'use client'

import { NodeSelection, TextSelection } from '@tiptap/pm/state'
import type { Editor } from '@tiptap/react'
import * as React from 'react'
import { useHotkeys } from 'react-hotkeys-hook'
// --- Icons ---
import { HeadingFiveIcon } from '~/components/tiptap/tiptap-icons/heading-five-icon'
import { HeadingFourIcon } from '~/components/tiptap/tiptap-icons/heading-four-icon'
import { HeadingOneIcon } from '~/components/tiptap/tiptap-icons/heading-one-icon'
import { HeadingSixIcon } from '~/components/tiptap/tiptap-icons/heading-six-icon'
import { HeadingThreeIcon } from '~/components/tiptap/tiptap-icons/heading-three-icon'
import { HeadingTwoIcon } from '~/components/tiptap/tiptap-icons/heading-two-icon'
// --- Hooks ---
import { useIsMobile } from '~/hooks/use-mobile'
import { useTiptapEditor } from '~/hooks/use-tiptap-editor'
// --- Lib ---
import {
  findNodePosition,
  isNodeInSchema,
  isNodeTypeSelected,
  isValidPosition,
} from '~/utils/tiptap_utils'

export type Level = 1 | 2 | 3 | 4 | 5 | 6

/**
 * Configuration for the heading functionality
 */
export interface UseHeadingConfig {
  /**
   * The Tiptap editor instance.
   */
  editor?: Editor | null
  /**
   * The heading level.
   */
  level: Level
  /**
   * Whether the button should hide when heading is not available.
   * @default false
   */
  hideWhenUnavailable?: boolean
  /**
   * Callback function called after a successful heading toggle.
   */
  onToggled?: () => void
}

export const headingIcons = {
  1: HeadingOneIcon,
  2: HeadingTwoIcon,
  3: HeadingThreeIcon,
  4: HeadingFourIcon,
  5: HeadingFiveIcon,
  6: HeadingSixIcon,
}

export const HEADING_SHORTCUT_KEYS: Record<Level, string> = {
  1: 'ctrl+alt+1',
  2: 'ctrl+alt+2',
  3: 'ctrl+alt+3',
  4: 'ctrl+alt+4',
  5: 'ctrl+alt+5',
  6: 'ctrl+alt+6',
}

/**
 * Checks if heading can be toggled in the current editor state
 */
export function canToggle(editor: Editor | null, level?: Level, turnInto: boolean = true): boolean {
  if (!editor || !editor.isEditable) return false
  if (!isNodeInSchema('heading', editor) || isNodeTypeSelected(editor, ['image'])) return false

  if (!turnInto) {
    return level ? editor.can().setNode('heading', { level }) : editor.can().setNode('heading')
  }

  try {
    const view = editor.view
    const state = view.state
    const selection = state.selection

    if (selection.empty || selection instanceof TextSelection) {
      const pos = findNodePosition({
        editor,
        node: state.selection.$anchor.node(1),
      })?.pos
      if (!isValidPosition(pos)) return false
    }

    return true
  } catch {
    return false
  }
}

/**
 * Checks if heading is currently active
 */
export function isHeadingActive(editor: Editor | null, level?: Level | Level[]): boolean {
  if (!editor || !editor.isEditable) return false

  if (Array.isArray(level)) {
    return level.some((l) => editor.isActive('heading', { level: l }))
  }

  return level ? editor.isActive('heading', { level }) : editor.isActive('heading')
}

/**
 * Toggles heading in the editor
 */
export function toggleHeading(editor: Editor | null, level: Level | Level[]): boolean {
  if (!editor || !editor.isEditable) return false

  const levels = Array.isArray(level) ? level : [level]
  const toggleLevel = levels.find((l) => canToggle(editor, l))

  if (!toggleLevel) return false

  try {
    const view = editor.view
    let state = view.state
    let tr = state.tr

    // No selection, find the cursor position
    if (state.selection.empty || state.selection instanceof TextSelection) {
      const pos = findNodePosition({
        editor,
        node: state.selection.$anchor.node(1),
      })?.pos
      if (!isValidPosition(pos)) return false

      tr = tr.setSelection(NodeSelection.create(state.doc, pos))
      view.dispatch(tr)
      state = view.state
    }

    const selection = state.selection
    let chain = editor.chain().focus()

    // Handle NodeSelection
    if (selection instanceof NodeSelection) {
      const firstChild = selection.node.firstChild?.firstChild
      const lastChild = selection.node.lastChild?.lastChild

      const from = firstChild ? selection.from + firstChild.nodeSize : selection.from + 1

      const to = lastChild ? selection.to - lastChild.nodeSize : selection.to - 1

      chain = chain.setTextSelection({ from, to }).clearNodes()
    }

    const isActive = levels.some((l) => editor.isActive('heading', { level: l }))

    const toggle = isActive
      ? chain.setNode('paragraph')
      : chain.setNode('heading', { level: toggleLevel })

    toggle.run()

    editor.chain().focus().selectTextblockEnd().run()

    return true
  } catch {
    return false
  }
}

/**
 * Determines if the heading button should be shown
 */
export function shouldShowButton(props: {
  editor: Editor | null
  level?: Level | Level[]
  hideWhenUnavailable: boolean
}): boolean {
  const { editor, level, hideWhenUnavailable } = props

  if (!editor || !editor.isEditable) return false
  if (!isNodeInSchema('heading', editor)) return false

  if (hideWhenUnavailable && !editor.isActive('code')) {
    if (Array.isArray(level)) {
      return level.some((l) => canToggle(editor, l))
    }
    return canToggle(editor, level)
  }

  return true
}

/**
 * Custom hook that provides heading functionality for Tiptap editor
 *
 * @example
 * ```tsx
 * // Simple usage
 * function MySimpleHeadingButton() {
 *   const { isVisible, isActive, handleToggle, Icon } = useHeading({ level: 1 })
 *
 *   if (!isVisible) return null
 *
 *   return (
 *     <button
 *       onClick={handleToggle}
 *       aria-pressed={isActive}
 *     >
 *       <Icon />
 *       Heading 1
 *     </button>
 *   )
 * }
 *
 * // Advanced usage with configuration
 * function MyAdvancedHeadingButton() {
 *   const { isVisible, isActive, handleToggle, label, Icon } = useHeading({
 *     level: 2,
 *     editor: myEditor,
 *     hideWhenUnavailable: true,
 *     onToggled: (isActive) => console.log('Heading toggled:', isActive)
 *   })
 *
 *   if (!isVisible) return null
 *
 *   return (
 *     <MyButton
 *       onClick={handleToggle}
 *       aria-label={label}
 *       aria-pressed={isActive}
 *     >
 *       <Icon />
 *       Toggle Heading 2
 *     </MyButton>
 *   )
 * }
 * ```
 */
export function useHeading(config: UseHeadingConfig) {
  const { editor: providedEditor, level, hideWhenUnavailable = false, onToggled } = config

  const { editor } = useTiptapEditor(providedEditor)
  const isMobile = useIsMobile()
  const [isVisible, setIsVisible] = React.useState<boolean>(true)
  const canToggleState = canToggle(editor, level)
  const isActive = isHeadingActive(editor, level)

  React.useEffect(() => {
    if (!editor) return

    const handleSelectionUpdate = () => {
      setIsVisible(shouldShowButton({ editor, level, hideWhenUnavailable }))
    }

    handleSelectionUpdate()

    editor.on('selectionUpdate', handleSelectionUpdate)

    return () => {
      editor.off('selectionUpdate', handleSelectionUpdate)
    }
  }, [editor, level, hideWhenUnavailable])

  const handleToggle = React.useCallback(() => {
    if (!editor) return false

    const success = toggleHeading(editor, level)
    if (success) {
      onToggled?.()
    }
    return success
  }, [editor, level, onToggled])

  useHotkeys(
    HEADING_SHORTCUT_KEYS[level],
    (event) => {
      event.preventDefault()
      handleToggle()
    },
    {
      enabled: isVisible && canToggleState,
      enableOnContentEditable: !isMobile,
      enableOnFormTags: true,
    },
  )

  return {
    isVisible,
    isActive,
    handleToggle,
    canToggle: canToggleState,
    label: `Heading ${level}`,
    shortcutKeys: HEADING_SHORTCUT_KEYS[level],
    Icon: headingIcons[level],
  }
}