import Vue from 'vue'
import Emoji from './Emoji.vue'

export default Vue.component('MessageContent', {
	props: {
		item: {
			type: Object,
			required: true,
		},
	},
	render(createElement) {
		return formatMessage(createElement, this.item)
	},
})

/**
 * Transform the Status into Vue elements
 *
 * filters out all tags except <br />, <p>, <span> and <a>.
 *
 * Links that are hashtags or mentions are rewritten to link to the local profile or hashtag page
 * All external links have `rel="nofollow noopener noreferrer"` and `target="_blank"` set.
 *
 * All attributes other than `href` for links are stripped from the content
 *
 * @param {Function} createElement
 * @param {import('../types/Mastodon').Status} item
 */
export function formatMessage(createElement, item) {
	if (!item.tags) {
		item.tags = []
	}
	const parser = new DOMParser()
	const dom = parser.parseFromString(`<div id="rootwrapper">${item.content}</div>`, 'text/html')
	const element = dom.getElementById('rootwrapper')
	const cleaned = cleanCopy(createElement, element, item)
	return cleaned
}

/**
 *
 * @param {Function} createElement
 * @param {HTMLElement} node
 * @param {import('../types/Mastodon').Status} context
 */
function domToVue(createElement, node, context) {
	switch (node.tagName) {
	case 'P':
		return cleanCopy(createElement, node, context)
	case 'BR':
		return cleanCopy(createElement, node, context)
	case 'SPAN':
		return cleanCopy(createElement, node, context)
	case 'A':
		// @ts-ignore - if tagName === 'A' then node is instance of HTMLLinkElement
		return cleanLink(createElement, node, context)
	default:
		return transformText(createElement, node.textContent ?? '')
	}
}

const mentionRegex = /(\W|^)((@\w+)@[\w.-_]+)/i
const hashTagRegex = /(\W|^)(#\w+)/i

/**
 *
 * @param {Function} createElement
 * @param {string} text
 */
function transformText(createElement, text) {
	return transformTextRegex(text, [
		{
			regex: mentionRegex,
			onMatch: match => [
				match[1],
				createElement(
					'router-link',
					{
						props: {
							to: {
								name: 'profile',
								params: { account: match[2].slice(1) },
							},
						},
					},
					[match[3]]
				),
			],
		},
		{
			regex: hashTagRegex,
			onMatch: match => [
				match[1],
				createElement(
					'router-link',
					{
						props: {
							to: {
								name: 'tags',
								params: { tag: match[2].slice(1) },
							},
						},
					},
					[match[2]]
				),
			],
		},
		{
			regex: emojiRe,
			onMatch: match => createElement(
				Emoji,
				{
					props: {
						emoji: match[0],
					},
				}
			),
		},
	])
}

/**
 * copy a node without any attributes and cleaning all children
 *
 * @param {Function} createElement
 * @param {HTMLElement} node
 * @param {import('../types/Mastodon').Status} context
 */
function cleanCopy(createElement, node, context) {
	const children = Array.from(node.childNodes).map(node => domToVue(createElement, node, context))
	return createElement(node.tagName, children)
}

/**
 *
 * @param {Function} createElement
 * @param {HTMLLinkElement} node
 * @param {import('../types/Mastodon').Status} context
 */
function cleanLink(createElement, node, context) {
	const type = getLinkType(node.className)
	const attributes = {}
	const tag = matchMention(context.mentions, node.getAttribute('href') ?? '', node.textContent ?? '')

	switch (type) {
	case 'mention':
		if (tag) {
			attributes.rel = 'nofollow noopener noreferrer'
			attributes.target = '_blank'
			attributes.href = node.getAttribute('href')
			attributes.title = tag.name

			return createElement('a', { attrs: attributes }, [transformText(createElement, node.textContent)])
		} else {
			return transformText(createElement, node.textContent)
		}
	case 'hashtag':
		return createElement(
			'router-link',
			{
				props: {
					to: {
						name: 'tags',
						params: { tag: node.textContent?.slice(1) },
					},
				},
			},
			[node.textContent]
		)
	default:
		attributes.rel = 'nofollow noopener noreferrer'
		attributes.target = '_blank'
		attributes.href = node.getAttribute('href')

		return createElement('a', { attrs: attributes }, [transformText(createElement, node.textContent)])
	}
}

/**
 *
 * @param {string} className
 */
function getLinkType(className) {
	const parts = className.split(' ')
	if (parts.includes('hashtag')) {
		return 'hashtag'
	}
	if (parts.includes('mention')) {
		return 'mention'
	}
	return ''
}

/**
 *
 * @param {Array} tags
 * @param {string} mentionHref
 * @param {string} mentionText
 */
function matchMention(tags, mentionHref, mentionText) {
	const mentionUrl = new URL(mentionHref)
	for (const tag of tags) {
		if (mentionText === tag.name) {
			return tag
		}

		// since the mention link href is not always equal to the href in the tag
		// we instead match the server and username separate
		const tagUrl = new URL(tag.href)
		if (tagUrl.host === mentionUrl.host) {
			const [, name] = tag.name.split('@')
			if (name === mentionText || '@' + name === mentionText) {
				return tag
			}
		}
	}
	return null
}

// RegExp based on emoji's official Unicode standards
// http://www.unicode.org/Public/UNIDATA/EmojiSources.txt
const emojiRe = /(?:\ud83d\udc68\ud83c\udffb\u200d\ud83e\udd1d\u200d\ud83d\udc68\ud83c[\udffc-\udfff]|\ud83d\udc68\ud83c\udffc\u200d\ud83e\udd1d\u200d\ud83d\udc68\ud83c[\udffb\udffd-\udfff]|\ud83d\udc68\ud83c\udffd\u200d\ud83e\udd1d\u200d\ud83d\udc68\ud83c[\udffb\udffc\udffe\udfff]|\ud83d\udc68\ud83c\udffe\u200d\ud83e\udd1d\u200d\ud83d\udc68\ud83c[\udffb-\udffd\udfff]|\ud83d\udc68\ud83c\udfff\u200d\ud83e\udd1d\u200d\ud83d\udc68\ud83c[\udffb-\udffe]|\ud83d\udc69\ud83c\udffb\u200d\ud83e\udd1d\u200d\ud83d\udc68\ud83c[\udffc-\udfff]|\ud83d\udc69\ud83c\udffb\u200d\ud83e\udd1d\u200d\ud83d\udc69\ud83c[\udffc-\udfff]|\ud83d\udc69\ud83c\udffc\u200d\ud83e\udd1d\u200d\ud83d\udc68\ud83c[\udffb\udffd-\udfff]|\ud83d\udc69\ud83c\udffc\u200d\ud83e\udd1d\u200d\ud83d\udc69\ud83c[\udffb\udffd-\udfff]|\ud83d\udc69\ud83c\udffd\u200d\ud83e\udd1d\u200d\ud83d\udc68\ud83c[\udffb\udffc\udffe\udfff]|\ud83d\udc69\ud83c\udffd\u200d\ud83e\udd1d\u200d\ud83d\udc69\ud83c[\udffb\udffc\udffe\udfff]|\ud83d\udc69\ud83c\udffe\u200d\ud83e\udd1d\u200d\ud83d\udc68\ud83c[\udffb-\udffd\udfff]|\ud83d\udc69\ud83c\udffe\u200d\ud83e\udd1d\u200d\ud83d\udc69\ud83c[\udffb-\udffd\udfff]|\ud83d\udc69\ud83c\udfff\u200d\ud83e\udd1d\u200d\ud83d\udc68\ud83c[\udffb-\udffe]|\ud83d\udc69\ud83c\udfff\u200d\ud83e\udd1d\u200d\ud83d\udc69\ud83c[\udffb-\udffe]|\ud83e\uddd1\ud83c\udffb\u200d\ud83e\udd1d\u200d\ud83e\uddd1\ud83c[\udffb-\udfff]|\ud83e\uddd1\ud83c\udffc\u200d\ud83e\udd1d\u200d\ud83e\uddd1\ud83c[\udffb-\udfff]|\ud83e\uddd1\ud83c\udffd\u200d\ud83e\udd1d\u200d\ud83e\uddd1\ud83c[\udffb-\udfff]|\ud83e\uddd1\ud83c\udffe\u200d\ud83e\udd1d\u200d\ud83e\uddd1\ud83c[\udffb-\udfff]|\ud83e\uddd1\ud83c\udfff\u200d\ud83e\udd1d\u200d\ud83e\uddd1\ud83c[\udffb-\udfff]|\ud83e\uddd1\u200d\ud83e\udd1d\u200d\ud83e\uddd1|\ud83d\udc6b\ud83c[\udffb-\udfff]|\ud83d\udc6c\ud83c[\udffb-\udfff]|\ud83d\udc6d\ud83c[\udffb-\udfff]|\ud83d[\udc6b-\udc6d])|(?:\ud83d[\udc68\udc69]|\ud83e\uddd1)(?:\ud83c[\udffb-\udfff])?\u200d(?:\u2695\ufe0f|\u2696\ufe0f|\u2708\ufe0f|\ud83c[\udf3e\udf73\udf7c\udf84\udf93\udfa4\udfa8\udfeb\udfed]|\ud83d[\udcbb\udcbc\udd27\udd2c\ude80\ude92]|\ud83e[\uddaf-\uddb3\uddbc\uddbd])|(?:\ud83c[\udfcb\udfcc]|\ud83d[\udd74\udd75]|\u26f9)((?:\ud83c[\udffb-\udfff]|\ufe0f)\u200d[\u2640\u2642]\ufe0f)|(?:\ud83c[\udfc3\udfc4\udfca]|\ud83d[\udc6e\udc70\udc71\udc73\udc77\udc81\udc82\udc86\udc87\ude45-\ude47\ude4b\ude4d\ude4e\udea3\udeb4-\udeb6]|\ud83e[\udd26\udd35\udd37-\udd39\udd3d\udd3e\uddb8\uddb9\uddcd-\uddcf\uddd6-\udddd])(?:\ud83c[\udffb-\udfff])?\u200d[\u2640\u2642]\ufe0f|(?:\ud83d\udc68\u200d\u2764\ufe0f\u200d\ud83d\udc8b\u200d\ud83d\udc68|\ud83d\udc68\u200d\ud83d\udc68\u200d\ud83d\udc66\u200d\ud83d\udc66|\ud83d\udc68\u200d\ud83d\udc68\u200d\ud83d\udc67\u200d\ud83d[\udc66\udc67]|\ud83d\udc68\u200d\ud83d\udc69\u200d\ud83d\udc66\u200d\ud83d\udc66|\ud83d\udc68\u200d\ud83d\udc69\u200d\ud83d\udc67\u200d\ud83d[\udc66\udc67]|\ud83d\udc69\u200d\u2764\ufe0f\u200d\ud83d\udc8b\u200d\ud83d[\udc68\udc69]|\ud83d\udc69\u200d\ud83d\udc69\u200d\ud83d\udc66\u200d\ud83d\udc66|\ud83d\udc69\u200d\ud83d\udc69\u200d\ud83d\udc67\u200d\ud83d[\udc66\udc67]|\ud83d\udc68\u200d\u2764\ufe0f\u200d\ud83d\udc68|\ud83d\udc68\u200d\ud83d\udc66\u200d\ud83d\udc66|\ud83d\udc68\u200d\ud83d\udc67\u200d\ud83d[\udc66\udc67]|\ud83d\udc68\u200d\ud83d\udc68\u200d\ud83d[\udc66\udc67]|\ud83d\udc68\u200d\ud83d\udc69\u200d\ud83d[\udc66\udc67]|\ud83d\udc69\u200d\u2764\ufe0f\u200d\ud83d[\udc68\udc69]|\ud83d\udc69\u200d\ud83d\udc66\u200d\ud83d\udc66|\ud83d\udc69\u200d\ud83d\udc67\u200d\ud83d[\udc66\udc67]|\ud83d\udc69\u200d\ud83d\udc69\u200d\ud83d[\udc66\udc67]|\ud83c\udff3\ufe0f\u200d\u26a7\ufe0f|\ud83c\udff3\ufe0f\u200d\ud83c\udf08|\ud83c\udff4\u200d\u2620\ufe0f|\ud83d\udc15\u200d\ud83e\uddba|\ud83d\udc3b\u200d\u2744\ufe0f|\ud83d\udc41\u200d\ud83d\udde8|\ud83d\udc68\u200d\ud83d[\udc66\udc67]|\ud83d\udc69\u200d\ud83d[\udc66\udc67]|\ud83d\udc6f\u200d\u2640\ufe0f|\ud83d\udc6f\u200d\u2642\ufe0f|\ud83e\udd3c\u200d\u2640\ufe0f|\ud83e\udd3c\u200d\u2642\ufe0f|\ud83e\uddde\u200d\u2640\ufe0f|\ud83e\uddde\u200d\u2642\ufe0f|\ud83e\udddf\u200d\u2640\ufe0f|\ud83e\udddf\u200d\u2642\ufe0f|\ud83d\udc08\u200d\u2b1b)|[#*0-9]\ufe0f?\u20e3|(?:[©®\u2122\u265f]\ufe0f)|(?:\ud83c[\udc04\udd70\udd71\udd7e\udd7f\ude02\ude1a\ude2f\ude37\udf21\udf24-\udf2c\udf36\udf7d\udf96\udf97\udf99-\udf9b\udf9e\udf9f\udfcd\udfce\udfd4-\udfdf\udff3\udff5\udff7]|\ud83d[\udc3f\udc41\udcfd\udd49\udd4a\udd6f\udd70\udd73\udd76-\udd79\udd87\udd8a-\udd8d\udda5\udda8\uddb1\uddb2\uddbc\uddc2-\uddc4\uddd1-\uddd3\udddc-\uddde\udde1\udde3\udde8\uddef\uddf3\uddfa\udecb\udecd-\udecf\udee0-\udee5\udee9\udef0\udef3]|[\u203c\u2049\u2139\u2194-\u2199\u21a9\u21aa\u231a\u231b\u2328\u23cf\u23ed-\u23ef\u23f1\u23f2\u23f8-\u23fa\u24c2\u25aa\u25ab\u25b6\u25c0\u25fb-\u25fe\u2600-\u2604\u260e\u2611\u2614\u2615\u2618\u2620\u2622\u2623\u2626\u262a\u262e\u262f\u2638-\u263a\u2640\u2642\u2648-\u2653\u2660\u2663\u2665\u2666\u2668\u267b\u267f\u2692-\u2697\u2699\u269b\u269c\u26a0\u26a1\u26a7\u26aa\u26ab\u26b0\u26b1\u26bd\u26be\u26c4\u26c5\u26c8\u26cf\u26d1\u26d3\u26d4\u26e9\u26ea\u26f0-\u26f5\u26f8\u26fa\u26fd\u2702\u2708\u2709\u270f\u2712\u2714\u2716\u271d\u2721\u2733\u2734\u2744\u2747\u2757\u2763\u2764\u27a1\u2934\u2935\u2b05-\u2b07\u2b1b\u2b1c\u2b50\u2b55\u3030\u303d\u3297\u3299])(?:\ufe0f|(?!\ufe0e))|(?:(?:\ud83c[\udfcb\udfcc]|\ud83d[\udd74\udd75\udd90]|[\u261d\u26f7\u26f9\u270c\u270d])(?:\ufe0f|(?!\ufe0e))|(?:\ud83c[\udf85\udfc2-\udfc4\udfc7\udfca]|\ud83d[\udc42\udc43\udc46-\udc50\udc66-\udc69\udc6e\udc70-\udc78\udc7c\udc81-\udc83\udc85-\udc87\udcaa\udd7a\udd95\udd96\ude45-\ude47\ude4b-\ude4f\udea3\udeb4-\udeb6\udec0\udecc]|\ud83e[\udd0c\udd0f\udd18-\udd1c\udd1e\udd1f\udd26\udd30-\udd39\udd3d\udd3e\udd77\uddb5\uddb6\uddb8\uddb9\uddbb\uddcd-\uddcf\uddd1-\udddd]|[\u270a\u270b]))(?:\ud83c[\udffb-\udfff])?|(?:\ud83c\udff4\udb40\udc67\udb40\udc62\udb40\udc65\udb40\udc6e\udb40\udc67\udb40\udc7f|\ud83c\udff4\udb40\udc67\udb40\udc62\udb40\udc73\udb40\udc63\udb40\udc74\udb40\udc7f|\ud83c\udff4\udb40\udc67\udb40\udc62\udb40\udc77\udb40\udc6c\udb40\udc73\udb40\udc7f|\ud83c\udde6\ud83c[\udde8-\uddec\uddee\uddf1\uddf2\uddf4\uddf6-\uddfa\uddfc\uddfd\uddff]|\ud83c\udde7\ud83c[\udde6\udde7\udde9-\uddef\uddf1-\uddf4\uddf6-\uddf9\uddfb\uddfc\uddfe\uddff]|\ud83c\udde8\ud83c[\udde6\udde8\udde9\uddeb-\uddee\uddf0-\uddf5\uddf7\uddfa-\uddff]|\ud83c\udde9\ud83c[\uddea\uddec\uddef\uddf0\uddf2\uddf4\uddff]|\ud83c\uddea\ud83c[\udde6\udde8\uddea\uddec\udded\uddf7-\uddfa]|\ud83c\uddeb\ud83c[\uddee-\uddf0\uddf2\uddf4\uddf7]|\ud83c\uddec\ud83c[\udde6\udde7\udde9-\uddee\uddf1-\uddf3\uddf5-\uddfa\uddfc\uddfe]|\ud83c\udded\ud83c[\uddf0\uddf2\uddf3\uddf7\uddf9\uddfa]|\ud83c\uddee\ud83c[\udde8-\uddea\uddf1-\uddf4\uddf6-\uddf9]|\ud83c\uddef\ud83c[\uddea\uddf2\uddf4\uddf5]|\ud83c\uddf0\ud83c[\uddea\uddec-\uddee\uddf2\uddf3\uddf5\uddf7\uddfc\uddfe\uddff]|\ud83c\uddf1\ud83c[\udde6-\udde8\uddee\uddf0\uddf7-\uddfb\uddfe]|\ud83c\uddf2\ud83c[\udde6\udde8-\udded\uddf0-\uddff]|\ud83c\uddf3\ud83c[\udde6\udde8\uddea-\uddec\uddee\uddf1\uddf4\uddf5\uddf7\uddfa\uddff]|\ud83c\uddf4\ud83c\uddf2|\ud83c\uddf5\ud83c[\udde6\uddea-\udded\uddf0-\uddf3\uddf7-\uddf9\uddfc\uddfe]|\ud83c\uddf6\ud83c\udde6|\ud83c\uddf7\ud83c[\uddea\uddf4\uddf8\uddfa\uddfc]|\ud83c\uddf8\ud83c[\udde6-\uddea\uddec-\uddf4\uddf7-\uddf9\uddfb\uddfd-\uddff]|\ud83c\uddf9\ud83c[\udde6\udde8\udde9\uddeb-\udded\uddef-\uddf4\uddf7\uddf9\uddfb\uddfc\uddff]|\ud83c\uddfa\ud83c[\udde6\uddec\uddf2\uddf3\uddf8\uddfe\uddff]|\ud83c\uddfb\ud83c[\udde6\udde8\uddea\uddec\uddee\uddf3\uddfa]|\ud83c\uddfc\ud83c[\uddeb\uddf8]|\ud83c\uddfd\ud83c\uddf0|\ud83c\uddfe\ud83c[\uddea\uddf9]|\ud83c\uddff\ud83c[\udde6\uddf2\uddfc]|\ud83c[\udccf\udd8e\udd91-\udd9a\udde6-\uddff\ude01\ude32-\ude36\ude38-\ude3a\ude50\ude51\udf00-\udf20\udf2d-\udf35\udf37-\udf7c\udf7e-\udf84\udf86-\udf93\udfa0-\udfc1\udfc5\udfc6\udfc8\udfc9\udfcf-\udfd3\udfe0-\udff0\udff4\udff8-\udfff]|\ud83d[\udc00-\udc3e\udc40\udc44\udc45\udc51-\udc65\udc6a\udc6f\udc79-\udc7b\udc7d-\udc80\udc84\udc88-\udca9\udcab-\udcfc\udcff-\udd3d\udd4b-\udd4e\udd50-\udd67\udda4\uddfb-\ude44\ude48-\ude4a\ude80-\udea2\udea4-\udeb3\udeb7-\udebf\udec1-\udec5\uded0-\uded2\uded5-\uded7\udeeb\udeec\udef4-\udefc\udfe0-\udfeb]|\ud83e[\udd0d\udd0e\udd10-\udd17\udd1d\udd20-\udd25\udd27-\udd2f\udd3a\udd3c\udd3f-\udd45\udd47-\udd76\udd78\udd7a-\uddb4\uddb7\uddba\uddbc-\uddcb\uddd0\uddde-\uddff\ude70-\ude74\ude78-\ude7a\ude80-\ude86\ude90-\udea8\udeb0-\udeb6\udec0-\udec2\uded0-\uded6]|[\u23e9-\u23ec\u23f0\u23f3\u267e\u26ce\u2705\u2728\u274c\u274e\u2753-\u2755\u2795-\u2797\u27b0\u27bf\ue50a])|\ufe0f/

/**
 *
 * @param {string} text
 * @param {Array} handlers
 */
function transformTextRegex(text, handlers) {
	const parts = []

	while (text.length > 0) {
		const result = handlers.reduce((bestMatch, handler) => {
			let match
			if ((match = handler.regex.exec(text))) {
				if (bestMatch.index === -1 || match.index < bestMatch.index) {
					return {
						index: match.index,
						match,
						onMatch: handler.onMatch,
					}
				}
			}
			return bestMatch
		}, { index: -1 })

		if (result.index !== -1) {
			if (result.index > 0) {
				parts.push(text.slice(0, result.index))
			}

			parts.push(result.onMatch(result.match))
			text = text.slice(result.index + result.match[0].length)
		} else {
			parts.push(text)
			return parts
		}
	}

	return parts
}