use std::mem::{size_of, transmute};
use winapi::ctypes::c_int;
use winapi::shared::minwindef::DWORD;
use winapi::um::winuser::{
  GetAsyncKeyState, GetSystemMetrics, SendInput, INPUT, INPUT_MOUSE, LPINPUT, MOUSEEVENTF_ABSOLUTE,
  MOUSEEVENTF_LEFTDOWN, MOUSEEVENTF_LEFTUP, MOUSEEVENTF_MIDDLEDOWN, MOUSEEVENTF_MIDDLEUP,
  MOUSEEVENTF_MOVE, MOUSEEVENTF_RIGHTDOWN, MOUSEEVENTF_RIGHTUP, MOUSEEVENTF_VIRTUALDESK,
  MOUSEINPUT, SM_CXVIRTUALSCREEN, SM_CYVIRTUALSCREEN, SM_XVIRTUALSCREEN, SM_YVIRTUALSCREEN,
  VK_LBUTTON, VK_MBUTTON, VK_RBUTTON, VK_XBUTTON1, VK_XBUTTON2,
};

use crate::mouse::{Button, ButtonState, Mouse};

impl Mouse {
  pub fn move_to(absolute: bool, dx: i32, dy: i32) {
    let width = unsafe { GetSystemMetrics(SM_CXVIRTUALSCREEN) };
    let height = unsafe { GetSystemMetrics(SM_CYVIRTUALSCREEN) };
    if width == 0 || height == 0 {
      return;
    }
    let pressed_left = Self::pressed(Button::Left);
    let pressed_right = Self::pressed(Button::Right);
    let pressed_middle = Self::pressed(Button::Middle);
    let mut dw_flags = MOUSEEVENTF_MOVE | MOUSEEVENTF_VIRTUALDESK;

    if absolute {
      dw_flags = dw_flags | MOUSEEVENTF_ABSOLUTE;
    }
    if pressed_left {
      dw_flags = dw_flags | MOUSEEVENTF_LEFTDOWN;
    }
    if pressed_right {
      dw_flags = dw_flags | MOUSEEVENTF_RIGHTDOWN;
    }
    if pressed_middle {
      dw_flags = dw_flags | MOUSEEVENTF_MIDDLEDOWN;
    }

    let mut input = INPUT {
      type_: INPUT_MOUSE,
      u: unsafe {
        transmute(MOUSEINPUT {
          dx: (dx - { GetSystemMetrics(SM_XVIRTUALSCREEN) }) * 65535 / {
            GetSystemMetrics(SM_CXVIRTUALSCREEN)
          },
          dy: (dy - { GetSystemMetrics(SM_YVIRTUALSCREEN) }) * 65535 / {
            GetSystemMetrics(SM_CYVIRTUALSCREEN)
          },
          mouseData: 0,
          dwFlags: dw_flags,
          time: 0,
          dwExtraInfo: 0,
        })
      },
    };
    unsafe { SendInput(1, &mut input as LPINPUT, size_of::<INPUT>() as c_int) };
  }

  pub fn press(button: Button) {
    let btn = Self::button_event(button, ButtonState::Press);

    let dw_flags = btn;

    let mut input = INPUT {
      type_: INPUT_MOUSE,
      u: unsafe {
        transmute(MOUSEINPUT {
          dx: 0,
          dy: 0,
          mouseData: 0,
          dwFlags: dw_flags,
          time: 0,
          dwExtraInfo: 0,
        })
      },
    };
    unsafe { SendInput(1, &mut input as LPINPUT, size_of::<INPUT>() as c_int) };
  }

  pub fn release(button: Button) {
    let btn = Self::button_event(button, ButtonState::Release);

    let dw_flags = btn;

    let mut input = INPUT {
      type_: INPUT_MOUSE,
      u: unsafe {
        transmute(MOUSEINPUT {
          dx: 0,
          dy: 0,
          mouseData: 0,
          dwFlags: dw_flags,
          time: 0,
          dwExtraInfo: 0,
        })
      },
    };
    unsafe { SendInput(1, &mut input as LPINPUT, size_of::<INPUT>() as c_int) };
  }

  pub fn pressed(button: Button) -> bool {
    (unsafe { GetAsyncKeyState(Self::button_virtual_key(button)) } >> 15) != 0
  }

  fn button_event(button: Button, state: ButtonState) -> DWORD {
    match state {
      ButtonState::Press => match button {
        Button::Left => MOUSEEVENTF_LEFTDOWN,
        Button::Middle => MOUSEEVENTF_MIDDLEDOWN,
        Button::Right => MOUSEEVENTF_RIGHTDOWN,
        _ => unimplemented!(),
      },
      ButtonState::Release => match button {
        Button::Left => MOUSEEVENTF_LEFTUP,
        Button::Middle => MOUSEEVENTF_MIDDLEUP,
        Button::Right => MOUSEEVENTF_RIGHTUP,
        _ => unimplemented!(),
      },
    }
  }

  fn button_virtual_key(button: Button) -> c_int {
    match button {
      Button::Left => VK_LBUTTON,
      Button::Middle => VK_MBUTTON,
      Button::Right => VK_RBUTTON,
      Button::X1 => VK_XBUTTON1,
      Button::X2 => VK_XBUTTON2,
      _ => unimplemented!(),
    }
  }
}