native (#594)

* Native Rust rewrite of agent-browser daemon

Single-binary Rust implementation replacing the Node.js/Playwright daemon
with direct CDP (Chrome DevTools Protocol) communication. Includes full
command parity, WebDriver/Safari/iOS backend routing, request tracking,
frame context management, CDP protocol codegen, and comprehensive tests.

* improvements

* fix ci

* fixes

* faster builds

cli/src/native/diff.rs

@@ -0,0 +1,195 @@
+use serde_json::{json, Value};
+use similar::{ChangeTag, TextDiff};
+
+pub struct ScreenshotDiffResult {
+    pub total_pixels: u64,
+    pub different_pixels: u64,
+    pub mismatch_percentage: f64,
+    pub matched: bool,
+    pub diff_image: Option<Vec<u8>>,
+    pub dimension_mismatch: Option<Value>,
+}
+
+pub struct SnapshotDiffResult {
+    pub diff: String,
+    pub additions: usize,
+    pub removals: usize,
+    pub unchanged: usize,
+    pub changed: bool,
+}
+
+pub fn diff_screenshot(
+    baseline: &[u8],
+    current: &[u8],
+    threshold: f64,
+) -> Result<ScreenshotDiffResult, String> {
+    let img_a = image::load_from_memory(baseline)
+        .map_err(|e| format!("Failed to decode baseline image: {}", e))?;
+    let img_b = image::load_from_memory(current)
+        .map_err(|e| format!("Failed to decode current image: {}", e))?;
+
+    let (wa, ha) = (img_a.width(), img_a.height());
+    let (wb, hb) = (img_b.width(), img_b.height());
+
+    if wa != wb || ha != hb {
+        return Ok(ScreenshotDiffResult {
+            total_pixels: (wa as u64) * (ha as u64),
+            different_pixels: (wa as u64) * (ha as u64),
+            mismatch_percentage: 100.0,
+            matched: false,
+            diff_image: None,
+            dimension_mismatch: Some(json!({
+                "expected": { "width": wa, "height": ha },
+                "actual": { "width": wb, "height": hb },
+            })),
+        });
+    }
+
+    let rgba_a = img_a.to_rgba8();
+    let rgba_b = img_b.to_rgba8();
+    let total = (wa as u64) * (ha as u64);
+    let max_color_distance = threshold * 255.0 * (3.0_f64).sqrt();
+    let mut different = 0u64;
+
+    let mut diff_img = image::RgbaImage::new(wa, ha);
+
+    for y in 0..ha {
+        for x in 0..wa {
+            let pa = rgba_a.get_pixel(x, y);
+            let pb = rgba_b.get_pixel(x, y);
+            let dr = (pa[0] as f64) - (pb[0] as f64);
+            let dg = (pa[1] as f64) - (pb[1] as f64);
+            let db = (pa[2] as f64) - (pb[2] as f64);
+            let dist = (dr * dr + dg * dg + db * db).sqrt();
+
+            if dist > max_color_distance {
+                different += 1;
+                diff_img.put_pixel(x, y, image::Rgba([255, 0, 0, 255]));
+            } else {
+                let gray = ((pa[0] as u16 + pa[1] as u16 + pa[2] as u16) / 3) as u8;
+                let dimmed = (gray as f64 * 0.3) as u8;
+                diff_img.put_pixel(x, y, image::Rgba([dimmed, dimmed, dimmed, 255]));
+            }
+        }
+    }
+
+    let mismatch = if total > 0 {
+        (different as f64 / total as f64) * 100.0
+    } else {
+        0.0
+    };
+
+    let diff_bytes = if different > 0 {
+        let mut buf = std::io::Cursor::new(Vec::new());
+        diff_img
+            .write_to(&mut buf, image::ImageFormat::Png)
+            .map_err(|e| format!("Failed to encode diff image: {}", e))?;
+        Some(buf.into_inner())
+    } else {
+        None
+    };
+
+    Ok(ScreenshotDiffResult {
+        total_pixels: total,
+        different_pixels: different,
+        mismatch_percentage: mismatch,
+        matched: different == 0,
+        diff_image: diff_bytes,
+        dimension_mismatch: None,
+    })
+}
+
+/// Compute a snapshot diff using the Myers algorithm via the `similar` crate.
+pub fn diff_snapshots(before: &str, after: &str) -> SnapshotDiffResult {
+    let text_diff = TextDiff::from_lines(before, after);
+
+    let mut additions = 0usize;
+    let mut removals = 0usize;
+    let mut unchanged = 0usize;
+
+    for change in text_diff.iter_all_changes() {
+        match change.tag() {
+            ChangeTag::Insert => additions += 1,
+            ChangeTag::Delete => removals += 1,
+            ChangeTag::Equal => unchanged += 1,
+        }
+    }
+
+    let changed = additions > 0 || removals > 0;
+
+    let diff = text_diff
+        .unified_diff()
+        .context_radius(3)
+        .header("before", "after")
+        .to_string();
+
+    SnapshotDiffResult {
+        diff,
+        additions,
+        removals,
+        unchanged,
+        changed,
+    }
+}
+
+/// Legacy JSON diff output for backwards compatibility.
+pub fn diff_text(a: &str, b: &str) -> Value {
+    let result = diff_snapshots(a, b);
+    json!({
+        "identical": !result.changed,
+        "additions": result.additions,
+        "removals": result.removals,
+        "deletions": result.removals,
+        "unchanged": result.unchanged,
+        "changed": result.changed,
+    })
+}
+
+pub fn diff_unified(a: &str, b: &str) -> String {
+    diff_snapshots(a, b).diff
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_diff_identical() {
+        let result = diff_text("hello\nworld", "hello\nworld");
+        assert_eq!(result.get("identical").unwrap(), true);
+        assert_eq!(result.get("changed").unwrap(), false);
+        assert_eq!(result.get("unchanged").unwrap(), 2);
+    }
+
+    #[test]
+    fn test_diff_additions() {
+        let result = diff_text("hello\n", "hello\nworld\n");
+        assert_eq!(result.get("identical").unwrap(), false);
+        assert_eq!(result.get("changed").unwrap(), true);
+        assert!(result.get("additions").unwrap().as_i64().unwrap() > 0);
+    }
+
+    #[test]
+    fn test_diff_deletions() {
+        let result = diff_text("hello\nworld\n", "hello\n");
+        assert_eq!(result.get("identical").unwrap(), false);
+        assert!(result.get("removals").unwrap().as_i64().unwrap() > 0);
+    }
+
+    #[test]
+    fn test_diff_unified_output() {
+        let output = diff_unified("a\nb\nc\n", "a\nx\nc\n");
+        assert!(output.contains("---"));
+        assert!(output.contains("+++"));
+    }
+
+    #[test]
+    fn test_snapshot_diff_struct() {
+        let result = diff_snapshots("line1\nline2\n", "line1\nline3\n");
+        assert!(result.changed);
+        assert_eq!(result.additions, 1);
+        assert_eq!(result.removals, 1);
+        assert_eq!(result.unchanged, 1);
+        assert!(!result.diff.is_empty());
+    }
+}