// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.

use std::io::Error;
use std::rc::Rc;

use deno_core::error::resource_unavailable;
use deno_core::error::AnyError;
use deno_core::op;
use deno_core::OpState;
use deno_core::Resource;
use deno_io::fs::FileResource;

#[cfg(unix)]
use deno_core::ResourceId;
#[cfg(unix)]
use nix::sys::termios;
#[cfg(unix)]
use std::cell::RefCell;
#[cfg(unix)]
use std::collections::HashMap;

#[cfg(unix)]
#[derive(Default, Clone)]
struct TtyModeStore(Rc<RefCell<HashMap<ResourceId, termios::Termios>>>);

#[cfg(unix)]
impl TtyModeStore {
  pub fn get(&self, id: ResourceId) -> Option<termios::Termios> {
    self.0.borrow().get(&id).map(ToOwned::to_owned)
  }

  pub fn take(&self, id: ResourceId) -> Option<termios::Termios> {
    self.0.borrow_mut().remove(&id)
  }

  pub fn set(&self, id: ResourceId, mode: termios::Termios) {
    self.0.borrow_mut().insert(id, mode);
  }
}

#[cfg(windows)]
use deno_core::error::custom_error;
#[cfg(windows)]
use winapi::shared::minwindef::DWORD;
#[cfg(windows)]
use winapi::um::wincon;

#[cfg(windows)]
fn get_fd_from_resource(
  resource: Rc<FileResource>,
) -> Result<std::os::windows::io::RawHandle, AnyError> {
  use winapi::um::handleapi;

  let Some(handle) = resource.backing_fd() else {
    return Err(resource_unavailable());
  };
  if handle == handleapi::INVALID_HANDLE_VALUE {
    return Err(Error::last_os_error().into());
  } else if handle.is_null() {
    return Err(custom_error("ReferenceError", "null handle"));
  }
  Ok(handle)
}

#[cfg(not(windows))]
fn get_fd_from_resource(
  resource: Rc<FileResource>,
) -> Result<std::os::unix::prelude::RawFd, AnyError> {
  match resource.backing_fd() {
    Some(fd) => Ok(fd),
    None => Err(resource_unavailable()),
  }
}

deno_core::extension!(
  deno_tty,
  ops = [op_stdin_set_raw, op_isatty, op_console_size],
  state = |state| {
    #[cfg(unix)]
    state.put(TtyModeStore::default());
  },
);

// ref: <https://learn.microsoft.com/en-us/windows/console/setconsolemode>
#[cfg(windows)]
const COOKED_MODE: DWORD =
  // enable line-by-line input (returns input only after CR is read)
  wincon::ENABLE_LINE_INPUT
  // enables real-time character echo to console display (requires ENABLE_LINE_INPUT)
  | wincon::ENABLE_ECHO_INPUT
  // system handles CTRL-C (with ENABLE_LINE_INPUT, also handles BS, CR, and LF) and other control keys (when using `ReadFile` or `ReadConsole`)
  | wincon::ENABLE_PROCESSED_INPUT;

#[cfg(windows)]
fn mode_raw_input_on(original_mode: DWORD) -> DWORD {
  original_mode & !COOKED_MODE | wincon::ENABLE_VIRTUAL_TERMINAL_INPUT
}

#[cfg(windows)]
fn mode_raw_input_off(original_mode: DWORD) -> DWORD {
  original_mode & !wincon::ENABLE_VIRTUAL_TERMINAL_INPUT | COOKED_MODE
}

#[op(fast)]
fn op_stdin_set_raw(
  state: &mut OpState,
  is_raw: bool,
  cbreak: bool,
) -> Result<(), AnyError> {
  let rid = 0; // stdin is always rid=0

  // From https://github.com/kkawakam/rustyline/blob/master/src/tty/windows.rs
  // and https://github.com/kkawakam/rustyline/blob/master/src/tty/unix.rs
  // and https://github.com/crossterm-rs/crossterm/blob/e35d4d2c1cc4c919e36d242e014af75f6127ab50/src/terminal/sys/windows.rs
  // Copyright (c) 2015 Katsu Kawakami & Rustyline authors. MIT license.
  // Copyright (c) 2019 Timon. MIT license.
  #[cfg(windows)]
  {
    use winapi::shared::minwindef::FALSE;
    use winapi::um::consoleapi;

    if cbreak {
      return Err(deno_core::error::not_supported());
    }

    FileResource::with_resource(state, rid, move |resource| {
      let handle = get_fd_from_resource(resource)?;
      let mut original_mode: DWORD = 0;
      // SAFETY: winapi call
      if unsafe { consoleapi::GetConsoleMode(handle, &mut original_mode) }
        == FALSE
      {
        return Err(Error::last_os_error().into());
      }

      let new_mode = if is_raw {
        mode_raw_input_on(original_mode)
      } else {
        mode_raw_input_off(original_mode)
      };

      // SAFETY: winapi call
      if unsafe { consoleapi::SetConsoleMode(handle, new_mode) } == FALSE {
        return Err(Error::last_os_error().into());
      }

      Ok(())
    })
  }
  #[cfg(unix)]
  {
    let tty_mode_store = state.borrow::<TtyModeStore>().clone();
    let previous_mode = tty_mode_store.get(rid);

    FileResource::with_resource(state, rid, move |resource| {
      let raw_fd = get_fd_from_resource(resource)?;

      if is_raw {
        let mut raw = match previous_mode {
          Some(mode) => mode,
          None => {
            // Save original mode.
            let original_mode = termios::tcgetattr(raw_fd)?;
            tty_mode_store.set(rid, original_mode.clone());
            original_mode
          }
        };

        raw.input_flags &= !(termios::InputFlags::BRKINT
          | termios::InputFlags::ICRNL
          | termios::InputFlags::INPCK
          | termios::InputFlags::ISTRIP
          | termios::InputFlags::IXON);

        raw.control_flags |= termios::ControlFlags::CS8;

        raw.local_flags &= !(termios::LocalFlags::ECHO
          | termios::LocalFlags::ICANON
          | termios::LocalFlags::IEXTEN);
        if !cbreak {
          raw.local_flags &= !(termios::LocalFlags::ISIG);
        }
        raw.control_chars[termios::SpecialCharacterIndices::VMIN as usize] = 1;
        raw.control_chars[termios::SpecialCharacterIndices::VTIME as usize] = 0;
        termios::tcsetattr(raw_fd, termios::SetArg::TCSADRAIN, &raw)?;
      } else {
        // Try restore saved mode.
        if let Some(mode) = tty_mode_store.take(rid) {
          termios::tcsetattr(raw_fd, termios::SetArg::TCSADRAIN, &mode)?;
        }
      }

      Ok(())
    })
  }
}

#[op(fast)]
fn op_isatty(
  state: &mut OpState,
  rid: u32,
  out: &mut [u8],
) -> Result<(), AnyError> {
  FileResource::with_resource(state, rid, move |resource| {
    let raw_fd = get_fd_from_resource(resource)?;
    #[cfg(windows)]
    {
      use winapi::shared::minwindef::FALSE;
      use winapi::um::consoleapi;

      let handle = raw_fd;
      let mut test_mode: DWORD = 0;
      // If I cannot get mode out of console, it is not a console.
      // TODO(bartlomieju):
      #[allow(clippy::undocumented_unsafe_blocks)]
      {
        out[0] = unsafe {
          consoleapi::GetConsoleMode(handle, &mut test_mode) != FALSE
        } as u8;
      }
    }
    #[cfg(unix)]
    {
      // TODO(bartlomieju):
      #[allow(clippy::undocumented_unsafe_blocks)]
      {
        out[0] = unsafe { libc::isatty(raw_fd as libc::c_int) == 1 } as u8;
      }
    }
    Ok(())
  })
}

#[op(fast)]
fn op_console_size(
  state: &mut OpState,
  result: &mut [u32],
) -> Result<(), AnyError> {
  fn check_console_size(
    state: &mut OpState,
    result: &mut [u32],
    rid: u32,
  ) -> Result<(), AnyError> {
    FileResource::with_resource(state, rid, move |resource| {
      let fd = get_fd_from_resource(resource)?;
      let size = console_size_from_fd(fd)?;
      result[0] = size.cols;
      result[1] = size.rows;
      Ok(())
    })
  }

  let mut last_result = Ok(());
  // Since stdio might be piped we try to get the size of the console for all
  // of them and return the first one that succeeds.
  for rid in [0, 1, 2] {
    last_result = check_console_size(state, result, rid);
    if last_result.is_ok() {
      return last_result;
    }
  }

  last_result
}

#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub struct ConsoleSize {
  pub cols: u32,
  pub rows: u32,
}

pub fn console_size(
  std_file: &std::fs::File,
) -> Result<ConsoleSize, std::io::Error> {
  #[cfg(windows)]
  {
    use std::os::windows::io::AsRawHandle;
    let handle = std_file.as_raw_handle();
    console_size_from_fd(handle)
  }
  #[cfg(unix)]
  {
    use std::os::unix::io::AsRawFd;
    let fd = std_file.as_raw_fd();
    console_size_from_fd(fd)
  }
}

#[cfg(windows)]
fn console_size_from_fd(
  handle: std::os::windows::io::RawHandle,
) -> Result<ConsoleSize, std::io::Error> {
  // SAFETY: winapi calls
  unsafe {
    let mut bufinfo: winapi::um::wincon::CONSOLE_SCREEN_BUFFER_INFO =
      std::mem::zeroed();

    if winapi::um::wincon::GetConsoleScreenBufferInfo(handle, &mut bufinfo) == 0
    {
      return Err(Error::last_os_error());
    }
    Ok(ConsoleSize {
      cols: bufinfo.dwSize.X as u32,
      rows: bufinfo.dwSize.Y as u32,
    })
  }
}

#[cfg(not(windows))]
fn console_size_from_fd(
  fd: std::os::unix::prelude::RawFd,
) -> Result<ConsoleSize, std::io::Error> {
  // SAFETY: libc calls
  unsafe {
    let mut size: libc::winsize = std::mem::zeroed();
    if libc::ioctl(fd, libc::TIOCGWINSZ, &mut size as *mut _) != 0 {
      return Err(Error::last_os_error());
    }
    Ok(ConsoleSize {
      cols: size.ws_col as u32,
      rows: size.ws_row as u32,
    })
  }
}

#[cfg(all(test, windows))]
mod tests {
  #[test]
  fn test_winos_raw_mode_transitions() {
    use crate::ops::tty::mode_raw_input_off;
    use crate::ops::tty::mode_raw_input_on;

    let known_off_modes =
      [0xf7 /* Win10/CMD */, 0x1f7 /* Win10/WinTerm */];
    let known_on_modes =
      [0x2f0 /* Win10/CMD */, 0x3f0 /* Win10/WinTerm */];

    // assert known transitions
    assert_eq!(known_on_modes[0], mode_raw_input_on(known_off_modes[0]));
    assert_eq!(known_on_modes[1], mode_raw_input_on(known_off_modes[1]));

    // assert ON-OFF round-trip is neutral
    assert_eq!(
      known_off_modes[0],
      mode_raw_input_off(mode_raw_input_on(known_off_modes[0]))
    );
    assert_eq!(
      known_off_modes[1],
      mode_raw_input_off(mode_raw_input_on(known_off_modes[1]))
    );
  }
}