/// Sanitization preset for ammonia HTML cleaning.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum SanitizePreset {
    /// Default ammonia settings. Allows most safe HTML.
    Permissive,
    /// Default ammonia settings (same sanitization as Permissive; the difference
    /// is at the Renderer level: Standard strips images, Permissive doesn't).
    Standard,
    /// Adds `rel="noopener noreferrer nofollow"` to all links.
    Strict,
    /// Only allows p, em, strong, code, br, pre tags.
    Minimal,
}

impl SanitizePreset {
    pub(crate) fn clean(&self, html: &str) -> String {
        match self {
            SanitizePreset::Permissive | SanitizePreset::Standard => ammonia::clean(html),
            SanitizePreset::Strict => ammonia::Builder::default()
                .link_rel(Some("noopener noreferrer nofollow"))
                .clean(html)
                .to_string(),
            SanitizePreset::Minimal => {
                let tags: std::collections::HashSet<&str> =
                    ["p", "em", "strong", "code", "br", "pre"]
                        .iter()
                        .copied()
                        .collect();
                ammonia::Builder::default()
                    .tags(tags)
                    .clean(html)
                    .to_string()
            }
        }
    }
}

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

    #[test]
    fn permissive_allows_safe_html() {
        let html = "<p>Hello <strong>world</strong></p>";
        let result = SanitizePreset::Permissive.clean(html);
        assert!(result.contains("<strong>world</strong>"));
    }

    #[test]
    fn permissive_strips_script() {
        let html = "<p>Hello</p><script>alert(1)</script>";
        let result = SanitizePreset::Permissive.clean(html);
        assert!(!result.contains("<script>"));
    }

    #[test]
    fn strict_adds_nofollow() {
        let html = r#"<a href="https://example.com">link</a>"#;
        let result = SanitizePreset::Strict.clean(html);
        assert!(result.contains("nofollow"));
        assert!(result.contains("noopener"));
    }

    #[test]
    fn minimal_strips_extra_tags() {
        let html = r#"<p>Hello <a href="x">link</a> <em>italic</em></p>"#;
        let result = SanitizePreset::Minimal.clean(html);
        assert!(result.contains("<em>italic</em>"));
        assert!(!result.contains("<a"));
        assert!(result.contains("link"));
    }

    #[test]
    fn minimal_keeps_code() {
        let html = "<pre><code>fn main()</code></pre>";
        let result = SanitizePreset::Minimal.clean(html);
        assert!(result.contains("<code>"));
        assert!(result.contains("<pre>"));
    }
}