wallfacer-core 0.7.0

Runtime fuzzing and invariant-testing harness for MCP servers — catch crashes, hangs, schema drift, and state leaks before they ship.
Documentation 
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//! Phase U — static HTML dashboard renderer.
//!
//! Reads a [`crate::corpus::Corpus`] (already-persisted findings)
//! and produces a single self-contained HTML file: inline CSS, no
//! external assets, no JavaScript dependency.
//!
//! Sections:
//! - **Summary** — total findings, breakdown by severity / kind /
//!   tool, run timestamp.
//! - **Findings table** — every finding with severity, kind, tool,
//!   message, timestamp, JSON details (collapsible via `<details>`).
//! - **Tool coverage** — when a [`crate::coverage::CoverageMatrix`]
//!   is supplied, render it as a coloured grid.
//!
//! Designed to be e-mailable / archivable — open the file in any
//! browser, anywhere, no server, no internet.

use std::collections::BTreeMap;
use std::fmt::Write as _;

use chrono::Utc;

use crate::{
    coverage::{CoverageCell, CoverageMatrix},
    finding::{Finding, FindingKind, Severity},
};

/// Optional inputs to [`render_html`]. `findings` is the only
/// required input; the rest enrich the dashboard with metadata
/// the corpus alone doesn't carry.
pub struct ReportInputs<'a> {
    /// Findings to render. Typically `corpus.list_findings()`.
    pub findings: &'a [Finding],
    /// Optional coverage matrix; when `Some`, a coverage section is
    /// added to the report.
    pub coverage: Option<&'a CoverageMatrix>,
    /// Free-form title (e.g. the project name). Defaults to
    /// `mcp-wallfacer report` when `None`.
    pub title: Option<&'a str>,
    /// Free-form server identifier (e.g. URL or package name).
    pub target: Option<&'a str>,
}

/// Renders a self-contained HTML dashboard. Returns the full
/// document as a `String` ready to be written to disk.
pub fn render_html(inputs: &ReportInputs<'_>) -> String {
    let title = inputs.title.unwrap_or("mcp-wallfacer report");
    let target = inputs.target.unwrap_or("(unspecified)");
    let now = Utc::now().to_rfc3339();

    let mut html = String::with_capacity(8 * 1024 + inputs.findings.len() * 1024);

    let _ = writeln!(html, "<!DOCTYPE html>");
    let _ = writeln!(html, "<html lang=\"en\">");
    let _ = writeln!(html, "<head>");
    let _ = writeln!(html, "<meta charset=\"utf-8\">");
    let _ = writeln!(
        html,
        "<meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">"
    );
    let _ = writeln!(html, "<title>{}</title>", esc(title));
    html.push_str(STYLES);
    let _ = writeln!(html, "</head>");
    let _ = writeln!(html, "<body>");

    // Header
    let _ = writeln!(html, "<header class=\"hero\">");
    let _ = writeln!(html, "<h1>{}</h1>", esc(title));
    let _ = writeln!(
        html,
        "<p class=\"meta\">Target: <code>{}</code> · Generated {}</p>",
        esc(target),
        esc(&now),
    );
    let _ = writeln!(html, "</header>");

    // Summary cards
    render_summary(&mut html, inputs.findings);

    // Coverage matrix (optional)
    if let Some(matrix) = inputs.coverage {
        render_coverage(&mut html, matrix);
    }

    // Findings table
    render_findings_table(&mut html, inputs.findings);

    let _ = writeln!(html, "<footer class=\"foot\">");
    let _ = writeln!(
        html,
        "Generated by <a href=\"https://github.com/lacausecrypto/mcp-wallfacer\">mcp-wallfacer</a> v{}",
        env!("CARGO_PKG_VERSION")
    );
    let _ = writeln!(html, "</footer>");

    let _ = writeln!(html, "</body></html>");
    html
}

fn render_summary(html: &mut String, findings: &[Finding]) {
    let total = findings.len();
    let mut by_severity: BTreeMap<Severity, usize> = BTreeMap::new();
    let mut by_kind: BTreeMap<&'static str, usize> = BTreeMap::new();
    let mut by_tool: BTreeMap<String, usize> = BTreeMap::new();
    for f in findings {
        *by_severity.entry(f.severity).or_insert(0) += 1;
        *by_kind.entry(f.kind.keyword()).or_insert(0) += 1;
        *by_tool.entry(f.tool.clone()).or_insert(0) += 1;
    }

    let _ = writeln!(html, "<section class=\"summary\">");
    let _ = writeln!(html, "<h2>Summary</h2>");
    let _ = writeln!(html, "<div class=\"cards\">");
    push_card(html, "Findings", &total.to_string(), "neutral");
    push_card(
        html,
        "Critical",
        &by_severity
            .get(&Severity::Critical)
            .unwrap_or(&0)
            .to_string(),
        "sev-critical",
    );
    push_card(
        html,
        "High",
        &by_severity.get(&Severity::High).unwrap_or(&0).to_string(),
        "sev-high",
    );
    push_card(
        html,
        "Medium",
        &by_severity.get(&Severity::Medium).unwrap_or(&0).to_string(),
        "sev-medium",
    );
    push_card(
        html,
        "Low",
        &by_severity.get(&Severity::Low).unwrap_or(&0).to_string(),
        "sev-low",
    );
    let _ = writeln!(html, "</div>");

    if !by_kind.is_empty() {
        let _ = writeln!(html, "<h3>By kind</h3>");
        let _ = writeln!(html, "<ul class=\"breakdown\">");
        for (kind, count) in &by_kind {
            let _ = writeln!(
                html,
                "<li><code>{}</code> &times; {}</li>",
                esc(kind),
                count
            );
        }
        let _ = writeln!(html, "</ul>");
    }
    if !by_tool.is_empty() {
        let _ = writeln!(html, "<h3>By tool</h3>");
        let _ = writeln!(html, "<ul class=\"breakdown\">");
        for (tool, count) in &by_tool {
            let _ = writeln!(
                html,
                "<li><code>{}</code> &times; {}</li>",
                esc(tool),
                count
            );
        }
        let _ = writeln!(html, "</ul>");
    }
    let _ = writeln!(html, "</section>");
}

fn push_card(html: &mut String, label: &str, value: &str, class: &str) {
    let _ = writeln!(
        html,
        "<div class=\"card {}\"><div class=\"card-value\">{}</div><div class=\"card-label\">{}</div></div>",
        esc(class),
        esc(value),
        esc(label),
    );
}

fn render_coverage(html: &mut String, matrix: &CoverageMatrix) {
    let _ = writeln!(html, "<section class=\"coverage\">");
    let _ = writeln!(html, "<h2>Tool coverage</h2>");
    let _ = writeln!(
        html,
        "<p class=\"meta\">{} / {} cells covered · {} tool(s) uncovered</p>",
        matrix.covered_cells(),
        matrix.total_cells(),
        matrix.uncovered_tools.len()
    );
    let _ = writeln!(html, "<table class=\"matrix\">");
    let _ = writeln!(html, "<thead><tr><th>Tool</th>");
    for pack in &matrix.packs {
        let _ = writeln!(html, "<th>{}</th>", esc(pack));
    }
    let _ = writeln!(html, "</tr></thead><tbody>");
    for tool in &matrix.tools {
        let _ = writeln!(html, "<tr><td><code>{}</code></td>", esc(tool));
        for pack in &matrix.packs {
            let cell = matrix
                .cells
                .get(tool)
                .and_then(|row| row.get(pack))
                .copied()
                .unwrap_or(CoverageCell::Uncovered);
            let (class, glyph) = match cell {
                CoverageCell::Covered => ("cov-covered", "●"),
                CoverageCell::Blocked => ("cov-blocked", "⊘"),
                CoverageCell::Uncovered => ("cov-uncovered", "·"),
            };
            let _ = writeln!(html, "<td class=\"{}\">{}</td>", class, glyph);
        }
        let _ = writeln!(html, "</tr>");
    }
    let _ = writeln!(html, "</tbody></table>");
    let _ = writeln!(html, "<p class=\"legend\">Legend: <span class=\"cov-covered\">●</span> covered &nbsp; <span class=\"cov-blocked\">⊘</span> blocked (destructive guard) &nbsp; <span class=\"cov-uncovered\">·</span> uncovered</p>");
    let _ = writeln!(html, "</section>");
}

fn render_findings_table(html: &mut String, findings: &[Finding]) {
    let _ = writeln!(html, "<section class=\"findings\">");
    let _ = writeln!(html, "<h2>Findings ({})</h2>", findings.len());
    if findings.is_empty() {
        let _ = writeln!(
            html,
            "<p class=\"meta\">no findings — pack run was clean.</p>"
        );
        let _ = writeln!(html, "</section>");
        return;
    }
    let _ = writeln!(html, "<table class=\"findings-table\">");
    let _ = writeln!(
        html,
        "<thead><tr><th>Severity</th><th>Kind</th><th>Tool</th><th>Message</th><th>Time</th></tr></thead>"
    );
    let _ = writeln!(html, "<tbody>");
    for finding in findings {
        let sev_class = match finding.severity {
            Severity::Critical => "sev-critical",
            Severity::High => "sev-high",
            Severity::Medium => "sev-medium",
            Severity::Low => "sev-low",
        };
        let kind_label = format_kind_label(&finding.kind);
        let _ = writeln!(html, "<tr>");
        let _ = writeln!(
            html,
            "<td class=\"{}\">{}</td>",
            sev_class,
            esc(&format!("{:?}", finding.severity).to_lowercase())
        );
        let _ = writeln!(html, "<td><code>{}</code></td>", esc(&kind_label));
        let _ = writeln!(html, "<td><code>{}</code></td>", esc(&finding.tool));
        let _ = writeln!(html, "<td>{}</td>", esc(&finding.message));
        let _ = writeln!(
            html,
            "<td class=\"meta\">{}</td>",
            esc(&finding.timestamp.to_rfc3339())
        );
        let _ = writeln!(html, "</tr>");
        // Detail row
        let _ = writeln!(html, "<tr class=\"detail-row\">");
        let _ = writeln!(html, "<td colspan=\"5\">");
        let _ = writeln!(
            html,
            "<details><summary>id <code>{}</code></summary>",
            esc(&finding.id)
        );
        let _ = writeln!(
            html,
            "<pre class=\"details-pre\">{}</pre>",
            esc(&finding.details)
        );
        let _ = writeln!(html, "</details>");
        let _ = writeln!(html, "</td></tr>");
    }
    let _ = writeln!(html, "</tbody></table>");
    let _ = writeln!(html, "</section>");
}

fn format_kind_label(kind: &FindingKind) -> String {
    match kind {
        FindingKind::Crash => "crash".to_string(),
        FindingKind::Hang { ms } => format!("hang ({ms} ms)"),
        FindingKind::SchemaViolation => "schema_violation".to_string(),
        FindingKind::PropertyFailure { invariant } => format!("property: {invariant}"),
        FindingKind::ProtocolError => "protocol_error".to_string(),
        FindingKind::StateLeak => "state_leak".to_string(),
        FindingKind::SequenceFailure {
            sequence,
            step_index,
            step_call,
        } => format!("sequence: {sequence} (step {step_index} `{step_call}`)"),
    }
}

/// HTML-escape `s` for safe insertion into element bodies and
/// attribute values. Handles the five characters required by the
/// HTML spec.
fn esc(s: &str) -> String {
    let mut out = String::with_capacity(s.len());
    for c in s.chars() {
        match c {
            '&' => out.push_str("&amp;"),
            '<' => out.push_str("&lt;"),
            '>' => out.push_str("&gt;"),
            '"' => out.push_str("&quot;"),
            '\'' => out.push_str("&#39;"),
            other => out.push(other),
        }
    }
    out
}

/// Inline CSS — kept tight (~4 KB) and self-contained so the
/// generated HTML works offline. No JS, no external assets.
const STYLES: &str = r#"<style>
:root {
  --bg: #0d1117;
  --fg: #c9d1d9;
  --muted: #8b949e;
  --accent: #58a6ff;
  --critical: #f85149;
  --high: #ff7b72;
  --medium: #d29922;
  --low: #58a6ff;
  --green: #3fb950;
  --yellow: #d29922;
  --grey: #484f58;
  --card: #161b22;
  --border: #30363d;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; background: var(--bg); color: var(--fg); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; line-height: 1.5; }
body { padding: 0 0 4rem; }
header.hero { padding: 2rem 2rem 1rem; border-bottom: 1px solid var(--border); }
header.hero h1 { margin: 0 0 .25rem; font-size: 1.6rem; }
.meta { color: var(--muted); font-size: .85rem; margin: .25rem 0; }
section { padding: 1.5rem 2rem; border-bottom: 1px solid var(--border); }
h2 { margin: 0 0 1rem; font-size: 1.2rem; }
h3 { margin: 1rem 0 .5rem; font-size: 1rem; color: var(--muted); font-weight: 500; }
code { background: var(--card); padding: 1px 6px; border-radius: 3px; font-family: ui-monospace, "SF Mono", Menlo, monospace; font-size: .9em; }
.cards { display: flex; gap: 1rem; flex-wrap: wrap; }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 8px; padding: 1rem 1.5rem; min-width: 110px; }
.card-value { font-size: 1.8rem; font-weight: 600; }
.card-label { color: var(--muted); font-size: .8rem; text-transform: uppercase; letter-spacing: .05em; }
.card.neutral .card-value { color: var(--fg); }
.card.sev-critical .card-value { color: var(--critical); }
.card.sev-high .card-value { color: var(--high); }
.card.sev-medium .card-value { color: var(--medium); }
.card.sev-low .card-value { color: var(--low); }
ul.breakdown { list-style: none; padding: 0; margin: 0; display: flex; gap: .75rem; flex-wrap: wrap; }
ul.breakdown li { background: var(--card); padding: .25rem .75rem; border-radius: 4px; font-size: .9rem; }
table { border-collapse: collapse; width: 100%; }
th, td { padding: .5rem .75rem; text-align: left; border-bottom: 1px solid var(--border); vertical-align: top; }
th { color: var(--muted); font-weight: 500; font-size: .8rem; text-transform: uppercase; letter-spacing: .03em; }
.findings-table tbody tr.detail-row td { padding-top: 0; }
.findings-table .sev-critical { color: var(--critical); font-weight: 600; }
.findings-table .sev-high { color: var(--high); font-weight: 600; }
.findings-table .sev-medium { color: var(--medium); }
.findings-table .sev-low { color: var(--low); }
details summary { cursor: pointer; color: var(--muted); }
.details-pre { background: var(--card); padding: 1rem; border-radius: 6px; overflow-x: auto; max-height: 30rem; font-size: .85rem; white-space: pre-wrap; word-break: break-word; }
table.matrix { font-size: .9rem; }
table.matrix th { font-size: .75rem; }
table.matrix td.cov-covered { color: var(--green); text-align: center; }
table.matrix td.cov-blocked { color: var(--yellow); text-align: center; }
table.matrix td.cov-uncovered { color: var(--grey); text-align: center; }
.legend { font-size: .85rem; color: var(--muted); }
.legend .cov-covered { color: var(--green); }
.legend .cov-blocked { color: var(--yellow); }
.legend .cov-uncovered { color: var(--grey); }
footer.foot { padding: 1rem 2rem; color: var(--muted); font-size: .85rem; }
footer.foot a { color: var(--accent); }
@media (max-width: 700px) {
  section, header.hero { padding: 1rem; }
  .cards { gap: .5rem; }
  .card { min-width: 80px; padding: .75rem 1rem; }
}
</style>
"#;

#[cfg(test)]
#[allow(clippy::expect_used, clippy::unwrap_used, clippy::panic)]
mod tests {
    use super::*;
    use crate::finding::{Finding, FindingKind, ReproInfo, Severity};
    use serde_json::json;

    fn finding(severity: Severity, kind: FindingKind) -> Finding {
        Finding::new(
            kind,
            "tool_x",
            "test message",
            "test details",
            ReproInfo {
                seed: 42,
                tool_call: json!({}),
                transport: "stdio".to_string(),
                composition_trail: Vec::new(),
            },
        )
        .with_severity(severity)
    }

    #[test]
    fn empty_report_renders_no_findings_message() {
        let html = render_html(&ReportInputs {
            findings: &[],
            coverage: None,
            title: None,
            target: None,
        });
        assert!(html.contains("<!DOCTYPE html>"));
        assert!(html.contains("no findings"));
        assert!(html.contains("Summary"));
    }

    #[test]
    fn html_escapes_finding_message_payloads() {
        let mut f = finding(Severity::High, FindingKind::Crash);
        f.message = "<script>alert('xss')</script>".to_string();
        let html = render_html(&ReportInputs {
            findings: &[f],
            coverage: None,
            title: None,
            target: None,
        });
        assert!(!html.contains("<script>alert"));
        assert!(html.contains("&lt;script&gt;"));
    }

    #[test]
    fn severity_buckets_appear_in_summary_cards() {
        let findings = vec![
            finding(Severity::Critical, FindingKind::Crash),
            finding(Severity::High, FindingKind::ProtocolError),
            finding(Severity::Medium, FindingKind::SchemaViolation),
        ];
        let html = render_html(&ReportInputs {
            findings: &findings,
            coverage: None,
            title: Some("test"),
            target: Some("python"),
        });
        // Each severity bucket appears with its count.
        assert!(html.contains("Critical"));
        assert!(html.contains("sev-critical"));
        assert!(html.contains("High"));
        assert!(html.contains("Medium"));
    }

    #[test]
    fn sequence_failure_kind_label_includes_step() {
        let f = finding(
            Severity::High,
            FindingKind::SequenceFailure {
                sequence: "stateful.delete_purges".to_string(),
                step_index: 2,
                step_call: "record_read".to_string(),
            },
        );
        let html = render_html(&ReportInputs {
            findings: &[f],
            coverage: None,
            title: None,
            target: None,
        });
        assert!(html.contains("stateful.delete_purges"));
        assert!(html.contains("step 2"));
    }
}