// Copyright (c) 2016 The vulkano developers
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or https://opensource.org/licenses/MIT>,
// at your option. All files in the project carrying such
// notice may not be copied, modified, or distributed except
// according to those terms.

//! Control and use of display devices (e.g. monitors).
//!
//! A `Display` represents a display device, which is usually a monitor but can also be something
//! else that can display graphical content. You do not create `Display` objects yourself, but
//! you get them from the physical device instead. To get a list of all available displays on the
//! system, you can call [`PhysicalDevice::display_properties`].
//!
//! A *display plane* is a single layer within a display device or graphics stack that a surface
//! can be created from. Depending on the setup used by the system, there may be one fixed
//! display plane for each display, multiple display planes for each display, or even
//! a pool of display planes that multiple displays can make use of.
//!
//! # Creating surfaces that render directly to a display
//!
//! - Choose the `Display` that you want to render to.
//! - Get display plane properties with [`PhysicalDevice::display_plane_properties`],
//!   and choose a display plane index that is supported with the chosen display.
//! - Choose a `DisplayMode`, which is the combination of a display, a resolution and a refresh
//!   rate. You can enumerate the modes available on a display with
//!   [`Display::display_mode_properties`], or create your own mode.
//!   A display can show multiple planes in a stacking fashion.
//! - Create a `Surface` object with `Surface::from_display_plane`,
//!   and pass the chosen `DisplayMode` and display plane index.

use crate::{
    cache::{OnceCache, WeakArcOnceCache},
    device::physical::PhysicalDevice,
    instance::{Instance, InstanceOwned, InstanceOwnedDebugWrapper},
    macros::vulkan_bitflags_enum,
    swapchain::SurfaceTransforms,
    Validated, ValidationError, VulkanError, VulkanObject,
};
use std::{
    hash::{Hash, Hasher},
    mem::MaybeUninit,
    ptr,
    sync::Arc,
};

/// A display device connected to a physical device.
#[derive(Debug)]
pub struct Display {
    physical_device: InstanceOwnedDebugWrapper<Arc<PhysicalDevice>>,
    handle: ash::vk::DisplayKHR,

    name: Option<String>,
    physical_dimensions: [u32; 2],
    physical_resolution: [u32; 2],
    supported_transforms: SurfaceTransforms,
    plane_reorder_possible: bool,
    persistent_content: bool,

    display_modes: WeakArcOnceCache<ash::vk::DisplayModeKHR, DisplayMode>,
}

impl Display {
    /// Creates a new `Display` from a raw object handle.
    ///
    /// # Safety
    ///
    /// - `properties` must match the properties retrieved from `physical_device`.
    #[inline]
    pub fn from_handle(
        physical_device: Arc<PhysicalDevice>,
        handle: ash::vk::DisplayKHR,
        properties: DisplayProperties,
    ) -> Arc<Self> {
        let DisplayProperties {
            name,
            physical_dimensions,
            physical_resolution,
            supported_transforms,
            plane_reorder_possible,
            persistent_content,
        } = properties;

        Arc::new(Self {
            physical_device: InstanceOwnedDebugWrapper(physical_device),
            handle,

            name,
            physical_dimensions,
            physical_resolution,
            supported_transforms,
            plane_reorder_possible,
            persistent_content,

            display_modes: WeakArcOnceCache::new(),
        })
    }

    /// Returns the physical device that this display belongs to.
    #[inline]
    pub fn physical_device(&self) -> &Arc<PhysicalDevice> {
        &self.physical_device
    }

    /// Returns the name of the display.
    #[inline]
    pub fn name(&self) -> Option<&str> {
        self.name.as_deref()
    }

    /// Returns the physical dimensions of the display, in millimeters.
    #[inline]
    pub fn physical_dimensions(&self) -> [u32; 2] {
        self.physical_dimensions
    }

    /// Returns the physical, or preferred, resolution of the display.
    #[inline]
    pub fn physical_resolution(&self) -> [u32; 2] {
        self.physical_resolution
    }

    /// Returns the transforms that are supported by the display.
    #[inline]
    pub fn supported_transforms(&self) -> SurfaceTransforms {
        self.supported_transforms
    }

    /// Returns whether planes on this display can have their z-order changed.
    #[inline]
    pub fn plane_reorder_possible(&self) -> bool {
        self.plane_reorder_possible
    }

    /// Returns whether the content of the display is buffered internally, and therefore persistent.
    #[inline]
    pub fn persistent_content(&self) -> bool {
        self.persistent_content
    }

    /// Returns the display modes that this display supports by default.
    pub fn display_mode_properties(self: &Arc<Self>) -> Result<Vec<Arc<DisplayMode>>, VulkanError> {
        let fns = self.physical_device.instance().fns();

        if self
            .instance()
            .enabled_extensions()
            .khr_get_display_properties2
        {
            let properties_vk = unsafe {
                loop {
                    let mut count = 0;
                    (fns.khr_get_display_properties2
                        .get_display_mode_properties2_khr)(
                        self.physical_device.handle(),
                        self.handle,
                        &mut count,
                        ptr::null_mut(),
                    )
                    .result()
                    .map_err(VulkanError::from)?;

                    let mut properties =
                        vec![ash::vk::DisplayModeProperties2KHR::default(); count as usize];
                    let result = (fns
                        .khr_get_display_properties2
                        .get_display_mode_properties2_khr)(
                        self.physical_device.handle(),
                        self.handle,
                        &mut count,
                        properties.as_mut_ptr(),
                    );

                    match result {
                        ash::vk::Result::SUCCESS => {
                            properties.set_len(count as usize);
                            break properties;
                        }
                        ash::vk::Result::INCOMPLETE => (),
                        err => return Err(VulkanError::from(err)),
                    }
                }
            };

            Ok(properties_vk
                .into_iter()
                .map(|properties_vk| {
                    let properties_vk = &properties_vk.display_mode_properties;
                    self.display_modes
                        .get_or_insert(properties_vk.display_mode, |&handle| {
                            DisplayMode::from_handle(
                                self.clone(),
                                handle,
                                DisplayModeCreateInfo {
                                    visible_region: [
                                        properties_vk.parameters.visible_region.width,
                                        properties_vk.parameters.visible_region.height,
                                    ],
                                    refresh_rate: properties_vk.parameters.refresh_rate,
                                    _ne: crate::NonExhaustive(()),
                                },
                            )
                        })
                })
                .collect())
        } else {
            let properties_vk = unsafe {
                loop {
                    let mut count = 0;
                    (fns.khr_display.get_display_mode_properties_khr)(
                        self.physical_device.handle(),
                        self.handle,
                        &mut count,
                        ptr::null_mut(),
                    )
                    .result()
                    .map_err(VulkanError::from)?;

                    let mut properties = Vec::with_capacity(count as usize);
                    let result = (fns.khr_display.get_display_mode_properties_khr)(
                        self.physical_device.handle(),
                        self.handle,
                        &mut count,
                        properties.as_mut_ptr(),
                    );

                    match result {
                        ash::vk::Result::SUCCESS => {
                            properties.set_len(count as usize);
                            break properties;
                        }
                        ash::vk::Result::INCOMPLETE => (),
                        err => return Err(VulkanError::from(err)),
                    }
                }
            };

            Ok(properties_vk
                .into_iter()
                .map(|properties_vk| {
                    self.display_modes
                        .get_or_insert(properties_vk.display_mode, |&handle| {
                            DisplayMode::from_handle(
                                self.clone(),
                                handle,
                                DisplayModeCreateInfo {
                                    visible_region: [
                                        properties_vk.parameters.visible_region.width,
                                        properties_vk.parameters.visible_region.height,
                                    ],
                                    refresh_rate: properties_vk.parameters.refresh_rate,
                                    _ne: crate::NonExhaustive(()),
                                },
                            )
                        })
                })
                .collect())
        }
    }
}

unsafe impl VulkanObject for Display {
    type Handle = ash::vk::DisplayKHR;

    #[inline]
    fn handle(&self) -> Self::Handle {
        self.handle
    }
}

unsafe impl InstanceOwned for Display {
    #[inline]
    fn instance(&self) -> &Arc<Instance> {
        self.physical_device.instance()
    }
}

impl PartialEq for Display {
    #[inline]
    fn eq(&self, other: &Self) -> bool {
        self.physical_device == other.physical_device && self.handle == other.handle
    }
}

impl Eq for Display {}

impl Hash for Display {
    #[inline]
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.physical_device.hash(state);
        self.handle.hash(state);
    }
}

/// The properties of a display.
#[derive(Clone, Debug)]
#[non_exhaustive]
pub struct DisplayProperties {
    /// The name of the display.
    pub name: Option<String>,

    /// The physical dimensions of the display, in millimeters.
    pub physical_dimensions: [u32; 2],

    /// The physical, or preferred, resolution of the display.
    pub physical_resolution: [u32; 2],

    /// The transforms that are supported by the display.
    pub supported_transforms: SurfaceTransforms,

    /// Whether planes on this display can have their z-order changed.
    pub plane_reorder_possible: bool,

    /// Whether the content of the display is buffered internally, and therefore persistent.
    pub persistent_content: bool,
}

/// Represents a mode on a specific display.
///
/// A display mode describes a supported display resolution and refresh rate.
#[derive(Debug)]
pub struct DisplayMode {
    display: InstanceOwnedDebugWrapper<Arc<Display>>,
    handle: ash::vk::DisplayModeKHR,

    visible_region: [u32; 2],
    refresh_rate: u32,

    display_plane_capabilities: OnceCache<u32, DisplayPlaneCapabilities>,
}

impl DisplayMode {
    /// Creates a custom display mode.
    #[inline]
    pub fn new(
        display: Arc<Display>,
        create_info: DisplayModeCreateInfo,
    ) -> Result<Arc<Self>, Validated<VulkanError>> {
        Self::validate_new(&display, &create_info)?;

        unsafe { Ok(Self::new_unchecked(display, create_info)?) }
    }

    fn validate_new(
        display: &Display,
        create_info: &DisplayModeCreateInfo,
    ) -> Result<(), Box<ValidationError>> {
        // VUID-vkCreateDisplayModeKHR-pCreateInfo-parameter
        create_info
            .validate(&display.physical_device)
            .map_err(|err| err.add_context("create_info"))?;

        Ok(())
    }

    #[cfg_attr(not(feature = "document_unchecked"), doc(hidden))]
    pub unsafe fn new_unchecked(
        display: Arc<Display>,
        create_info: DisplayModeCreateInfo,
    ) -> Result<Arc<Self>, VulkanError> {
        let &DisplayModeCreateInfo {
            visible_region,
            refresh_rate,
            _ne: _,
        } = &create_info;

        let physical_device = display.physical_device.clone();

        let create_info_vk = ash::vk::DisplayModeCreateInfoKHR {
            flags: ash::vk::DisplayModeCreateFlagsKHR::empty(),
            parameters: ash::vk::DisplayModeParametersKHR {
                visible_region: ash::vk::Extent2D {
                    width: visible_region[0],
                    height: visible_region[1],
                },
                refresh_rate,
            },
            ..Default::default()
        };

        let handle = {
            let fns = physical_device.instance().fns();
            let mut output = MaybeUninit::uninit();
            (fns.khr_display.create_display_mode_khr)(
                physical_device.handle(),
                display.handle,
                &create_info_vk,
                ptr::null(),
                output.as_mut_ptr(),
            )
            .result()
            .map_err(VulkanError::from)?;
            output.assume_init()
        };

        Ok(display.display_modes.get_or_insert(handle, |&handle| {
            Self::from_handle(display.clone(), handle, create_info)
        }))
    }

    /// Creates a new `DisplayMode` from a raw object handle.
    ///
    /// # Safety
    ///
    /// - `handle` must be a valid Vulkan object handle created from `display`.
    /// - `create_info` must match the info used to create the object, or retrieved from `display`.
    #[inline]
    pub fn from_handle(
        display: Arc<Display>,
        handle: ash::vk::DisplayModeKHR,
        create_info: DisplayModeCreateInfo,
    ) -> Arc<Self> {
        let DisplayModeCreateInfo {
            visible_region,
            refresh_rate,
            _ne: _,
        } = create_info;

        Arc::new(Self {
            display: InstanceOwnedDebugWrapper(display),
            handle,

            visible_region,
            refresh_rate,

            display_plane_capabilities: OnceCache::new(),
        })
    }

    /// Returns the display that this display mode belongs to.
    #[inline]
    pub fn display(&self) -> &Arc<Display> {
        &self.display
    }

    /// Returns the extent of the visible region.
    #[inline]
    pub fn visible_region(&self) -> [u32; 2] {
        self.visible_region
    }

    /// Returns the refresh rate in millihertz (i.e. `60_000` is 60 times per second).
    #[inline]
    pub fn refresh_rate(&self) -> u32 {
        self.refresh_rate
    }

    /// Returns the capabilities of a display plane, when used with this display mode.
    #[inline]
    pub fn display_plane_capabilities(
        &self,
        plane_index: u32,
    ) -> Result<DisplayPlaneCapabilities, Validated<VulkanError>> {
        self.validate_display_plane_capabilities(plane_index)?;

        unsafe { Ok(self.display_plane_capabilities_unchecked(plane_index)?) }
    }

    fn validate_display_plane_capabilities(
        &self,
        plane_index: u32,
    ) -> Result<(), Box<ValidationError>> {
        let display_plane_properties_raw = unsafe {
            self.display
                .physical_device
                .display_plane_properties_raw()
                .map_err(|_err| {
                    Box::new(ValidationError {
                        problem: "`PhysicalDevice::display_plane_properties` \
                        returned an error"
                            .into(),
                        ..Default::default()
                    })
                })?
        };

        if plane_index as usize >= display_plane_properties_raw.len() {
            return Err(Box::new(ValidationError {
                problem: "`plane_index` is not less than the number of display planes on the \
                    physical device"
                    .into(),
                ..Default::default()
            }));
        }

        Ok(())
    }

    #[cfg_attr(not(feature = "document_unchecked"), doc(hidden))]
    pub unsafe fn display_plane_capabilities_unchecked(
        &self,
        plane_index: u32,
    ) -> Result<DisplayPlaneCapabilities, VulkanError> {
        self.display_plane_capabilities
            .get_or_try_insert(plane_index, |&plane_index| unsafe {
                let fns = self.display.physical_device.instance().fns();

                let mut capabilities_vk = ash::vk::DisplayPlaneCapabilities2KHR::default();

                if self
                    .instance()
                    .enabled_extensions()
                    .khr_get_display_properties2
                {
                    let info_vk = ash::vk::DisplayPlaneInfo2KHR {
                        mode: self.handle,
                        plane_index,
                        ..Default::default()
                    };

                    (fns.khr_get_display_properties2
                        .get_display_plane_capabilities2_khr)(
                        self.display.physical_device.handle(),
                        &info_vk,
                        &mut capabilities_vk,
                    )
                    .result()
                    .map_err(VulkanError::from)?;
                } else {
                    (fns.khr_display.get_display_plane_capabilities_khr)(
                        self.display.physical_device.handle(),
                        self.handle,
                        plane_index,
                        &mut capabilities_vk.capabilities,
                    )
                    .result()
                    .map_err(VulkanError::from)?;
                }

                Ok(DisplayPlaneCapabilities {
                    supported_alpha: capabilities_vk.capabilities.supported_alpha.into(),
                    min_src_position: [
                        capabilities_vk.capabilities.min_src_position.x as u32,
                        capabilities_vk.capabilities.min_src_position.y as u32,
                    ],
                    max_src_position: [
                        capabilities_vk.capabilities.max_src_position.x as u32,
                        capabilities_vk.capabilities.max_src_position.y as u32,
                    ],
                    min_src_extent: [
                        capabilities_vk.capabilities.min_src_extent.width,
                        capabilities_vk.capabilities.min_src_extent.height,
                    ],
                    max_src_extent: [
                        capabilities_vk.capabilities.max_src_extent.width,
                        capabilities_vk.capabilities.max_src_extent.height,
                    ],
                    min_dst_position: [
                        capabilities_vk.capabilities.min_dst_position.x as u32,
                        capabilities_vk.capabilities.min_dst_position.y as u32,
                    ],
                    max_dst_position: [
                        capabilities_vk.capabilities.max_dst_position.x,
                        capabilities_vk.capabilities.max_dst_position.y,
                    ],
                    min_dst_extent: [
                        capabilities_vk.capabilities.min_dst_extent.width,
                        capabilities_vk.capabilities.min_dst_extent.height,
                    ],
                    max_dst_extent: [
                        capabilities_vk.capabilities.max_dst_extent.width,
                        capabilities_vk.capabilities.max_dst_extent.height,
                    ],
                })
            })
    }
}

unsafe impl VulkanObject for DisplayMode {
    type Handle = ash::vk::DisplayModeKHR;

    #[inline]
    fn handle(&self) -> Self::Handle {
        self.handle
    }
}

unsafe impl InstanceOwned for DisplayMode {
    #[inline]
    fn instance(&self) -> &Arc<Instance> {
        self.display.instance()
    }
}

impl PartialEq for DisplayMode {
    #[inline]
    fn eq(&self, other: &Self) -> bool {
        self.display == other.display && self.handle == other.handle
    }
}

impl Eq for DisplayMode {}

impl Hash for DisplayMode {
    #[inline]
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.display.hash(state);
        self.handle.hash(state);
    }
}

/// Parameters to create a new `DisplayMode`.
#[derive(Clone, Debug)]
pub struct DisplayModeCreateInfo {
    /// The extent of the visible region. Neither coordinate may be zero.
    ///
    /// The default value is `[0; 2]`, which must be overridden.
    pub visible_region: [u32; 2],

    /// The refresh rate in millihertz (i.e. `60_000` is 60 times per second).
    /// This must not be zero.
    ///
    /// The default value is 0, which must be overridden.
    pub refresh_rate: u32,

    pub _ne: crate::NonExhaustive,
}

impl Default for DisplayModeCreateInfo {
    #[inline]
    fn default() -> Self {
        Self {
            visible_region: [0; 2],
            refresh_rate: 0,
            _ne: crate::NonExhaustive(()),
        }
    }
}

impl DisplayModeCreateInfo {
    pub(crate) fn validate(
        &self,
        _physical_device: &PhysicalDevice,
    ) -> Result<(), Box<ValidationError>> {
        let &Self {
            visible_region,
            refresh_rate,
            _ne: _,
        } = self;

        if visible_region[0] == 0 {
            return Err(Box::new(ValidationError {
                context: "visible_region[0]".into(),
                problem: "is zero".into(),
                vuids: &["VUID-VkDisplayModeParametersKHR-width-01990"],
                ..Default::default()
            }));
        }

        if visible_region[1] == 0 {
            return Err(Box::new(ValidationError {
                context: "visible_region[1]".into(),
                problem: "is zero".into(),
                vuids: &["VUID-VkDisplayModeParametersKHR-height-01991"],
                ..Default::default()
            }));
        }

        if refresh_rate == 0 {
            return Err(Box::new(ValidationError {
                context: "refresh_rate".into(),
                problem: "is zero".into(),
                vuids: &["VUID-VkDisplayModeParametersKHR-refreshRate-01992"],
                ..Default::default()
            }));
        }

        Ok(())
    }
}

/// The properties of a display plane.
#[derive(Clone, Debug)]
#[non_exhaustive]
pub struct DisplayPlaneProperties {
    /// The display that the display plane is currently associated with.
    pub current_display: Option<Arc<Display>>,

    /// The current z-order of the plane. This will always be less than the total number of planes.
    pub current_stack_index: u32,
}

#[derive(Clone, Debug)]
pub(crate) struct DisplayPlanePropertiesRaw {
    pub(crate) current_display: Option<ash::vk::DisplayKHR>,
    pub(crate) current_stack_index: u32,
}

/// The capabilities of a display plane.
#[derive(Clone, Debug)]
#[non_exhaustive]
pub struct DisplayPlaneCapabilities {
    /// The supported alpha blending modes.
    pub supported_alpha: DisplayPlaneAlphaFlags,

    /// The minimum supported source rectangle offset.
    pub min_src_position: [u32; 2],

    /// The maximum supported source rectangle offset.
    pub max_src_position: [u32; 2],

    /// The minimum supported source rectangle size.
    pub min_src_extent: [u32; 2],

    /// The maximum supported source rectangle size.
    pub max_src_extent: [u32; 2],

    /// The minimum supported destination rectangle offset.
    pub min_dst_position: [u32; 2],

    /// The maximum supported destination rectangle offset.
    pub max_dst_position: [i32; 2],

    /// The minimum supported destination rectangle size.
    pub min_dst_extent: [u32; 2],

    /// The maximum supported destination rectangle size.
    pub max_dst_extent: [u32; 2],
}

vulkan_bitflags_enum! {
    #[non_exhaustive]

    /// A set of [`DisplayPlaneAlpha`] values.
    DisplayPlaneAlphaFlags,

    /// The alpha blending mode to use for a display mode.
    DisplayPlaneAlpha,

    = DisplayPlaneAlphaFlagsKHR(u32);

    /// The source image is treated as opaque.
    OPAQUE, Opaque = OPAQUE,

    /// Use a single global alpha value that will be used for all pixels in the source image.
    GLOBAL, Global = GLOBAL,

    /// Use the alpha component of each pixel in the source image.
    PER_PIXEL, PerPixel = PER_PIXEL,

    /// Use the alpha component of each pixel in the source image,
    /// but treat the other components as having already been multiplied by the alpha component.
    PER_PIXEL_PREMULTIPLIED, PerPixelPremultiplied = PER_PIXEL_PREMULTIPLIED,
}