feat(rust): add syntax highlighting for command's fenced code blocks

implementations/rust/ockam/ockam_command/Cargo.toml

@@ -40,7 +40,7 @@ dockerfile = "../../../../tools/cross/Cross.Dockerfile.armv7"
 # `../ockam`) and the `ockam` binary (in `./src/bin/ockam.rs`). I won't
 # enumerate them here, but an example: `rustdoc` will try to place the docs for
 # both of these in the same path, without realizing it, which may result in one
-# overwriting the other)
+# overwriting the other
 #
 # Anyway a result, we disable them for the binary crate, which is just a single
 # file (`src/bin/ockam.rs`) which contains a single function call into
@@ -86,6 +86,7 @@ open = "5.1.2"
 opentelemetry = { version = "0.22.0", features = ["metrics", "trace"] }
 opentelemetry-otlp = { version = "0.15.0", features = ["metrics", "tls", "logs", "trace"], default-features = false }
 pem-rfc7468 = { version = "0.7.0", features = ["std"] }
+r3bl_ansi_color = "0.6.9"
 r3bl_rs_utils_core = "0.9.12"
 r3bl_tui = "0.5.2"
 r3bl_tuify = "0.1.25"
@@ -103,6 +104,7 @@ serde_yaml = "0.9"
 shellexpand = { version = "3.1.0", default-features = false, features = ["base-0"] }
 strip-ansi-escapes = "0.2.0"
 syntect = { version = "5.2.0", default-features = false, features = ["default-syntaxes", "regex-onig"] }
+termbg = "0"
 thiserror = "1"
 time = { version = "0.3", default-features = false, features = ["std", "local-offset"] }
 tiny_http = "0.12.0"

implementations/rust/ockam/ockam_command/src/docs.rs

@@ -1,13 +1,14 @@
-use crate::terminal::TerminalBackground;
 use colorful::Colorful;
 use ockam_core::env::get_env_with_default;
 use once_cell::sync::Lazy;
+use r3bl_ansi_color::{AnsiStyledText, Color, Style as StyleAnsi};
+use std::time::Duration;
 use syntect::{
     easy::HighlightLines,
-    highlighting::{Style, Theme, ThemeSet},
+    highlighting::{Style, Theme as SyntectTheme, ThemeSet},
     parsing::Regex,
     parsing::SyntaxSet,
-    util::{as_24_bit_terminal_escaped, LinesWithEndings},
+    util::LinesWithEndings,
 };
 
 const FOOTER: &str = "
@@ -26,15 +27,25 @@ discord channel https://discord.ockam.io
 
 static SYNTAX_SET: Lazy<SyntaxSet> = Lazy::new(SyntaxSet::load_defaults_newlines);
 static HEADER_RE: Lazy<Regex> = Lazy::new(|| Regex::new("^[A-Za-z][A-Za-z0-9 ]+:$".into()));
-static THEME: Lazy<Option<Theme>> = Lazy::new(|| {
-    let theme_name = match TerminalBackground::detect_background_color() {
-        TerminalBackground::Light => "base16-ocean.light",
-        TerminalBackground::Dark => "base16-ocean.dark",
-        TerminalBackground::Unknown => return None,
-    };
+static THEME: Lazy<Option<SyntectTheme>> = Lazy::new(|| {
     let mut theme_set = ThemeSet::load_defaults();
-    let theme = theme_set.themes.remove(theme_name).unwrap();
-    Some(theme)
+    match termbg::theme(Duration::from_millis(100)) {
+        Ok(termbg::Theme::Light) => theme_set.themes.remove("base16-ocean.light"),
+        Ok(termbg::Theme::Dark) => theme_set.themes.remove("base16-ocean.dark"),
+        Err(_) => None,
+    }
+});
+static DEFAULT_THEME: Lazy<SyntectTheme> = Lazy::new(|| {
+    let mut theme_set = ThemeSet::load_defaults();
+    theme_set.themes.remove("base16-ocean.dark").unwrap_or(
+        theme_set.themes.remove("base16-ocean.light").unwrap_or(
+            theme_set
+                .themes
+                .pop_first()
+                .map(|(_, theme)| theme)
+                .unwrap_or_default(),
+        ),
+    )
 });
 
 fn is_markdown() -> bool {
@@ -74,7 +85,7 @@ pub(crate) fn after_help(text: &str) -> &'static str {
 
 /// Render the string if the document should be displayed in a terminal
 /// Otherwise, if it is a Markdown document just return a static string
-pub(crate) fn render(body: &str) -> &'static str {
+fn render(body: &str) -> &'static str {
     if is_markdown() {
         Box::leak(body.to_string().into_boxed_str())
     } else {
@@ -86,76 +97,88 @@ pub(crate) fn render(body: &str) -> &'static str {
 /// Use a shell syntax highlighter to render the fenced code blocks in terminals
 fn process_terminal_docs(input: String) -> String {
     let mut output: Vec<String> = Vec::new();
+    let mut code_highlighter = FencedCodeBlockHighlighter::new();
 
-    let mut _code_highlighter = FencedCodeBlockHighlighter::new();
-
-    for line in LinesWithEndings::from(input.as_str()) {
-        // TODO: fix the fenced code block highlighter (currently disabled) - then use _code_highlighter here
+    for line in LinesWithEndings::from(&input) {
+        // Check if the current line is a code block start/end or content.
+        let is_code_line = code_highlighter.process_line(&mut output, line);
 
-        // Replace headers with bold and underline text
-        if HEADER_RE.is_match(line) {
-            output.push(line.to_string().bold().underlined().to_string());
-        }
-        // Replace subheaders with underlined text
-        else if line.starts_with("#### ") {
-            output.push(line.replace("#### ", "").underlined().to_string());
-        }
-        // Catch all
-        else {
-            output.push(line.to_string());
+        // The line is not part of a code block, so process normally.
+        if !is_code_line {
+            // Replace headers with bold and underline text
+            if HEADER_RE.is_match(line) {
+                output.push(line.to_string().bold().underlined().to_string());
+            }
+            // Replace subheaders with underlined text
+            else if line.starts_with("#### ") {
+                output.push(line.replace("#### ", "").underlined().to_string());
+            }
+            // No processing
+            else {
+                output.push(line.to_string());
+            }
         }
     }
     output.join("")
 }
 
 struct FencedCodeBlockHighlighter<'a> {
-    inner: Option<HighlightLines<'a>>,
+    inner: HighlightLines<'a>,
     in_fenced_block: bool,
 }
 
 impl FencedCodeBlockHighlighter<'_> {
     fn new() -> Self {
-        let inner = match &*THEME {
-            Some(theme) => {
-                let syntax = SYNTAX_SET.find_syntax_by_extension("sh").unwrap();
-                Some(HighlightLines::new(syntax, theme))
-            }
-            None => None,
-        };
+        let syntax = SYNTAX_SET.find_syntax_by_extension("sh").unwrap();
+        let theme = THEME.as_ref().unwrap_or(&DEFAULT_THEME);
         Self {
-            inner,
+            inner: HighlightLines::new(syntax, theme),
             in_fenced_block: false,
         }
     }
 
-    // TODO: fix the fenced code block highlighter, as it does not work on macOS or Linux
-    #[allow(dead_code)]
-    fn process_line(&mut self, line: &str, output: &mut Vec<String>) -> bool {
-        if let Some(highlighter) = &mut self.inner {
-            if line == "```sh\n" {
-                self.in_fenced_block = true;
-                return true;
-            }
+    fn process_line(&mut self, output: &mut Vec<String>, line: &str) -> bool {
+        if line == "```sh\n" {
+            self.in_fenced_block = true;
+            return true;
+        }
 
-            if !self.in_fenced_block {
-                return false;
-            }
+        if !self.in_fenced_block {
+            return false;
+        }
 
-            if line == "```\n" {
-                // Push a reset to clear the coloring.
-                output.push("\x1b[0m".to_string());
-                self.in_fenced_block = false;
-                return true;
-            }
+        if line == "```\n" {
+            // Push a reset to clear the coloring.
+            output.push("\x1b[0m".to_string());
+            self.in_fenced_block = false;
+            return true;
+        }
 
-            // Highlight the code line
-            let ranges: Vec<(Style, &str)> = highlighter
-                .highlight_line(line, &SYNTAX_SET)
-                .unwrap_or_default();
-            output.push(as_24_bit_terminal_escaped(&ranges[..], false));
-            true
-        } else {
-            false
+        // Highlight the code line
+        let highlighted: Vec<(Style, &str)> = self
+            .inner
+            .highlight_line(line, &SYNTAX_SET)
+            .unwrap_or_default();
+
+        // Convert each syntect range to an ANSI styled string
+        Self::write(output, &highlighted);
+
+        true
+    }
+
+    /// Writes a vector of syntect highlighted strings as ANSI styled strings
+    fn write(output: &mut Vec<String>, highlighted: &Vec<(Style, &str)>) {
+        for (style, text) in highlighted {
+            let ansi_styled_text = AnsiStyledText {
+                text,
+                style: &[StyleAnsi::Foreground(Color::Rgb(
+                    style.foreground.r,
+                    style.foreground.g,
+                    style.foreground.b,
+                ))],
+            };
+
+            output.push(ansi_styled_text.to_string());
         }
     }
 }
@@ -174,3 +197,55 @@ fn enrich_preview_tag(text: &str) -> String {
     let container = format!("<div class=\"chip t\">{}{}</div>", preview, tooltip);
     text.replace("[Preview]", &container)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_syntax_highlighting() {
+        let mut highlighter = FencedCodeBlockHighlighter::new();
+        let mut output = Vec::new();
+
+        // Simulate the start of a code block
+        assert!(highlighter.process_line(&mut output, "```sh\n"));
+
+        // Simulate processing a line of code within the code block
+        let code_line = "echo \"Hello, world!\"\n";
+        let highlighted = highlighter.process_line(&mut output, code_line);
+
+        // We expect this line to be processed (highlighted)
+        assert!(highlighted);
+
+        // The output should contain the syntax highlighted version of the code line
+        // This is a simplistic check for ANSI escape codes
+        assert!(output.last().unwrap().contains("\x1b["));
+
+        // Simulate the end of a code block
+        assert!(highlighter.process_line(&mut output, "```\n"));
+
+        // Check that the highlighting is reset at the end
+        assert!(output.last().unwrap().contains("\x1b[0m"));
+    }
+
+    #[test]
+    fn test_process_terminal_docs_with_code_blocks() {
+        let input = "```sh
+        # To enroll a known identity
+        $ ockam project ticket --member id_identifier
+
+        # To generate an enrollment ticket that can be used to enroll a device
+        $ ockam project ticket --attribute component=control
+        ```";
+
+        let result = render(input);
+        assert!(
+            result.contains("\x1b["),
+            "The output should contain ANSI escape codes."
+        );
+        assert!(
+            result.contains("\x1b[0m"),
+            "The output should reset ANSI coloring at the end."
+        );
+    }
+}