use std::io::{self, Write};
use std::net::TcpStream;
use std::time::Duration;
use std::env;
use colored::Colorize;
use regex::Regex;
use std::process;

mod resp;

const DEFAULT_PORT: u16 = 9880;
const PROMPT_NAME: &str = "futriix";
const CONNECTION_TIMEOUT_SECS: u64 = 2;

fn main() {
    let (host, port) = parse_args();
    let addr = format!("{}:{}", host, port);

    let stream = match TcpStream::connect_timeout(
        &addr.parse().unwrap(),
        Duration::from_secs(CONNECTION_TIMEOUT_SECS)
    ) {
        Ok(stream) => stream,
        Err(e) if e.kind() == io::ErrorKind::ConnectionRefused => {
            eprintln!("{}", "Connection refused".red());
            process::exit(1);
        },
        Err(e) => {
            eprintln!("Connection error: {}", e);
            process::exit(1);
        }
    };

    println!("Connected to {}", addr.green());
    run_repl_loop(stream, &host, port);
}

fn parse_args() -> (String, u16) {
    let args: Vec<String> = env::args().collect();
    let mut host = "127.0.0.1".to_string();
    let mut port = DEFAULT_PORT;

    if args.len() > 1 {
        let re = Regex::new(r"^(?:([^:]+):)?([^:]+)(?::(\d+))?$").unwrap();
        if let Some(caps) = re.captures(&args[1]) {
            if let Some(h) = caps.get(2) {
                host = h.as_str().to_string();
            }
            if let Some(p) = caps.get(3) {
                port = p.as_str().parse().unwrap_or(DEFAULT_PORT);
            }
        }
    }
    (host, port)
}

fn run_repl_loop(stream: TcpStream, host: &str, port: u16) {
    let mut input = String::new();
    loop {
        print_prompt(host, port);
        input.clear();
        
        if io::stdin().read_line(&mut input).is_err() {
            eprintln!("{}", "Failed to read input".red());
            continue;
        }

        let input = input.trim();
        if input.is_empty() {
            continue;
        }

        if input.eq_ignore_ascii_case("quit") || input.eq_ignore_ascii_case("exit") {
            break;
        }

        if !is_valid_command(input) {
            eprintln!("{}", "Error: Invalid command format".red());
            continue;
        }

        match send_command(&stream, input) {
            Ok(response) => print_response(&response),
            Err(e) => {
                if is_connection_error(&e) {
                    eprintln!("{}", "Connection error".red());
                    break;
                }
                eprintln!("{}", format!("Error: {}", e.to_string().replace("KeyDB", "Futriix")).red());
            }
        }
    }
}

fn print_prompt(host: &str, port: u16) {
    let prompt = format!("{}:{}:{}:~>", PROMPT_NAME, host, port);
    print!("{} ", prompt.green());
    io::stdout().flush().unwrap();
}

fn is_valid_command(cmd: &str) -> bool {
    !cmd.is_empty() &&
    !cmd.chars().any(|c| c.is_control()) &&
    cmd.split_whitespace().next().is_some()
}

fn send_command(stream: &TcpStream, command: &str) -> io::Result<resp::Value> {
    let parts: Vec<&str> = command.split_whitespace().collect();
    let mut resp_command = format!("*{}\r\n", parts.len());
    
    for part in parts {
        resp_command.push_str(&format!("${}\r\n{}\r\n", part.len(), part));
    }

    let mut stream = stream.try_clone()?;
    stream.write_all(resp_command.as_bytes())?;

    let mut decoder = resp::Decoder::new(&stream);
    decoder.decode()
}

fn print_response(value: &resp::Value) {
    match value {
        resp::Value::SimpleString(s) | resp::Value::BulkString(s) => {
            println!("{}", s.replace("KeyDB", "Futriix"));
        },
        resp::Value::Error(e) => {
            println!("{}", format!("(error) {}", e.replace("KeyDB", "Futriix")).red());
        },
        resp::Value::Integer(i) => println!("(integer) {}", i),
        resp::Value::Array(arr) => {
            for (i, item) in arr.iter().enumerate() {
                print!("{}) ", i + 1);
                print_response(item);
            }
        },
        resp::Value::Null => println!("(nil)"),
    }
}

fn is_connection_error(error: &io::Error) -> bool {
    matches!(
        error.kind(),
        io::ErrorKind::ConnectionAborted |
        io::ErrorKind::ConnectionReset |
        io::ErrorKind::BrokenPipe
    )
}