use std::io::{Read, Write};
use std::net::{TcpListener, TcpStream};
use std::sync::{Arc, Mutex};
use std::thread;

#[derive(Debug, Deserialize)]
struct MessageOuter {
    auth: Option<String>,
    message: Message,
    to: String,
}

#[derive(Debug, Deserialize)]
struct Message {
    body: String,
    from: Option<String>,
}

fn parse_message(input: &str) -> MessageOuter {
    let mut auth: Option<String> = None;
    let mut body = String::new();
    let mut from = None;
    let mut to = String::new();

    for line in input.lines() {
        let mut parts = line.split_whitespace();
        if let Some(field) = parts.next() {
            if let Some(value) = parts.next() {
                match field {
                    "AUTH" => auth = Some(value.to_string()),
                    "BODY" => body = value.to_string(),
                    "FROM" => from = Some(value.to_string()),
                    "TO" => to = value.to_string(),
                    _ => {}
                }
            }
        }
    }

    let message_outer = MessageOuter {
        auth,
        message: Message { body, from },
        to,
    };

    message_outer
}

fn read_from(mut stream: TcpStream) -> MessageOuter {
    let mut buf = Vec::new();
    let mut message_outer = MessageOuter {
        auth: None,
        message: Message {
            body: "".to_string(),
            from: None,
        },
        to: "".to_string(),
    };

    while let Ok(bytes_read) = stream.read_to_end(&mut buf) {
        if bytes_read == 0 {
            break;
        }

        message_outer = parse_message(
            String::from_utf8(buf.clone()).as_ref().unwrap()
        );
    }

    message_outer.message.from = Some(
        message_outer.message.from.unwrap_or_else(|| "anon".to_string())
    );

    message_outer
}

fn main() {
    let listener = TcpListener::bind("127.0.0.1:8080")
        .expect("Failed to bind address");

    println!("Server listening on 127.0.0.1:8080");

    let client_list: Arc<Mutex<Vec<TcpStream>>> = Arc::new(
        Mutex::new(vec![])
    );

    for stream in listener.incoming() {
        match stream {
            Ok(stream) => {
                let client_list = Arc::clone(&client_list);
                thread::spawn(move || {
                    // Add the client's stream to the client list
                    client_list.lock().unwrap().push(stream.try_clone().unwrap());

                    let message = read_from(stream);

                    // Send the received message to all connected clients
                    let serialized_message = serde_json::to_string(&message).unwrap();
                    let client_list = client_list.lock().unwrap();
                    for client in &*client_list {
                        if let Err(e) = client.write_all(serialized_message.as_bytes()) {
                            eprintln!("Failed to write to client: {}", e);
                        }
                        if let Err(e) = client.flush() {
                            eprintln!("Failed to flush stream: {}", e);
                        }
                    }

                    // Remove the client's stream from the client list
                    client_list
                        .lock()
                        .unwrap()
                        .retain(|client| client
                            .peer_addr()
                            .unwrap() != stream.peer_addr().unwrap());
                });
            }
            Err(err) => {
                eprintln!("Error accepting client connection: {}");
            }
        }
    }
}