use std::fs;
use std::path::PathBuf;
use serde_json::{json, Value};
use anyhow::{Result, anyhow};
use super::super::Tool;
use super::super::ToolCtx;

pub struct Todowrite;

impl Tool for Todowrite {
    fn name(&self) -> &'static str {
        "todowrite"
    }

    fn description(&self) -> &'static str {
        "Append a task to the session todo list. The todo persists in the session directory and is visible in the Todo panel."
    }

    fn parameters(&self) -> Value {
        json!({
            "type": "object",
            "properties": {
                "task": {
                    "type": "string",
                    "description": "Task description to add"
                }
            },
            "required": ["task"]
        })
    }

    fn run(&self, ctx: &ToolCtx, args: &Value) -> Result<String> {
        let task = args.get("task")
            .and_then(|v| v.as_str())
            .ok_or_else(|| anyhow!("missing required argument: task"))?;

        let path: PathBuf = ctx.session_dir.join("todo.md");
        let now = chrono::Utc::now();
        let timestamp = now.format("%Y-%m-%d %H:%M:%S");
        let line = format!("- [ ] {} ({})\n", task, timestamp);

        fs::OpenOptions::new()
            .create(true)
            .append(true)
            .open(&path)
            .map_err(|e| anyhow!("failed to open todo.md: {}", e))?
            .write_all(line.as_bytes())
            .map_err(|e| anyhow!("failed to write to todo.md: {}", e))?;

        Ok(format!("added task to todo.md: {}", task))
    }
}

use std::io::Write;