use std::io;
use std::net::TcpListener;
use std::net::TcpStream;
use std::thread;

use rusty_http::Http;
use rusty_http::Request;
use rusty_http::Response;
use rusty_http::StatusCode;

fn add(request: Request, response: Response) -> io::Result<()> {
    let Some(a) = request.params.get("a") else {
        response.status_code(StatusCode::BadRequest)
        .set_header("Content-Type", "text/html").flush()?
        .add_to_body("<h1>400 Bad Request</h1>")
        .add_to_body("<p>Parameter 'a' not found</p>").flush()?;
        
        return Ok(());
    };

    let Some(b) = request.params.get("b") else {
        response.status_code(StatusCode::BadRequest)
        .set_header("Content-Type", "text/html").flush()?
        .add_to_body("<h1>400 Bad Request</h1>")
        .add_to_body("<p>Parameter 'b' not found</p>").flush()?;
        
        return Ok(());
    };

    let Ok(a) = a.parse::<u8>() else {
        response.status_code(StatusCode::BadRequest)
        .set_header("Content-Type", "text/html").flush()?
        .add_to_body("<h1>400 Bad Request</h1>")
        .add_to_body("<p>Parameter 'a' can only be a number from 0 to 255</p>").flush()?;
        
        return Ok(());
    };

    let Ok(b) = b.parse::<u8>() else {
        response.status_code(StatusCode::BadRequest)
        .set_header("Content-Type", "text/html").flush()?
        .add_to_body("<h1>400 Bad Request</h1>")
        .add_to_body("<p>Parameter 'b' can only be a number from 0 to 255</p>").flush()?;
        
        return Ok(());
    };

    let content = format!("<h1>{} + {} = {}</h1>", a, b, a as u16 + b as u16);

    response.status_code(StatusCode::Ok)
    .set_header("Content-Type", "text/html").flush()?
    .add_to_body(content).flush()?;

    Ok(())
}

fn sub(request: Request, response: Response) -> io::Result<()> {
    let Some(a) = request.params.get("a") else {
        response.status_code(StatusCode::BadRequest)
        .set_header("Content-Type", "text/html").flush()?
        .add_to_body("<h1>400 Bad Request</h1>")
        .add_to_body("<p>Parameter 'a' not found</p>").flush()?;
        
        return Ok(());
    };

    let Some(b) = request.params.get("b") else {
        response.status_code(StatusCode::BadRequest)
        .set_header("Content-Type", "text/html").flush()?
        .add_to_body("<h1>400 Bad Request</h1>")
        .add_to_body("<p>Parameter 'b' not found</p>").flush()?;
        
        return Ok(());
    };

    let Ok(a) = a.parse::<u8>() else {
        response.status_code(StatusCode::BadRequest)
        .set_header("Content-Type", "text/html").flush()?
        .add_to_body("<h1>400 Bad Request</h1>")
        .add_to_body("<p>Parameter 'a' can only be a number from 0 to 255</p>").flush()?;
        
        return Ok(());
    };

    let Ok(b) = b.parse::<u8>() else {
        response.status_code(StatusCode::BadRequest)
        .set_header("Content-Type", "text/html").flush()?
        .add_to_body("<h1>400 Bad Request</h1>")
        .add_to_body("<p>Parameter 'b' can only be a number from 0 to 255</p>").flush()?;
        
        return Ok(());
    };

    let content = format!("<h1>{} - {} = {}</h1>", a, b, a as i16 - b as i16);

    response.status_code(StatusCode::Ok)
    .set_header("Content-Type", "text/html").flush()?
    .add_to_body(content).flush()?;

    Ok(())
}

fn not_found(request: Request, response: Response) -> io::Result<()> {
    let content = format!("<p>Page '{}' could not been found</p>", request.uri);

    response.status_code(StatusCode::NotFound)
    .set_header("Content-Type", "text/html").flush()?
    .add_to_body("<h1>404 Not Found</h1>")
    .add_to_body(content).flush()?;

    Ok(())
}

fn init_stream(stream: TcpStream) -> io::Result<()> {
    let (request, response) = Http::from(stream)?;

    match request.uri.as_str() {
        "/add" => add(request, response)?,
        "/sub" => sub(request, response)?,
        _      => not_found(request, response)?
    }

    Ok(())
}

fn main() -> io::Result<()> {
    let listener = TcpListener::bind("127.0.0.1:8080")?;

    for stream in listener.incoming().filter_map(Result::ok) {
        thread::spawn(|| init_stream(stream));
    }

    Ok(())
}