use super::ns_string;
use crate::platform;
use cocoa::{
    appkit::NSScreen,
    base::{id, nil},
    foundation::{NSArray, NSDictionary, NSPoint, NSRect, NSSize},
};
use core_foundation::{
    number::{kCFNumberIntType, CFNumberGetValue, CFNumberRef},
    uuid::{CFUUIDGetUUIDBytes, CFUUIDRef},
};
use core_graphics::display::CGDirectDisplayID;
use pathfinder_geometry::{rect::RectF, vector::vec2f};
use std::{any::Any, ffi::c_void};
use uuid::Uuid;

#[link(name = "ApplicationServices", kind = "framework")]
extern "C" {
    pub fn CGDisplayCreateUUIDFromDisplayID(display: CGDirectDisplayID) -> CFUUIDRef;
}

#[derive(Debug)]
pub struct Screen {
    pub(crate) native_screen: id,
}

impl Screen {
    /// Get the screen with the given UUID.
    pub fn find_by_id(uuid: Uuid) -> Option<Self> {
        Self::all().find(|screen| platform::Screen::display_uuid(screen) == Some(uuid))
    }

    /// Get the primary screen - the one with the menu bar, and whose bottom left
    /// corner is at the origin of the AppKit coordinate system.
    fn primary() -> Self {
        Self::all().next().unwrap()
    }

    pub fn all() -> impl Iterator<Item = Self> {
        unsafe {
            let native_screens = NSScreen::screens(nil);
            (0..NSArray::count(native_screens)).map(move |ix| Screen {
                native_screen: native_screens.objectAtIndex(ix),
            })
        }
    }

    /// Convert the given rectangle in screen coordinates from GPUI's
    /// coordinate system to the AppKit coordinate system.
    ///
    /// In GPUI's coordinates, the origin is at the top left of the primary screen, with
    /// the Y axis pointing downward. In the AppKit coordindate system, the origin is at the
    /// bottom left of the primary screen, with the Y axis pointing upward.
    pub(crate) fn screen_rect_to_native(rect: RectF) -> NSRect {
        let primary_screen_height = unsafe { Self::primary().native_screen.frame().size.height };
        NSRect::new(
            NSPoint::new(
                rect.origin_x() as f64,
                primary_screen_height - rect.origin_y() as f64 - rect.height() as f64,
            ),
            NSSize::new(rect.width() as f64, rect.height() as f64),
        )
    }

    /// Convert the given rectangle in screen coordinates from the AppKit
    /// coordinate system to GPUI's coordinate system.
    ///
    /// In GPUI's coordinates, the origin is at the top left of the primary screen, with
    /// the Y axis pointing downward. In the AppKit coordindate system, the origin is at the
    /// bottom left of the primary screen, with the Y axis pointing upward.
    pub(crate) fn screen_rect_from_native(rect: NSRect) -> RectF {
        let primary_screen_height = unsafe { Self::primary().native_screen.frame().size.height };
        RectF::new(
            vec2f(
                rect.origin.x as f32,
                (primary_screen_height - rect.origin.y - rect.size.height) as f32,
            ),
            vec2f(rect.size.width as f32, rect.size.height as f32),
        )
    }
}

impl platform::Screen for Screen {
    fn as_any(&self) -> &dyn Any {
        self
    }

    fn display_uuid(&self) -> Option<uuid::Uuid> {
        unsafe {
            // Screen ids are not stable. Further, the default device id is also unstable across restarts.
            // CGDisplayCreateUUIDFromDisplayID is stable but not exposed in the bindings we use.
            // This approach is similar to that which winit takes
            // https://github.com/rust-windowing/winit/blob/402cbd55f932e95dbfb4e8b5e8551c49e56ff9ac/src/platform_impl/macos/monitor.rs#L99
            let device_description = self.native_screen.deviceDescription();

            let key = ns_string("NSScreenNumber");
            let device_id_obj = device_description.objectForKey_(key);
            if device_id_obj.is_null() {
                // Under some circumstances, especially display re-arrangements or display locking, we seem to get a null pointer
                // to the device id. See: https://linear.app/zed-industries/issue/Z-257/lock-screen-crash-with-multiple-monitors
                return None;
            }

            let mut device_id: u32 = 0;
            CFNumberGetValue(
                device_id_obj as CFNumberRef,
                kCFNumberIntType,
                (&mut device_id) as *mut _ as *mut c_void,
            );
            let cfuuid = CGDisplayCreateUUIDFromDisplayID(device_id as CGDirectDisplayID);
            if cfuuid.is_null() {
                return None;
            }

            let bytes = CFUUIDGetUUIDBytes(cfuuid);
            Some(Uuid::from_bytes([
                bytes.byte0,
                bytes.byte1,
                bytes.byte2,
                bytes.byte3,
                bytes.byte4,
                bytes.byte5,
                bytes.byte6,
                bytes.byte7,
                bytes.byte8,
                bytes.byte9,
                bytes.byte10,
                bytes.byte11,
                bytes.byte12,
                bytes.byte13,
                bytes.byte14,
                bytes.byte15,
            ]))
        }
    }

    fn bounds(&self) -> RectF {
        unsafe { Self::screen_rect_from_native(self.native_screen.frame()) }
    }

    fn content_bounds(&self) -> RectF {
        unsafe { Self::screen_rect_from_native(self.native_screen.visibleFrame()) }
    }
}