From fa0282e00eda33f71a6554ef01705a99dcd6eb7b Mon Sep 17 00:00:00 2001
From: Ellaisbae <ellaisiewele@gmail.com>
Date: Thu, 28 May 2026 05:52:09 +0200
Subject: [PATCH] feat: add JSON diff output mode

---
 src/cli/args.rs     | 22 +++++++++++++++++++
 src/cli/commands.rs | 51 ++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 70 insertions(+), 3 deletions(-)

diff --git a/src/cli/args.rs b/src/cli/args.rs
index 4025fc9d..5cf6c6ca 100644
--- a/src/cli/args.rs
+++ b/src/cli/args.rs
@@ -1036,6 +1036,24 @@ mod tests {
         assert_eq!(args.contract.to_str().unwrap(), "contract.wasm");
         assert_eq!(args.network_snapshot.unwrap().to_str().unwrap(), "state.json");
     }
+
+    #[test]
+    fn replay_accepts_format_flag() {
+        let cli = Cli::parse_from([
+            "soroban-debug",
+            "replay",
+            "trace.json",
+            "--format",
+            "json",
+        ]);
+
+        let Commands::Replay(args) = cli.command.expect("replay command expected") else {
+            panic!("replay command expected");
+        };
+
+        assert_eq!(args.format, OutputFormat::Json);
+        assert_eq!(args.trace_file.to_str().unwrap(), "trace.json");
+    }
 }
 }
 
@@ -1241,6 +1259,10 @@ pub struct ReplayArgs {
     /// Show verbose output during replay
     #[arg(short, long)]
     pub verbose: bool,
+
+    /// Output format for the diff report (pretty or json)
+    #[arg(long, value_enum, default_value_t = OutputFormat::Pretty)]
+    pub format: OutputFormat,
 }
 
 #[derive(Parser)]
diff --git a/src/cli/commands.rs b/src/cli/commands.rs
index cbee9755..1df95d80 100644
--- a/src/cli/commands.rs
+++ b/src/cli/commands.rs
@@ -2046,9 +2046,50 @@ pub fn replay(args: ReplayArgs, verbosity: Verbosity) -> Result<()> {
     }
 
     // Compare results
-    print_info("\n--- Comparison ---");
+    if args.format == OutputFormat::Pretty {
+        print_info("\n--- Comparison ---");
+    }
+
     let report = crate::compare::CompareEngine::compare(&truncated_original, &replayed_trace);
-    let rendered = crate::compare::CompareEngine::render_report(&report);
+    
+    let rendered = match args.format {
+        OutputFormat::Json => {
+            let mut matched_steps = 0;
+            let mut mismatched_steps = 0;
+            for line in &report.flow_diff.diff_lines {
+                match line {
+                    crate::compare::engine::DiffLine::Same(_) => matched_steps += 1,
+                    _ => mismatched_steps += 1,
+                }
+            }
+
+            let metadata = serde_json::json!({
+                "trace_file": args.trace_file.display().to_string(),
+                "contract_used": contract_path.display().to_string(),
+                "replay_until": args.replay_until,
+                "is_partial_replay": is_partial_replay,
+                "flow_stats": {
+                    "matched_steps": matched_steps,
+                    "mismatched_steps": mismatched_steps,
+                    "skipped_steps": original_trace.call_sequence.len().saturating_sub(truncated_original.call_sequence.len()),
+                }
+            });
+            
+            let mut report_value = serde_json::to_value(&report).map_err(|e| {
+                DebuggerError::FileError(format!("Failed to serialize comparison report: {}", e))
+            })?;
+            
+            if let Some(obj) = report_value.as_object_mut() {
+                obj.insert("replay_metadata".to_string(), metadata);
+            }
+
+            let envelope = crate::output::VersionedOutput::success("replay", &report_value);
+            serde_json::to_string_pretty(&envelope).map_err(|e| {
+                DebuggerError::FileError(format!("Failed to serialize replay JSON output: {}", e))
+            })?
+        }
+        OutputFormat::Pretty => crate::compare::CompareEngine::render_report(&report),
+    };
 
     if let Some(output_path) = &args.output {
         std::fs::write(output_path, &rendered).map_err(|e| {
@@ -2059,7 +2100,11 @@ pub fn replay(args: ReplayArgs, verbosity: Verbosity) -> Result<()> {
         })?;
         print_success(format!("\nReplay report written to: {:?}", output_path));
     } else {
-        logging::log_display(rendered, logging::LogLevel::Info);
+        if args.format == OutputFormat::Json {
+            println!("{}", rendered);
+        } else {
+            logging::log_display(rendered, logging::LogLevel::Info);
+        }
     }
 
     if verbosity == Verbosity::Verbose {