Found',
+        json: () => Promise.resolve({ message: 'Task not found' }),
+      })
+
+      await expect(apiClient.getTask('nonexistent-id')).rejects.toThrow(
+        'Task not found'
+      )
+    })
+  })
+
+  describe('createTask', () => {
+    it('should create task successfully', async () => {
+      const newTaskData: CreateTaskRequest = {
+        title: 'New Task',
+        description: 'New Description',
+      }
+
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        status: 201,
+        statusText: 'Created',
+        json: () => Promise.resolve(mockTask),
+      })
+
+      const result = await apiClient.createTask(newTaskData)
+
+      expect(mockFetch).toHaveBeenCalledWith('/api/tasks', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(newTaskData),
+      })
+      expect(result).toEqual(mockTask)
+    })
+
+    it('should handle validation errors', async () => {
+      const invalidData: CreateTaskRequest = {
+        title: '',
+      }
+
+      mockFetch.mockResolvedValueOnce({
+        ok: false,
+        status: 422,
+        statusText: 'Unprocessable Entity',
+        json: () => Promise.resolve({ message: 'Title must not be empty' }),
+      })
+
+      await expect(apiClient.createTask(invalidData)).rejects.toThrow(
+        'Title must not be empty'
+      )
+    })
+  })
+
+  describe('updateTask', () => {
+    it('should update task successfully', async () => {
+      const updateData: UpdateTaskRequest = {
+        title: 'Updated Task',
+        status: TaskStatus.Done,
+      }
+
+      const updatedTask = { ...mockTask, ...updateData }
+
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        status: 200,
+        statusText: 'OK',
+        json: () => Promise.resolve(updatedTask),
+      })
+
+      const result = await apiClient.updateTask(mockTask.id, updateData)
+
+      expect(mockFetch).toHaveBeenCalledWith(`/api/tasks/${mockTask.id}`, {
+        method: 'PUT',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(updateData),
+      })
+      expect(result).toEqual(updatedTask)
+    })
+
+    it('should handle partial updates', async () => {
+      const updateData: UpdateTaskRequest = {
+        status: TaskStatus.Done,
+      }
+
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        status: 200,
+        statusText: 'OK',
+        json: () => Promise.resolve({ ...mockTask, status: TaskStatus.Done }),
+      })
+
+      const result = await apiClient.updateTask(mockTask.id, updateData)
+
+      expect(result.status).toBe(TaskStatus.Done)
+    })
+  })
+
+  describe('deleteTask', () => {
+    it('should delete task successfully', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        status: 204,
+        statusText: 'No Content',
+      })
+
+      const result = await apiClient.deleteTask(mockTask.id)
+      expect(result).toBeNull()
+
+      expect(mockFetch).toHaveBeenCalledWith(`/api/tasks/${mockTask.id}`, {
+        method: 'DELETE',
+        headers: { 'Content-Type': 'application/json' },
+      })
+    })
+
+    it('should handle delete errors', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: false,
+        status: 404,
+        statusText: 'Not Found',
+        json: () => Promise.resolve({ message: 'Task not found' }),
+      })
+
+      await expect(apiClient.deleteTask('nonexistent-id')).rejects.toThrow(
+        'Task not found'
+      )
+    })
+  })
+
+  describe('Error Handling', () => {
+    it('should handle network errors', async () => {
+      mockFetch.mockRejectedValueOnce(new Error('Network error'))
+
+      await expect(apiClient.listTasks()).rejects.toThrow('Network error')
+    })
+
+    it('should handle malformed JSON responses', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: false,
+        status: 500,
+        statusText: 'Internal Server Error',
+        json: () => Promise.reject(new Error('Invalid JSON')),
+      })
+
+      await expect(apiClient.listTasks()).rejects.toThrow(
+        'HTTP 500: Internal Server Error'
+      )
+    })
+
+    it('should handle responses with no error message', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: false,
+        status: 400,
+        statusText: 'Bad Request',
+        json: () => Promise.resolve({}),
+      })
+
+      await expect(apiClient.listTasks()).rejects.toThrow(
+        'HTTP 400: Bad Request'
+      )
+    })
+  })
+})

frontend/app/services/api.ts

@@ -0,0 +1,113 @@
+import {
+  Task,
+  CreateTaskRequest,
+  UpdateTaskRequest,
+  ApiError,
+} from '~/types/task'
+
+const API_BASE_URL = '/api'
+
+class ApiClient {
+  private async fetchWrapper<T>(
+    endpoint: string,
+    options: RequestInit = {}
+  ): Promise<T> {
+    const url = `${API_BASE_URL}${endpoint}`
+
+    const config: RequestInit = {
+      headers: {
+        'Content-Type': 'application/json',
+        ...options.headers,
+      },
+      ...options,
+    }
+
+    if (process.env.NODE_ENV === 'development') {
+      console.log(`API Request: ${config.method || 'GET'} ${url}`, {
+        body: config.body,
+        headers: config.headers,
+      })
+    }
+
+    try {
+      const response = await fetch(url, config)
+
+      if (process.env.NODE_ENV === 'development') {
+        console.log(`API Response: ${response.status} ${response.statusText}`, {
+          url,
+          status: response.status,
+        })
+      }
+
+      if (!response.ok) {
+        let errorMessage = `HTTP ${response.status}: ${response.statusText}`
+
+        try {
+          const errorData = await response.json()
+          errorMessage = errorData.message || errorMessage
+        } catch {
+          // If JSON parsing fails, use the default error message
+        }
+
+        throw new Error(errorMessage)
+      }
+
+      if (response.status === 204) {
+        return null as T
+      }
+
+      const data = await response.json()
+
+      if (process.env.NODE_ENV === 'development') {
+        console.log('API Response Data:', data)
+      }
+
+      return data
+    } catch (error) {
+      const apiError: ApiError = {
+        message:
+          error instanceof Error ? error.message : 'Unknown error occurred',
+        status:
+          error instanceof Error && 'status' in error
+            ? (error as { status?: number }).status
+            : undefined,
+      }
+
+      if (process.env.NODE_ENV === 'development') {
+        console.error('API Error:', apiError)
+      }
+
+      throw apiError
+    }
+  }
+
+  async listTasks(): Promise<Task[]> {
+    return this.fetchWrapper<Task[]>('/tasks')
+  }
+
+  async getTask(id: string): Promise<Task> {
+    return this.fetchWrapper<Task>(`/tasks/${id}`)
+  }
+
+  async createTask(data: CreateTaskRequest): Promise<Task> {
+    return this.fetchWrapper<Task>('/tasks', {
+      method: 'POST',
+      body: JSON.stringify(data),
+    })
+  }
+
+  async updateTask(id: string, data: UpdateTaskRequest): Promise<Task> {
+    return this.fetchWrapper<Task>(`/tasks/${id}`, {
+      method: 'PUT',
+      body: JSON.stringify(data),
+    })
+  }
+
+  async deleteTask(id: string): Promise<void> {
+    return this.fetchWrapper<void>(`/tasks/${id}`, {
+      method: 'DELETE',
+    })
+  }
+}
+
+export const apiClient = new ApiClient()

frontend/app/types/task.ts

@@ -0,0 +1,35 @@
+export enum TaskStatus {
+  Todo = 'todo',
+  Done = 'done',
+  Backlog = 'backlog',
+}
+
+export interface Task {
+  id: string
+  title: string
+  description: string | null
+  status: TaskStatus
+  created_at: string
+  updated_at: string
+  completed_at: string | null
+}
+
+export interface CreateTaskRequest {
+  title: string
+  description?: string
+}
+
+export interface UpdateTaskRequest {
+  title?: string
+  description?: string
+  status?: TaskStatus
+}
+
+export interface ApiError {
+  message: string
+  status?: number
+}
+
+export interface TaskListResponse {
+  tasks: Task[]
+}