"use client"

import { NodeSelection, TextSelection } from "@tiptap/pm/state"
import type {Editor} from "@tiptap/react";
import { useCallback, useEffect, useState } from "react"

// --- Hooks ---
import { CodeBlockIcon } from "@/components/tiptap-icons/code-block-icon"
import { useTiptapEditor } from "@/hooks/use-tiptap-editor"

// --- Lib ---
import {
  findNodePosition,
  getSelectedBlockNodes,
  isNodeInSchema,
  isNodeTypeSelected,
  isValidPosition,
  selectionWithinConvertibleTypes,
} from "@/lib/tiptap-utils"

// --- Icons ---

export const CODE_BLOCK_SHORTCUT_KEY = "mod+alt+c"

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

/**
 * Checks if code block can be toggled in the current editor state
 */
export function canToggle(
  editor: Editor | null,
  turnInto: boolean = true
): boolean {
  if (!editor || !editor.isEditable) {
return false
}

  if (
    !isNodeInSchema("codeBlock", editor) ||
    isNodeTypeSelected(editor, ["image"])
  ) {
return false
}

  if (!turnInto) {
    return editor.can().toggleNode("codeBlock", "paragraph")
  }

  // Ensure selection is in nodes we're allowed to convert
  if (
    !selectionWithinConvertibleTypes(editor, [
      "paragraph",
      "heading",
      "bulletList",
      "orderedList",
      "taskList",
      "blockquote",
      "codeBlock",
    ])
  ) {
return false
}

  // Either we can toggle code block directly on the selection,
  // or we can clear formatting/nodes to arrive at a code block.
  return (
    editor.can().toggleNode("codeBlock", "paragraph") ||
    editor.can().clearNodes()
  )
}

/**
 * Toggles code block in the editor
 */
export function toggleCodeBlock(editor: Editor | null): boolean {
  if (!editor || !editor.isEditable) {
return false
}

  if (!canToggle(editor)) {
return false
}

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

    const blocks = getSelectedBlockNodes(editor)

    // In case a selection contains multiple blocks, we only allow
    // toggling to nide if there's exactly one block selected
    // we also dont block the canToggle since it will fall back to the bottom logic
    const isPossibleToTurnInto =
      selectionWithinConvertibleTypes(editor, [
        "paragraph",
        "heading",
        "bulletList",
        "orderedList",
        "taskList",
        "blockquote",
        "codeBlock",
      ]) && blocks.length === 1

    // No selection, find the the cursor position
    if (
      (state.selection.empty || state.selection instanceof TextSelection) &&
      isPossibleToTurnInto
    ) {
      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

      const resolvedFrom = state.doc.resolve(from)
      const resolvedTo = state.doc.resolve(to)

      chain = chain
        .setTextSelection(TextSelection.between(resolvedFrom, resolvedTo))
        .clearNodes()
    }

    const toggle = editor.isActive("codeBlock")
      ? chain.setNode("paragraph")
      : chain.toggleNode("codeBlock", "paragraph")

    toggle.run()

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

    return true
  } catch {
    return false
  }
}

/**
 * Determines if the code block button should be shown
 */
export function shouldShowButton(props: {
  editor: Editor | null
  hideWhenUnavailable: boolean
}): boolean {
  const { editor, hideWhenUnavailable } = props

  if (!editor) {
return false
}

  if (!hideWhenUnavailable) {
    return true
  }

  if (!editor.isEditable) {
return false
}

  if (!isNodeInSchema("codeBlock", editor)) {
return false
}

  if (!editor.isActive("code")) {
    return canToggle(editor)
  }

  return true
}

/**
 * Custom hook that provides code block functionality for Tiptap editor
 *
 * @example
 * ```tsx
 * // Simple usage - no params needed
 * function MySimpleCodeBlockButton() {
 *   const { isVisible, isActive, handleToggle } = useCodeBlock()
 *
 *   if (!isVisible) return null
 *
 *   return (
 *     <button
 *       onClick={handleToggle}
 *       aria-pressed={isActive}
 *     >
 *       Code Block
 *     </button>
 *   )
 * }
 *
 * // Advanced usage with configuration
 * function MyAdvancedCodeBlockButton() {
 *   const { isVisible, isActive, handleToggle, label } = useCodeBlock({
 *     editor: myEditor,
 *     hideWhenUnavailable: true,
 *     onToggled: (isActive) => console.log('Code block toggled:', isActive)
 *   })
 *
 *   if (!isVisible) return null
 *
 *   return (
 *     <MyButton
 *       onClick={handleToggle}
 *       aria-label={label}
 *       aria-pressed={isActive}
 *     >
 *       Toggle Code Block
 *     </MyButton>
 *   )
 * }
 * ```
 */
export function useCodeBlock(config?: UseCodeBlockConfig) {
  const {
    editor: providedEditor,
    hideWhenUnavailable = false,
    onToggled,
  } = config || {}

  const { editor } = useTiptapEditor(providedEditor)
  const [isVisible, setIsVisible] = useState<boolean>(true)
  const canToggleState = canToggle(editor)
  const isActive = editor?.isActive("codeBlock") || false

  useEffect(() => {
    if (!editor) {
return
}

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

    handleSelectionUpdate()

    editor.on("selectionUpdate", handleSelectionUpdate)

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

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

    const success = toggleCodeBlock(editor)

    if (success) {
      onToggled?.()
    }

    return success
  }, [editor, onToggled])

  return {
    isVisible,
    isActive,
    handleToggle,
    canToggle: canToggleState,
    label: "Code Block",
    shortcutKeys: CODE_BLOCK_SHORTCUT_KEY,
    Icon: CodeBlockIcon,
  }
}