'use client'

import { useEffect, useCallback, useState, createContext, useContext, ReactNode } from 'react'
import { useRouter } from 'next/navigation'
import { X, Command, Search } from 'lucide-react'
import clsx from 'clsx'

// ============================================================================
// TYPES
// ============================================================================

interface Shortcut {
  key: string
  label: string
  description: string
  action: () => void
  category: 'navigation' | 'actions' | 'global'
  requiresModifier?: boolean
}

interface KeyboardShortcutsContextType {
  shortcuts: Shortcut[]
  registerShortcut: (shortcut: Shortcut) => void
  unregisterShortcut: (key: string) => void
  showHelp: boolean
  setShowHelp: (show: boolean) => void
}

// ============================================================================
// CONTEXT
// ============================================================================

const KeyboardShortcutsContext = createContext<KeyboardShortcutsContextType | null>(null)

export function useKeyboardShortcuts() {
  const context = useContext(KeyboardShortcutsContext)
  if (!context) {
    throw new Error('useKeyboardShortcuts must be used within KeyboardShortcutsProvider')
  }
  return context
}

// ============================================================================
// PROVIDER
// ============================================================================

export function KeyboardShortcutsProvider({ 
  children,
  shortcuts: defaultShortcuts = [],
}: { 
  children: ReactNode
  shortcuts?: Shortcut[]
}) {
  const router = useRouter()
  const [shortcuts, setShortcuts] = useState<Shortcut[]>(defaultShortcuts)
  const [showHelp, setShowHelp] = useState(false)

  const registerShortcut = useCallback((shortcut: Shortcut) => {
    setShortcuts(prev => {
      const existing = prev.find(s => s.key === shortcut.key)
      if (existing) return prev
      return [...prev, shortcut]
    })
  }, [])

  const unregisterShortcut = useCallback((key: string) => {
    setShortcuts(prev => prev.filter(s => s.key !== key))
  }, [])

  // Handle keyboard events
  useEffect(() => {
    const handleKeyDown = (e: KeyboardEvent) => {
      // Ignore if user is typing in an input
      if (
        e.target instanceof HTMLInputElement ||
        e.target instanceof HTMLTextAreaElement ||
        e.target instanceof HTMLSelectElement ||
        (e.target as HTMLElement)?.isContentEditable
      ) {
        return
      }

      // Show help with ?
      if (e.key === '?' && !e.metaKey && !e.ctrlKey) {
        e.preventDefault()
        setShowHelp(true)
        return
      }

      // Close help with Escape
      if (e.key === 'Escape' && showHelp) {
        e.preventDefault()
        setShowHelp(false)
        return
      }

      // Find matching shortcut
      const shortcut = shortcuts.find(s => {
        if (s.requiresModifier) {
          return (e.metaKey || e.ctrlKey) && e.key.toLowerCase() === s.key.toLowerCase()
        }
        return e.key.toLowerCase() === s.key.toLowerCase() && !e.metaKey && !e.ctrlKey
      })

      if (shortcut) {
        e.preventDefault()
        shortcut.action()
      }
    }

    window.addEventListener('keydown', handleKeyDown)
    return () => window.removeEventListener('keydown', handleKeyDown)
  }, [shortcuts, showHelp])

  return (
    <KeyboardShortcutsContext.Provider value={{ shortcuts, registerShortcut, unregisterShortcut, showHelp, setShowHelp }}>
      {children}
      {showHelp && <ShortcutsModal shortcuts={shortcuts} onClose={() => setShowHelp(false)} />}
    </KeyboardShortcutsContext.Provider>
  )
}

// ============================================================================
// SHORTCUTS MODAL
// ============================================================================

function ShortcutsModal({ shortcuts, onClose }: { shortcuts: Shortcut[]; onClose: () => void }) {
  const categories = {
    navigation: shortcuts.filter(s => s.category === 'navigation'),
    actions: shortcuts.filter(s => s.category === 'actions'),
    global: shortcuts.filter(s => s.category === 'global'),
  }

  return (
    <div 
      className="fixed inset-0 z-[100] bg-background/80 backdrop-blur-sm flex items-center justify-center p-4"
      onClick={onClose}
    >
      <div 
        className="w-full max-w-lg bg-background border border-border/50 rounded-2xl shadow-2xl overflow-hidden"
        onClick={e => e.stopPropagation()}
      >
        {/* Header */}
        <div className="flex items-center justify-between px-6 py-4 border-b border-border/50 bg-background-secondary/50">
          <div className="flex items-center gap-3">
            <div className="w-9 h-9 bg-accent/10 rounded-xl flex items-center justify-center">
              <Command className="w-4 h-4 text-accent" />
            </div>
            <h2 className="text-lg font-semibold text-foreground">Keyboard Shortcuts</h2>
          </div>
          <button
            onClick={onClose}
            className="p-2 text-foreground-muted hover:text-foreground rounded-lg hover:bg-foreground/5 transition-colors"
          >
            <X className="w-5 h-5" />
          </button>
        </div>

        {/* Content */}
        <div className="p-6 max-h-[60vh] overflow-y-auto space-y-6">
          {/* Navigation */}
          {categories.navigation.length > 0 && (
            <div>
              <h3 className="text-xs font-semibold text-foreground-subtle uppercase tracking-wider mb-3">Navigation</h3>
              <div className="space-y-2">
                {categories.navigation.map(shortcut => (
                  <ShortcutRow key={shortcut.key} shortcut={shortcut} />
                ))}
              </div>
            </div>
          )}

          {/* Actions */}
          {categories.actions.length > 0 && (
            <div>
              <h3 className="text-xs font-semibold text-foreground-subtle uppercase tracking-wider mb-3">Actions</h3>
              <div className="space-y-2">
                {categories.actions.map(shortcut => (
                  <ShortcutRow key={shortcut.key} shortcut={shortcut} />
                ))}
              </div>
            </div>
          )}

          {/* Global */}
          {categories.global.length > 0 && (
            <div>
              <h3 className="text-xs font-semibold text-foreground-subtle uppercase tracking-wider mb-3">Global</h3>
              <div className="space-y-2">
                {categories.global.map(shortcut => (
                  <ShortcutRow key={shortcut.key} shortcut={shortcut} />
                ))}
              </div>
            </div>
          )}
        </div>

        {/* Footer */}
        <div className="px-6 py-3 border-t border-border/50 bg-background-secondary/30">
          <p className="text-xs text-foreground-subtle text-center">
            Press <kbd className="px-1.5 py-0.5 bg-foreground/10 rounded text-foreground-muted">?</kbd> anytime to show this help
          </p>
        </div>
      </div>
    </div>
  )
}

function ShortcutRow({ shortcut }: { shortcut: Shortcut }) {
  return (
    <div className="flex items-center justify-between py-2 px-3 rounded-lg hover:bg-foreground/5 transition-colors">
      <div>
        <p className="text-sm font-medium text-foreground">{shortcut.label}</p>
        <p className="text-xs text-foreground-subtle">{shortcut.description}</p>
      </div>
      <div className="flex items-center gap-1">
        {shortcut.requiresModifier && (
          <>
            <kbd className="px-2 py-1 bg-foreground/10 rounded text-xs font-mono text-foreground-muted">⌘</kbd>
            <span className="text-foreground-subtle">+</span>
          </>
        )}
        <kbd className="px-2 py-1 bg-foreground/10 rounded text-xs font-mono text-foreground-muted uppercase">
          {shortcut.key}
        </kbd>
      </div>
    </div>
  )
}

// ============================================================================
// USER BACKEND SHORTCUTS
// ============================================================================

export function useUserShortcuts() {
  const router = useRouter()
  const { registerShortcut, unregisterShortcut, setShowHelp } = useKeyboardShortcuts()

  useEffect(() => {
    const userShortcuts: Shortcut[] = [
      // Navigation
      { key: 'g', label: 'Go to Dashboard', description: 'Navigate to dashboard', action: () => router.push('/dashboard'), category: 'navigation' },
      { key: 'w', label: 'Go to Watchlist', description: 'Navigate to watchlist', action: () => router.push('/watchlist'), category: 'navigation' },
      { key: 'p', label: 'Go to Portfolio', description: 'Navigate to portfolio', action: () => router.push('/portfolio'), category: 'navigation' },
      { key: 'a', label: 'Go to Auctions', description: 'Navigate to auctions', action: () => router.push('/auctions'), category: 'navigation' },
      { key: 'i', label: 'Go to Intelligence', description: 'Navigate to TLD intelligence', action: () => router.push('/intelligence'), category: 'navigation' },
      { key: 's', label: 'Go to Settings', description: 'Navigate to settings', action: () => router.push('/settings'), category: 'navigation' },
      // Actions
      { key: 'n', label: 'Add Domain', description: 'Quick add a new domain', action: () => document.querySelector<HTMLInputElement>('input[placeholder*="domain"]')?.focus(), category: 'actions' },
      { key: 'k', label: 'Search', description: 'Focus search input', action: () => document.querySelector<HTMLInputElement>('input[type="text"]')?.focus(), category: 'actions', requiresModifier: true },
      // Global
      { key: '?', label: 'Show Shortcuts', description: 'Display this help', action: () => setShowHelp(true), category: 'global' },
      { key: 'Escape', label: 'Close Modal', description: 'Close any open modal', action: () => {}, category: 'global' },
    ]

    userShortcuts.forEach(registerShortcut)

    return () => {
      userShortcuts.forEach(s => unregisterShortcut(s.key))
    }
  }, [router, registerShortcut, unregisterShortcut, setShowHelp])
}

// ============================================================================
// ADMIN SHORTCUTS
// ============================================================================

export function useAdminShortcuts() {
  const router = useRouter()
  const { registerShortcut, unregisterShortcut, setShowHelp } = useKeyboardShortcuts()

  useEffect(() => {
    const adminShortcuts: Shortcut[] = [
      // Navigation
      { key: 'o', label: 'Overview', description: 'Go to admin overview', action: () => {}, category: 'navigation' },
      { key: 'u', label: 'Users', description: 'Go to users management', action: () => {}, category: 'navigation' },
      { key: 'b', label: 'Blog', description: 'Go to blog management', action: () => {}, category: 'navigation' },
      { key: 'y', label: 'System', description: 'Go to system status', action: () => {}, category: 'navigation' },
      // Actions
      { key: 'r', label: 'Refresh Data', description: 'Refresh current data', action: () => window.location.reload(), category: 'actions' },
      { key: 'e', label: 'Export', description: 'Export current data', action: () => {}, category: 'actions' },
      // Global
      { key: '?', label: 'Show Shortcuts', description: 'Display this help', action: () => setShowHelp(true), category: 'global' },
      { key: 'd', label: 'Back to Dashboard', description: 'Return to user dashboard', action: () => router.push('/dashboard'), category: 'global' },
    ]

    adminShortcuts.forEach(registerShortcut)

    return () => {
      adminShortcuts.forEach(s => unregisterShortcut(s.key))
    }
  }, [router, registerShortcut, unregisterShortcut, setShowHelp])
}

// ============================================================================
// SHORTCUT HINT COMPONENT
// ============================================================================

export function ShortcutHint({ shortcut, className }: { shortcut: string; className?: string }) {
  return (
    <kbd className={clsx(
      "hidden sm:inline-flex items-center justify-center",
      "px-1.5 py-0.5 text-[10px] font-mono uppercase",
      "bg-foreground/5 text-foreground-subtle border border-border/50 rounded",
      className
    )}>
      {shortcut}
    </kbd>
  )
}