//! Tauri command for launching the Python `command_builder` GUI.
//!
//! The Python fork ships a separate yaml-editing tool at
//! `python/tools/command_builder/` (a pywebview-based GUI). Without a launcher
//! button in the main Tauri GUI the user has no easy way to find it.
//!
//! Resolution order for the python checkout:
//!   1. `JARVIS_PYTHON_DIR` env override
//!   2. Sibling `python/` directory next to this jarvis-rust checkout
//!   3. `C:\Jarvis\python` (the dev box default)
//!
//! We don't ship the Python fork inside the Rust binary — this launcher just
//! tries to spawn it. If Python isn't installed, we open the docs URL instead.

use std::path::{Path, PathBuf};
use std::process::Command;

fn locate_python_dir() -> Option<PathBuf> {
    if let Ok(p) = std::env::var("JARVIS_PYTHON_DIR") {
        let pp = PathBuf::from(p);
        if pp.is_dir() {
            return Some(pp);
        }
    }
    if let Ok(exe) = std::env::current_exe() {
        let mut dir = exe.parent().map(|p| p.to_path_buf());
        for _ in 0..6 {
            if let Some(d) = &dir {
                let candidate = d.join("python");
                if candidate.join("tools").join("command_builder").is_dir() {
                    return Some(candidate);
                }
                dir = d.parent().map(|p| p.to_path_buf());
            }
        }
    }
    let fallback = PathBuf::from(r"C:\Jarvis\python");
    if fallback.join("tools").join("command_builder").is_dir() {
        return Some(fallback);
    }
    None
}

/// Find a python interpreter to run the builder with. Prefers the project's
/// `.venv\Scripts\python.exe` (where all deps are installed), then `python`.
fn python_bin(py_dir: &Path) -> PathBuf {
    let venv = py_dir.join(".venv").join("Scripts").join("python.exe");
    if venv.is_file() {
        venv
    } else {
        PathBuf::from("python")
    }
}

#[tauri::command]
pub fn open_command_builder() -> Result<String, String> {
    let py_dir = locate_python_dir()
        .ok_or_else(|| "Python fork not found. Set JARVIS_PYTHON_DIR or install at C:\\Jarvis\\python.".to_string())?;
    let py = python_bin(&py_dir);

    Command::new(&py)
        .args(["-m", "tools.command_builder"])
        .current_dir(&py_dir)
        .spawn()
        .map_err(|e| format!("Failed to launch command builder: {} (using {})", e, py.display()))?;

    Ok(format!("Launched from {}", py_dir.display()))
}