[MFM] Improve various parsing

Resolve #2779
Resolve #3053

src/mfm/parse/elements/hashtag.ts

@@ -8,7 +8,9 @@ export type TextElementHashtag = {
 	hashtag: string;
 };
 
-export default function(text: string, isBegin: boolean) {
+export default function(text: string, before: string) {
+	const isBegin = before == '';
+
 	if (!(/^\s#[^\s\.,!\?#]+/.test(text) || (isBegin && /^#[^\s\.,!\?#]+/.test(text)))) return null;
 	const isHead = text.startsWith('#');
 	const hashtag = text.match(/^\s?#[^\s\.,!\?#]+/)[0];

src/mfm/parse/elements/mention.ts

@@ -12,9 +12,10 @@ export type TextElementMention = {
 	host: string;
 };
 
-export default function(text: string) {
+export default function(text: string, before: string) {
 	const match = text.match(/^@[a-z0-9_]+(?:@[a-z0-9\.\-]+[a-z0-9])?/i);
 	if (!match) return null;
+	if (/[a-zA-Z0-9]$/.test(before)) return null;
 	const mention = match[0];
 	const { username, host } = parseAcct(mention.substr(1));
 	const canonical = host != null ? `@${username}@${toUnicode(host)}` : mention;

src/mfm/parse/elements/quote.ts

@@ -8,7 +8,9 @@ export type TextElementQuote = {
 	quote: string;
 };
 
-export default function(text: string, isBegin: boolean) {
+export default function(text: string, before: string) {
+	const isBegin = before == '';
+
 	const match = text.match(/^"([\s\S]+?)\n"/) || text.match(/^\n>([\s\S]+?)(\n\n|$)/) ||
 		(isBegin ? text.match(/^>([\s\S]+?)(\n\n|$)/) : null);
 

src/mfm/parse/elements/title.ts

@@ -8,7 +8,9 @@ export type TextElementTitle = {
 	title: string;
 };
 
-export default function(text: string, isBegin: boolean) {
+export default function(text: string, before: string) {
+	const isBegin = before == '';
+
 	const match = isBegin ? text.match(/^(【|\[)(.+?)(】|])\n/) : text.match(/^\n(【|\[)(.+?)(】|])\n/);
 	if (!match) return null;
 	return {

src/mfm/parse/elements/url.ts

@@ -8,12 +8,13 @@ export type TextElementUrl = {
 	url: string;
 };
 
-export default function(text: string) {
+export default function(text: string, before: string) {
 	const match = text.match(/^https?:\/\/[\w\/:%#@\$&\?!\(\)\[\]~\.,=\+\-]+/);
 	if (!match) return null;
 	let url = match[0];
 	if (url.endsWith('.')) url = url.substr(0, url.lastIndexOf('.'));
 	if (url.endsWith(',')) url = url.substr(0, url.lastIndexOf(','));
+	if (url.endsWith(')') && before.endsWith('(')) url = url.substr(0, url.lastIndexOf(')'));
 	return {
 		type: 'url',
 		content: url,