import { invoke } from "@tauri-apps/api/core";
import { useEffect, useState } from "react";
import { ShellFamily } from "./commandAssembly";

// Cache the (constant, per-session) lookup so every CommandBuilder mount shares
// one invoke. PowerShell needs its own quoting; bash/zsh/fish are all POSIX.
let cached: Promise<ShellFamily> | undefined;
function loadShellFamily(): Promise<ShellFamily> {
  if (!cached) {
    cached = invoke<string>("get_shell_info")
      .then((s): ShellFamily => (s === "powershell" ? "powershell" : "posix"))
      // Not inside Tauri (bare `pnpm dev`) or command failed: POSIX is the safe
      // default (identical to PowerShell for values without embedded quotes).
      .catch((): ShellFamily => "posix");
  }
  return cached;
}

/**
 * The shell family the app spawns, used to quote assembled commands. Resolved
 * from the backend's `get_shell_info` (the shell `async_create_shell` actually
 * launched), defaulting to "posix" until it loads.
 */
export function useShellFamily(): ShellFamily {
  const [shell, setShell] = useState<ShellFamily>("posix");
  useEffect(() => {
    let active = true;
    loadShellFamily().then((family) => {
      if (active) setShell(family);
    });
    return () => {
      active = false;
    };
  }, []);
  return shell;
}