pub use crate::cli_agent_runtime::AgentStreamRequest;
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::path::{Path, PathBuf};
use std::process::{ExitStatus, Stdio};

/// Status returned by `check_claude_cli`.
#[derive(Debug, Serialize, Clone)]
pub struct ClaudeCliStatus {
    pub installed: bool,
    pub version: Option<String>,
}

/// Event emitted to the frontend during a streaming claude session.
#[derive(Debug, Serialize, Clone)]
#[serde(tag = "kind")]
pub enum ClaudeStreamEvent {
    /// Session initialised — carries the session ID for future `--resume`.
    Init { session_id: String },
    /// Incremental text chunk.
    TextDelta { text: String },
    /// Incremental thinking/reasoning chunk.
    ThinkingDelta { text: String },
    /// A tool call started (agent mode only).
    ToolStart {
        tool_name: String,
        tool_id: String,
        #[serde(skip_serializing_if = "Option::is_none")]
        input: Option<String>,
    },
    /// A tool call finished (agent mode only).
    ToolDone {
        tool_id: String,
        #[serde(skip_serializing_if = "Option::is_none")]
        output: Option<String>,
    },
    /// Final result text + session ID.
    Result { text: String, session_id: String },
    /// Something went wrong.
    Error { message: String },
    /// Stream finished.
    Done,
}

/// Parameters accepted by `stream_claude_chat`.
#[derive(Debug, Deserialize)]
pub struct ChatStreamRequest {
    pub message: String,
    pub system_prompt: Option<String>,
    pub session_id: Option<String>,
}

// ---------------------------------------------------------------------------
// Finding the `claude` binary
// ---------------------------------------------------------------------------

pub(crate) fn find_claude_binary() -> Result<PathBuf, String> {
    if let Some(binary) = find_claude_binary_on_path() {
        return Ok(binary);
    }

    if let Some(binary) = find_claude_binary_in_user_shell() {
        return Ok(binary);
    }

    if let Some(binary) = crate::cli_agent_runtime::find_executable_binary_candidate(
        claude_binary_candidates(),
        "Claude CLI",
    )? {
        return Ok(binary);
    }

    Err("Claude CLI not found. Install it: https://docs.anthropic.com/en/docs/claude-code".into())
}

fn find_claude_binary_on_path() -> Option<PathBuf> {
    crate::hidden_command(claude_path_lookup_command())
        .arg("claude")
        .output()
        .ok()
        .and_then(|output| path_from_successful_output(&output))
}

fn claude_path_lookup_command() -> &'static str {
    if cfg!(windows) {
        "where"
    } else {
        "which"
    }
}

fn find_claude_binary_in_user_shell() -> Option<PathBuf> {
    user_shell_candidates()
        .into_iter()
        .filter(|shell| shell.exists())
        .find_map(|shell| claude_path_from_shell(&shell))
}

fn user_shell_candidates() -> Vec<PathBuf> {
    let mut shells = Vec::new();
    if let Some(shell) = std::env::var_os("SHELL") {
        if !shell.is_empty() {
            shells.push(PathBuf::from(shell));
        }
    }
    shells.push(PathBuf::from("/bin/zsh"));
    shells.push(PathBuf::from("/bin/bash"));
    shells
}

fn claude_path_from_shell(shell: &Path) -> Option<PathBuf> {
    crate::hidden_command(shell)
        .arg("-lc")
        .arg("command -v claude")
        .output()
        .ok()
        .and_then(|output| path_from_successful_output(&output))
}

fn path_from_successful_output(output: &std::process::Output) -> Option<PathBuf> {
    if output.status.success() {
        first_existing_path(&String::from_utf8_lossy(&output.stdout))
    } else {
        None
    }
}

fn first_existing_path(stdout: &str) -> Option<PathBuf> {
    first_existing_path_for_platform(stdout, cfg!(windows))
}

fn first_existing_path_for_platform(stdout: &str, windows: bool) -> Option<PathBuf> {
    let mut paths = stdout.lines().filter_map(existing_path);
    if windows {
        return paths.find(|path| crate::cli_agent_runtime::has_windows_cli_extension(path));
    }

    paths.next()
}

fn existing_path(line: &str) -> Option<PathBuf> {
    let trimmed = line.trim();
    if trimmed.is_empty() {
        return None;
    }
    let candidate = PathBuf::from(trimmed);
    candidate.exists().then_some(candidate)
}

fn claude_binary_candidates() -> Vec<PathBuf> {
    dirs::home_dir()
        .map(|home| claude_binary_candidates_for_home(&home))
        .unwrap_or_default()
}

fn claude_binary_candidates_for_home(home: &Path) -> Vec<PathBuf> {
    let mut candidates = vec![
        home.join(".local/bin/claude"),
        home.join(".local/bin/claude.exe"),
        home.join(".claude/local/claude"),
        home.join(".claude/local/claude.exe"),
        home.join(".local/share/mise/shims/claude"),
        home.join(".local/share/mise/shims/claude.exe"),
        home.join(".asdf/shims/claude"),
        home.join(".asdf/shims/claude.exe"),
        home.join(".npm-global/bin/claude"),
        home.join(".npm-global/bin/claude.cmd"),
        home.join(".npm-global/bin/claude.exe"),
        home.join(".npm/bin/claude"),
        home.join(".npm/bin/claude.cmd"),
        home.join(".npm/bin/claude.exe"),
        home.join(".linuxbrew/bin/claude"),
        home.join("AppData/Roaming/npm/claude.cmd"),
        home.join("AppData/Roaming/npm/claude.exe"),
        home.join("AppData/Local/pnpm/claude.cmd"),
        home.join("AppData/Local/pnpm/claude.exe"),
        home.join("scoop/shims/claude.exe"),
        PathBuf::from("/home/linuxbrew/.linuxbrew/bin/claude"),
        PathBuf::from("/opt/homebrew/bin/claude"),
        PathBuf::from("/usr/local/bin/claude"),
    ];
    candidates.extend(nvm_claude_binary_candidates_for_home(home));
    candidates
}

fn nvm_claude_binary_candidates_for_home(home: &Path) -> Vec<PathBuf> {
    let Ok(entries) = std::fs::read_dir(home.join(".nvm/versions/node")) else {
        return Vec::new();
    };

    let mut candidates = entries
        .filter_map(Result::ok)
        .map(|entry| entry.path())
        .filter(|path| path.is_dir())
        .map(|path| path.join("bin").join("claude"))
        .collect::<Vec<_>>();
    candidates.sort();
    candidates
}

// ---------------------------------------------------------------------------
// Public Tauri commands
// ---------------------------------------------------------------------------

/// Check whether the `claude` CLI is installed and return its version.
pub fn check_cli() -> ClaudeCliStatus {
    let bin = match find_claude_binary() {
        Ok(b) => b,
        Err(_) => {
            return ClaudeCliStatus {
                installed: false,
                version: None,
            }
        }
    };

    ClaudeCliStatus {
        installed: true,
        version: crate::cli_agent_runtime::version_for_binary(&bin),
    }
}

/// Spawn `claude -p` for a simple chat (no tools) and stream events via the
/// provided callback.  Returns the session ID for future `--resume` calls.
pub fn run_chat_stream<F>(req: ChatStreamRequest, mut emit: F) -> Result<String, String>
where
    F: FnMut(ClaudeStreamEvent),
{
    let bin = find_claude_binary()?;
    let invocation = crate::claude_invocation::chat(&req);
    run_claude_subprocess(
        ClaudeSubprocessRequest {
            bin: &bin,
            args: &invocation.args,
            fallback_args: &invocation.fallback_args,
            stdin_text: invocation.stdin_text.as_deref(),
            cwd: None,
        },
        &mut emit,
    )
}

/// Spawn `claude -p` with full tool access and MCP vault tools for an agent task.
pub fn run_agent_stream<F>(req: AgentStreamRequest, mut emit: F) -> Result<String, String>
where
    F: FnMut(ClaudeStreamEvent),
{
    let bin = find_claude_binary()?;
    let invocation = crate::claude_invocation::agent(&req)?;
    run_claude_subprocess(
        ClaudeSubprocessRequest {
            bin: &bin,
            args: &invocation.args,
            fallback_args: &invocation.fallback_args,
            stdin_text: invocation.stdin_text.as_deref(),
            cwd: Some(&req.vault_path),
        },
        &mut emit,
    )
}

/// Mutable state accumulated across the JSON stream for a single subprocess.
struct StreamState {
    session_id: String,
    /// Accumulates `input_json_delta` chunks keyed by tool_use id.
    tool_inputs: HashMap<String, String>,
    /// The tool_use id of the block currently being streamed.
    current_tool_id: Option<String>,
    /// Tracks whether response text has already been emitted for this run.
    emitted_text: bool,
}

struct ClaudeSubprocessRequest<'a> {
    bin: &'a Path,
    args: &'a [String],
    fallback_args: &'a [Vec<String>],
    stdin_text: Option<&'a str>,
    cwd: Option<&'a str>,
}

struct ClaudeCommandRequest<'a> {
    bin: &'a Path,
    args: &'a [String],
    cwd: Option<&'a str>,
}

#[derive(Clone, Copy)]
struct ClaudeStderr<'a>(&'a str);

impl<'a> ClaudeStderr<'a> {
    fn is_empty(self) -> bool {
        self.0.is_empty()
    }

    fn lines(self) -> std::str::Lines<'a> {
        self.0.lines()
    }

    fn to_ascii_lowercase(self) -> String {
        self.0.to_ascii_lowercase()
    }
}

struct ClaudeFailure<'a> {
    stderr: ClaudeStderr<'a>,
    status: ExitStatus,
}

#[derive(Clone, Copy)]
struct TextDeltaChunk<'a>(&'a str);

impl<'a> TextDeltaChunk<'a> {
    fn is_empty(self) -> bool {
        self.0.is_empty()
    }

    fn as_str(self) -> &'a str {
        self.0
    }
}

#[derive(Clone, Copy)]
struct ToolUseId<'a>(&'a str);

impl<'a> ToolUseId<'a> {
    fn as_str(self) -> &'a str {
        self.0
    }
}

/// Core subprocess runner shared by chat and agent modes.
/// When `cwd` is `Some`, the subprocess starts with that working directory.
fn run_claude_subprocess<F>(
    request: ClaudeSubprocessRequest<'_>,
    emit: &mut F,
) -> Result<String, String>
where
    F: FnMut(ClaudeStreamEvent),
{
    let attempts = std::iter::once(request.args)
        .chain(request.fallback_args.iter().map(Vec::as_slice))
        .enumerate();

    for (index, attempt_args) in attempts {
        let mut state = StreamState {
            session_id: String::new(),
            tool_inputs: HashMap::new(),
            current_tool_id: None,
            emitted_text: false,
        };

        let cmd = build_claude_command(ClaudeCommandRequest {
            bin: request.bin,
            args: attempt_args,
            cwd: request.cwd,
        })?;
        let process = crate::cli_agent_runtime::JsonLineProcess::new(cmd, "claude")
            .with_stdin(request.stdin_text);
        let run = crate::cli_agent_runtime::run_json_line_process_with_stdin(
            process,
            emit,
            |message| ClaudeStreamEvent::Error { message },
            |json, emit, session_id| {
                dispatch_event(json, &mut state, emit);
                *session_id = state.session_id.clone();
            },
        )?;

        if !run.status.success() && state.session_id.is_empty() {
            let has_fallback = index < request.fallback_args.len();
            let stderr = ClaudeStderr(&run.stderr_output);
            if has_fallback && is_unsupported_claude_flag_error(stderr) {
                continue;
            }

            emit(ClaudeStreamEvent::Error {
                message: format_failed_claude_exit(ClaudeFailure {
                    stderr,
                    status: run.status,
                }),
            });
        }

        emit(ClaudeStreamEvent::Done);
        return Ok(state.session_id);
    }

    Ok(String::new())
}

fn build_claude_command(
    request: ClaudeCommandRequest<'_>,
) -> Result<std::process::Command, String> {
    let target = crate::cli_agent_runtime::command_target_avoiding_windows_cmd_shim(request.bin)?;
    let mut cmd = crate::hidden_command(&target.program);
    crate::cli_agent_runtime::configure_agent_command_environment(&mut cmd, request.bin);
    if let Some(first_arg) = target.first_arg {
        cmd.arg(first_arg);
    }
    cmd.args(request.args)
        .env_remove("CLAUDECODE") // prevent "nested session" guard
        .stdin(Stdio::null())
        .stdout(Stdio::piped())
        .stderr(Stdio::piped());
    if let Some(dir) = request.cwd {
        cmd.current_dir(dir);
    }
    Ok(cmd)
}

fn format_failed_claude_exit(failure: ClaudeFailure<'_>) -> String {
    if is_claude_auth_error(failure.stderr) {
        return "Claude CLI is not authenticated. Run `claude auth login` in your terminal.".into();
    }

    if failure.stderr.is_empty() {
        format!("claude exited with status {}", failure.status)
    } else {
        failure
            .stderr
            .lines()
            .take(3)
            .collect::<Vec<_>>()
            .join("\n")
    }
}

fn is_claude_auth_error(stderr: ClaudeStderr<'_>) -> bool {
    let lower = stderr.to_ascii_lowercase();
    ["not logged in", "authentication", "auth"]
        .iter()
        .any(|pattern| lower.contains(pattern))
}

fn is_unsupported_claude_flag_error(stderr: ClaudeStderr<'_>) -> bool {
    let lower = stderr.to_ascii_lowercase();
    let mentions_compat_flag = ["--tools", "--no-session-persistence"]
        .iter()
        .any(|flag| lower.contains(flag));
    let looks_unsupported = [
        "unknown option",
        "unknown argument",
        "unrecognized option",
        "unexpected argument",
        "unknown command-line option",
    ]
    .iter()
    .any(|pattern| lower.contains(pattern));

    mentions_compat_flag && looks_unsupported
}

/// Parse a single JSON line from the stream and emit the appropriate event.
fn dispatch_event<F>(json: &serde_json::Value, state: &mut StreamState, emit: &mut F)
where
    F: FnMut(ClaudeStreamEvent),
{
    let msg_type = json["type"].as_str().unwrap_or("");

    match msg_type {
        // --- System init → capture session_id ---
        "system" if json["subtype"].as_str() == Some("init") => {
            if let Some(sid) = json["session_id"].as_str() {
                state.session_id = sid.to_string();
                emit(ClaudeStreamEvent::Init {
                    session_id: sid.to_string(),
                });
            }
        }

        // --- Streaming partial events (text deltas, tool_use starts) ---
        "stream_event" => {
            dispatch_stream_event(json, state, emit);
        }

        // --- Tool progress (agent mode) ---
        "tool_progress" => {
            if let (Some(name), Some(id)) =
                (json["tool_name"].as_str(), json["tool_use_id"].as_str())
            {
                emit(ClaudeStreamEvent::ToolStart {
                    tool_name: name.to_string(),
                    tool_id: id.to_string(),
                    input: None,
                });
            }
        }

        // --- Tool result (agent mode) ---
        "tool_result" => {
            if let Some(id) = json["tool_use_id"].as_str() {
                let output = extract_tool_result_text(json);
                emit(ClaudeStreamEvent::ToolDone {
                    tool_id: id.to_string(),
                    output,
                });
            }
        }

        // --- Final result ---
        "result" => {
            let sid = json["session_id"].as_str().unwrap_or("").to_string();
            if !sid.is_empty() {
                state.session_id = sid.clone();
            }
            let text = if state.emitted_text {
                String::new()
            } else {
                let text = json["result"].as_str().unwrap_or("").to_string();
                if !text.is_empty() {
                    state.emitted_text = true;
                }
                text
            };
            emit(ClaudeStreamEvent::Result {
                text,
                session_id: sid,
            });
        }

        // --- Complete assistant message (fallback for text when no partials) ---
        "assistant" => {
            if let Some(content) = json["message"]["content"].as_array() {
                let emit_text = !state.emitted_text;
                for block in content {
                    dispatch_assistant_content_block(block, emit_text, state, emit);
                }
            }
        }

        _ => {} // ignore other event types
    }
}

/// Handle a `stream_event` (partial assistant message).
fn dispatch_stream_event<F>(json: &serde_json::Value, state: &mut StreamState, emit: &mut F)
where
    F: FnMut(ClaudeStreamEvent),
{
    let event = &json["event"];
    let event_type = event["type"].as_str().unwrap_or("");

    match event_type {
        "content_block_delta" => {
            let delta = &event["delta"];
            match delta["type"].as_str() {
                Some("text_delta") => {
                    if let Some(text) = delta["text"].as_str() {
                        emit_text_delta(TextDeltaChunk(text), state, emit);
                    }
                }
                Some("thinking_delta") => {
                    if let Some(text) = delta["thinking"].as_str() {
                        emit(ClaudeStreamEvent::ThinkingDelta {
                            text: text.to_string(),
                        });
                    }
                }
                Some("input_json_delta") => {
                    if let (Some(partial), Some(ref tid)) =
                        (delta["partial_json"].as_str(), &state.current_tool_id)
                    {
                        state
                            .tool_inputs
                            .entry(tid.clone())
                            .or_default()
                            .push_str(partial);
                    }
                }
                _ => {}
            }
        }
        "content_block_start" => {
            let block = &event["content_block"];
            if block["type"].as_str() == Some("tool_use") {
                if let (Some(id), Some(name)) = (block["id"].as_str(), block["name"].as_str()) {
                    state.current_tool_id = Some(id.to_string());
                    state.tool_inputs.entry(id.to_string()).or_default();
                    emit(ClaudeStreamEvent::ToolStart {
                        tool_name: name.to_string(),
                        tool_id: id.to_string(),
                        input: None,
                    });
                }
            }
        }
        "content_block_stop" => {
            state.current_tool_id = None;
        }
        _ => {}
    }
}

fn dispatch_assistant_content_block<F>(
    block: &serde_json::Value,
    emit_text: bool,
    state: &mut StreamState,
    emit: &mut F,
) where
    F: FnMut(ClaudeStreamEvent),
{
    match block["type"].as_str() {
        Some("text") if emit_text => {
            if let Some(text) = block["text"].as_str() {
                emit_text_delta(TextDeltaChunk(text), state, emit);
            }
        }
        Some("tool_use") => {
            if let (Some(id), Some(name)) = (block["id"].as_str(), block["name"].as_str()) {
                let input = format_tool_input(&block["input"], state, ToolUseId(id));
                emit(ClaudeStreamEvent::ToolStart {
                    tool_name: name.to_string(),
                    tool_id: id.to_string(),
                    input,
                });
            }
        }
        _ => {}
    }
}

fn emit_text_delta<F>(text: TextDeltaChunk<'_>, state: &mut StreamState, emit: &mut F)
where
    F: FnMut(ClaudeStreamEvent),
{
    if !text.is_empty() {
        state.emitted_text = true;
    }
    emit(ClaudeStreamEvent::TextDelta {
        text: text.as_str().to_string(),
    });
}

/// Build the tool input string, preferring accumulated delta chunks over the
/// block's `input` field (which may be empty at stream start).
fn format_tool_input(
    block_input: &serde_json::Value,
    state: &StreamState,
    tool_id: ToolUseId<'_>,
) -> Option<String> {
    if let Some(accumulated) = state.tool_inputs.get(tool_id.as_str()) {
        if !accumulated.is_empty() {
            return Some(accumulated.clone());
        }
    }
    if !block_input.is_null() && block_input.as_object().is_some_and(|o| !o.is_empty()) {
        return Some(block_input.to_string());
    }
    None
}

/// Extract displayable text from a `tool_result` event.
fn extract_tool_result_text(json: &serde_json::Value) -> Option<String> {
    // String content field
    if let Some(s) = json["content"].as_str() {
        return Some(s.to_string());
    }
    // Array of content blocks (Claude format)
    if let Some(arr) = json["content"].as_array() {
        let texts: Vec<&str> = arr.iter().filter_map(|b| b["text"].as_str()).collect();
        if !texts.is_empty() {
            return Some(texts.join("\n"));
        }
    }
    // Fallback: "output" field
    json["output"].as_str().map(|s| s.to_string())
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::ai_agents::AiAgentPermissionMode;
    use std::ffi::OsStr;
    use std::ffi::OsString;
    use std::process::Command;

    #[cfg(target_os = "linux")]
    fn current_test_binary() -> PathBuf {
        std::fs::read_link("/proc/self/exe").unwrap()
    }

    #[cfg(target_os = "macos")]
    fn current_test_binary() -> PathBuf {
        let pid = std::process::id().to_string();
        let output = Command::new("/bin/ps")
            .args(["-p", pid.as_str(), "-o", "comm="])
            .output()
            .unwrap();
        let path = String::from_utf8(output.stdout).unwrap();
        PathBuf::from(path.trim())
    }

    fn assert_binary_candidates_include(home: &Path, expected: &[PathBuf]) {
        let candidates = claude_binary_candidates_for_home(home);
        for candidate in expected {
            assert!(
                candidates.contains(candidate),
                "missing {}",
                candidate.display()
            );
        }
    }

    #[test]
    fn check_cli_returns_status() {
        let status = check_cli();
        if status.installed {
            assert!(status.version.is_some());
        } else {
            assert!(status.version.is_none());
        }
    }

    #[test]
    fn claude_binary_candidates_include_nvm_managed_node_installs() {
        let home = tempfile::tempdir().unwrap();
        let claude = home.path().join(".nvm/versions/node/v22.12.0/bin/claude");
        std::fs::create_dir_all(claude.parent().unwrap()).unwrap();
        std::fs::write(&claude, "#!/bin/sh\n").unwrap();

        let candidates = claude_binary_candidates_for_home(home.path());

        assert!(candidates.contains(&claude), "missing {}", claude.display());
    }

    #[test]
    fn windows_path_lookup_prefers_cmd_shim_over_extensionless_npm_script() {
        let dir = tempfile::tempdir().unwrap();
        let shell_script = dir.path().join("claude");
        let cmd_shim = dir.path().join("claude.cmd");
        std::fs::write(&shell_script, "#!/bin/sh\n").unwrap();
        std::fs::write(&cmd_shim, "@ECHO off\n").unwrap();

        let stdout = format!("{}\n{}\n", shell_script.display(), cmd_shim.display());

        assert_eq!(
            first_existing_path_for_platform(&stdout, true),
            Some(cmd_shim)
        );
    }

    #[test]
    fn unsupported_claude_flag_errors_are_detected() {
        assert!(is_unsupported_claude_flag_error(ClaudeStderr(
            "error: unknown option '--tools'"
        )));
        assert!(is_unsupported_claude_flag_error(ClaudeStderr(
            "Unknown argument: --no-session-persistence"
        )));
        assert!(!is_unsupported_claude_flag_error(ClaudeStderr(
            "Claude CLI is not authenticated"
        )));
    }

    // --- dispatch_event / dispatch_stream_event ---

    fn new_state() -> StreamState {
        StreamState {
            session_id: String::new(),
            tool_inputs: HashMap::new(),
            current_tool_id: None,
            emitted_text: false,
        }
    }

    /// Run dispatch_event on the given JSON and return (session_id, events).
    fn run_dispatch(json: serde_json::Value) -> (String, Vec<ClaudeStreamEvent>) {
        let mut state = new_state();
        let mut events = vec![];
        dispatch_event(&json, &mut state, &mut |e| events.push(e));
        (state.session_id, events)
    }

    #[derive(Clone, Copy)]
    struct InitialSessionId<'a>(&'a str);

    /// Run dispatch_event with a pre-set session_id.
    fn run_dispatch_with_sid(
        json: serde_json::Value,
        initial_sid: InitialSessionId<'_>,
    ) -> (String, Vec<ClaudeStreamEvent>) {
        let mut state = new_state();
        state.session_id = initial_sid.0.to_string();
        let mut events = vec![];
        dispatch_event(&json, &mut state, &mut |e| events.push(e));
        (state.session_id, events)
    }

    /// Run multiple dispatch_event calls sharing state (for multi-event sequences).
    fn run_dispatch_sequence(
        events_json: Vec<serde_json::Value>,
    ) -> (StreamState, Vec<ClaudeStreamEvent>) {
        let mut state = new_state();
        let mut events = vec![];
        for json in &events_json {
            dispatch_event(json, &mut state, &mut |e| events.push(e));
        }
        (state, events)
    }

    #[test]
    fn dispatch_event_handles_init() {
        let (sid, events) = run_dispatch(serde_json::json!({
            "type": "system", "subtype": "init", "session_id": "test-session-123"
        }));
        assert_eq!(sid, "test-session-123");
        assert!(
            matches!(&events[0], ClaudeStreamEvent::Init { session_id } if session_id == "test-session-123")
        );
    }

    #[test]
    fn dispatch_event_system_without_init_subtype_is_ignored() {
        let (_, events) = run_dispatch(serde_json::json!({ "type": "system", "subtype": "other" }));
        assert!(events.is_empty());
    }

    #[test]
    fn dispatch_event_system_init_without_session_id_is_ignored() {
        let (sid, events) =
            run_dispatch(serde_json::json!({ "type": "system", "subtype": "init" }));
        assert!(events.is_empty());
        assert!(sid.is_empty());
    }

    #[test]
    fn dispatch_event_handles_text_delta() {
        let (_, events) = run_dispatch(serde_json::json!({
            "type": "stream_event",
            "event": { "type": "content_block_delta", "index": 0, "delta": { "type": "text_delta", "text": "Hello" } }
        }));
        assert!(matches!(&events[0], ClaudeStreamEvent::TextDelta { text } if text == "Hello"));
    }

    #[test]
    fn dispatch_event_handles_tool_start() {
        let (_, events) = run_dispatch(serde_json::json!({
            "type": "stream_event",
            "event": { "type": "content_block_start", "index": 1, "content_block": { "type": "tool_use", "id": "tool_abc", "name": "read_note", "input": {} } }
        }));
        assert!(
            matches!(&events[0], ClaudeStreamEvent::ToolStart { tool_name, tool_id, .. } if tool_name == "read_note" && tool_id == "tool_abc")
        );
    }

    #[test]
    fn dispatch_event_handles_result() {
        let (sid, events) = run_dispatch(serde_json::json!({
            "type": "result", "subtype": "success", "result": "All done!", "session_id": "sess-456"
        }));
        assert_eq!(sid, "sess-456");
        assert!(
            matches!(&events[0], ClaudeStreamEvent::Result { text, session_id } if text == "All done!" && session_id == "sess-456")
        );
    }

    #[test]
    fn dispatch_event_result_with_empty_session_id() {
        let (sid, events) = run_dispatch_with_sid(
            serde_json::json!({ "type": "result", "result": "text here" }),
            InitialSessionId("prev-session"),
        );
        assert_eq!(sid, "prev-session");
        assert!(
            matches!(&events[0], ClaudeStreamEvent::Result { text, .. } if text == "text here")
        );
    }

    #[test]
    fn dispatch_event_handles_tool_progress() {
        let (_, events) = run_dispatch(serde_json::json!({
            "type": "tool_progress", "tool_name": "search_notes", "tool_use_id": "tool_xyz"
        }));
        assert!(
            matches!(&events[0], ClaudeStreamEvent::ToolStart { tool_name, tool_id, .. } if tool_name == "search_notes" && tool_id == "tool_xyz")
        );
    }

    #[test]
    fn dispatch_event_tool_progress_missing_fields_is_ignored() {
        let (_, events) =
            run_dispatch(serde_json::json!({ "type": "tool_progress", "tool_name": "x" }));
        assert!(events.is_empty());
    }

    #[test]
    fn dispatch_event_handles_assistant_with_tool_use() {
        let (_, events) = run_dispatch(serde_json::json!({
            "type": "assistant",
            "message": { "content": [
                { "type": "text", "text": "Let me search." },
                { "type": "tool_use", "id": "tu_1", "name": "search_notes", "input": {} }
            ] }
        }));
        assert_eq!(events.len(), 2);
        assert!(
            matches!(&events[0], ClaudeStreamEvent::TextDelta { text } if text == "Let me search.")
        );
        assert!(
            matches!(&events[1], ClaudeStreamEvent::ToolStart { tool_name, tool_id, .. } if tool_name == "search_notes" && tool_id == "tu_1")
        );
    }

    #[test]
    fn dispatch_event_result_after_text_delta_does_not_duplicate_response_text() {
        let (state, events) = run_dispatch_sequence(vec![
            serde_json::json!({
                "type": "stream_event",
                "event": { "type": "content_block_delta", "delta": { "type": "text_delta", "text": "Visible reply" } }
            }),
            serde_json::json!({
                "type": "result",
                "session_id": "session-1",
                "result": "Visible reply"
            }),
        ]);

        assert_eq!(state.session_id, "session-1");
        assert!(matches!(&events[..],
                [
                    ClaudeStreamEvent::TextDelta { text },
                    ClaudeStreamEvent::Result { text: result_text, session_id },
                ] if text == "Visible reply" && result_text.is_empty() && session_id == "session-1"));
    }

    #[test]
    fn dispatch_event_assistant_without_content_is_noop() {
        let (_, events) = run_dispatch(serde_json::json!({ "type": "assistant", "message": {} }));
        assert!(events.is_empty());
    }

    #[test]
    fn dispatch_event_ignores_unknown() {
        let (_, events) =
            run_dispatch(serde_json::json!({ "type": "some_future_type", "data": 42 }));
        assert!(events.is_empty());
    }

    #[test]
    fn dispatch_stream_event_input_json_delta_accumulates_silently() {
        // input_json_delta doesn't emit events directly — it accumulates in state
        let (_, events) = run_dispatch(serde_json::json!({
            "type": "stream_event",
            "event": { "type": "content_block_delta", "index": 0, "delta": { "type": "input_json_delta", "partial_json": "{}" } }
        }));
        assert!(events.is_empty());
    }

    #[test]
    fn dispatch_stream_event_non_tool_block_start_is_ignored() {
        let (_, events) = run_dispatch(serde_json::json!({
            "type": "stream_event",
            "event": { "type": "content_block_start", "index": 0, "content_block": { "type": "text", "text": "" } }
        }));
        assert!(events.is_empty());
    }

    #[test]
    fn dispatch_stream_event_unknown_type_is_ignored() {
        let (_, events) = run_dispatch(serde_json::json!({
            "type": "stream_event", "event": { "type": "message_stop" }
        }));
        assert!(events.is_empty());
    }

    #[test]
    fn dispatch_event_handles_tool_result_string_content() {
        let (_, events) = run_dispatch(serde_json::json!({
            "type": "tool_result",
            "tool_use_id": "tool_abc",
            "content": "Found 3 notes matching query"
        }));
        assert_eq!(events.len(), 1);
        assert!(
            matches!(&events[0], ClaudeStreamEvent::ToolDone { tool_id, output }
                if tool_id == "tool_abc" && output.as_deref() == Some("Found 3 notes matching query"))
        );
    }

    #[test]
    fn dispatch_event_handles_tool_result_array_content() {
        let (_, events) = run_dispatch(serde_json::json!({
            "type": "tool_result",
            "tool_use_id": "tool_def",
            "content": [{ "type": "text", "text": "Line 1" }, { "type": "text", "text": "Line 2" }]
        }));
        assert!(
            matches!(&events[0], ClaudeStreamEvent::ToolDone { output, .. }
                if output.as_deref() == Some("Line 1\nLine 2"))
        );
    }

    #[test]
    fn dispatch_event_tool_result_missing_tool_id_is_ignored() {
        let (_, events) = run_dispatch(serde_json::json!({
            "type": "tool_result", "content": "result text"
        }));
        assert!(events.is_empty());
    }

    #[test]
    fn dispatch_accumulates_input_json_deltas() {
        let (_, events) = run_dispatch_sequence(vec![
            // Start tool_use block
            serde_json::json!({
                "type": "stream_event",
                "event": { "type": "content_block_start", "content_block": { "type": "tool_use", "id": "t1", "name": "search_notes", "input": {} } }
            }),
            // Input delta chunks
            serde_json::json!({
                "type": "stream_event",
                "event": { "type": "content_block_delta", "delta": { "type": "input_json_delta", "partial_json": "{\"query\":" } }
            }),
            serde_json::json!({
                "type": "stream_event",
                "event": { "type": "content_block_delta", "delta": { "type": "input_json_delta", "partial_json": "\"test\"}" } }
            }),
            // Stop block
            serde_json::json!({
                "type": "stream_event",
                "event": { "type": "content_block_stop" }
            }),
            // Assistant message triggers ToolStart with accumulated input
            serde_json::json!({
                "type": "assistant",
                "message": { "content": [
                    { "type": "tool_use", "id": "t1", "name": "search_notes", "input": { "query": "test" } }
                ] }
            }),
        ]);
        // First event: ToolStart with no input (from content_block_start)
        assert!(matches!(
            &events[0],
            ClaudeStreamEvent::ToolStart { input: None, .. }
        ));
        // Second event: ToolStart with accumulated input (from assistant)
        assert!(
            matches!(&events[1], ClaudeStreamEvent::ToolStart { input: Some(inp), .. }
                if inp == "{\"query\":\"test\"}")
        );
    }

    #[test]
    fn dispatch_assistant_uses_block_input_when_no_deltas() {
        let (_, events) = run_dispatch(serde_json::json!({
            "type": "assistant",
            "message": { "content": [
                { "type": "tool_use", "id": "tu_x", "name": "create_note", "input": { "title": "Hello", "content": "world" } }
            ] }
        }));
        assert!(
            matches!(&events[0], ClaudeStreamEvent::ToolStart { input: Some(inp), .. }
                if inp.contains("title") && inp.contains("Hello"))
        );
    }

    #[test]
    fn content_block_stop_clears_current_tool() {
        let (state, _) = run_dispatch_sequence(vec![
            serde_json::json!({
                "type": "stream_event",
                "event": { "type": "content_block_start", "content_block": { "type": "tool_use", "id": "t1", "name": "x", "input": {} } }
            }),
            serde_json::json!({
                "type": "stream_event",
                "event": { "type": "content_block_stop" }
            }),
        ]);
        assert!(state.current_tool_id.is_none());
    }

    // --- run_claude_subprocess with mock scripts ---

    #[test]
    fn build_claude_command_keeps_streaming_process_contract() {
        let bin = PathBuf::from("claude");
        let args = vec!["-p".to_string(), "hello".to_string()];
        let command = build_claude_command(ClaudeCommandRequest {
            bin: &bin,
            args: &args,
            cwd: Some("/tmp/vault"),
        })
        .unwrap();
        let actual_args: Vec<OsString> = command.get_args().map(OsStr::to_os_string).collect();
        let claude_code_env = command
            .get_envs()
            .find(|(key, _)| *key == OsStr::new("CLAUDECODE"))
            .map(|(_, value)| value.map(OsStr::to_os_string));

        assert_eq!(
            (
                command.get_program().to_os_string(),
                actual_args,
                command.get_current_dir().map(Path::to_path_buf),
                claude_code_env,
            ),
            (
                OsString::from("claude"),
                vec![OsString::from("-p"), OsString::from("hello")],
                Some(PathBuf::from("/tmp/vault")),
                Some(None),
            ),
        );
    }

    #[test]
    fn build_claude_command_avoids_windows_cmd_shim_for_prompt_args() {
        let dir = tempfile::tempdir().unwrap();
        let shim = dir.path().join("claude.cmd");
        let script = dir
            .path()
            .join("node_modules")
            .join("@anthropic-ai")
            .join("claude-code")
            .join("cli.js");
        std::fs::create_dir_all(script.parent().unwrap()).unwrap();
        std::fs::write(&script, "console.log('claude')\n").unwrap();
        std::fs::write(
            &shim,
            r#"@ECHO off
"%_prog%" "%~dp0\node_modules\@anthropic-ai\claude-code\cli.js" %*
"#,
        )
        .unwrap();

        let args = vec![
            "-p".to_string(),
            "Rename the note after reading the active vault".to_string(),
        ];
        let command = build_claude_command(ClaudeCommandRequest {
            bin: &shim,
            args: &args,
            cwd: Some("/tmp/vault"),
        })
        .unwrap();
        let actual_args = command.get_args().collect::<Vec<_>>();

        assert_ne!(
            command.get_program(),
            shim.as_os_str(),
            "Claude npm .cmd shims cannot safely receive prompt args directly"
        );
        assert_eq!(actual_args.first().copied(), Some(script.as_os_str()));
        assert!(actual_args.iter().any(|arg| *arg == OsStr::new("-p")));
        assert!(actual_args
            .iter()
            .any(|arg| *arg == OsStr::new("Rename the note after reading the active vault")));
        assert_eq!(command.get_current_dir(), Some(Path::new("/tmp/vault")));
    }

    #[cfg(unix)]
    #[derive(Clone, Copy)]
    struct MockClaudeScript<'a>(&'a str);

    #[cfg(unix)]
    #[derive(Clone, Copy)]
    struct MockClaudeArgs<'a>(&'a [String]);

    #[cfg(unix)]
    #[derive(Clone, Copy)]
    struct MockClaudeStdin<'a>(Option<&'a str>);

    #[cfg(unix)]
    fn run_mock_script(
        script: MockClaudeScript<'_>,
    ) -> (Result<String, String>, Vec<ClaudeStreamEvent>) {
        run_mock_script_with_args(script, MockClaudeArgs(&[]))
    }

    #[cfg(unix)]
    fn run_mock_script_with_args(
        script: MockClaudeScript<'_>,
        args: MockClaudeArgs<'_>,
    ) -> (Result<String, String>, Vec<ClaudeStreamEvent>) {
        run_mock_script_with_args_and_stdin(script, args, MockClaudeStdin(None))
    }

    #[cfg(unix)]
    fn run_mock_script_with_args_and_stdin(
        script: MockClaudeScript<'_>,
        args: MockClaudeArgs<'_>,
        stdin_text: MockClaudeStdin<'_>,
    ) -> (Result<String, String>, Vec<ClaudeStreamEvent>) {
        use std::os::unix::fs::PermissionsExt;
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("mock-claude");
        std::fs::write(&path, script.0).unwrap();
        std::fs::set_permissions(&path, std::fs::Permissions::from_mode(0o755)).unwrap();
        let mut events = vec![];
        let result = run_claude_subprocess(
            ClaudeSubprocessRequest {
                bin: &path,
                args: args.0,
                fallback_args: &[],
                stdin_text: stdin_text.0,
                cwd: None,
            },
            &mut |e| events.push(e),
        );
        (result, events)
    }

    #[cfg(unix)]
    #[test]
    fn run_subprocess_parses_ndjson_stream() {
        let (result, events) = run_mock_script(MockClaudeScript(concat!(
            "#!/bin/sh\n",
            "echo '{\"type\":\"system\",\"subtype\":\"init\",\"session_id\":\"s1\"}'\n",
            "echo '{\"type\":\"stream_event\",\"event\":{\"type\":\"content_block_delta\",\"index\":0,\"delta\":{\"type\":\"text_delta\",\"text\":\"Hi\"}}}'\n",
            "echo '{\"type\":\"result\",\"result\":\"Done\",\"session_id\":\"s1\"}'\n",
        )));
        assert_eq!(result.unwrap(), "s1");
        assert!(matches!(&events[0], ClaudeStreamEvent::Init { session_id } if session_id == "s1"));
        assert!(matches!(&events[1], ClaudeStreamEvent::TextDelta { text } if text == "Hi"));
        assert!(matches!(&events[2], ClaudeStreamEvent::Result { .. }));
        assert!(matches!(&events[3], ClaudeStreamEvent::Done));
    }

    #[cfg(unix)]
    #[test]
    fn run_subprocess_retries_with_fallback_args_for_removed_flags() {
        use std::os::unix::fs::PermissionsExt;

        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("mock-claude");
        std::fs::write(
            &path,
            concat!(
                "#!/bin/sh\n",
                "for arg in \"$@\"; do\n",
                "  if [ \"$arg\" = \"--tools\" ]; then\n",
                "    echo \"error: unknown option '--tools'\" >&2\n",
                "    exit 1\n",
                "  fi\n",
                "done\n",
                "echo '{\"type\":\"system\",\"subtype\":\"init\",\"session_id\":\"fallback\"}'\n",
                "echo '{\"type\":\"result\",\"result\":\"Done\",\"session_id\":\"fallback\"}'\n",
            ),
        )
        .unwrap();
        std::fs::set_permissions(&path, std::fs::Permissions::from_mode(0o755)).unwrap();

        let args = vec!["--tools".to_string(), "Read".to_string()];
        let fallback_args = vec![vec!["--allowedTools".to_string(), "Read".to_string()]];
        let mut events = vec![];
        let result = run_claude_subprocess(
            ClaudeSubprocessRequest {
                bin: &path,
                args: &args,
                fallback_args: &fallback_args,
                stdin_text: None,
                cwd: None,
            },
            &mut |event| events.push(event),
        );

        assert_eq!(result.unwrap(), "fallback");
        assert!(matches!(
            events.first(),
            Some(ClaudeStreamEvent::Init { session_id }) if session_id == "fallback"
        ));
        assert!(!events
            .iter()
            .any(|event| matches!(event, ClaudeStreamEvent::Error { .. })));
        assert!(matches!(events.last(), Some(ClaudeStreamEvent::Done)));
    }

    #[test]
    fn run_subprocess_closes_stdin_even_when_parent_stdin_pipe_is_open() {
        use std::io::Read;
        use std::time::{Duration, Instant};

        let mut child = Command::new(current_test_binary())
            .arg("stdin_probe_parent_child")
            .arg("--ignored")
            .arg("--nocapture")
            .env("TOLARIA_STDIN_PROBE_CHILD", "1")
            .stdin(Stdio::piped())
            .stdout(Stdio::piped())
            .stderr(Stdio::piped())
            .spawn()
            .unwrap();
        let child_stdin = child.stdin.take().unwrap();
        let mut stdout = child.stdout.take().unwrap();
        let mut stderr = child.stderr.take().unwrap();
        let deadline = Instant::now() + Duration::from_secs(5);

        let status = loop {
            if let Some(status) = child.try_wait().unwrap() {
                break status;
            }
            if Instant::now() >= deadline {
                child.kill().unwrap();
                drop(child_stdin);
                panic!("stdin probe child timed out");
            }
            std::thread::sleep(Duration::from_millis(10));
        };

        drop(child_stdin);
        let mut stdout_text = String::new();
        let mut stderr_text = String::new();
        stdout.read_to_string(&mut stdout_text).unwrap();
        stderr.read_to_string(&mut stderr_text).unwrap();

        assert!(
            status.success(),
            "stdin probe child failed with {status}\nstdout:\n{stdout_text}\nstderr:\n{stderr_text}"
        );
    }

    #[ignore = "spawned by run_subprocess_closes_stdin_even_when_parent_stdin_pipe_is_open"]
    #[test]
    fn stdin_probe_parent_child() {
        if std::env::var_os("TOLARIA_STDIN_PROBE_CHILD").is_none() {
            return;
        }

        let fake_bin = current_test_binary();
        let args = vec![
            "stdin_probe_mock_claude_child".to_string(),
            "--ignored".to_string(),
            "--nocapture".to_string(),
        ];
        std::env::set_var("TOLARIA_STDIN_PROBE_MOCK_CLAUDE_CHILD", "1");
        let mut events = vec![];
        let result = run_claude_subprocess(
            ClaudeSubprocessRequest {
                bin: &fake_bin,
                args: &args,
                fallback_args: &[],
                stdin_text: None,
                cwd: None,
            },
            &mut |event| events.push(event),
        );
        std::env::remove_var("TOLARIA_STDIN_PROBE_MOCK_CLAUDE_CHILD");

        assert_eq!(result.unwrap(), "stdin-ok");
        assert!(matches!(
            events.first(),
            Some(ClaudeStreamEvent::Result { text, session_id })
                if text == "stdin closed" && session_id == "stdin-ok"
        ));
        assert!(matches!(events.last(), Some(ClaudeStreamEvent::Done)));
    }

    #[ignore = "spawned by stdin_probe_parent_child"]
    #[test]
    fn stdin_probe_mock_claude_child() {
        if std::env::var_os("TOLARIA_STDIN_PROBE_MOCK_CLAUDE_CHILD").is_none() {
            return;
        }

        use std::io::Read;

        let mut stdin = String::new();
        std::io::stdin().read_to_string(&mut stdin).unwrap();
        assert!(stdin.is_empty(), "stdin was not EOF");
        println!(
            "{}",
            serde_json::json!({
                "type": "result",
                "result": "stdin closed",
                "session_id": "stdin-ok"
            })
        );
    }

    #[cfg(unix)]
    #[test]
    fn run_subprocess_skips_blank_and_non_json_lines() {
        let (result, events) = run_mock_script(MockClaudeScript(concat!(
            "#!/bin/sh\n",
            "echo ''\n",
            "echo 'not json at all'\n",
            "echo '{\"type\":\"result\",\"result\":\"ok\",\"session_id\":\"s2\"}'\n",
        )));
        assert_eq!(result.unwrap(), "s2");
        assert!(matches!(&events[0], ClaudeStreamEvent::Result { text, .. } if text == "ok"));
        assert!(matches!(&events[1], ClaudeStreamEvent::Done));
    }

    #[cfg(unix)]
    #[test]
    fn run_subprocess_emits_error_on_nonzero_exit() {
        let (_, events) = run_mock_script(MockClaudeScript(
            "#!/bin/sh\necho 'auth problem' >&2\nexit 1\n",
        ));
        assert!(events
            .iter()
            .any(|e| matches!(e, ClaudeStreamEvent::Error { .. })));
        assert!(matches!(events.last().unwrap(), ClaudeStreamEvent::Done));
    }

    #[cfg(unix)]
    #[test]
    fn run_subprocess_detects_auth_error_in_stderr() {
        let (_, events) = run_mock_script(MockClaudeScript(
            "#!/bin/sh\necho 'not logged in' >&2\nexit 1\n",
        ));
        assert!(events.iter().any(|e| matches!(e, ClaudeStreamEvent::Error { message } if message.contains("not authenticated"))));
    }

    #[cfg(unix)]
    #[test]
    fn run_subprocess_reports_exit_code_on_empty_stderr() {
        let (_, events) = run_mock_script(MockClaudeScript("#!/bin/sh\nexit 2\n"));
        assert!(events.iter().any(
            |e| matches!(e, ClaudeStreamEvent::Error { message } if message.contains("exited with"))
        ));
    }

    #[cfg(unix)]
    #[test]
    fn run_subprocess_success_with_no_events() {
        let (result, events) = run_mock_script(MockClaudeScript("#!/bin/sh\nexit 0\n"));
        assert!(result.is_ok());
        assert!(matches!(events.last().unwrap(), ClaudeStreamEvent::Done));
    }

    #[cfg(unix)]
    #[test]
    fn run_subprocess_passes_args_through() {
        let args: Vec<String> = vec!["--foo".into(), "bar".into()];
        let (_, events) = run_mock_script_with_args(
            MockClaudeScript(concat!(
                "#!/bin/sh\n",
                "echo \"{\\\"type\\\":\\\"result\\\",\\\"result\\\":\\\"$*\\\",\\\"session_id\\\":\\\"sx\\\"}\"\n",
            )),
            MockClaudeArgs(&args),
        );
        let text = events.iter().find_map(|e| match e {
            ClaudeStreamEvent::Result { text, .. } => Some(text.as_str()),
            _ => None,
        });
        assert!(text.unwrap().contains("--foo"));
    }

    #[cfg(unix)]
    #[test]
    fn run_subprocess_writes_prompt_to_stdin() {
        let args: Vec<String> = vec!["-p".into()];
        let (result, events) = run_mock_script_with_args_and_stdin(
            MockClaudeScript(concat!(
                "#!/bin/sh\n",
                "stdin=$(cat)\n",
                "if [ \"$stdin\" != \"hello from stdin\" ]; then\n",
                "  echo \"unexpected stdin: $stdin\" >&2\n",
                "  exit 3\n",
                "fi\n",
                "echo '{\"type\":\"result\",\"result\":\"stdin ok\",\"session_id\":\"sx\"}'\n",
            )),
            MockClaudeArgs(&args),
            MockClaudeStdin(Some("hello from stdin")),
        );

        assert_eq!(result.unwrap(), "sx");
        assert!(events.iter().any(
            |event| matches!(event, ClaudeStreamEvent::Result { text, .. } if text == "stdin ok")
        ));
    }

    // --- find_claude_binary ---

    #[test]
    fn claude_binary_candidates_include_supported_local_and_toolchain_installs() {
        let home = PathBuf::from("/Users/alex");
        let expected = [
            home.join(".local/bin/claude"),
            home.join(".claude/local/claude"),
            home.join(".local/share/mise/shims/claude"),
            home.join(".npm-global/bin/claude"),
        ];

        assert_binary_candidates_include(&home, &expected);
    }

    #[test]
    fn claude_binary_candidates_include_linuxbrew_installs() {
        let home = PathBuf::from("/home/alex");
        let expected = [
            home.join(".linuxbrew/bin/claude"),
            PathBuf::from("/home/linuxbrew/.linuxbrew/bin/claude"),
        ];

        assert_binary_candidates_include(&home, &expected);
    }

    #[test]
    fn claude_binary_candidates_include_windows_exe_installs() {
        let home = PathBuf::from(r"C:\Users\alex");
        let expected = [
            home.join(".local/bin/claude.exe"),
            home.join(".claude/local/claude.exe"),
            home.join("AppData/Roaming/npm/claude.cmd"),
        ];

        assert_binary_candidates_include(&home, &expected);
    }

    #[test]
    fn claude_path_lookup_command_matches_current_platform() {
        let expected = if cfg!(windows) { "where" } else { "which" };

        assert_eq!(claude_path_lookup_command(), expected);
    }

    #[test]
    fn find_existing_binary_finds_windows_exe_candidate() {
        let dir = tempfile::tempdir().unwrap();
        let claude = dir.path().join(".local/bin/claude.exe");
        std::fs::create_dir_all(claude.parent().unwrap()).unwrap();
        std::fs::write(&claude, "").unwrap();
        #[cfg(unix)]
        {
            use std::os::unix::fs::PermissionsExt;

            std::fs::set_permissions(&claude, std::fs::Permissions::from_mode(0o755)).unwrap();
        }

        assert_eq!(
            crate::cli_agent_runtime::find_executable_binary_candidate(
                claude_binary_candidates_for_home(dir.path()),
                "Claude CLI",
            )
            .unwrap(),
            Some(claude)
        );
    }

    #[test]
    fn find_claude_binary_returns_result() {
        let result = find_claude_binary();
        // On dev machines claude may be installed; on CI it may not.
        // Either way, the function should return Ok(path) or Err(message).
        match &result {
            Ok(path) => assert!(path.exists()),
            Err(msg) => assert!(msg.contains("not found")),
        }
    }

    // --- run_chat_stream / run_agent_stream error paths ---

    #[test]
    fn run_chat_stream_returns_result() {
        let req = ChatStreamRequest {
            message: "test".into(),
            system_prompt: None,
            session_id: None,
        };
        let mut events = vec![];
        // This will either succeed (if claude is installed) or fail (if not).
        let result = run_chat_stream(req, |e| events.push(e));
        // Either way the function should have returned without panicking.
        assert!(result.is_ok() || result.is_err());
    }

    #[test]
    fn run_agent_stream_returns_result() {
        let req = AgentStreamRequest {
            message: "test".into(),
            system_prompt: Some("sys".into()),
            vault_path: "/tmp/nonexistent".into(),
            vault_paths: Vec::new(),
            permission_mode: AiAgentPermissionMode::Safe,
        };
        let mut events = vec![];
        let result = run_agent_stream(req, |e| events.push(e));
        assert!(result.is_ok() || result.is_err());
    }

    #[test]
    fn run_subprocess_spawn_failure() {
        let fake_bin = PathBuf::from("/nonexistent/binary/path");
        let mut events = vec![];
        let result = run_claude_subprocess(
            ClaudeSubprocessRequest {
                bin: &fake_bin,
                args: &[],
                fallback_args: &[],
                stdin_text: None,
                cwd: None,
            },
            &mut |e| events.push(e),
        );
        assert!(result.is_err());
        assert!(result.unwrap_err().contains("Failed to start claude"));
    }

    #[cfg(unix)]
    #[test]
    fn run_subprocess_with_tool_progress_and_assistant() {
        let (result, events) = run_mock_script(MockClaudeScript(concat!(
            "#!/bin/sh\n",
            "echo '{\"type\":\"system\",\"subtype\":\"init\",\"session_id\":\"s3\"}'\n",
            "echo '{\"type\":\"tool_progress\",\"tool_name\":\"search\",\"tool_use_id\":\"t1\"}'\n",
            "echo '{\"type\":\"assistant\",\"message\":{\"content\":[{\"type\":\"tool_use\",\"id\":\"t2\",\"name\":\"read\",\"input\":{}}]}}'\n",
            "echo '{\"type\":\"result\",\"result\":\"fin\",\"session_id\":\"s3\"}'\n",
        )));
        assert_eq!(result.unwrap(), "s3");
        assert!(events.len() >= 4);
    }

    #[cfg(unix)]
    #[test]
    fn run_subprocess_success_exit_with_session_id_skips_error() {
        let (_, events) = run_mock_script(MockClaudeScript(concat!(
            "#!/bin/sh\n",
            "echo '{\"type\":\"system\",\"subtype\":\"init\",\"session_id\":\"s4\"}'\n",
            "echo 'some warning' >&2\n",
            "exit 1\n",
        )));
        // Should NOT have an error event because session_id is non-empty
        assert!(!events
            .iter()
            .any(|e| matches!(e, ClaudeStreamEvent::Error { .. })));
    }
}