use std::{
    collections::HashMap,
    fs,
    io::{self, BufRead, BufReader, Write},
    os::unix::net::UnixListener,
    path::Path,
    sync::{Arc, RwLock},
    thread,
};

use crate::{energy::ProcessInfo, Pid};

pub struct LoggingSocketService {
    path: String,
    process_info: Arc<RwLock<HashMap<Pid, ProcessInfo>>>,
}

impl LoggingSocketService {
    pub fn new(path: &str, process_info: Arc<RwLock<HashMap<Pid, ProcessInfo>>>) -> Self {
        LoggingSocketService {
            path: path.to_string(),
            process_info,
        }
    }

    pub fn run(self) {
        thread::spawn(move || {
            let listener = UnixListener::bind(self.path.clone()).unwrap();
            for stream in listener.incoming() {
                let mut socket = stream.unwrap();
                let mut reader = BufReader::new(socket.try_clone().unwrap());
                let mut line = String::new();
                while let Ok(bytes_read) = reader.read_line(&mut line) {
                    if bytes_read == 0 {
                        break;
                    }
                    if let Ok(pid) = line.trim().parse::<Pid>() {
                        socket
                            .write_all(self.handle_request(pid).as_bytes())
                            .unwrap();
                    } else {
                        socket
                            .write_all(
                                format!("Failed to get energy for pid: {}\n", line.trim_end())
                                    .as_bytes(),
                            )
                            .unwrap();
                    }
                    line.clear();
                }
            }
        });
    }

    fn handle_request(&self, pid: i32) -> String {
        let mut output = String::new();
        use std::fmt::Write;
        if pid == -1 {
            for (pid, info) in self.process_info.read().unwrap().iter() {
                writeln!(&mut output, "{pid},{},{}", info.energy, info.tree_energy).unwrap();
            }
            writeln!(&mut output, "#",).unwrap();
            return output;
        }

        if let Some(info) = self.process_info.read().unwrap().get(&pid) {
            format!(
                "pid: {pid} process: {}J process tree: {}J\n",
                info.energy, info.tree_energy
            )
        } else {
            format!("Unknown pid: {pid}\n")
        }
    }
}

pub fn start_logging_socket_service(
    path: &str,
    process_info: Arc<RwLock<HashMap<Pid, ProcessInfo>>>,
) -> io::Result<()> {
    if Path::new(path).exists() {
        fs::remove_file(path)?;
    }
    let socket = LoggingSocketService::new(path, process_info);
    socket.run();
    Ok(())
}