// 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.

//! Gather information about rendering, held in query pools.
//!
//! In Vulkan, queries are not created individually. Instead you manipulate **query pools**, which
//! represent a collection of queries. Whenever you use a query, you have to specify both the query
//! pool and the slot id within that query pool.

use crate::{
    buffer::BufferContents,
    device::{Device, DeviceOwned},
    instance::InstanceOwnedDebugWrapper,
    macros::{impl_id_counter, vulkan_bitflags},
    DeviceSize, Requires, RequiresAllOf, RequiresOneOf, Validated, ValidationError, VulkanError,
    VulkanObject,
};
use std::{
    ffi::c_void,
    mem::{size_of_val, MaybeUninit},
    num::NonZeroU64,
    ops::Range,
    ptr,
    sync::Arc,
};

/// A collection of one or more queries of a particular type.
#[derive(Debug)]
pub struct QueryPool {
    handle: ash::vk::QueryPool,
    device: InstanceOwnedDebugWrapper<Arc<Device>>,
    id: NonZeroU64,

    query_type: QueryType,
    query_count: u32,
}

impl QueryPool {
    /// Creates a new `QueryPool`.
    #[inline]
    pub fn new(
        device: Arc<Device>,
        create_info: QueryPoolCreateInfo,
    ) -> Result<Arc<QueryPool>, Validated<VulkanError>> {
        Self::validate_new(&device, &create_info)?;

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

    #[cfg_attr(not(feature = "document_unchecked"), doc(hidden))]
    pub unsafe fn new_unchecked(
        device: Arc<Device>,
        create_info: QueryPoolCreateInfo,
    ) -> Result<Arc<QueryPool>, VulkanError> {
        let &QueryPoolCreateInfo {
            ref query_type,
            query_count,
            _ne: _,
        } = &create_info;

        let pipeline_statistics = if let &QueryType::PipelineStatistics(flags) = query_type {
            flags.into()
        } else {
            ash::vk::QueryPipelineStatisticFlags::empty()
        };

        let create_info_vk = ash::vk::QueryPoolCreateInfo {
            flags: ash::vk::QueryPoolCreateFlags::empty(),
            query_type: query_type.into(),
            query_count,
            pipeline_statistics,
            ..Default::default()
        };

        let handle = unsafe {
            let fns = device.fns();
            let mut output = MaybeUninit::uninit();
            (fns.v1_0.create_query_pool)(
                device.handle(),
                &create_info_vk,
                ptr::null(),
                output.as_mut_ptr(),
            )
            .result()
            .map_err(VulkanError::from)?;
            output.assume_init()
        };

        Ok(Self::from_handle(device, handle, create_info))
    }

    fn validate_new(
        device: &Device,
        create_info: &QueryPoolCreateInfo,
    ) -> Result<(), Box<ValidationError>> {
        create_info
            .validate(device)
            .map_err(|err| err.add_context("create_info"))?;

        Ok(())
    }

    /// Creates a new `QueryPool` from a raw object handle.
    ///
    /// # Safety
    ///
    /// - `handle` must be a valid Vulkan object handle created from `device`.
    /// - `create_info` must match the info used to create the object.
    #[inline]
    pub unsafe fn from_handle(
        device: Arc<Device>,
        handle: ash::vk::QueryPool,
        create_info: QueryPoolCreateInfo,
    ) -> Arc<QueryPool> {
        let QueryPoolCreateInfo {
            query_type,
            query_count,
            _ne: _,
        } = create_info;

        Arc::new(QueryPool {
            handle,
            device: InstanceOwnedDebugWrapper(device),
            id: Self::next_id(),
            query_type,
            query_count,
        })
    }

    /// Returns the query type of the pool.
    #[inline]
    pub fn query_type(&self) -> &QueryType {
        &self.query_type
    }

    /// Returns the number of query slots of this query pool.
    #[inline]
    pub fn query_count(&self) -> u32 {
        self.query_count
    }

    /// Copies the results of a range of queries to a buffer on the CPU.
    ///
    /// [`self.ty().result_len()`] will be written for each query in the range, plus 1 extra
    /// element per query if [`WITH_AVAILABILITY`] is enabled. The provided buffer must be large
    /// enough to hold the data.
    ///
    /// `true` is returned if every result was available and written to the buffer. `false`
    /// is returned if some results were not yet available; these will not be written to the buffer.
    ///
    /// See also [`copy_query_pool_results`].
    ///
    /// [`self.ty().result_len()`]: QueryType::result_len
    /// [`WITH_AVAILABILITY`]: QueryResultFlags::WITH_AVAILABILITY
    /// [`copy_query_pool_results`]: crate::command_buffer::AutoCommandBufferBuilder::copy_query_pool_results
    #[inline]
    pub fn get_results<T>(
        &self,
        range: Range<u32>,
        destination: &mut [T],
        flags: QueryResultFlags,
    ) -> Result<bool, Validated<VulkanError>>
    where
        T: QueryResultElement,
    {
        self.validate_get_results(range.clone(), destination, flags)?;

        unsafe { Ok(self.get_results_unchecked(range, destination, flags)?) }
    }

    fn validate_get_results<T>(
        &self,
        range: Range<u32>,
        destination: &[T],
        flags: QueryResultFlags,
    ) -> Result<(), Box<ValidationError>>
    where
        T: QueryResultElement,
    {
        flags.validate_device(&self.device).map_err(|err| {
            err.add_context("flags")
                .set_vuids(&["VUID-vkGetQueryPoolResults-flags-parameter"])
        })?;

        if destination.is_empty() {
            return Err(Box::new(ValidationError {
                context: "destination".into(),
                problem: "is empty".into(),
                vuids: &["VUID-vkGetQueryPoolResults-dataSize-arraylength"],
                ..Default::default()
            }));
        }

        if range.is_empty() {
            return Err(Box::new(ValidationError {
                context: "range".into(),
                problem: "is empty".into(),
                // vuids?
                ..Default::default()
            }));
        }

        if range.end > self.query_count {
            return Err(Box::new(ValidationError {
                problem: "`range.end` is greater than `self.query_count`".into(),
                vuids: &[
                    "VUID-vkGetQueryPoolResults-firstQuery-00813",
                    "VUID-vkGetQueryPoolResults-firstQuery-00816",
                ],
                ..Default::default()
            }));
        }

        // VUID-vkGetQueryPoolResults-flags-02828
        // VUID-vkGetQueryPoolResults-flags-00815
        // Ensured by the Rust alignment of T.

        // VUID-vkGetQueryPoolResults-stride-08993
        // Ensured by choosing the stride ourselves.

        let per_query_len = self.query_type.result_len()
            + flags.intersects(QueryResultFlags::WITH_AVAILABILITY) as DeviceSize;
        let required_len = per_query_len * range.len() as DeviceSize;

        if (destination.len() as DeviceSize) < required_len {
            return Err(Box::new(ValidationError {
                context: "destination.len()".into(),
                problem: "is less than the number of elements required for the query type, and \
                    the provided range and flags"
                    .into(),
                vuids: &["VUID-vkGetQueryPoolResults-dataSize-00817"],
                ..Default::default()
            }));
        }

        match &self.query_type {
            QueryType::Timestamp => {
                if flags.intersects(QueryResultFlags::PARTIAL) {
                    return Err(Box::new(ValidationError {
                        problem: "`self.query_type()` is `QueryType::Timestamp`, but \
                            `flags` contains `QueryResultFlags::PARTIAL`"
                            .into(),
                        vuids: &["VUID-vkGetQueryPoolResults-queryType-00818"],
                        ..Default::default()
                    }));
                }
            }
            QueryType::Occlusion
            | QueryType::PipelineStatistics(_)
            | QueryType::AccelerationStructureCompactedSize
            | QueryType::AccelerationStructureSerializationSize
            | QueryType::AccelerationStructureSerializationBottomLevelPointers
            | QueryType::AccelerationStructureSize => (),
        }

        Ok(())
    }

    #[cfg_attr(not(feature = "document_unchecked"), doc(hidden))]
    pub unsafe fn get_results_unchecked<T>(
        &self,
        range: Range<u32>,
        destination: &mut [T],
        flags: QueryResultFlags,
    ) -> Result<bool, VulkanError>
    where
        T: QueryResultElement,
    {
        let per_query_len = self.query_type.result_len()
            + flags.intersects(QueryResultFlags::WITH_AVAILABILITY) as DeviceSize;
        let stride = per_query_len * std::mem::size_of::<T>() as DeviceSize;

        let result = unsafe {
            let fns = self.device.fns();
            (fns.v1_0.get_query_pool_results)(
                self.device.handle(),
                self.handle(),
                range.start,
                range.len() as u32,
                size_of_val(destination),
                destination.as_mut_ptr() as *mut c_void,
                stride,
                ash::vk::QueryResultFlags::from(flags) | T::FLAG,
            )
        };

        match result {
            ash::vk::Result::SUCCESS => Ok(true),
            ash::vk::Result::NOT_READY => Ok(false),
            err => Err(VulkanError::from(err)),
        }
    }
}

impl Drop for QueryPool {
    #[inline]
    fn drop(&mut self) {
        unsafe {
            let fns = self.device.fns();
            (fns.v1_0.destroy_query_pool)(self.device.handle(), self.handle, ptr::null());
        }
    }
}

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

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

unsafe impl DeviceOwned for QueryPool {
    #[inline]
    fn device(&self) -> &Arc<Device> {
        &self.device
    }
}

impl_id_counter!(QueryPool);

/// Parameters to create a new `QueryPool`.
#[derive(Clone, Debug)]
pub struct QueryPoolCreateInfo {
    /// The type of query that the pool should be for.
    ///
    /// There is no default value.
    pub query_type: QueryType,

    /// The number of queries to create in the pool.
    ///
    /// The default value is `0`, which must be overridden.
    pub query_count: u32,

    pub _ne: crate::NonExhaustive,
}

impl QueryPoolCreateInfo {
    /// Returns a `QueryPoolCreateInfo` with the specified `query_type`.
    #[inline]
    pub fn query_type(query_type: QueryType) -> Self {
        Self {
            query_type,
            query_count: 0,
            _ne: crate::NonExhaustive(()),
        }
    }

    pub(crate) fn validate(&self, device: &Device) -> Result<(), Box<ValidationError>> {
        let &Self {
            ref query_type,
            query_count,
            _ne: _,
        } = self;

        query_type.validate_device(device).map_err(|err| {
            err.add_context("query_type")
                .set_vuids(&["VUID-VkQueryPoolCreateInfo-queryType-parameter"])
        })?;

        match query_type {
            QueryType::PipelineStatistics(flags) => {
                if !device.enabled_features().pipeline_statistics_query {
                    return Err(Box::new(ValidationError {
                        context: "query_type".into(),
                        problem: "is `QueryType::PipelineStatistics`".into(),
                        requires_one_of: RequiresOneOf(&[RequiresAllOf(&[Requires::Feature(
                            "pipeline_statistics_query",
                        )])]),
                        vuids: &["VUID-VkQueryPoolCreateInfo-queryType-00791"],
                    }));
                }

                flags.validate_device(device).map_err(|err| {
                    err.add_context("query_type.flags")
                        .set_vuids(&["VUID-VkQueryPoolCreateInfo-queryType-00792"])
                })?;
            }
            QueryType::Occlusion
            | QueryType::Timestamp
            | QueryType::AccelerationStructureCompactedSize
            | QueryType::AccelerationStructureSerializationSize
            | QueryType::AccelerationStructureSerializationBottomLevelPointers
            | QueryType::AccelerationStructureSize => (),
        };

        if query_count == 0 {
            return Err(Box::new(ValidationError {
                context: "query_count".into(),
                problem: "is 0".into(),
                vuids: &["VUID-VkQueryPoolCreateInfo-queryCount-02763"],
                ..Default::default()
            }));
        }

        Ok(())
    }
}

/// The type of query that a query pool should perform.
#[derive(Clone, Debug)]
#[repr(i32)]
#[non_exhaustive]
pub enum QueryType {
    /// Tracks the number of samples that pass per-fragment tests (e.g. the depth test).
    ///
    /// Used with the [`begin_query`] and [`end_query`] commands.
    ///
    /// [`begin_query`]: crate::command_buffer::AutoCommandBufferBuilder::begin_query
    /// [`end_query`]: crate::command_buffer::AutoCommandBufferBuilder::end_query
    Occlusion = ash::vk::QueryType::OCCLUSION.as_raw(),

    /// Tracks statistics on pipeline invocations and their input data.
    ///
    /// Used with the [`begin_query`] and [`end_query`] commands.
    ///
    /// [`begin_query`]: crate::command_buffer::AutoCommandBufferBuilder::begin_query
    /// [`end_query`]: crate::command_buffer::AutoCommandBufferBuilder::end_query
    PipelineStatistics(QueryPipelineStatisticFlags) =
        ash::vk::QueryType::PIPELINE_STATISTICS.as_raw(),

    /// Writes timestamps at chosen points in a command buffer.
    ///
    /// Used with the [`write_timestamp`] command.
    ///
    /// [`write_timestamp`]: crate::command_buffer::AutoCommandBufferBuilder::write_timestamp
    Timestamp = ash::vk::QueryType::TIMESTAMP.as_raw(),

    /// Queries the size of data resulting from a
    /// [`CopyAccelerationStructureMode::Compact`] operation.
    ///
    /// Used with the [`write_acceleration_structures_properties`] command.
    ///
    /// [`CopyAccelerationStructureMode::Compact`]: crate::acceleration_structure::CopyAccelerationStructureMode::Compact
    /// [`write_acceleration_structures_properties`]: crate::command_buffer::AutoCommandBufferBuilder::write_acceleration_structures_properties
    AccelerationStructureCompactedSize =
        ash::vk::QueryType::ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR.as_raw(),

    /// Queries the size of data resulting from a
    /// [`CopyAccelerationStructureMode::Serialize`] operation.
    ///
    /// Used with the [`write_acceleration_structures_properties`] command.
    ///
    /// [`CopyAccelerationStructureMode::Serialize`]: crate::acceleration_structure::CopyAccelerationStructureMode::Serialize
    /// [`write_acceleration_structures_properties`]: crate::command_buffer::AutoCommandBufferBuilder::write_acceleration_structures_properties
    AccelerationStructureSerializationSize =
        ash::vk::QueryType::ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR.as_raw(),

    /// For a top-level acceleration structure, queries the number of bottom-level acceleration
    /// structure handles that will be written during a
    /// [`CopyAccelerationStructureMode::Serialize`] operation.
    ///
    /// Used with the [`write_acceleration_structures_properties`] command.
    ///
    /// [`CopyAccelerationStructureMode::Serialize`]: crate::acceleration_structure::CopyAccelerationStructureMode::Serialize
    /// [`write_acceleration_structures_properties`]: crate::command_buffer::AutoCommandBufferBuilder::write_acceleration_structures_properties
    AccelerationStructureSerializationBottomLevelPointers =
        ash::vk::QueryType::ACCELERATION_STRUCTURE_SERIALIZATION_BOTTOM_LEVEL_POINTERS_KHR.as_raw(),

    /// Queries the total size of an acceleration structure.
    ///
    /// Used with the [`write_acceleration_structures_properties`] command.
    ///
    /// [`write_acceleration_structures_properties`]: crate::command_buffer::AutoCommandBufferBuilder::write_acceleration_structures_properties
    AccelerationStructureSize = ash::vk::QueryType::ACCELERATION_STRUCTURE_SIZE_KHR.as_raw(),
}

impl QueryType {
    /// Returns the number of [`QueryResultElement`]s that are needed to hold the result of a
    /// single query of this type.
    ///
    /// - For [`Occlusion`] and [`Timestamp`] queries, this returns 1.
    /// - For [`PipelineStatistics`] queries, this returns the number of statistics flags enabled.
    ///
    /// If the results are retrieved with [`WITH_AVAILABILITY`] enabled, then an additional element
    /// is required per query.
    ///
    /// [`Occlusion`]: QueryType::Occlusion
    /// [`Timestamp`]: QueryType::Timestamp
    /// [`PipelineStatistics`]: QueryType::PipelineStatistics
    /// [`WITH_AVAILABILITY`]: QueryResultFlags::WITH_AVAILABILITY
    #[inline]
    pub const fn result_len(&self) -> DeviceSize {
        match self {
            Self::Occlusion
            | Self::Timestamp
            | Self::AccelerationStructureCompactedSize
            | Self::AccelerationStructureSerializationSize
            | Self::AccelerationStructureSerializationBottomLevelPointers
            | Self::AccelerationStructureSize => 1,
            Self::PipelineStatistics(flags) => flags.count() as DeviceSize,
        }
    }

    pub(crate) fn validate_device(&self, device: &Device) -> Result<(), Box<ValidationError>> {
        match self {
            QueryType::Occlusion => (),
            QueryType::PipelineStatistics(_) => (),
            QueryType::Timestamp => (),
            QueryType::AccelerationStructureCompactedSize => {
                if !device.enabled_extensions().khr_acceleration_structure {
                    return Err(Box::new(ValidationError {
                        problem: "is `QueryType::AccelerationStructureCompactedSize`".into(),
                        requires_one_of: RequiresOneOf(&[RequiresAllOf(&[
                            Requires::DeviceExtension("khr_acceleration_structure"),
                        ])]),
                        ..Default::default()
                    }));
                }
            }
            QueryType::AccelerationStructureSerializationSize => {
                if !device.enabled_extensions().khr_acceleration_structure {
                    return Err(Box::new(ValidationError {
                        problem: "is `QueryType::AccelerationStructureSerializationSize`".into(),
                        requires_one_of: RequiresOneOf(&[RequiresAllOf(&[
                            Requires::DeviceExtension("khr_acceleration_structure"),
                        ])]),
                        ..Default::default()
                    }));
                }
            }
            QueryType::AccelerationStructureSerializationBottomLevelPointers => {
                if !device.enabled_extensions().khr_ray_tracing_maintenance1 {
                    return Err(Box::new(ValidationError {
                        problem:
                            "is `QueryType::AccelerationStructureSerializationBottomLevelPointers`"
                                .into(),
                        requires_one_of: RequiresOneOf(&[RequiresAllOf(&[
                            Requires::DeviceExtension("khr_ray_tracing_maintenance1"),
                        ])]),
                        ..Default::default()
                    }));
                }
            }
            QueryType::AccelerationStructureSize => {
                if !device.enabled_extensions().khr_ray_tracing_maintenance1 {
                    return Err(Box::new(ValidationError {
                        problem: "is `QueryType::AccelerationStructureSize`".into(),
                        requires_one_of: RequiresOneOf(&[RequiresAllOf(&[
                            Requires::DeviceExtension("khr_ray_tracing_maintenance1"),
                        ])]),
                        ..Default::default()
                    }));
                }
            }
        }

        Ok(())
    }
}

impl From<&QueryType> for ash::vk::QueryType {
    #[inline]
    fn from(value: &QueryType) -> Self {
        match value {
            QueryType::Occlusion => ash::vk::QueryType::OCCLUSION,
            QueryType::PipelineStatistics(_) => ash::vk::QueryType::PIPELINE_STATISTICS,
            QueryType::Timestamp => ash::vk::QueryType::TIMESTAMP,
            QueryType::AccelerationStructureCompactedSize => {
                ash::vk::QueryType::ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR
            }
            QueryType::AccelerationStructureSerializationSize => {
                ash::vk::QueryType::ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR
            }
            QueryType::AccelerationStructureSerializationBottomLevelPointers => {
                ash::vk::QueryType::ACCELERATION_STRUCTURE_SERIALIZATION_BOTTOM_LEVEL_POINTERS_KHR
            }
            QueryType::AccelerationStructureSize => {
                ash::vk::QueryType::ACCELERATION_STRUCTURE_SIZE_KHR
            }
        }
    }
}

vulkan_bitflags! {
    #[non_exhaustive]

    /// Flags that control how a query is to be executed.
    QueryControlFlags = QueryControlFlags(u32);

    /// For occlusion queries, specifies that the result must reflect the exact number of
    /// tests passed. If not enabled, the query may return a result of 1 even if more fragments
    /// passed the test.
    PRECISE = PRECISE,
}

vulkan_bitflags! {
    #[non_exhaustive]

    /// For pipeline statistics queries, the statistics that should be gathered.
    QueryPipelineStatisticFlags impl {
        /// Returns `true` if `self` contains any flags referring to compute operations.
        #[inline]
        pub const fn is_compute(self) -> bool {
            self.intersects(QueryPipelineStatisticFlags::COMPUTE_SHADER_INVOCATIONS)
        }

        /// Returns `true` if `self` contains any flags referring to graphics operations.
        #[inline]
        pub const fn is_graphics(self) -> bool {
            self.intersects(
                (QueryPipelineStatisticFlags::INPUT_ASSEMBLY_VERTICES)
                    .union(QueryPipelineStatisticFlags::INPUT_ASSEMBLY_PRIMITIVES)
                    .union(QueryPipelineStatisticFlags::VERTEX_SHADER_INVOCATIONS)
                    .union(QueryPipelineStatisticFlags::GEOMETRY_SHADER_INVOCATIONS)
                    .union(QueryPipelineStatisticFlags::GEOMETRY_SHADER_PRIMITIVES)
                    .union(QueryPipelineStatisticFlags::CLIPPING_INVOCATIONS)
                    .union(QueryPipelineStatisticFlags::CLIPPING_PRIMITIVES)
                    .union(QueryPipelineStatisticFlags::FRAGMENT_SHADER_INVOCATIONS)
                    .union(QueryPipelineStatisticFlags::TESSELLATION_CONTROL_SHADER_PATCHES)
                    .union(QueryPipelineStatisticFlags::TESSELLATION_EVALUATION_SHADER_INVOCATIONS),
            )
        }
    }
    = QueryPipelineStatisticFlags(u32);

    /// Count the number of vertices processed by the input assembly.
    INPUT_ASSEMBLY_VERTICES = INPUT_ASSEMBLY_VERTICES,

    /// Count the number of primitives processed by the input assembly.
    INPUT_ASSEMBLY_PRIMITIVES = INPUT_ASSEMBLY_PRIMITIVES,

    /// Count the number of times a vertex shader is invoked.
    VERTEX_SHADER_INVOCATIONS = VERTEX_SHADER_INVOCATIONS,

    /// Count the number of times a geometry shader is invoked.
    GEOMETRY_SHADER_INVOCATIONS = GEOMETRY_SHADER_INVOCATIONS,

    /// Count the number of primitives generated by geometry shaders.
    GEOMETRY_SHADER_PRIMITIVES = GEOMETRY_SHADER_PRIMITIVES,

    /// Count the number of times the clipping stage is invoked on a primitive.
    CLIPPING_INVOCATIONS = CLIPPING_INVOCATIONS,

    /// Count the number of primitives that are output by the clipping stage.
    CLIPPING_PRIMITIVES = CLIPPING_PRIMITIVES,

    /// Count the number of times a fragment shader is invoked.
    FRAGMENT_SHADER_INVOCATIONS = FRAGMENT_SHADER_INVOCATIONS,

    /// Count the number of patches processed by a tessellation control shader.
    TESSELLATION_CONTROL_SHADER_PATCHES = TESSELLATION_CONTROL_SHADER_PATCHES,

    /// Count the number of times a tessellation evaluation shader is invoked.
    TESSELLATION_EVALUATION_SHADER_INVOCATIONS = TESSELLATION_EVALUATION_SHADER_INVOCATIONS,

    /// Count the number of times a compute shader is invoked.
    COMPUTE_SHADER_INVOCATIONS = COMPUTE_SHADER_INVOCATIONS,

    /* TODO: enable
    // TODO: document
    TASK_SHADER_INVOCATIONS = TASK_SHADER_INVOCATIONS_NV
    RequiresOneOf([
        RequiresAllOf([DeviceExtension(nv_mesh_shader)]),
    ]),*/

    /* TODO: enable
    // TODO: document
    MESH_SHADER_INVOCATIONS = MESH_SHADER_INVOCATIONS_NV
    RequiresOneOf([
        RequiresAllOf([DeviceExtension(nv_mesh_shader)]),
    ]),*/
}

/// A trait for elements of buffers that can be used as a destination for query results.
///
/// # Safety
/// This is implemented for `u32` and `u64`. Unless you really know what you're doing, you should
/// not implement this trait for any other type.
pub unsafe trait QueryResultElement: BufferContents + Sized {
    const FLAG: ash::vk::QueryResultFlags;
}

unsafe impl QueryResultElement for u32 {
    const FLAG: ash::vk::QueryResultFlags = ash::vk::QueryResultFlags::empty();
}

unsafe impl QueryResultElement for u64 {
    const FLAG: ash::vk::QueryResultFlags = ash::vk::QueryResultFlags::TYPE_64;
}

vulkan_bitflags! {
    #[non_exhaustive]

    /// Flags to control how the results of a query should be retrieved.
    ///
    /// `VK_QUERY_RESULT_64_BIT` is not included, as it is determined automatically via the
    /// [`QueryResultElement`] trait.
    QueryResultFlags = QueryResultFlags(u32);

    /// Wait for the results to become available before writing the results.
    WAIT = WAIT,

    /// Write an additional element to the end of each query's results, indicating the availability
    /// of the results:
    /// - Nonzero: The results are available, and have been written to the element(s) preceding.
    /// - Zero: The results are not yet available, and have not been written.
    WITH_AVAILABILITY = WITH_AVAILABILITY,

    /// Allow writing partial results to the buffer, instead of waiting until they are fully
    /// available.
    PARTIAL = PARTIAL,

    /* TODO: enable
    // TODO: document
    WITH_STATUS = WITH_STATUS_KHR
    RequiresOneOf([
        RequiresAllOf([DeviceExtension(khr_video_queue)]),
    ]),*/
}

#[cfg(test)]
mod tests {
    use super::QueryPoolCreateInfo;
    use crate::{
        query::{QueryPipelineStatisticFlags, QueryPool, QueryType},
        Validated,
    };

    #[test]
    fn pipeline_statistics_feature() {
        let (device, _) = gfx_dev_and_queue!();
        let query_type = QueryType::PipelineStatistics(QueryPipelineStatisticFlags::empty());
        assert!(matches!(
            QueryPool::new(
                device,
                QueryPoolCreateInfo {
                    query_count: 256,
                    ..QueryPoolCreateInfo::query_type(query_type)
                },
            ),
            Err(Validated::ValidationError(_)),
        ));
    }
}