Function add_matcher_handler

atomic-agent/src/hooks/agy.rs:1178–1216

Add a handler inside a matcher group (`PreToolUse`, `PostToolUse`). Reuses an existing `""` matcher if present, otherwise appends a new one. Returns `true` if the handler was added.

(group: &mut Value, event: &str, command: &str)

/// Reuses an existing `""` matcher if present, otherwise appends a new one.
/// Returns `true` if the handler was added.
fn add_matcher_handler(group: &mut Value, event: &str, command: &str) -> bool {
    let Some(obj) = group.as_object_mut() else {
        return false;
    };

    let entry = obj
        .entry(event.to_string())
        .or_insert_with(|| Value::Array(Vec::new()));
    let Some(list) = entry.as_array_mut() else {
        return false;
    };

    if event_list_has_atomic(list) {
        return false;
    }

    let mut handler = Map::new();
    handler.insert("type".to_string(), Value::String("command".to_string()));
    handler.insert("command".to_string(), Value::String(command.to_string()));

    // Reuse an existing empty matcher group if one exists.
    for matcher_group in list.iter_mut() {
        if matcher_group.get("matcher").and_then(Value::as_str) == Some("") {
            if let Some(hooks) = matcher_group.get_mut("hooks").and_then(Value::as_array_mut) {
                hooks.push(Value::Object(handler));
                return true;
            }
        }
    }

    let mut matcher_group = Map::new();
    matcher_group.insert("matcher".to_string(), Value::String(String::new()));
    matcher_group.insert(
        "hooks".to_string(),
        Value::Array(vec![Value::Object(handler)]),
    );
    list.push(Value::Object(matcher_group));
    true
}

/// Remove all Atomic hook commands from every event list in a group,
/// dropping emptied matcher groups and empty event lists.