mod async;
mod cursor;

pub use self::{async::*, cursor::*};

use std::ops::Deref;
use std::ops::BitAnd;

use cocoa::{
    appkit::{NSApp, NSWindowStyleMask},
    base::{id, nil},
    foundation::{NSAutoreleasePool, NSRect, NSUInteger},
};
use core_graphics::display::CGDisplay;
use objc::runtime::{BOOL, Class, Object, Sel, YES};

use platform_impl::platform::ffi;

// Replace with `!` once stable
#[derive(Debug)]
pub enum Never {}

pub fn has_flag<T>(bitset: T, flag: T) -> bool
where T:
    Copy + PartialEq + BitAnd<T, Output = T>
{
    bitset & flag == flag
}

pub const EMPTY_RANGE: ffi::NSRange = ffi::NSRange {
    location: ffi::NSNotFound as NSUInteger,
    length: 0,
};

pub struct IdRef(id);

impl IdRef {
    pub fn new(inner: id) -> IdRef {
        IdRef(inner)
    }

    #[allow(dead_code)]
    pub fn retain(inner: id) -> IdRef {
        if inner != nil {
            let () = unsafe { msg_send![inner, retain] };
        }
        IdRef(inner)
    }

    pub fn non_nil(self) -> Option<IdRef> {
        if self.0 == nil { None } else { Some(self) }
    }
}

impl Drop for IdRef {
    fn drop(&mut self) {
        if self.0 != nil {
            unsafe {
                let pool = NSAutoreleasePool::new(nil);
                let () = msg_send![self.0, release];
                pool.drain();
            };
        }
    }
}

impl Deref for IdRef {
    type Target = id;
    fn deref<'a>(&'a self) -> &'a id {
        &self.0
    }
}

impl Clone for IdRef {
    fn clone(&self) -> IdRef {
        if self.0 != nil {
            let _: id = unsafe { msg_send![self.0, retain] };
        }
        IdRef(self.0)
    }
}

// For consistency with other platforms, this will...
// 1. translate the bottom-left window corner into the top-left window corner
// 2. translate the coordinate from a bottom-left origin coordinate system to a top-left one
pub fn bottom_left_to_top_left(rect: NSRect) -> f64 {
    CGDisplay::main().pixels_high() as f64 - (rect.origin.y + rect.size.height)
}

pub unsafe fn superclass<'a>(this: &'a Object) -> &'a Class {
    let superclass: id = msg_send![this, superclass];
    &*(superclass as *const _)
}

pub unsafe fn create_input_context(view: id) -> IdRef {
    let input_context: id = msg_send![class!(NSTextInputContext), alloc];
    let input_context: id = msg_send![input_context, initWithClient:view];
    IdRef::new(input_context)
}

#[allow(dead_code)]
pub unsafe fn open_emoji_picker() {
    let () = msg_send![NSApp(), orderFrontCharacterPalette:nil];
}

pub extern fn yes(_: &Object, _: Sel) -> BOOL {
    YES
}

pub unsafe fn toggle_style_mask(window: id, view: id, mask: NSWindowStyleMask, on: bool) {
    use cocoa::appkit::NSWindow;

    let current_style_mask = window.styleMask();
    if on {
        window.setStyleMask_(current_style_mask | mask);
    } else {
        window.setStyleMask_(current_style_mask & (!mask));
    }

    // If we don't do this, key handling will break. Therefore, never call `setStyleMask` directly!
    window.makeFirstResponder_(view);
}