git.r.bdr.sh - rbdr/gema_texto/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 ///
  11 /// # Examples
  12 /// ```
  13 /// use std::fs::read_to_string;
  14 /// use gema_texto::gemini_parser::parse;
  15 /// use gema_texto::html_renderer::render_html;
  16 ///
  17 /// let gemini_source = "\
  18 /// # Hello
  19 /// This is some gemini text!
  20 /// => https://test Go to the test page.
  21 /// ";
  22 ///
  23 /// let gemini_lines = parse(&gemini_source);
  24 /// let html_source = render_html(&gemini_lines);
  25 /// println!("{html_source}");
  26 /// ```
  27 #[must_use]
  28 pub fn render_html(lines: &[GeminiLine]) -> String {
  29     let mut heading_stack = Vec::new();
  30     let mut last_line: Option<&GeminiLine> = None;
  31     let mut result = String::new();
  32
  33     for line in lines {
  34         result.push_str(&line_preamble(line, last_line, &mut heading_stack));
  35         result.push_str(&line_content(line));
  36         result.push('\n');
  37         last_line = Some(line);
  38     }
  39
  40     result.push_str(&finalize_html(&heading_stack, last_line));
  41     result
  42 }
  43
  44 fn line_preamble(
  45     line: &GeminiLine,
  46     last_line: Option<&GeminiLine>,
  47     heading_stack: &mut Vec<u8>,
  48 ) -> String {
  49     let mut html = String::new();
  50
  51     if let Some(last_line) = last_line {
  52         match last_line {
  53             GeminiLine::ListItem(_) => match line {
  54                 GeminiLine::ListItem(_) => {}
  55                 _ => html.push_str("</ul>\n"),
  56             },
  57             GeminiLine::Quote(_) => match line {
  58                 GeminiLine::Quote(_) => {}
  59                 _ => html.push_str("</blockquote>\n"),
  60             },
  61             _ => {}
  62         }
  63     }
  64
  65     match line {
  66         GeminiLine::Heading(level, _) => {
  67             while let Some(open_heading) = heading_stack.pop() {
  68                 // You just encountered a more important heading.
  69                 // Put it back. Desist.
  70                 if open_heading < *level {
  71                     heading_stack.push(open_heading);
  72                     break;
  73                 }
  74
  75                 html.push_str("</section>\n");
  76
  77                 if open_heading == *level {
  78                     break;
  79                 }
  80             }
  81             heading_stack.push(*level);
  82             html.push_str(&format!("<section class=\"h{level}\">\n"));
  83         }
  84         GeminiLine::ListItem(_) => match last_line {
  85             Some(GeminiLine::ListItem(_)) => {}
  86             _ => html.push_str("<ul>\n"),
  87         },
  88         GeminiLine::Quote(_) => match last_line {
  89             Some(GeminiLine::Quote(_)) => {}
  90             _ => html.push_str("<blockquote>\n"),
  91         },
  92         _ => {}
  93     }
  94
  95     html
  96 }
  97
  98 fn line_content(line: &GeminiLine) -> String {
  99     match line {
 100         GeminiLine::Text(content, false) => format!("<p>{content}</p>"),
 101         GeminiLine::Link(url, text) => {
 102             let display = if text.is_empty() { url } else { text };
 103             format!("<p class=\"a\"><a href=\"{url}\">{display}</a></p>")
 104         }
 105         GeminiLine::Heading(level, content) => format!("<h{level}>{content}</h{level}>"),
 106         GeminiLine::ListItem(content) => format!("<li>{content}</li>"),
 107         GeminiLine::PreformattedToggle(true, alt_text) => {
 108             format!("<pre aria-label=\"{alt_text}\">")
 109         }
 110         GeminiLine::PreformattedToggle(false, _) => "</pre>".to_string(),
 111         GeminiLine::Text(content, true) | GeminiLine::Quote(content) => content.to_string(),
 112     }
 113 }
 114
 115 fn finalize_html(heading_stack: &[u8], last_line: Option<&GeminiLine>) -> String {
 116     let mut html = String::new();
 117
 118     match last_line {
 119         Some(GeminiLine::ListItem(_)) => html.push_str("</ul>\n"),
 120         Some(GeminiLine::Quote(_)) => html.push_str("</blockquote>\n"),
 121         _ => {}
 122     }
 123
 124     for _ in heading_stack {
 125         html.push_str("</section>\n");
 126     }
 127
 128     html
 129 }
 130
 131 #[cfg(test)]
 132 mod tests {
 133     use super::*;
 134
 135     #[test]
 136     fn test_simple_text() {
 137         let input = vec![GeminiLine::Text("Hello world".to_string(), false)];
 138         assert_eq!(render_html(&input), "<p>Hello world</p>\n");
 139     }
 140
 141     #[test]
 142     fn test_heading_nesting() {
 143         let input = vec![
 144             GeminiLine::Heading(1, "Top".to_string()),
 145             GeminiLine::Heading(2, "Sub".to_string()),
 146             GeminiLine::Heading(3, "SubSub".to_string()),
 147             GeminiLine::Heading(2, "Another Sub".to_string()),
 148         ];
 149         assert_eq!(
 150             render_html(&input),
 151             "<section class=\"h1\">\n\
 152              <h1>Top</h1>\n\
 153              <section class=\"h2\">\n\
 154              <h2>Sub</h2>\n\
 155              <section class=\"h3\">\n\
 156              <h3>SubSub</h3>\n\
 157              </section>\n\
 158              </section>\n\
 159              <section class=\"h2\">\n\
 160              <h2>Another Sub</h2>\n\
 161              </section>\n\
 162              </section>\n"
 163         );
 164     }
 165
 166     #[test]
 167     fn test_list_transitions() {
 168         let input = vec![
 169             GeminiLine::ListItem("First".to_string()),
 170             GeminiLine::ListItem("Second".to_string()),
 171             GeminiLine::Text("Break".to_string(), false),
 172             GeminiLine::ListItem("New list".to_string()),
 173         ];
 174         assert_eq!(
 175             render_html(&input),
 176             "<ul>\n\
 177              <li>First</li>\n\
 178              <li>Second</li>\n\
 179              </ul>\n\
 180              <p>Break</p>\n\
 181              <ul>\n\
 182              <li>New list</li>\n\
 183              </ul>\n"
 184         );
 185     }
 186
 187     #[test]
 188     fn test_quote_transitions() {
 189         let input = vec![
 190             GeminiLine::Quote("First quote".to_string()),
 191             GeminiLine::Quote("Still quoting".to_string()),
 192             GeminiLine::Text("Normal text".to_string(), false),
 193             GeminiLine::Quote("New quote".to_string()),
 194         ];
 195         assert_eq!(
 196             render_html(&input),
 197             "<blockquote>\n\
 198              First quote\n\
 199              Still quoting\n\
 200              </blockquote>\n\
 201              <p>Normal text</p>\n\
 202              <blockquote>\n\
 203              New quote\n\
 204              </blockquote>\n"
 205         );
 206     }
 207
 208     #[test]
 209     fn test_preformatted() {
 210         let input = vec![
 211             GeminiLine::PreformattedToggle(true, "code".to_string()),
 212             GeminiLine::Text("let x = 42;".to_string(), true),
 213             GeminiLine::PreformattedToggle(false, String::new()),
 214         ];
 215         assert_eq!(
 216             render_html(&input),
 217             "<pre aria-label=\"code\">\n\
 218              let x = 42;\n\
 219              </pre>\n"
 220         );
 221     }
 222
 223     #[test]
 224     fn test_links() {
 225         let input = vec![
 226             GeminiLine::Link("https://example.com".to_string(), "Example".to_string()),
 227             GeminiLine::Link("https://rust-lang.org".to_string(), String::new()),
 228         ];
 229         assert_eq!(
 230             render_html(&input),
 231             "<p class=\"a\"><a href=\"https://example.com\">Example</a></p>\n\
 232              <p class=\"a\"><a href=\"https://rust-lang.org\">https://rust-lang.org</a></p>\n"
 233         );
 234     }
 235
 236     #[test]
 237     fn test_complex_nesting() {
 238         let input = vec![
 239             GeminiLine::Heading(1, "Title".to_string()),
 240             GeminiLine::Text("Intro".to_string(), false),
 241             GeminiLine::Heading(2, "Section".to_string()),
 242             GeminiLine::ListItem("Point 1".to_string()),
 243             GeminiLine::ListItem("Point 2".to_string()),
 244             GeminiLine::Quote("Important quote".to_string()),
 245             GeminiLine::Heading(2, "Another Section".to_string()),
 246         ];
 247         assert_eq!(
 248             render_html(&input),
 249             "<section class=\"h1\">\n\
 250              <h1>Title</h1>\n\
 251              <p>Intro</p>\n\
 252              <section class=\"h2\">\n\
 253              <h2>Section</h2>\n\
 254              <ul>\n\
 255              <li>Point 1</li>\n\
 256              <li>Point 2</li>\n\
 257              </ul>\n\
 258              <blockquote>\n\
 259              Important quote\n\
 260              </blockquote>\n\
 261              </section>\n\
 262              <section class=\"h2\">\n\
 263              <h2>Another Section</h2>\n\
 264              </section>\n\
 265              </section>\n"
 266         );
 267     }
 268
 269     #[test]
 270     fn test_empty_input() {
 271         let input = Vec::new();
 272         assert_eq!(render_html(&input), "");
 273     }
 274 }