import { ref, onMounted, onUnmounted } from 'vue'

export interface KeyboardShortcut {
  key: string
  code: string
  description: string
  action: () => void
  preventDefault?: boolean
  ctrlKey?: boolean
  shiftKey?: boolean
  altKey?: boolean
  metaKey?: boolean
}

export interface KeyboardOptions {
  ignoreInputs?: boolean
  ignoreContentEditable?: boolean
}

export function useKeyboard(options: KeyboardOptions = {}) {
  const shortcuts = ref<Map<string, KeyboardShortcut>>(new Map())
  const isEnabled = ref(true)
  const lastKeyPressed = ref<string>('')
  const keySequence = ref<string[]>([])
  
  const defaultOptions: Required<KeyboardOptions> = {
    ignoreInputs: true,
    ignoreContentEditable: true,
    ...options
  }
  
  // 檢查是否應該忽略按鍵事件
  const shouldIgnoreEvent = (event: KeyboardEvent): boolean => {
    if (!isEnabled.value) return true
    
    const target = event.target as HTMLElement
    
    // 檢查是否在輸入框中
    if (defaultOptions.ignoreInputs) {
      if (target instanceof HTMLInputElement || 
          target instanceof HTMLTextAreaElement ||
          target instanceof HTMLSelectElement) {
        return true
      }
    }
    
    // 檢查是否在可編輯元素中
    if (defaultOptions.ignoreContentEditable) {
      if (target.contentEditable === 'true') {
        return true
      }
    }
    
    return false
  }
  
  // 生成快捷鍵的唯一標識符
  const generateShortcutKey = (shortcut: Omit<KeyboardShortcut, 'action' | 'description'>): string => {
    const modifiers = []
    if (shortcut.ctrlKey) modifiers.push('ctrl')
    if (shortcut.shiftKey) modifiers.push('shift')
    if (shortcut.altKey) modifiers.push('alt')
    if (shortcut.metaKey) modifiers.push('meta')
    
    return [...modifiers, shortcut.code.toLowerCase()].join('+')
  }
  
  // 檢查事件是否匹配快捷鍵
  const matchesShortcut = (event: KeyboardEvent, shortcut: KeyboardShortcut): boolean => {
    return (
      event.code === shortcut.code &&
      !!event.ctrlKey === !!shortcut.ctrlKey &&
      !!event.shiftKey === !!shortcut.shiftKey &&
      !!event.altKey === !!shortcut.altKey &&
      !!event.metaKey === !!shortcut.metaKey
    )
  }
  
  // 註冊快捷鍵
  const register = (shortcut: KeyboardShortcut) => {
    const key = generateShortcutKey(shortcut)
    shortcuts.value.set(key, shortcut)
  }
  
  // 批量註冊快捷鍵
  const registerMultiple = (shortcutList: KeyboardShortcut[]) => {
    shortcutList.forEach(shortcut => register(shortcut))
  }
  
  // 取消註冊快捷鍵
  const unregister = (code: string, modifiers?: {
    ctrlKey?: boolean
    shiftKey?: boolean
    altKey?: boolean
    metaKey?: boolean
  }) => {
    const key = generateShortcutKey({ 
      code, 
      key: '',
      ...modifiers 
    })
    shortcuts.value.delete(key)
  }
  
  // 清空所有快捷鍵
  const clear = () => {
    shortcuts.value.clear()
  }
  
  // 啟用/禁用快捷鍵
  const enable = () => {
    isEnabled.value = true
  }
  
  const disable = () => {
    isEnabled.value = false
  }
  
  const toggle = () => {
    isEnabled.value = !isEnabled.value
  }
  
  // 獲取所有已註冊的快捷鍵
  const getShortcuts = () => {
    return Array.from(shortcuts.value.values())
  }
  
  // 按鍵事件處理器
  const handleKeydown = (event: KeyboardEvent) => {
    if (shouldIgnoreEvent(event)) return
    
    lastKeyPressed.value = event.code
    keySequence.value.push(event.code)
    
    // 限制序列長度
    if (keySequence.value.length > 5) {
      keySequence.value.shift()
    }
    
    // 查找匹配的快捷鍵
    for (const shortcut of shortcuts.value.values()) {
      if (matchesShortcut(event, shortcut)) {
        if (shortcut.preventDefault !== false) {
          event.preventDefault()
        }
        
        try {
          shortcut.action()
        } catch (error) {
          console.error('快捷鍵執行錯誤:', error)
        }
        
        break
      }
    }
  }
  
  // 常用快捷鍵預設集
  const presets = {
    // 詞彙學習相關
    vocabulary: [
      {
        key: 'Space',
        code: 'Space',
        description: '播放/暫停音頻',
        action: () => {}
      },
      {
        key: 'ArrowRight',
        code: 'ArrowRight',
        description: '下一個詞彙',
        action: () => {}
      },
      {
        key: 'ArrowLeft',
        code: 'ArrowLeft',
        description: '上一個詞彙',
        action: () => {}
      },
      {
        key: 'h',
        code: 'KeyH',
        description: '顯示/隱藏幫助',
        action: () => {}
      },
      {
        key: 'a',
        code: 'KeyA',
        description: '切換自動播放',
        action: () => {}
      },
      {
        key: 'r',
        code: 'KeyR',
        description: '重播音頻',
        action: () => {}
      }
    ] as KeyboardShortcut[],
    
    // 練習模式相關
    practice: [
      {
        key: 'Enter',
        code: 'Enter',
        description: '提交答案',
        action: () => {}
      },
      {
        key: 'n',
        code: 'KeyN',
        description: '下一題',
        action: () => {}
      },
      {
        key: 's',
        code: 'KeyS',
        description: '跳過題目',
        action: () => {}
      },
      {
        key: 'Escape',
        code: 'Escape',
        description: '退出練習',
        action: () => {}
      }
    ] as KeyboardShortcut[],
    
    // 通用導航
    navigation: [
      {
        key: 'Escape',
        code: 'Escape',
        description: '返回上一頁',
        action: () => {}
      },
      {
        key: 'f',
        code: 'KeyF',
        description: '全螢幕模式',
        action: () => {}
      },
      {
        key: '/',
        code: 'Slash',
        description: '搜索',
        action: () => {}
      }
    ] as KeyboardShortcut[]
  }
  
  // 生命週期
  onMounted(() => {
    document.addEventListener('keydown', handleKeydown)
  })
  
  onUnmounted(() => {
    document.removeEventListener('keydown', handleKeydown)
  })
  
  return {
    // 狀態
    shortcuts,
    isEnabled,
    lastKeyPressed,
    keySequence,
    
    // 方法
    register,
    registerMultiple,
    unregister,
    clear,
    enable,
    disable,
    toggle,
    getShortcuts,
    
    // 預設集
    presets
  }
}