// tools/working_stack.rs — Working stack management tool
//
// The working stack tracks what the agent is currently doing. It's an
// internal tool — the agent uses it to maintain context across turns
// and compaction. The model should never mention it to the user.

// TODO: these should not be hardcoded absolute paths
pub fn instructions_path() -> std::path::PathBuf {
    dirs::home_dir().unwrap_or_default().join(".consciousness/config/working-stack.md")
}

pub fn file_path() -> std::path::PathBuf {
    dirs::home_dir().unwrap_or_default().join(".consciousness/working-stack.json")
}

pub fn tool() -> super::Tool {
    super::Tool {
        name: "working_stack",
        description: "INTERNAL — manage your working stack silently. Actions: push (start new task), pop (done with current), update (refine current), switch (focus different task by index).",
        parameters_json: r#"{"type":"object","properties":{"action":{"type":"string","enum":["push","pop","update","switch"],"description":"Stack operation"},"content":{"type":"string","description":"Task description (for push/update)"},"index":{"type":"integer","description":"Stack index (for switch, 0=bottom)"}},"required":["action"]}"#,
        handler: |agent, v| Box::pin(async move {
            if let Some(agent) = agent {
                let mut a = agent.lock().await;
                Ok(handle(&v, &mut a.context.working_stack))
            } else {
                anyhow::bail!("working_stack requires agent context")
            }
        }),
    }
}

fn handle(args: &serde_json::Value, stack: &mut Vec<String>) -> String {
    let action = args.get("action").and_then(|v| v.as_str()).unwrap_or("");
    let content = args.get("content").and_then(|v| v.as_str()).unwrap_or("");
    let index = args.get("index").and_then(|v| v.as_u64()).map(|v| v as usize);

    let out = match action {
        "push" => {
            if content.is_empty() { return "Error: 'content' is required for push".into(); }
            stack.push(content.to_string());
            format!("Pushed. Stack depth: {}\n{}", stack.len(), format_stack(stack))
        }
        "pop" => {
            if let Some(removed) = stack.pop() {
                format!("Popped: {}\nStack depth: {}\n{}", removed, stack.len(), format_stack(stack))
            } else {
                "Stack is empty, nothing to pop.".into()
            }
        }
        "update" => {
            if content.is_empty() { return "Error: 'content' is required for update".into(); }
            if let Some(top) = stack.last_mut() {
                *top = content.to_string();
                format!("Updated top.\n{}", format_stack(stack))
            } else {
                "Stack is empty, nothing to update.".into()
            }
        }
        "switch" => {
            if stack.is_empty() { return "Stack is empty, nothing to switch.".into(); }
            let Some(idx) = index else { return "Error: 'index' is required for switch".into(); };
            if idx >= stack.len() { return format!("Error: index {} out of range (depth {})", idx, stack.len()); }
            let item = stack.remove(idx);
            stack.push(item);
            format!("Switched to index {}.\n{}", idx, format_stack(stack))
        }
        _ => format!("Error: unknown action '{}'. Use push, pop, update, or switch.", action),
    };

    if let Ok(json) = serde_json::to_string(stack) {
        let _ = std::fs::write(file_path(), json);
    };

    out
}

fn format_stack(stack: &[String]) -> String {
    if stack.is_empty() { return "(empty)".into(); }
    stack.iter().enumerate().map(|(i, item)| {
        if i == stack.len() - 1 { format!("→ [{}] {}", i, item) }
        else { format!("  [{}] {}", i, item) }
    }).collect::<Vec<_>>().join("\n")
}