git.r.bdr.sh - rbdr/page/blob - src/html_renderer.rs

   1 use crate::gemini_parser::GeminiLine;
   2
   3 /// Renders HTML from a vector of `GeminiLine` elements.
   4 ///
   5 /// # Arguments
   6 /// * `lines` - Vector of `GeminiLine` elements to render
   7 ///
   8 /// # Returns
   9 /// A String containing the rendered HTML.
  10 pub fn render_html(lines: &[GeminiLine]) -> String {
  11     let mut heading_stack = Vec::new();
  12     let mut last_line: Option<&GeminiLine> = None;
  13     let mut result = String::new();
  14
  15     for line in lines {
  16         result.push_str(&line_preamble(line, last_line, &mut heading_stack));
  17         result.push_str(&line_content(line));
  18         result.push('\n');
  19         last_line = Some(line);
  20     }
  21
  22     result.push_str(&finalize_html(&heading_stack, last_line));
  23     result
  24 }
  25
  26 fn line_preamble(
  27     line: &GeminiLine,
  28     last_line: Option<&GeminiLine>,
  29     heading_stack: &mut Vec<u8>,
  30 ) -> String {
  31     let mut html = String::new();
  32
  33     if let Some(last_line) = last_line {
  34         match last_line {
  35             GeminiLine::ListItem(_) => match line {
  36                 GeminiLine::ListItem(_) => {}
  37                 _ => html.push_str("</ul>\n"),
  38             },
  39             GeminiLine::Quote(_) => match line {
  40                 GeminiLine::Quote(_) => {}
  41                 _ => html.push_str("</blockquote>\n"),
  42             },
  43             _ => {}
  44         }
  45     }
  46
  47     match line {
  48         GeminiLine::Heading(level, _) => {
  49             while let Some(open_heading) = heading_stack.pop() {
  50                 // You just encountered a more important heading.
  51                 // Put it back. Desist.
  52                 if open_heading < *level {
  53                     heading_stack.push(open_heading);
  54                     break;
  55                 }
  56
  57                 html.push_str("</section>\n");
  58
  59                 if open_heading == *level {
  60                     break;
  61                 }
  62             }
  63             heading_stack.push(*level);
  64             html.push_str(&format!("<section class=\"h{level}\">\n"));
  65         }
  66         GeminiLine::ListItem(_) => match last_line {
  67             Some(GeminiLine::ListItem(_)) => {}
  68             _ => html.push_str("<ul>\n"),
  69         },
  70         GeminiLine::Quote(_) => match last_line {
  71             Some(GeminiLine::Quote(_)) => {}
  72             _ => html.push_str("<blockquote>\n"),
  73         },
  74         _ => {}
  75     }
  76
  77     html
  78 }
  79
  80 fn line_content(line: &GeminiLine) -> String {
  81     match line {
  82         GeminiLine::Text(content, false) => format!("<p>{content}</p>"),
  83         GeminiLine::Link(url, text) => {
  84             let display = if text.is_empty() { url } else { text };
  85             format!("<p class=\"a\"><a href=\"{url}\">{display}</a></p>")
  86         }
  87         GeminiLine::Heading(level, content) => format!("<h{level}>{content}</h{level}>"),
  88         GeminiLine::ListItem(content) => format!("<li>{content}</li>"),
  89         GeminiLine::PreformattedToggle(true, alt_text) => {
  90             format!("<pre aria-label=\"{alt_text}\">")
  91         }
  92         GeminiLine::PreformattedToggle(false, _) => "</pre>".to_string(),
  93         GeminiLine::Text(content, true) | GeminiLine::Quote(content) => content.to_string(),
  94     }
  95 }
  96
  97 fn finalize_html(heading_stack: &[u8], last_line: Option<&GeminiLine>) -> String {
  98     let mut html = String::new();
  99
 100     match last_line {
 101         Some(GeminiLine::ListItem(_)) => html.push_str("</ul>\n"),
 102         Some(GeminiLine::Quote(_)) => html.push_str("</blockquote>\n"),
 103         _ => {}
 104     }
 105
 106     for _ in heading_stack {
 107         html.push_str("</section>\n");
 108     }
 109
 110     html
 111 }
 112
 113 #[cfg(test)]
 114 mod tests {
 115     use super::*;
 116
 117     #[test]
 118     fn test_simple_text() {
 119         let input = vec![GeminiLine::Text("Hello world".to_string(), false)];
 120         assert_eq!(render_html(&input), "<p>Hello world</p>\n");
 121     }
 122
 123     #[test]
 124     fn test_heading_nesting() {
 125         let input = vec![
 126             GeminiLine::Heading(1, "Top".to_string()),
 127             GeminiLine::Heading(2, "Sub".to_string()),
 128             GeminiLine::Heading(3, "SubSub".to_string()),
 129             GeminiLine::Heading(2, "Another Sub".to_string()),
 130         ];
 131         assert_eq!(
 132             render_html(&input),
 133             "<section class=\"h1\">\n\
 134              <h1>Top</h1>\n\
 135              <section class=\"h2\">\n\
 136              <h2>Sub</h2>\n\
 137              <section class=\"h3\">\n\
 138              <h3>SubSub</h3>\n\
 139              </section>\n\
 140              </section>\n\
 141              <section class=\"h2\">\n\
 142              <h2>Another Sub</h2>\n\
 143              </section>\n\
 144              </section>\n"
 145         );
 146     }
 147
 148     #[test]
 149     fn test_list_transitions() {
 150         let input = vec![
 151             GeminiLine::ListItem("First".to_string()),
 152             GeminiLine::ListItem("Second".to_string()),
 153             GeminiLine::Text("Break".to_string(), false),
 154             GeminiLine::ListItem("New list".to_string()),
 155         ];
 156         assert_eq!(
 157             render_html(&input),
 158             "<ul>\n\
 159              <li>First</li>\n\
 160              <li>Second</li>\n\
 161              </ul>\n\
 162              <p>Break</p>\n\
 163              <ul>\n\
 164              <li>New list</li>\n\
 165              </ul>\n"
 166         );
 167     }
 168
 169     #[test]
 170     fn test_quote_transitions() {
 171         let input = vec![
 172             GeminiLine::Quote("First quote".to_string()),
 173             GeminiLine::Quote("Still quoting".to_string()),
 174             GeminiLine::Text("Normal text".to_string(), false),
 175             GeminiLine::Quote("New quote".to_string()),
 176         ];
 177         assert_eq!(
 178             render_html(&input),
 179             "<blockquote>\n\
 180              First quote\n\
 181              Still quoting\n\
 182              </blockquote>\n\
 183              <p>Normal text</p>\n\
 184              <blockquote>\n\
 185              New quote\n\
 186              </blockquote>\n"
 187         );
 188     }
 189
 190     #[test]
 191     fn test_preformatted() {
 192         let input = vec![
 193             GeminiLine::PreformattedToggle(true, "code".to_string()),
 194             GeminiLine::Text("let x = 42;".to_string(), true),
 195             GeminiLine::PreformattedToggle(false, String::new()),
 196         ];
 197         assert_eq!(
 198             render_html(&input),
 199             "<pre aria-label=\"code\">\n\
 200              let x = 42;\n\
 201              </pre>\n"
 202         );
 203     }
 204
 205     #[test]
 206     fn test_links() {
 207         let input = vec![
 208             GeminiLine::Link("https://example.com".to_string(), "Example".to_string()),
 209             GeminiLine::Link("https://rust-lang.org".to_string(), "".to_string()),
 210         ];
 211         assert_eq!(
 212             render_html(&input),
 213             "<p class=\"a\"><a href=\"https://example.com\">Example</a></p>\n\
 214              <p class=\"a\"><a href=\"https://rust-lang.org\">https://rust-lang.org</a></p>\n"
 215         );
 216     }
 217
 218     #[test]
 219     fn test_complex_nesting() {
 220         let input = vec![
 221             GeminiLine::Heading(1, "Title".to_string()),
 222             GeminiLine::Text("Intro".to_string(), false),
 223             GeminiLine::Heading(2, "Section".to_string()),
 224             GeminiLine::ListItem("Point 1".to_string()),
 225             GeminiLine::ListItem("Point 2".to_string()),
 226             GeminiLine::Quote("Important quote".to_string()),
 227             GeminiLine::Heading(2, "Another Section".to_string()),
 228         ];
 229         assert_eq!(
 230             render_html(&input),
 231             "<section class=\"h1\">\n\
 232              <h1>Title</h1>\n\
 233              <p>Intro</p>\n\
 234              <section class=\"h2\">\n\
 235              <h2>Section</h2>\n\
 236              <ul>\n\
 237              <li>Point 1</li>\n\
 238              <li>Point 2</li>\n\
 239              </ul>\n\
 240              <blockquote>\n\
 241              Important quote\n\
 242              </blockquote>\n\
 243              </section>\n\
 244              <section class=\"h2\">\n\
 245              <h2>Another Section</h2>\n\
 246              </section>\n\
 247              </section>\n"
 248         );
 249     }
 250
 251     #[test]
 252     fn test_empty_input() {
 253         let input = Vec::new();
 254         assert_eq!(render_html(&input), "");
 255     }
 256 }