use nix::fcntl::{fcntl, F_GETFL, F_SETFL, OFlag};
use nix::pty::{ForkptyResult, forkpty, PtyMaster};
use nix::unistd::{execv, read, write};

use minifb::{Key, KeyRepeat, Window, WindowOptions};

use std::vec;
use std::ffi::CString;

use vte::{Params, Parser, Perform};

use zeno::{Join, Mask, Stroke};

// window stuff
const WIDTH: usize = 640;
const HEIGHT: usize = 360;

// yoinked from vte docs
struct Performer;
impl Perform for Performer {
    fn print(&mut self, c: char) {
        println!("[print] {:?}", c);
    }

    fn execute(&mut self, byte: u8) {
        println!("[execute] {:02x}", byte);
    }

    fn hook(&mut self, params: &Params, intermediates: &[u8], ignore: bool, c: char) {
        println!(
            "[hook] params={:?}, intermediates={:?}, ignore={:?}, char={:?}",
            params, intermediates, ignore, c
        );
    }

    fn put(&mut self, byte: u8) {
        println!("[put] {:02x}", byte);
    }

    fn unhook(&mut self) {
        println!("[unhook]");
    }

    fn osc_dispatch(&mut self, params: &[&[u8]], bell_terminated: bool) {
        println!("[osc_dispatch] params={:?} bell_terminated={}", params, bell_terminated);
    }

    fn csi_dispatch(&mut self, params: &Params, intermediates: &[u8], ignore: bool, c: char) {
        println!(
            "[csi_dispatch] params={:#?}, intermediates={:?}, ignore={:?}, char={:?}",
            params, intermediates, ignore, c
        );
    }

    fn esc_dispatch(&mut self, intermediates: &[u8], ignore: bool, byte: u8) {
        println!(
            "[esc_dispatch] intermediates={:?}, ignore={:?}, byte={:02x}",
            intermediates, ignore, byte
        );
    }
}

fn main() {
    let mut buffer: Vec<u32> = vec![0; WIDTH * HEIGHT];
    let mut window = Window::new(
        "rust-term",
        WIDTH,
        HEIGHT,
        WindowOptions::default(),
    ).unwrap();

    window.set_target_fps(60);

    let pty = spawn_pty("/home/andromeda/.nix-profile/bin/sh").unwrap();
    println!("{:?}", &pty);
    let pty_flags = fcntl(&pty, F_GETFL).unwrap();
    fcntl(&pty, F_SETFL(OFlag::from_bits_truncate(pty_flags) | OFlag::O_NONBLOCK)).unwrap();

    let mut statemachine = Parser::new();
    let mut performer = Performer;
    let mut buf = [0u8; 2048];

    while window.is_open() && !window.is_key_down(Key::Escape) {

        let mask = Mask::new("M 8,56 32,8 56,56 Z")
            .size(WIDTH.try_into().unwrap(), HEIGHT.try_into().unwrap())
            .style(Stroke::new(8.0).join(Join::Round))
            .render()
            .0;

        // windowing stuff
        for (p, a) in buffer.iter_mut().zip(mask.iter()) {
            let a0 = *a as u32;
            *p = a0 << 24 | 0x00FF0000;
            *p =
                if a0 > 0
                { a0 << 16 | a0 << 8 | a0 }
                else { 0x00000000 };
        }
        let keys = window.get_keys_pressed(KeyRepeat::No);
        window.update_with_buffer(&buffer, WIDTH, HEIGHT).unwrap();

        // other stuff
        match read(&pty, &mut buf) {
            Ok(0) => (),
            Ok(n) => statemachine.advance(&mut performer, &buf[..n]),
            Err(_e) => (),
        };
        if !keys.is_empty() {
            let bytes: Vec<u8> = keys.iter()
                // TODO apply modifiers
                .map(|key| key_to_u8(*key, false, false))
                .collect();
            write(&pty, bytes.as_slice());
        };
    }
}

// forks a new pty and returns file descriptor of the master
fn spawn_pty(shell: &str) -> Option<PtyMaster> {
    // SAFETY safe unless os out of PTYs; incredibly unlikely
    match unsafe {forkpty(None, None)} {
        Ok(fork_pty_res) => match fork_pty_res {
            ForkptyResult::Parent {child:_, master} => {

                // SAFETY `master` is a valid PtyMaster
                return Some(unsafe{PtyMaster::from_owned_fd(master)});
            }
            ForkptyResult::Child =>{
                let _ = execv::<CString>(&CString::new(shell).unwrap(), &[]);
                return None;
            }
        },
        Err(_e) => return None,
    };
}

// WARNING not functional; missing some keys and also modifiers
fn key_to_u8(key: Key, shift: bool, ctrl: bool) -> u8 {
    let base = match key {
        Key::Key0 => b'0',
        Key::Key1 => b'1',
        Key::Key2 => b'2',
        Key::Key3 => b'3',
        Key::Key4 => b'4',
        Key::Key5 => b'5',
        Key::Key6 => b'6',
        Key::Key7 => b'7',
        Key::Key8 => b'8',
        Key::Key9 => b'9',
        Key::A => b'a',
        Key::B => b'b',
        Key::C => b'c',
        Key::D => b'd',
        Key::E => b'e',
        Key::F => b'f',
        Key::G => b'g',
        Key::H => b'h',
        Key::I => b'i',
        Key::J => b'j',
        Key::K => b'k',
        Key::L => b'l',
        Key::M => b'm',
        Key::N => b'n',
        Key::O => b'o',
        Key::P => b'p',
        Key::Q => b'q',
        Key::R => b'r',
        Key::S => b's',
        Key::T => b't',
        Key::U => b'u',
        Key::V => b'v',
        Key::W => b'w',
        Key::X => b'x',
        Key::Y => b'y',
        Key::Z => b'z',
        Key::F1 => 0,
        Key::F2 => 0,
        Key::F3 => 0,
        Key::F4 => 0,
        Key::F5 => 0,
        Key::F6 => 0,
        Key::F7 => 0,
        Key::F8 => 0,
        Key::F9 => 0,
        Key::F10 => 0,
        Key::F11 => 0,
        Key::F12 => 0,
        Key::F13 => 0,
        Key::F14 => 0,
        Key::F15 => 0,
        Key::Down => 0,
        Key::Left => 0,
        Key::Right => 0,
        Key::Up => 0,
        Key::Apostrophe => b'\'',
        Key::Backquote => b'`',
        Key::Backslash => b'\\',
        Key::Comma => b',',
        Key::Equal => b'=',
        Key::LeftBracket => b'[',
        Key::Minus => b'-',
        Key::Period => b'.',
        Key::RightBracket => b']',
        Key::Semicolon => b';',
        Key::Slash => b'/',
        Key::Backspace => 8,
        Key::Delete => 127,
        Key::End => 0,
        Key::Enter => b'\n',
        Key::Escape => 27,
        Key::Home => 0,
        Key::Insert => 0,
        Key::Menu => 0,
        Key::PageDown => 0,
        Key::PageUp => 0,
        Key::Pause => 0,
        Key::Space => b' ',
        Key::Tab => b'\t',
        Key::NumLock => 0,
        Key::CapsLock => 0,
        Key::ScrollLock => 0,
        Key::LeftShift => 0,
        Key::RightShift => 0,
        Key::LeftCtrl => 0,
        Key::RightCtrl => 0,
        Key::NumPad0 => 0,
        Key::NumPad1 => 0,
        Key::NumPad2 => 0,
        Key::NumPad3 => 0,
        Key::NumPad4 => 0,
        Key::NumPad5 => 0,
        Key::NumPad6 => 0,
        Key::NumPad7 => 0,
        Key::NumPad8 => 0,
        Key::NumPad9 => 0,
        Key::NumPadDot => 0,
        Key::NumPadSlash => 0,
        Key::NumPadAsterisk => 0,
        Key::NumPadMinus => 0,
        Key::NumPadPlus => 0,
        Key::NumPadEnter => 0,
        Key::LeftAlt => 0,
        Key::RightAlt => 0,
        Key::LeftSuper => 0,
        Key::RightSuper => 0,
        Key::Unknown => 0,
        Key::Count => 0,
    };

    let base_shift = if shift {
        match base {
            b'0' => b')',
            b'1' => b'!',
            b'2' => b'@',
            b'3' => b'#',
            b'4' => b'$',
            b'5' => b'%',
            b'6' => b'^',
            b'7' => b'&',
            b'8' => b'*',
            b'9' => b'(',
            b'a'..=b'z' => base - 32,
            b'\'' => b'"',
            b'`' => b'~',
            b'\\' => b'|',
            b',' => b'<',
            b'=' => b'+',
            b'[' => b'{',
            b'-' => b'_',
            b'.' => b'>',
            b']' => b'}',
            b';' => b':',
            b'/' => b'?',
            _ => base,
        }
    } else { base };

    let base_shift_ctrl = if ctrl {
        base_shift & 0x1F
    } else { base_shift };

    return base_shift_ctrl;
}