import type { Content, Editor } from '@tiptap/core'
import { Decoration, DecorationSet } from '@tiptap/pm/view'
import type { EditorState, Transaction } from '@tiptap/pm/state'
import type { EditorView } from '@tiptap/pm/view'
import { browser } from '$app/environment'
import type { Snippet } from 'svelte'

export interface ShouldShowProps {
	editor: Editor
	element: HTMLElement
	view: EditorView
	state: EditorState
	oldState?: EditorState
	from: number
	to: number
}

export const findColors = (doc: Node) => {
	const hexColor = /(#[0-9a-f]{3,6})\b/gi
	const decorations: Decoration[] = []

	doc.descendants((node, position) => {
		if (!node.text) {
			return
		}

		Array.from(node.text.matchAll(hexColor)).forEach((match) => {
			const color = match[0]
			const index = match.index || 0
			const from = position + index
			const to = from + color.length
			const decoration = Decoration.inline(from, to, {
				class: 'color',
				style: `--color: ${color}`
			})

			decorations.push(decoration)
		})
	})

	return DecorationSet.create(doc, decorations)
}

/**
 * Check if the current browser is mac or not
 */
export const isMac = browser
	? navigator.userAgent.includes('Macintosh') || navigator.userAgent.includes('Mac OS X')
	: false

/**
 * Dupilcate content at the current selection
 * @param editor Editor instance
 * @param node Node to be duplicated
 */
export const duplicateContent = (editor: Editor, node: Node) => {
	const { view } = editor
	const { state } = view
	const { selection } = state

	editor
		.chain()
		.insertContentAt(selection.to, node.toJSON(), {
			updateSelection: true
		})
		.focus(selection.to)
		.run()
}

/**
 * Function to handle paste event of an image
 * @param editor Editor - editor instance
 * @param maxSize number - max size of the image to be pasted in MB, default is 2MB
 */
export function getHandlePaste(editor: Editor, maxSize: number = 2) {
	return (view: EditorView, event: ClipboardEvent) => {
		const item = event.clipboardData?.items[0]

		if (item?.type.indexOf('image') !== 0) {
			return
		}

		const file = item.getAsFile()
		if (file === null || file.size === undefined) return
		const filesize = (file?.size / 1024 / 1024).toFixed(4)

		if (filesize && Number(filesize) > maxSize) {
			window.alert(`too large image! filesize: ${filesize} mb`)
			return
		}

		const reader = new FileReader()
		reader.readAsDataURL(file)
		reader.onload = (e) => {
			if (e.target?.result) {
				editor.commands.insertContent({
					type: 'image',
					attrs: {
						src: e.target.result as string,
						alt: '',
						mediaId: null // No media ID for pasted images
					}
				})
			}
		}
	}
}

/**
 * Sets focus on the editor and moves the cursor to the clicked text position,
 * defaulting to the end of the document if the click is outside any text.
 *
 * @param editor - Editor instance
 * @param event - Optional MouseEvent or KeyboardEvent triggering the focus
 */
export function focusEditor(editor: Editor | undefined, event?: MouseEvent | KeyboardEvent) {
	if (!editor) return
	// Check if there is a text selection already (i.e. a non-empty selection)
	const selection = window.getSelection()
	if (selection && selection.toString().length > 0) {
		// Focus the editor without modifying selection
		editor.chain().focus().run()
		return
	}
	if (event instanceof MouseEvent) {
		const { clientX, clientY } = event
		const pos = editor.view.posAtCoords({ left: clientX, top: clientY })?.pos
		if (pos == null) {
			// If not a valid position, move cursor to the end of the document
			const endPos = editor.state.doc.content.size
			editor.chain().focus().setTextSelection(endPos).run()
		} else {
			editor.chain().focus().setTextSelection(pos).run()
		}
	} else {
		editor.chain().focus().run()
	}
}

/**
 * Props for Edra's editor component
 */
export interface EdraProps {
	class?: string
	content?: Content
	editable?: boolean
	limit?: number
	editor?: Editor
	showSlashCommands?: boolean
	showLinkBubbleMenu?: boolean
	showTableBubbleMenu?: boolean
	/**
	 * Callback function to be called when the content is updated
	 * @param content
	 */
	onUpdate?: (props: { editor: Editor; transaction: Transaction }) => void
	children?: Snippet<[]>
}