use alloc::{boxed::Box, format};
use io::{Read, Seek, Write};

use crate::{
    scheduler::ACTIVE_PID,
    virtual_fs::{FILE_SYSTEM, VirtualFileSystem, VirtualNode},
};

#[derive(Debug)]
pub struct VirtualStdin {}

#[derive(Debug)]
pub struct VirtualStdinNode {}

impl VirtualStdin {
    pub fn new() -> Self {
        Self {}
    }
}

impl VirtualFileSystem for VirtualStdin {
    fn open(
        &mut self,
        path: &bffs::path::Path,
    ) -> Result<alloc::boxed::Box<dyn crate::virtual_fs::VirtualNode + '_>, io::Error> {
        if !path.is_empty() {
            Err(io::Error::from(io::ErrorKind::NotADirectory))
        } else {
            Ok(Box::new(VirtualStdinNode {}))
        }
    }
}


impl Read for VirtualStdinNode {
    fn read(&mut self, buf: &mut [u8]) -> Result<usize, io::Error> {
        let pid = ACTIVE_PID.load(core::sync::atomic::Ordering::Relaxed);
        unsafe {
            FILE_SYSTEM
                .open(format!("/proc/{pid}/0").as_ref())
                .unwrap()
                .read(buf)
        }
    }
}

impl Seek for VirtualStdinNode {
    fn seek(&mut self, pos: io::SeekFrom) -> Result<u64, io::Error> {
        let pid = ACTIVE_PID.load(core::sync::atomic::Ordering::Relaxed);
        unsafe {
            FILE_SYSTEM
                .open(format!("/proc/{pid}/0").as_ref())
                .unwrap()
                .seek(pos)
        }
    }
}

impl Write for VirtualStdinNode {
    fn write(&mut self, buf: &[u8]) -> Result<usize, io::Error> {
        let pid = ACTIVE_PID.load(core::sync::atomic::Ordering::Relaxed);
        unsafe {
            FILE_SYSTEM
                .open(format!("/proc/{pid}/0").as_ref())
                .unwrap()
                .write(buf)
        }
    }

    fn flush(&mut self) -> Result<(), io::Error> {
        let pid = ACTIVE_PID.load(core::sync::atomic::Ordering::Relaxed);
        unsafe {
            FILE_SYSTEM
                .open(format!("/proc/{pid}/0").as_ref())
                .unwrap()
                .flush()
        }
    }
}

impl VirtualNode for VirtualStdinNode {}