stupid but working autolinking

Cargo.toml

@@ -25,4 +25,5 @@ tera = "1"
 
 chrono = "0.4"
 regex = "1"
+linkify = "0.4"
 percent-encoding = "2.1.0"

src/main.rs

@@ -9,6 +9,7 @@ use actix_web::error::ErrorInternalServerError;
 use actix_web::{error, get, http, middleware, web, App, Error, HttpResponse, HttpServer};
 use chrono::{DateTime, Local};
 use clap::{App as ClapApp, Arg};
+use linkify::LinkFinder;
 use log::info;
 use percent_encoding::utf8_percent_encode;
 use pulldown_cmark::{html, Options, Parser};
@@ -197,8 +198,9 @@ async fn render(
 
 fn preprocess(string: String) -> String {
     let double_brackets = Regex::new(r"\[\[(?P<inner>[\w .]+)\]\]").unwrap();
+    let finder = LinkFinder::new();
 
-    double_brackets
+    let result = double_brackets
         .replace_all(string.as_str(), |caps: &Captures| {
             format!(
                 "[{}]({})",
@@ -206,5 +208,25 @@ fn preprocess(string: String) -> String {
                 utf8_percent_encode(&caps[1], percent_encoding::NON_ALPHANUMERIC)
             )
         })
-        .to_string()
+        .to_string();
+
+    let result_vec = Vec::from(result.as_str());
+    let start_delims = vec![b'(', b'<'];
+    let end_delims = vec![b')', b'>'];
+    let links = finder.links(result.as_str()).filter(|link| {
+        (link.start() == 0 || link.end() == result.len())
+            || (!start_delims.contains(&result_vec[link.start() - 1])
+                && !end_delims.contains(&result_vec[link.end() + 1]))
+    });
+
+    let mut offset = 0;
+    let mut result_string = result.to_string();
+    for link in links {
+        let orig = link.as_str();
+        let new = format!("<{}>", orig);
+        result_string.replace_range((link.start() + offset)..(link.end() + offset), new.as_str());
+        offset += new.len() - orig.len();
+    }
+
+    result_string
 }