Split into gui and client crates (#30)

Reviewed-on: #30
Reviewed-by: restitux <restitux@ohea.xyz>
Co-authored-by: Sam Sartor <me@samsartor.com>
Co-committed-by: Sam Sartor <me@samsartor.com>

client/src/msghtml.rs

@@ -0,0 +1,110 @@
+// This is a fork of https://github.com/mehmetcansahin/html-purifier
+
+use lol_html::html_content::{Comment, Element};
+use lol_html::{comments, element, rewrite_str, RewriteStrSettings};
+
+pub struct AllowedElement {
+    pub name: &'static str,
+    pub attributes: &'static [&'static str],
+}
+
+const ALLOWED: &'static [AllowedElement] = &[
+    AllowedElement {
+        name: "div",
+        attributes: &[],
+    },
+    AllowedElement {
+        name: "b",
+        attributes: &[],
+    },
+    AllowedElement {
+        name: "strong",
+        attributes: &[],
+    },
+    AllowedElement {
+        name: "i",
+        attributes: &[],
+    },
+    AllowedElement {
+        name: "em",
+        attributes: &[],
+    },
+    AllowedElement {
+        name: "u",
+        attributes: &[],
+    },
+    AllowedElement {
+        name: "a",
+        attributes: &["href", "title"],
+    },
+    AllowedElement {
+        name: "ul",
+        attributes: &[],
+    },
+    AllowedElement {
+        name: "ol",
+        attributes: &[],
+    },
+    AllowedElement {
+        name: "li",
+        attributes: &[],
+    },
+    AllowedElement {
+        name: "p",
+        attributes: &["style"],
+    },
+    AllowedElement {
+        name: "br",
+        attributes: &[],
+    },
+    AllowedElement {
+        name: "span",
+        attributes: &["style"],
+    },
+    AllowedElement {
+        name: "img",
+        attributes: &["width", "height", "alt", "src"],
+    },
+];
+
+pub fn process_message_html(input: &str) -> String {
+    let element_handler = |el: &mut Element| {
+        let find = ALLOWED.iter().find(|e| e.name.eq(&el.tag_name()));
+        match find {
+            Some(find) => {
+                let remove_attributes = el
+                    .attributes()
+                    .iter()
+                    .filter(|e| find.attributes.iter().any(|a| a.eq(&e.name())) == false)
+                    .map(|m| m.name())
+                    .collect::<Vec<String>>();
+                for attr in remove_attributes {
+                    el.remove_attribute(&attr);
+                }
+            }
+            None => {
+                el.remove_and_keep_content();
+            }
+        }
+        if el.tag_name() == "a" {
+            el.set_attribute("target", "_blank");
+        }
+        Ok(())
+    };
+    let comment_handler = |c: &mut Comment| {
+        c.remove();
+        Ok(())
+    };
+    let output = rewrite_str(
+        input,
+        RewriteStrSettings {
+            element_content_handlers: vec![
+                element!("*", element_handler),
+                comments!("*", comment_handler),
+            ],
+            ..RewriteStrSettings::default()
+        },
+    )
+    .unwrap();
+    return output;
+}