//! Rendering helpers with no knowledge of routes: Markdown, syntax
//! highlighting, diffs, the history graph, and human times. Each is pure
//! and unit tested.

pub mod diff;
pub mod graph;
pub mod highlight;
pub mod markdown;
pub mod time;

/// HTML-escape text for insertion into element content or attributes.
pub fn escape(s: &str) -> String {
    let mut out = String::with_capacity(s.len());
    for c in s.chars() {
        match c {
            '&' => out.push_str("&"),
            '<' => out.push_str("&lt;"),
            '>' => out.push_str("&gt;"),
            '"' => out.push_str("&quot;"),
            '\'' => out.push_str("&#39;"),
            _ => out.push(c),
        }
    }
    out
}

/// `1.2 KiB`, `3.4 MiB`, `512 B`.
pub fn bytes(n: u64) -> String {
    const UNITS: [&str; 5] = ["B", "KiB", "MiB", "GiB", "TiB"];
    let mut v = n as f64;
    let mut i = 0;
    while v >= 1024.0 && i < UNITS.len() - 1 {
        v /= 1024.0;
        i += 1;
    }
    if i == 0 {
        format!("{n} B")
    } else {
        format!("{v:.1} {}", UNITS[i])
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn escaping_and_sizes() {
        assert_eq!(escape("<a href=\"x\">&'"), "&lt;a href=&quot;x&quot;&gt;&amp;&#39;");
        assert_eq!(bytes(512), "512 B");
        assert_eq!(bytes(1536), "1.5 KiB");
        assert_eq!(bytes(5 << 20), "5.0 MiB");
    }
}