add: actually parse arrow alignment for markdown

crates/shared/src/markdown.rs

@@ -4,6 +4,7 @@ use std::collections::HashSet;
 
 /// Render markdown input into HTML
 pub fn render_markdown(input: &str) -> String {
+    let input = &parse_alignment(input);
     let options = Options {
         compile: CompileOptions {
             allow_any_img_src: false,
@@ -45,7 +46,7 @@ pub fn render_markdown(input: &str) -> String {
     Builder::default()
         .generic_attributes(allowed_attributes)
         .add_tags(&[
-            "video", "source", "img", "b", "span", "p", "i", "strong", "em", "a",
+            "video", "source", "img", "b", "span", "p", "i", "strong", "em", "a", "align",
         ])
         .rm_tags(&["script", "style", "link", "canvas"])
         .add_tag_attributes("a", &["href", "target"])
@@ -57,7 +58,124 @@ pub fn render_markdown(input: &str) -> String {
             "loading=\"lazy\" src=\"/api/v1/util/proxy?url=http",
         )
         .replace("<video loading=", "<video controls loading=")
-        .replace("--&gt;", "<align class=\"right\">")
-        .replace("-&gt;", "<align class=\"center\">")
-        .replace("&lt;-", "</align>")
+}
+
+fn parse_alignment_line(line: &str, output: &mut String, buffer: &mut String, is_in_pre: bool) {
+    if is_in_pre {
+        output.push_str(&format!("{line}\n"));
+        return;
+    }
+
+    let mut is_alignment_waiting: bool = false;
+    let mut alignment_center: bool = false;
+    let mut has_dash: bool = false;
+    let mut escape: bool = false;
+
+    for char in line.chars() {
+        if alignment_center && char != '-' {
+            // last char was <, but we didn't receive a hyphen directly after
+            alignment_center = false;
+            buffer.push('<');
+        }
+
+        if has_dash && char != '>' {
+            // the last char was -, meaning we need to flip has_dash and push the char since we haven't used it
+            has_dash = false;
+            buffer.push('-');
+        }
+
+        match char {
+            '\\' => {
+                escape = true;
+                continue;
+            }
+            '-' => {
+                if escape {
+                    buffer.push(char);
+                    escape = false;
+                    continue;
+                }
+
+                if alignment_center && is_alignment_waiting {
+                    // this means the previous element was <, so we're wrapping up alignment now
+                    alignment_center = false;
+                    is_alignment_waiting = false;
+                    output.push_str(&format!("<align class=\"center\">{buffer}</align>"));
+                    buffer.clear();
+                    continue;
+                }
+
+                has_dash = true;
+
+                if !is_alignment_waiting {
+                    // we need to go ahead and push/clear the buffer so we don't capture the stuff that came before this
+                    // this only needs to be done on the first of these for a single alignment block
+                    output.push_str(&format!("{buffer}\n"));
+                    buffer.clear();
+                }
+            }
+            '<' => {
+                if escape {
+                    buffer.push(char);
+                    escape = false;
+                    continue;
+                }
+
+                alignment_center = true;
+                continue;
+            }
+            '>' => {
+                if escape {
+                    buffer.push(char);
+                    escape = false;
+                    continue;
+                }
+
+                if has_dash {
+                    has_dash = false;
+
+                    // if we're already waiting for aligmment, this means this is the SECOND aligner arrow
+                    if is_alignment_waiting {
+                        is_alignment_waiting = false;
+                        output.push_str(&format!("<align class=\"right\">{buffer}</align>"));
+                        buffer.clear();
+                        continue;
+                    }
+
+                    // we're now waiting for the next aligner
+                    is_alignment_waiting = true;
+                    continue;
+                } else {
+                    buffer.push('>');
+                }
+            }
+            _ => buffer.push(char),
+        }
+
+        escape = false;
+    }
+
+    output.push_str(&format!("{buffer}\n"));
+    buffer.clear();
+}
+
+pub fn parse_alignment(input: &str) -> String {
+    let lines = input.split("\n");
+
+    let mut is_in_pre: bool = false;
+    let mut output = String::new();
+    let mut buffer = String::new();
+
+    for line in lines {
+        match line {
+            "```" => {
+                is_in_pre = !is_in_pre;
+                output.push_str(&format!("{line}\n"));
+            }
+            _ => parse_alignment_line(line, &mut output, &mut buffer, is_in_pre),
+        }
+    }
+
+    output.push_str(&buffer);
+    output
 }