use anyhow::{Context, Result};
use grokboy_core::{ChatMessage, Config, stream_chat};
use std::io::{self, Write};
use std::process::ExitCode;

const SYSTEM: &str = "You are GrokBoy, a concise local coding assistant. Prefer clear, short answers. Traditional Chinese is welcome when the user writes in Chinese.";

#[tokio::main]
async fn main() -> ExitCode {
    if let Err(err) = run().await {
        eprintln!("error: {err:#}");
        return ExitCode::FAILURE;
    }
    ExitCode::SUCCESS
}

async fn run() -> Result<()> {
    let mut args = std::env::args().skip(1);
    let cmd = args.next().unwrap_or_else(|| "help".into());
    match cmd.as_str() {
        "chat" => cmd_chat().await,
        "version" | "-V" | "--version" => {
            println!("grokboy {}", env!("CARGO_PKG_VERSION"));
            Ok(())
        }
        "help" | "-h" | "--help" | _ => {
            print_help();
            Ok(())
        }
    }
}

fn print_help() {
    println!(
        "\
GrokBoy — minimal local CLI agent (P0: chat)

USAGE:
  grokboy chat          Interactive streaming chat
  grokboy version
  grokboy help

ENV:
  GROKBOY_API_KEY       API key (or XAI_API_KEY / OPENAI_API_KEY)
  GROKBOY_BASE_URL      default https://api.x.ai/v1
  GROKBOY_MODEL         default grok-4

P0 has no tools yet. P1 will add shell/files + ReAct.
"
    );
}

async fn cmd_chat() -> Result<()> {
    let config = Config::from_env().map_err(anyhow::Error::msg)?;
    println!(
        "GrokBoy chat  model={}  base={}",
        config.model, config.base_url
    );
    println!("Type a message. Empty line or /exit to quit.\n");

    let mut history = vec![ChatMessage::system(SYSTEM)];
    let stdin = io::stdin();
    let mut stdout = io::stdout();

    loop {
        print!("you> ");
        stdout.flush().ok();
        let mut line = String::new();
        if stdin.read_line(&mut line).context("stdin")? == 0 {
            println!();
            break;
        }
        let input = line.trim();
        if input.is_empty() || input == "/exit" || input == "/quit" {
            break;
        }
        history.push(ChatMessage::user(input));

        print!("assistant> ");
        stdout.flush().ok();
        let reply = stream_chat(&config, &history, |delta| {
            print!("{delta}");
            let _ = io::stdout().flush();
        })
        .await?;
        println!("\n");
        history.push(ChatMessage::assistant(reply));
    }
    Ok(())
}