use libc::printf;

use crate::simulator::{machine::{ExceptionType, Machine}, error::{MachineOk, MachineError}};


pub const SC_SHUTDOWN: u8 =	0;
pub const SC_EXIT: u8 =	1;
pub const SC_EXEC: u8 =	2;
pub const SC_JOIN: u8 =	3;
pub const SC_CREATE: u8 = 4;
pub const SC_OPEN: u8 =	5;
pub const SC_READ: u8 =	6;
pub const SC_WRITE: u8 = 7;
pub const SC_SEEK: u8 = 8;
pub const SC_CLOSE: u8 = 9;
pub const SC_NEW_THREAD: u8 = 10;
pub const SC_YIELD: u8 =	 11;
pub const SC_PERROR: u8 = 12;
pub const SC_P: u8 = 13;
pub const SC_V: u8 = 14;
pub const SC_SEM_CREATE: u8 = 15 ;
pub const SC_SEM_DESTROY: u8 = 16;
pub const SC_LOCK_CREATE: u8 = 17 ;
pub const SC_LOCK_DESTROY: u8 = 18 ;
pub const SC_LOCK_ACQUIRE: u8 = 19 ;
pub const SC_LOCK_RELEASE: u8 = 20 ;
pub const SC_COND_CREATE: u8 = 21 ;
pub const SC_COND_DESTROY: u8 = 22 ;
pub const SC_COND_WAIT: u8 = 23 ;
pub const SC_COND_SIGNAL: u8 = 24;
pub const SC_COND_BROADCAST: u8 = 25;
pub const SC_TTY_SEND: u8 = 26;
pub const SC_TTY_RECEIVE: u8 = 27;
pub const SC_MKDIR: u8 = 28;
pub const SC_RMDIR: u8 = 29;
pub const SC_REMOVE: u8 = 30;
pub const SC_FSLIST: u8 = 31;
pub const SC_SYS_TIME: u8 = 32 ;
pub const SC_MMAP: u8 = 33;
pub const SC_DEBUG: u8 = 34;

pub const CONSOLE_OUTPUT: u8 = 1;

// todo : returns new types, not just machine errors and machine ok
pub fn call(exception: ExceptionType, machine: &Machine) -> Result<MachineOk, MachineError> {

    match exception {
        ExceptionType::NoException => todo!(),
        ExceptionType::SyscallException => syscall(machine),
        ExceptionType::PagefaultException => todo!(),
        ExceptionType::ReadOnlyException => todo!(),
        ExceptionType::BusErrorException => todo!(),
        ExceptionType::AddressErrorException => todo!(),
        ExceptionType::OverflowException => todo!(),
        ExceptionType::IllegalInstrException => todo!(),
        ExceptionType::NumExceptionTypes => todo!(),
    }
}

fn syscall(machine: &Machine) -> Result<MachineOk, MachineError> {
    let call_type = machine.read_int_register(17) as u8;

    match call_type {
        SC_SHUTDOWN => Ok(MachineOk::Shutdown),
        SC_EXIT => todo!(),
        SC_EXEC => todo!(),
        SC_JOIN => todo!(),
        SC_CREATE => todo!(),
        SC_OPEN => todo!(),
        SC_READ => todo!(),
        SC_WRITE => {

            let address = machine.read_int_register(10);
            let size = machine.read_int_register(11);
            // openfileid or 1 (console)
            let f = machine.read_int_register(12);

            // load buffer
            let mut buffer = "".to_string();
            for i in 0..size {
                match char::from_digit(machine.read_memory(1, (address + i) as usize) as u32, 2) {
                    Some(c) => buffer.push(c),
                    None => todo!() // Throw a proper error
                }
            }

            if f as u8 == CONSOLE_OUTPUT {
                println!("{}", buffer); // todo replace with console driver in the future
            } else {
                todo!("SC_WRITE to file is not yet implemented")
            }

            Ok(MachineOk::Ok)
        },
        SC_SEEK => todo!(),
        SC_CLOSE => todo!(),
        SC_NEW_THREAD => todo!(),
        SC_YIELD => todo!(),
        SC_PERROR => todo!(),
        SC_P => todo!(),
        SC_V => todo!(),
        SC_SEM_CREATE => todo!(),
        SC_SEM_DESTROY => todo!(),
        SC_LOCK_CREATE => todo!(),
        SC_LOCK_DESTROY => todo!(),
        SC_LOCK_ACQUIRE => todo!(),
        SC_LOCK_RELEASE => todo!(),
        SC_COND_CREATE => todo!(),
        SC_COND_DESTROY => todo!(),
        SC_COND_WAIT => todo!(),
        SC_COND_SIGNAL => todo!(),
        SC_COND_BROADCAST => todo!(),
        SC_TTY_SEND => todo!(),
        SC_TTY_RECEIVE => todo!(),
        SC_MKDIR => todo!(),
        SC_RMDIR => todo!(),
        SC_REMOVE => todo!(),
        SC_FSLIST => todo!(),
        SC_SYS_TIME => todo!(),
        SC_MMAP => todo!(),
        SC_DEBUG => todo!(),
        _ => todo!()
    }
}