scud/commands/spawn/headless/

runner.rs

//! Headless runner implementations for different harnesses
//!
//! This module provides the `HeadlessRunner` trait and implementations for running
//! AI coding agents (Claude Code and OpenCode) in headless/non-interactive mode,
//! parsing their streaming JSON output into unified `StreamEvent` types.

use anyhow::Result;
use std::future::Future;
use std::path::Path;
use std::pin::Pin;
use std::process::Stdio;
use tokio::io::{AsyncBufReadExt, BufReader};
use tokio::process::{Child, Command};
use tokio::sync::mpsc;

use super::events::{StreamEvent, StreamEventKind};
use crate::commands::spawn::terminal::{find_harness_binary, Harness};

/// Boxed async result type for dyn-compatible async trait methods
pub type BoxFuture<'a, T> = Pin<Box<dyn Future<Output = T> + Send + 'a>>;

/// Handle to a running headless session
pub struct SessionHandle {
    /// Task ID this session is for
    pub task_id: String,
    /// Harness session ID (for continuation)
    pub session_id: Option<String>,
    /// Child process
    child: Child,
    /// Event receiver
    pub events: mpsc::Receiver<StreamEvent>,
}

impl SessionHandle {
    /// Wait for the session to complete
    pub async fn wait(mut self) -> Result<bool> {
        let status = self.child.wait().await?;
        Ok(status.success())
    }
    
    /// Interrupt the session (send SIGINT)
    pub fn interrupt(&mut self) -> Result<()> {
        #[cfg(unix)]
        {
            if let Some(pid) = self.child.id() {
                // Send SIGINT using kill command (avoids nix dependency)
                let _ = std::process::Command::new("kill")
                    .arg("-INT")
                    .arg(pid.to_string())
                    .status();
            }
        }

        #[cfg(not(unix))]
        {
            // On non-Unix, just kill the process
            let _ = self.child.start_kill();
        }

        Ok(())
    }

    /// Kill the session immediately
    pub fn kill(&mut self) -> Result<()> {
        self.child.start_kill()?;
        Ok(())
    }

    /// Get the process ID
    pub fn pid(&self) -> Option<u32> {
        self.child.id()
    }
}

/// Trait for headless agent execution
///
/// Implementations provide the ability to start agents in headless mode
/// with streaming JSON output, and to generate commands for interactive
/// session continuation.
///
/// This trait uses boxed futures to be dyn-compatible, allowing runtime
/// polymorphism via `Box<dyn HeadlessRunner>`.
pub trait HeadlessRunner: Send + Sync {
    /// Start an agent with a prompt
    ///
    /// Returns a SessionHandle that can be used to receive events,
    /// wait for completion, or interrupt the session.
    fn start<'a>(
        &'a self,
        task_id: &'a str,
        prompt: &'a str,
        working_dir: &'a Path,
        model: Option<&'a str>,
    ) -> BoxFuture<'a, Result<SessionHandle>>;

    /// Get the command to launch interactive mode for session continuation
    ///
    /// Returns the command and arguments needed to resume the session
    /// interactively (e.g., `claude --resume <session_id>`).
    fn interactive_command(&self, session_id: &str) -> Vec<String>;

    /// Get the harness type this runner supports
    fn harness(&self) -> Harness;
}

/// Claude Code headless runner
///
/// Runs Claude Code in headless mode with `--output-format stream-json`,
/// parsing the streaming JSON events for display in TUI/GUI.
pub struct ClaudeHeadless {
    binary_path: String,
    allowed_tools: Vec<String>,
}

impl ClaudeHeadless {
    /// Create a new Claude headless runner
    ///
    /// Finds the Claude binary in PATH or common installation locations.
    pub fn new() -> Result<Self> {
        let binary_path = find_harness_binary(Harness::Claude)?.to_string();
        Ok(Self {
            binary_path,
            allowed_tools: vec![
                "Read".to_string(),
                "Write".to_string(),
                "Edit".to_string(),
                "Bash".to_string(),
                "Glob".to_string(),
                "Grep".to_string(),
            ],
        })
    }

    /// Create with an explicit binary path (useful for testing)
    #[cfg(test)]
    pub fn with_binary_path(path: impl Into<String>) -> Self {
        Self {
            binary_path: path.into(),
            allowed_tools: vec![],
        }
    }

    /// Set the allowed tools for this runner
    pub fn with_allowed_tools(mut self, tools: Vec<String>) -> Self {
        self.allowed_tools = tools;
        self
    }

    /// Get the binary path
    pub fn binary_path(&self) -> &str {
        &self.binary_path
    }
}

impl HeadlessRunner for ClaudeHeadless {
    fn start<'a>(
        &'a self,
        task_id: &'a str,
        prompt: &'a str,
        working_dir: &'a Path,
        model: Option<&'a str>,
    ) -> BoxFuture<'a, Result<SessionHandle>> {
        Box::pin(async move {
            let mut cmd = Command::new(&self.binary_path);

            // Core headless flags
            cmd.arg("-p").arg(prompt);
            cmd.arg("--output-format").arg("stream-json");
            cmd.arg("--verbose");
            cmd.arg("--dangerously-skip-permissions");

            // Model selection
            if let Some(m) = model {
                cmd.arg("--model").arg(m);
            }

            // Allowed tools
            if !self.allowed_tools.is_empty() {
                cmd.arg("--allowedTools")
                    .arg(self.allowed_tools.join(","));
            }

            // Working directory and environment
            cmd.current_dir(working_dir);
            cmd.env("SCUD_TASK_ID", task_id);

            // Capture stdout for streaming
            cmd.stdout(Stdio::piped());
            cmd.stderr(Stdio::piped());

            let mut child = cmd.spawn()?;

            // Create event channel
            let (tx, rx) = mpsc::channel(1000);

            // Spawn task to read stdout and parse events
            let stdout = child.stdout.take().expect("stdout was piped");
            let task_id_clone = task_id.to_string();

            tokio::spawn(async move {
                let reader = BufReader::new(stdout);
                let mut lines = reader.lines();

                while let Ok(Some(line)) = lines.next_line().await {
                    if let Some(event) = parse_claude_event(&line) {
                        if tx.send(event).await.is_err() {
                            break;
                        }
                    }
                }

                // Send completion event
                let _ = tx.send(StreamEvent::complete(true)).await;
            });

            Ok(SessionHandle {
                task_id: task_id_clone,
                session_id: None, // Will be set when we parse session_id from events
                child,
                events: rx,
            })
        })
    }

    fn interactive_command(&self, session_id: &str) -> Vec<String> {
        vec![
            self.binary_path.clone(),
            "--resume".to_string(),
            session_id.to_string(),
        ]
    }

    fn harness(&self) -> Harness {
        Harness::Claude
    }
}

/// Parse a line of Claude stream-json output into a StreamEvent
fn parse_claude_event(line: &str) -> Option<StreamEvent> {
    let json: serde_json::Value = serde_json::from_str(line).ok()?;

    let event_type = json.get("type")?.as_str()?;

    match event_type {
        "stream_event" => {
            // Check for text delta
            if let Some(delta) = json.pointer("/event/delta") {
                if delta.get("type")?.as_str()? == "text_delta" {
                    let text = delta.get("text")?.as_str()?;
                    return Some(StreamEvent::text_delta(text));
                }
            }
            None
        }
        "assistant" | "content_block_delta" => {
            // Alternative text delta format
            if let Some(text) = json.pointer("/delta/text").and_then(|v| v.as_str()) {
                return Some(StreamEvent::text_delta(text));
            }
            if let Some(text) = json.pointer("/content/0/text").and_then(|v| v.as_str()) {
                return Some(StreamEvent::text_delta(text));
            }
            None
        }
        "tool_use" => {
            let tool_name = json.get("name")?.as_str()?;
            let tool_id = json.get("id").and_then(|v| v.as_str()).unwrap_or("unknown");
            let input = json
                .get("input")
                .cloned()
                .unwrap_or(serde_json::Value::Null);
            let input_summary = summarize_json(&input);
            Some(StreamEvent::tool_start(tool_name, tool_id, &input_summary))
        }
        "tool_result" => {
            let tool_id = json
                .get("tool_use_id")
                .and_then(|v| v.as_str())
                .unwrap_or("unknown");
            let success = !json
                .get("is_error")
                .and_then(|v| v.as_bool())
                .unwrap_or(false);
            Some(StreamEvent::new(StreamEventKind::ToolResult {
                tool_name: String::new(), // Not always available
                tool_id: tool_id.to_string(),
                success,
            }))
        }
        "result" => {
            // Check for session_id
            if let Some(session_id) = json.get("session_id").and_then(|v| v.as_str()) {
                return Some(StreamEvent::new(StreamEventKind::SessionAssigned {
                    session_id: session_id.to_string(),
                }));
            }
            // Otherwise treat as completion
            Some(StreamEvent::complete(true))
        }
        "error" => {
            let message = json
                .get("error")
                .and_then(|e| e.as_str())
                .or_else(|| json.get("message").and_then(|e| e.as_str()))
                .unwrap_or("Unknown error");
            Some(StreamEvent::error(message))
        }
        _ => None,
    }
}

/// OpenCode headless runner
///
/// Runs OpenCode CLI in headless mode using `opencode run --format json`
/// and parses the streaming JSON output into unified StreamEvent types.
pub struct OpenCodeHeadless {
    binary_path: String,
}

impl OpenCodeHeadless {
    /// Create a new OpenCode headless runner
    ///
    /// Locates the OpenCode binary using the standard harness discovery mechanism.
    pub fn new() -> Result<Self> {
        let binary_path = find_harness_binary(Harness::OpenCode)?.to_string();
        Ok(Self { binary_path })
    }

    /// Create with an explicit binary path (useful for testing)
    #[cfg(test)]
    pub fn with_binary_path(path: impl Into<String>) -> Self {
        Self {
            binary_path: path.into(),
        }
    }
}

impl HeadlessRunner for OpenCodeHeadless {
    fn start<'a>(
        &'a self,
        task_id: &'a str,
        prompt: &'a str,
        working_dir: &'a Path,
        model: Option<&'a str>,
    ) -> BoxFuture<'a, Result<SessionHandle>> {
        Box::pin(async move {
            // OpenCode uses `run` command with JSON format for headless streaming
            let mut cmd = Command::new(&self.binary_path);

            cmd.arg("run");
            cmd.arg("--format").arg("json");
            cmd.arg("--variant").arg("minimal");

            if let Some(m) = model {
                cmd.arg("--model").arg(m);
            }

            cmd.arg(prompt);
            cmd.current_dir(working_dir);
            cmd.env("SCUD_TASK_ID", task_id);
            cmd.stdout(Stdio::piped());
            cmd.stderr(Stdio::piped());

            let mut child = cmd.spawn()?;
            let (tx, rx) = mpsc::channel(1000);

            let stdout = child.stdout.take().expect("stdout was piped");

            tokio::spawn(async move {
                let reader = BufReader::new(stdout);
                let mut lines = reader.lines();

                while let Ok(Some(line)) = lines.next_line().await {
                    if let Some(event) = parse_opencode_event(&line) {
                        if tx.send(event).await.is_err() {
                            break;
                        }
                    }
                }

                let _ = tx.send(StreamEvent::complete(true)).await;
            });

            Ok(SessionHandle {
                task_id: task_id.to_string(),
                session_id: None,
                child,
                events: rx,
            })
        })
    }

    fn interactive_command(&self, session_id: &str) -> Vec<String> {
        // OpenCode uses attach command for session continuation
        vec![
            self.binary_path.clone(),
            "attach".to_string(),
            "http://localhost:4096".to_string(),
            "--session".to_string(),
            session_id.to_string(),
        ]
    }

    fn harness(&self) -> Harness {
        Harness::OpenCode
    }
}

/// Enum-based runner that wraps concrete implementations
///
/// This provides polymorphism without requiring the trait to be object-safe.
/// Use this instead of `Box<dyn HeadlessRunner>` when you need to store
/// or pass around a runner of unknown concrete type.
pub enum AnyRunner {
    Claude(ClaudeHeadless),
    OpenCode(OpenCodeHeadless),
}

impl AnyRunner {
    /// Create a runner for the specified harness
    pub fn new(harness: Harness) -> Result<Self> {
        match harness {
            Harness::Claude => Ok(AnyRunner::Claude(ClaudeHeadless::new()?)),
            Harness::OpenCode => Ok(AnyRunner::OpenCode(OpenCodeHeadless::new()?)),
        }
    }

    /// Start an agent with a prompt
    pub async fn start(
        &self,
        task_id: &str,
        prompt: &str,
        working_dir: &Path,
        model: Option<&str>,
    ) -> Result<SessionHandle> {
        match self {
            AnyRunner::Claude(runner) => runner.start(task_id, prompt, working_dir, model).await,
            AnyRunner::OpenCode(runner) => runner.start(task_id, prompt, working_dir, model).await,
        }
    }

    /// Get the command to launch interactive mode for session continuation
    pub fn interactive_command(&self, session_id: &str) -> Vec<String> {
        match self {
            AnyRunner::Claude(runner) => runner.interactive_command(session_id),
            AnyRunner::OpenCode(runner) => runner.interactive_command(session_id),
        }
    }

    /// Get the harness type this runner supports
    pub fn harness(&self) -> Harness {
        match self {
            AnyRunner::Claude(runner) => runner.harness(),
            AnyRunner::OpenCode(runner) => runner.harness(),
        }
    }
}

/// Create a headless runner for the specified harness
///
/// This is a convenience function that returns an `AnyRunner` enum
/// which provides a unified interface for all runner implementations.
pub fn create_runner(harness: Harness) -> Result<AnyRunner> {
    AnyRunner::new(harness)
}

/// Parse a line of OpenCode JSON output into a StreamEvent
///
/// OpenCode CLI (`opencode run --format json`) outputs newline-delimited JSON events
/// with the following structure:
///
/// - `{"type": "assistant", "message": {"content": [{"text": "..."}]}}` - Text output
/// - `{"type": "tool_call", "subtype": "started", "tool_call": {"name": "...", "input": {...}}}` - Tool start
/// - `{"type": "tool_call", "subtype": "completed", "tool_call": {...}, "result": {...}}` - Tool result
/// - `{"type": "result", "success": true}` - Completion
/// - `{"type": "error", "message": "..."}` - Error
/// - `{"type": "session", "session_id": "..."}` - Session assignment
///
/// Returns `None` for unparseable or unknown event types (graceful degradation).
pub fn parse_opencode_event(line: &str) -> Option<StreamEvent> {
    let json: serde_json::Value = serde_json::from_str(line).ok()?;

    let event_type = json.get("type")?.as_str()?;

    match event_type {
        // Assistant text output - may have various content structures
        "assistant" | "message" | "content" => {
            // Try multiple paths for text content
            let text = json
                .pointer("/message/content/0/text")
                .or_else(|| json.pointer("/content/0/text"))
                .or_else(|| json.pointer("/message/text"))
                .or_else(|| json.get("text"))
                .or_else(|| json.get("delta"))
                .and_then(|v| v.as_str())?;
            Some(StreamEvent::text_delta(text))
        }

        // Tool call events with subtype
        "tool_call" | "tool_use" => {
            let subtype = json
                .get("subtype")
                .or_else(|| json.get("status"))
                .and_then(|v| v.as_str())
                .unwrap_or("started");

            match subtype {
                "started" | "start" | "pending" => {
                    // Extract tool name from various possible locations
                    let tool_name = json
                        .pointer("/tool_call/name")
                        .or_else(|| json.pointer("/tool_call/tool"))
                        .or_else(|| json.get("name"))
                        .or_else(|| json.get("tool"))
                        .and_then(|v| v.as_str())
                        .unwrap_or("unknown");

                    // Extract tool ID
                    let tool_id = json
                        .pointer("/tool_call/id")
                        .or_else(|| json.get("id"))
                        .or_else(|| json.get("tool_id"))
                        .and_then(|v| v.as_str())
                        .unwrap_or("");

                    // Extract and summarize input
                    let input = json
                        .pointer("/tool_call/input")
                        .or_else(|| json.get("input"))
                        .cloned()
                        .unwrap_or(serde_json::Value::Null);
                    let input_summary = summarize_json(&input);

                    Some(StreamEvent::tool_start(tool_name, tool_id, &input_summary))
                }
                "completed" | "complete" | "done" | "success" => {
                    let tool_name = json
                        .pointer("/tool_call/name")
                        .or_else(|| json.get("name"))
                        .or_else(|| json.get("tool"))
                        .and_then(|v| v.as_str())
                        .unwrap_or("");

                    let tool_id = json
                        .pointer("/tool_call/id")
                        .or_else(|| json.get("id"))
                        .or_else(|| json.get("tool_id"))
                        .and_then(|v| v.as_str())
                        .unwrap_or("");

                    // Check for error in result
                    let success = !json
                        .pointer("/result/is_error")
                        .or_else(|| json.get("is_error"))
                        .or_else(|| json.get("error"))
                        .map(|v| v.as_bool().unwrap_or(false) || v.is_string())
                        .unwrap_or(false);

                    Some(StreamEvent::new(StreamEventKind::ToolResult {
                        tool_name: tool_name.to_string(),
                        tool_id: tool_id.to_string(),
                        success,
                    }))
                }
                "failed" | "error" => {
                    let tool_name = json
                        .pointer("/tool_call/name")
                        .or_else(|| json.get("name"))
                        .and_then(|v| v.as_str())
                        .unwrap_or("");

                    let tool_id = json
                        .pointer("/tool_call/id")
                        .or_else(|| json.get("id"))
                        .and_then(|v| v.as_str())
                        .unwrap_or("");

                    Some(StreamEvent::new(StreamEventKind::ToolResult {
                        tool_name: tool_name.to_string(),
                        tool_id: tool_id.to_string(),
                        success: false,
                    }))
                }
                _ => None,
            }
        }

        // Completion event
        "result" | "done" | "complete" => {
            let success = json
                .get("success")
                .and_then(|v| v.as_bool())
                .unwrap_or(true);
            Some(StreamEvent::complete(success))
        }

        // Error event
        "error" => {
            let message = json
                .get("message")
                .or_else(|| json.get("error"))
                .and_then(|v| v.as_str())
                .unwrap_or("Unknown error");
            Some(StreamEvent::error(message))
        }

        // Session assignment
        "session" | "session_start" | "init" => {
            let session_id = json
                .get("session_id")
                .or_else(|| json.get("id"))
                .and_then(|v| v.as_str())?;
            Some(StreamEvent::new(StreamEventKind::SessionAssigned {
                session_id: session_id.to_string(),
            }))
        }

        // Unknown event type - return None for graceful handling
        _ => None,
    }
}

/// Summarize JSON input for compact display
///
/// Produces a short, human-readable summary of JSON values:
/// - Objects: `{key1, key2, ...}` (max 3 keys)
/// - Strings: First 50 chars with ellipsis
/// - Other: JSON stringified, truncated
fn summarize_json(value: &serde_json::Value) -> String {
    match value {
        serde_json::Value::Object(obj) => {
            let keys: Vec<&str> = obj.keys().map(|k| k.as_str()).take(3).collect();
            if keys.is_empty() {
                "{}".to_string()
            } else if keys.len() < obj.len() {
                format!("{{{},...}}", keys.join(", "))
            } else {
                format!("{{{}}}", keys.join(", "))
            }
        }
        serde_json::Value::String(s) => {
            if s.len() > 50 {
                format!("\"{}...\"", &s[..47])
            } else {
                format!("\"{}\"", s)
            }
        }
        serde_json::Value::Null => String::new(),
        serde_json::Value::Array(arr) => {
            format!("[{} items]", arr.len())
        }
        other => {
            let s = other.to_string();
            if s.len() > 50 {
                format!("{}...", &s[..47])
            } else {
                s
            }
        }
    }
}

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

    // =======================
    // Claude event parsing
    // =======================

    #[test]
    fn test_parse_claude_text_delta() {
        let line =
            r#"{"type":"stream_event","event":{"delta":{"type":"text_delta","text":"Hello"}}}"#;
        let event = parse_claude_event(line);
        assert!(matches!(
            event,
            Some(StreamEvent {
                kind: StreamEventKind::TextDelta { ref text },
                ..
            }) if text == "Hello"
        ));
    }

    #[test]
    fn test_parse_claude_tool_use() {
        let line =
            r#"{"type":"tool_use","name":"Read","id":"tool_1","input":{"path":"src/main.rs"}}"#;
        let event = parse_claude_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::ToolStart {
                    ref tool_name,
                    ref tool_id,
                    ref input_summary,
                },
                ..
            }) => {
                assert_eq!(tool_name, "Read");
                assert_eq!(tool_id, "tool_1");
                assert!(input_summary.contains("path"));
            }
            _ => panic!("Expected ToolStart"),
        }
    }

    #[test]
    fn test_parse_claude_error() {
        let line = r#"{"type":"error","error":"Rate limit exceeded"}"#;
        let event = parse_claude_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::Error { ref message },
                ..
            }) => {
                assert_eq!(message, "Rate limit exceeded");
            }
            _ => panic!("Expected Error event"),
        }
    }

    #[test]
    fn test_parse_claude_result_with_session() {
        let line = r#"{"type":"result","session_id":"sess-abc123"}"#;
        let event = parse_claude_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::SessionAssigned { ref session_id },
                ..
            }) => {
                assert_eq!(session_id, "sess-abc123");
            }
            _ => panic!("Expected SessionAssigned"),
        }
    }

    #[test]
    fn test_parse_claude_result_completion() {
        let line = r#"{"type":"result"}"#;
        let event = parse_claude_event(line);
        assert!(matches!(
            event,
            Some(StreamEvent {
                kind: StreamEventKind::Complete { success: true },
                ..
            })
        ));
    }

    #[test]
    fn test_parse_claude_tool_result() {
        let line = r#"{"type":"tool_result","tool_use_id":"tool_1","content":"success"}"#;
        let event = parse_claude_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::ToolResult {
                    ref tool_id,
                    success,
                    ..
                },
                ..
            }) => {
                assert_eq!(tool_id, "tool_1");
                assert!(success);
            }
            _ => panic!("Expected ToolResult"),
        }
    }

    #[test]
    fn test_parse_claude_tool_result_error() {
        let line = r#"{"type":"tool_result","tool_use_id":"tool_2","is_error":true}"#;
        let event = parse_claude_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::ToolResult { success, .. },
                ..
            }) => {
                assert!(!success);
            }
            _ => panic!("Expected ToolResult with failure"),
        }
    }

    #[test]
    fn test_parse_claude_unknown_type_returns_none() {
        let line = r#"{"type":"unknown_event","data":"test"}"#;
        let event = parse_claude_event(line);
        assert!(event.is_none());
    }

    #[test]
    fn test_claude_interactive_command() {
        let runner = ClaudeHeadless::with_binary_path("/usr/local/bin/claude");
        let cmd = runner.interactive_command("sess_123");
        assert_eq!(cmd[0], "/usr/local/bin/claude");
        assert_eq!(cmd[1], "--resume");
        assert_eq!(cmd[2], "sess_123");
    }

    // =======================
    // OpenCode event parsing
    // =======================

    #[test]
    fn test_parse_assistant_text_with_message_content() {
        let line = r#"{"type": "assistant", "message": {"content": [{"text": "Hello world"}]}}"#;
        let event = parse_opencode_event(line);
        assert!(matches!(
            event,
            Some(StreamEvent {
                kind: StreamEventKind::TextDelta { ref text },
                ..
            }) if text == "Hello world"
        ));
    }

    #[test]
    fn test_parse_content_type_with_text() {
        let line = r#"{"type": "content", "content": [{"text": "Response text"}]}"#;
        let event = parse_opencode_event(line);
        assert!(matches!(
            event,
            Some(StreamEvent {
                kind: StreamEventKind::TextDelta { ref text },
                ..
            }) if text == "Response text"
        ));
    }

    #[test]
    fn test_parse_message_type_with_direct_text() {
        let line = r#"{"type": "message", "text": "Direct text"}"#;
        let event = parse_opencode_event(line);
        assert!(matches!(
            event,
            Some(StreamEvent {
                kind: StreamEventKind::TextDelta { ref text },
                ..
            }) if text == "Direct text"
        ));
    }

    #[test]
    fn test_parse_assistant_with_delta_field() {
        let line = r#"{"type": "assistant", "delta": "Streaming chunk"}"#;
        let event = parse_opencode_event(line);
        assert!(matches!(
            event,
            Some(StreamEvent {
                kind: StreamEventKind::TextDelta { ref text },
                ..
            }) if text == "Streaming chunk"
        ));
    }

    // ===================
    // Tool call parsing
    // ===================

    #[test]
    fn test_parse_tool_call_started() {
        let line = r#"{"type": "tool_call", "subtype": "started", "tool_call": {"name": "read_file", "id": "tool_1", "input": {"path": "src/main.rs"}}}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind:
                    StreamEventKind::ToolStart {
                        ref tool_name,
                        ref tool_id,
                        ref input_summary,
                    },
                ..
            }) => {
                assert_eq!(tool_name, "read_file");
                assert_eq!(tool_id, "tool_1");
                assert!(input_summary.contains("path"));
            }
            _ => panic!("Expected ToolStart, got {:?}", event),
        }
    }

    #[test]
    fn test_parse_tool_use_start() {
        let line = r#"{"type": "tool_use", "status": "start", "name": "bash", "id": "t123"}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind:
                    StreamEventKind::ToolStart {
                        ref tool_name,
                        ref tool_id,
                        ..
                    },
                ..
            }) => {
                assert_eq!(tool_name, "bash");
                assert_eq!(tool_id, "t123");
            }
            _ => panic!("Expected ToolStart"),
        }
    }

    #[test]
    fn test_parse_tool_call_completed() {
        let line = r#"{"type": "tool_call", "subtype": "completed", "tool_call": {"name": "write_file", "id": "t2"}, "result": {}}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind:
                    StreamEventKind::ToolResult {
                        ref tool_name,
                        ref tool_id,
                        success,
                    },
                ..
            }) => {
                assert_eq!(tool_name, "write_file");
                assert_eq!(tool_id, "t2");
                assert!(success);
            }
            _ => panic!("Expected ToolResult"),
        }
    }

    #[test]
    fn test_parse_tool_call_with_error() {
        let line = r#"{"type": "tool_call", "subtype": "completed", "name": "bash", "result": {"is_error": true}}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind:
                    StreamEventKind::ToolResult {
                        success, ..
                    },
                ..
            }) => {
                assert!(!success);
            }
            _ => panic!("Expected ToolResult with failure"),
        }
    }

    #[test]
    fn test_parse_tool_call_failed_subtype() {
        let line = r#"{"type": "tool_call", "subtype": "failed", "name": "git", "id": "t3"}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind:
                    StreamEventKind::ToolResult {
                        success, ..
                    },
                ..
            }) => {
                assert!(!success);
            }
            _ => panic!("Expected failed ToolResult"),
        }
    }

    // ===================
    // Completion parsing
    // ===================

    #[test]
    fn test_parse_result_success() {
        let line = r#"{"type": "result", "success": true}"#;
        let event = parse_opencode_event(line);
        assert!(matches!(
            event,
            Some(StreamEvent {
                kind: StreamEventKind::Complete { success: true },
                ..
            })
        ));
    }

    #[test]
    fn test_parse_result_failure() {
        let line = r#"{"type": "result", "success": false}"#;
        let event = parse_opencode_event(line);
        assert!(matches!(
            event,
            Some(StreamEvent {
                kind: StreamEventKind::Complete { success: false },
                ..
            })
        ));
    }

    #[test]
    fn test_parse_done_type() {
        let line = r#"{"type": "done"}"#;
        let event = parse_opencode_event(line);
        assert!(matches!(
            event,
            Some(StreamEvent {
                kind: StreamEventKind::Complete { success: true },
                ..
            })
        ));
    }

    // ===================
    // Error parsing
    // ===================

    #[test]
    fn test_parse_error_with_message() {
        let line = r#"{"type": "error", "message": "Connection failed"}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::Error { ref message },
                ..
            }) => {
                assert_eq!(message, "Connection failed");
            }
            _ => panic!("Expected Error event"),
        }
    }

    #[test]
    fn test_parse_error_with_error_field() {
        let line = r#"{"type": "error", "error": "Rate limited"}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::Error { ref message },
                ..
            }) => {
                assert_eq!(message, "Rate limited");
            }
            _ => panic!("Expected Error event"),
        }
    }

    // ===================
    // Session parsing
    // ===================

    #[test]
    fn test_parse_session_assignment() {
        let line = r#"{"type": "session", "session_id": "sess_abc123"}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::SessionAssigned { ref session_id },
                ..
            }) => {
                assert_eq!(session_id, "sess_abc123");
            }
            _ => panic!("Expected SessionAssigned"),
        }
    }

    #[test]
    fn test_parse_session_with_id_field() {
        let line = r#"{"type": "init", "id": "session_xyz"}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::SessionAssigned { ref session_id },
                ..
            }) => {
                assert_eq!(session_id, "session_xyz");
            }
            _ => panic!("Expected SessionAssigned"),
        }
    }

    // ===================
    // Edge cases
    // ===================

    #[test]
    fn test_parse_unknown_event_returns_none() {
        let line = r#"{"type": "custom_event", "data": "something"}"#;
        let event = parse_opencode_event(line);
        assert!(event.is_none());
    }

    #[test]
    fn test_parse_invalid_json_returns_none() {
        let line = "not json at all";
        let event = parse_opencode_event(line);
        assert!(event.is_none());
    }

    #[test]
    fn test_parse_missing_type_returns_none() {
        let line = r#"{"message": "no type field"}"#;
        let event = parse_opencode_event(line);
        assert!(event.is_none());
    }

    #[test]
    fn test_parse_empty_json_returns_none() {
        let line = "{}";
        let event = parse_opencode_event(line);
        assert!(event.is_none());
    }

    // ===================
    // JSON summarization
    // ===================

    #[test]
    fn test_summarize_json_object() {
        let value = serde_json::json!({"path": "/foo", "content": "bar"});
        let summary = summarize_json(&value);
        assert!(summary.contains("path"));
        assert!(summary.contains("content"));
    }

    #[test]
    fn test_summarize_json_object_truncated() {
        let value = serde_json::json!({
            "key1": "v1",
            "key2": "v2",
            "key3": "v3",
            "key4": "v4"
        });
        let summary = summarize_json(&value);
        assert!(summary.contains("..."));
    }

    #[test]
    fn test_summarize_json_empty_object() {
        let value = serde_json::json!({});
        let summary = summarize_json(&value);
        assert_eq!(summary, "{}");
    }

    #[test]
    fn test_summarize_json_string() {
        let value = serde_json::json!("short string");
        let summary = summarize_json(&value);
        assert_eq!(summary, "\"short string\"");
    }

    #[test]
    fn test_summarize_json_long_string() {
        let long = "a".repeat(100);
        let value = serde_json::json!(long);
        let summary = summarize_json(&value);
        assert!(summary.len() < 60);
        assert!(summary.ends_with("...\""));
    }

    #[test]
    fn test_summarize_json_null() {
        let value = serde_json::Value::Null;
        let summary = summarize_json(&value);
        assert_eq!(summary, "");
    }

    #[test]
    fn test_summarize_json_array() {
        let value = serde_json::json!([1, 2, 3, 4, 5]);
        let summary = summarize_json(&value);
        assert_eq!(summary, "[5 items]");
    }

    #[test]
    fn test_summarize_json_number() {
        let value = serde_json::json!(42);
        let summary = summarize_json(&value);
        assert_eq!(summary, "42");
    }

    // ===================
    // Interactive command
    // ===================

    #[test]
    fn test_interactive_command_format() {
        let runner = OpenCodeHeadless::with_binary_path("/usr/local/bin/opencode");
        let cmd = runner.interactive_command("session_123");
        assert_eq!(cmd[0], "/usr/local/bin/opencode");
        assert_eq!(cmd[1], "attach");
        assert!(cmd.contains(&"--session".to_string()));
        assert!(cmd.contains(&"session_123".to_string()));
    }

    // ===================
    // OpenCodeHeadless struct tests
    // ===================

    #[test]
    fn test_opencode_headless_with_binary_path() {
        let runner = OpenCodeHeadless::with_binary_path("/custom/path/opencode");
        // Verify harness returns OpenCode
        assert!(matches!(runner.harness(), Harness::OpenCode));
    }

    #[test]
    fn test_opencode_interactive_command_structure() {
        let runner = OpenCodeHeadless::with_binary_path("/bin/opencode");
        let cmd = runner.interactive_command("sess-xyz-789");

        // Should produce: opencode attach http://localhost:4096 --session sess-xyz-789
        assert_eq!(cmd.len(), 5);
        assert_eq!(cmd[0], "/bin/opencode");
        assert_eq!(cmd[1], "attach");
        assert_eq!(cmd[2], "http://localhost:4096");
        assert_eq!(cmd[3], "--session");
        assert_eq!(cmd[4], "sess-xyz-789");
    }

    #[test]
    fn test_opencode_harness_type() {
        let runner = OpenCodeHeadless::with_binary_path("opencode");
        assert_eq!(runner.harness(), Harness::OpenCode);
    }

    // ===================
    // ClaudeHeadless struct tests
    // ===================

    #[test]
    fn test_claude_headless_with_binary_path() {
        let runner = ClaudeHeadless::with_binary_path("/custom/claude");
        assert_eq!(runner.binary_path(), "/custom/claude");
        assert!(matches!(runner.harness(), Harness::Claude));
    }

    #[test]
    fn test_claude_headless_with_allowed_tools() {
        let runner = ClaudeHeadless::with_binary_path("/bin/claude")
            .with_allowed_tools(vec!["Read".to_string(), "Write".to_string()]);
        // The runner should accept the tools (no getter, but constructor works)
        assert_eq!(runner.binary_path(), "/bin/claude");
    }

    #[test]
    fn test_claude_interactive_command_structure() {
        let runner = ClaudeHeadless::with_binary_path("/usr/bin/claude");
        let cmd = runner.interactive_command("sess-abc-123");

        // Should produce: claude --resume sess-abc-123
        assert_eq!(cmd.len(), 3);
        assert_eq!(cmd[0], "/usr/bin/claude");
        assert_eq!(cmd[1], "--resume");
        assert_eq!(cmd[2], "sess-abc-123");
    }

    #[test]
    fn test_claude_harness_type() {
        let runner = ClaudeHeadless::with_binary_path("claude");
        assert_eq!(runner.harness(), Harness::Claude);
    }

    // ===================
    // AnyRunner enum tests
    // ===================

    #[test]
    fn test_any_runner_claude_variant() {
        let runner = AnyRunner::Claude(ClaudeHeadless::with_binary_path("/bin/claude"));
        assert_eq!(runner.harness(), Harness::Claude);

        let cmd = runner.interactive_command("session-1");
        assert_eq!(cmd[0], "/bin/claude");
        assert_eq!(cmd[1], "--resume");
    }

    #[test]
    fn test_any_runner_opencode_variant() {
        let runner = AnyRunner::OpenCode(OpenCodeHeadless::with_binary_path("/bin/opencode"));
        assert_eq!(runner.harness(), Harness::OpenCode);

        let cmd = runner.interactive_command("session-2");
        assert_eq!(cmd[0], "/bin/opencode");
        assert_eq!(cmd[1], "attach");
    }

    #[test]
    fn test_any_runner_harness_matches() {
        let claude = AnyRunner::Claude(ClaudeHeadless::with_binary_path("claude"));
        let opencode = AnyRunner::OpenCode(OpenCodeHeadless::with_binary_path("opencode"));

        // Verify harness() returns correct type for each variant
        assert!(matches!(claude.harness(), Harness::Claude));
        assert!(matches!(opencode.harness(), Harness::OpenCode));
    }

    // ===================
    // Additional OpenCode parsing edge cases
    // ===================

    #[test]
    fn test_parse_opencode_tool_with_pending_status() {
        let line = r#"{"type": "tool_call", "status": "pending", "tool": "write_file", "id": "t99"}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind:
                    StreamEventKind::ToolStart {
                        ref tool_name,
                        ref tool_id,
                        ..
                    },
                ..
            }) => {
                assert_eq!(tool_name, "write_file");
                assert_eq!(tool_id, "t99");
            }
            _ => panic!("Expected ToolStart for pending status"),
        }
    }

    #[test]
    fn test_parse_opencode_tool_done_status() {
        let line = r#"{"type": "tool_call", "subtype": "done", "name": "exec", "id": "t50"}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind:
                    StreamEventKind::ToolResult {
                        ref tool_name,
                        success,
                        ..
                    },
                ..
            }) => {
                assert_eq!(tool_name, "exec");
                assert!(success);
            }
            _ => panic!("Expected ToolResult for done subtype"),
        }
    }

    #[test]
    fn test_parse_opencode_tool_success_status() {
        let line =
            r#"{"type": "tool_use", "subtype": "success", "tool_call": {"name": "bash", "id": "t77"}}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::ToolResult { success, .. },
                ..
            }) => {
                assert!(success);
            }
            _ => panic!("Expected ToolResult for success subtype"),
        }
    }

    #[test]
    fn test_parse_opencode_complete_type() {
        let line = r#"{"type": "complete", "success": true}"#;
        let event = parse_opencode_event(line);
        assert!(matches!(
            event,
            Some(StreamEvent {
                kind: StreamEventKind::Complete { success: true },
                ..
            })
        ));
    }

    #[test]
    fn test_parse_opencode_session_start_type() {
        let line = r#"{"type": "session_start", "session_id": "sess-start-001"}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::SessionAssigned { ref session_id },
                ..
            }) => {
                assert_eq!(session_id, "sess-start-001");
            }
            _ => panic!("Expected SessionAssigned for session_start type"),
        }
    }

    #[test]
    fn test_parse_opencode_assistant_with_message_text() {
        let line = r#"{"type": "assistant", "message": {"text": "Thinking about this..."}}"#;
        let event = parse_opencode_event(line);
        assert!(matches!(
            event,
            Some(StreamEvent {
                kind: StreamEventKind::TextDelta { ref text },
                ..
            }) if text == "Thinking about this..."
        ));
    }

    #[test]
    fn test_parse_opencode_tool_call_error_subtype() {
        let line = r#"{"type": "tool_call", "subtype": "error", "tool_call": {"name": "git", "id": "t88"}}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind:
                    StreamEventKind::ToolResult {
                        ref tool_name,
                        success,
                        ..
                    },
                ..
            }) => {
                assert_eq!(tool_name, "git");
                assert!(!success);
            }
            _ => panic!("Expected failed ToolResult for error subtype"),
        }
    }

    #[test]
    fn test_parse_opencode_tool_with_nested_input() {
        let line = r#"{"type": "tool_call", "subtype": "started", "tool_call": {"name": "write_file", "id": "t100", "input": {"path": "src/lib.rs", "content": "// Code here", "mode": "overwrite"}}}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind:
                    StreamEventKind::ToolStart {
                        ref tool_name,
                        ref input_summary,
                        ..
                    },
                ..
            }) => {
                assert_eq!(tool_name, "write_file");
                // Input should be summarized with keys
                assert!(input_summary.contains("path"));
            }
            _ => panic!("Expected ToolStart with input summary"),
        }
    }

    #[test]
    fn test_parse_opencode_tool_result_with_error_string() {
        let line = r#"{"type": "tool_call", "subtype": "completed", "name": "bash", "error": "Command not found"}"#;
        let event = parse_opencode_event(line);
        match event {
            Some(StreamEvent {
                kind: StreamEventKind::ToolResult { success, .. },
                ..
            }) => {
                // error field as string should indicate failure
                assert!(!success);
            }
            _ => panic!("Expected failed ToolResult"),
        }
    }

    #[test]
    fn test_parse_opencode_unknown_subtype_returns_none() {
        let line = r#"{"type": "tool_call", "subtype": "unknown_status", "name": "bash"}"#;
        let event = parse_opencode_event(line);
        assert!(event.is_none());
    }
}