//! Graphics command list

use crate::{
    com::WeakPtr, resource::DiscardRegion, CommandAllocator, CpuDescriptor, DescriptorHeap, Format,
    GpuAddress, GpuDescriptor, IndexCount, InstanceCount, PipelineState, Rect, Resource, RootIndex,
    RootSignature, Subresource, VertexCount, VertexOffset, WorkGroupCount, HRESULT,
};
use std::{mem, ptr};
use winapi::um::d3d12;

#[repr(u32)]
#[derive(Clone, Copy)]
pub enum CmdListType {
    Direct = d3d12::D3D12_COMMAND_LIST_TYPE_DIRECT,
    Bundle = d3d12::D3D12_COMMAND_LIST_TYPE_BUNDLE,
    Compute = d3d12::D3D12_COMMAND_LIST_TYPE_COMPUTE,
    Copy = d3d12::D3D12_COMMAND_LIST_TYPE_COPY,
    // VideoDecode = d3d12::D3D12_COMMAND_LIST_TYPE_VIDEO_DECODE,
    // VideoProcess = d3d12::D3D12_COMMAND_LIST_TYPE_VIDEO_PROCESS,
}

bitflags! {
    pub struct ClearFlags: u32 {
        const DEPTH = d3d12::D3D12_CLEAR_FLAG_DEPTH;
        const STENCIL = d3d12::D3D12_CLEAR_FLAG_STENCIL;
    }
}

#[repr(transparent)]
pub struct IndirectArgument(d3d12::D3D12_INDIRECT_ARGUMENT_DESC);

impl IndirectArgument {
    pub fn draw() -> Self {
        IndirectArgument(d3d12::D3D12_INDIRECT_ARGUMENT_DESC {
            Type: d3d12::D3D12_INDIRECT_ARGUMENT_TYPE_DRAW,
            ..unsafe { mem::zeroed() }
        })
    }

    pub fn draw_indexed() -> Self {
        IndirectArgument(d3d12::D3D12_INDIRECT_ARGUMENT_DESC {
            Type: d3d12::D3D12_INDIRECT_ARGUMENT_TYPE_DRAW_INDEXED,
            ..unsafe { mem::zeroed() }
        })
    }

    pub fn dispatch() -> Self {
        IndirectArgument(d3d12::D3D12_INDIRECT_ARGUMENT_DESC {
            Type: d3d12::D3D12_INDIRECT_ARGUMENT_TYPE_DISPATCH,
            ..unsafe { mem::zeroed() }
        })
    }

    pub fn vertex_buffer(slot: u32) -> Self {
        let mut desc = d3d12::D3D12_INDIRECT_ARGUMENT_DESC {
            Type: d3d12::D3D12_INDIRECT_ARGUMENT_TYPE_VERTEX_BUFFER_VIEW,
            ..unsafe { mem::zeroed() }
        };
        *unsafe { desc.u.VertexBuffer_mut() } =
            d3d12::D3D12_INDIRECT_ARGUMENT_DESC_VertexBuffer { Slot: slot };
        IndirectArgument(desc)
    }

    pub fn constant(root_index: RootIndex, dest_offset_words: u32, count: u32) -> Self {
        let mut desc = d3d12::D3D12_INDIRECT_ARGUMENT_DESC {
            Type: d3d12::D3D12_INDIRECT_ARGUMENT_TYPE_CONSTANT,
            ..unsafe { mem::zeroed() }
        };
        *unsafe { desc.u.Constant_mut() } = d3d12::D3D12_INDIRECT_ARGUMENT_DESC_Constant {
            RootParameterIndex: root_index,
            DestOffsetIn32BitValues: dest_offset_words,
            Num32BitValuesToSet: count,
        };
        IndirectArgument(desc)
    }

    pub fn constant_buffer_view(root_index: RootIndex) -> Self {
        let mut desc = d3d12::D3D12_INDIRECT_ARGUMENT_DESC {
            Type: d3d12::D3D12_INDIRECT_ARGUMENT_TYPE_CONSTANT_BUFFER_VIEW,
            ..unsafe { mem::zeroed() }
        };
        *unsafe { desc.u.ConstantBufferView_mut() } =
            d3d12::D3D12_INDIRECT_ARGUMENT_DESC_ConstantBufferView {
                RootParameterIndex: root_index,
            };
        IndirectArgument(desc)
    }

    pub fn shader_resource_view(root_index: RootIndex) -> Self {
        let mut desc = d3d12::D3D12_INDIRECT_ARGUMENT_DESC {
            Type: d3d12::D3D12_INDIRECT_ARGUMENT_TYPE_SHADER_RESOURCE_VIEW,
            ..unsafe { mem::zeroed() }
        };
        *unsafe { desc.u.ShaderResourceView_mut() } =
            d3d12::D3D12_INDIRECT_ARGUMENT_DESC_ShaderResourceView {
                RootParameterIndex: root_index,
            };
        IndirectArgument(desc)
    }

    pub fn unordered_access_view(root_index: RootIndex) -> Self {
        let mut desc = d3d12::D3D12_INDIRECT_ARGUMENT_DESC {
            Type: d3d12::D3D12_INDIRECT_ARGUMENT_TYPE_UNORDERED_ACCESS_VIEW,
            ..unsafe { mem::zeroed() }
        };
        *unsafe { desc.u.UnorderedAccessView_mut() } =
            d3d12::D3D12_INDIRECT_ARGUMENT_DESC_UnorderedAccessView {
                RootParameterIndex: root_index,
            };
        IndirectArgument(desc)
    }
}

#[repr(transparent)]
pub struct ResourceBarrier(d3d12::D3D12_RESOURCE_BARRIER);

impl ResourceBarrier {
    pub fn transition(
        resource: Resource,
        subresource: Subresource,
        state_before: d3d12::D3D12_RESOURCE_STATES,
        state_after: d3d12::D3D12_RESOURCE_STATES,
        flags: d3d12::D3D12_RESOURCE_BARRIER_FLAGS,
    ) -> Self {
        let mut barrier = d3d12::D3D12_RESOURCE_BARRIER {
            Type: d3d12::D3D12_RESOURCE_BARRIER_TYPE_TRANSITION,
            Flags: flags,
            ..unsafe { mem::zeroed() }
        };
        unsafe {
            *barrier.u.Transition_mut() = d3d12::D3D12_RESOURCE_TRANSITION_BARRIER {
                pResource: resource.as_mut_ptr(),
                Subresource: subresource,
                StateBefore: state_before,
                StateAfter: state_after,
            };
        }
        ResourceBarrier(barrier)
    }
}

pub type CommandSignature = WeakPtr<d3d12::ID3D12CommandSignature>;
pub type CommandList = WeakPtr<d3d12::ID3D12CommandList>;
pub type GraphicsCommandList = WeakPtr<d3d12::ID3D12GraphicsCommandList>;

impl GraphicsCommandList {
    pub fn as_list(&self) -> CommandList {
        unsafe { CommandList::from_raw(self.as_mut_ptr() as *mut _) }
    }

    pub fn close(&self) -> HRESULT {
        unsafe { self.Close() }
    }

    pub fn reset(&self, allocator: CommandAllocator, initial_pso: PipelineState) -> HRESULT {
        unsafe { self.Reset(allocator.as_mut_ptr(), initial_pso.as_mut_ptr()) }
    }

    pub fn discard_resource(&self, resource: Resource, region: DiscardRegion) {
        debug_assert!(region.subregions.start < region.subregions.end);
        unsafe {
            self.DiscardResource(
                resource.as_mut_ptr(),
                &d3d12::D3D12_DISCARD_REGION {
                    NumRects: region.rects.len() as _,
                    pRects: region.rects.as_ptr(),
                    FirstSubresource: region.subregions.start,
                    NumSubresources: region.subregions.end - region.subregions.start - 1,
                },
            );
        }
    }

    pub fn clear_depth_stencil_view(
        &self,
        dsv: CpuDescriptor,
        flags: ClearFlags,
        depth: f32,
        stencil: u8,
        rects: &[Rect],
    ) {
        let num_rects = rects.len() as _;
        let rects = if num_rects > 0 {
            rects.as_ptr()
        } else {
            ptr::null()
        };
        unsafe {
            self.ClearDepthStencilView(dsv, flags.bits(), depth, stencil, num_rects, rects);
        }
    }

    pub fn clear_render_target_view(&self, rtv: CpuDescriptor, color: [f32; 4], rects: &[Rect]) {
        let num_rects = rects.len() as _;
        let rects = if num_rects > 0 {
            rects.as_ptr()
        } else {
            ptr::null()
        };
        unsafe {
            self.ClearRenderTargetView(rtv, &color, num_rects, rects);
        }
    }

    pub fn dispatch(&self, count: WorkGroupCount) {
        unsafe {
            self.Dispatch(count[0], count[1], count[2]);
        }
    }

    pub fn draw(
        &self,
        num_vertices: VertexCount,
        num_instances: InstanceCount,
        start_vertex: VertexCount,
        start_instance: InstanceCount,
    ) {
        unsafe {
            self.DrawInstanced(num_vertices, num_instances, start_vertex, start_instance);
        }
    }

    pub fn draw_indexed(
        &self,
        num_indices: IndexCount,
        num_instances: InstanceCount,
        start_index: IndexCount,
        base_vertex: VertexOffset,
        start_instance: InstanceCount,
    ) {
        unsafe {
            self.DrawIndexedInstanced(
                num_indices,
                num_instances,
                start_index,
                base_vertex,
                start_instance,
            );
        }
    }

    pub fn set_index_buffer(&self, gpu_address: GpuAddress, size: u32, format: Format) {
        let ibv = d3d12::D3D12_INDEX_BUFFER_VIEW {
            BufferLocation: gpu_address,
            SizeInBytes: size,
            Format: format,
        };
        unsafe {
            self.IASetIndexBuffer(&ibv);
        }
    }

    pub fn set_blend_factor(&self, factor: [f32; 4]) {
        unsafe {
            self.OMSetBlendFactor(&factor);
        }
    }

    pub fn set_stencil_reference(&self, reference: u32) {
        unsafe {
            self.OMSetStencilRef(reference);
        }
    }

    pub fn set_pipeline_state(&self, pso: PipelineState) {
        unsafe {
            self.SetPipelineState(pso.as_mut_ptr());
        }
    }

    pub fn execute_bundle(&self, bundle: GraphicsCommandList) {
        unsafe {
            self.ExecuteBundle(bundle.as_mut_ptr());
        }
    }

    pub fn set_descriptor_heaps(&self, heaps: &[DescriptorHeap]) {
        unsafe {
            self.SetDescriptorHeaps(
                heaps.len() as _,
                heaps.as_ptr() as *mut &DescriptorHeap as *mut _,
            );
        }
    }

    pub fn set_compute_root_signature(&self, signature: RootSignature) {
        unsafe {
            self.SetComputeRootSignature(signature.as_mut_ptr());
        }
    }

    pub fn set_graphics_root_signature(&self, signature: RootSignature) {
        unsafe {
            self.SetGraphicsRootSignature(signature.as_mut_ptr());
        }
    }

    pub fn set_compute_root_descriptor_table(
        &self,
        root_index: RootIndex,
        base_descriptor: GpuDescriptor,
    ) {
        unsafe {
            self.SetComputeRootDescriptorTable(root_index, base_descriptor);
        }
    }

    pub fn set_compute_root_constant_buffer_view(
        &self,
        root_index: RootIndex,
        buffer_location: GpuAddress,
    ) {
        unsafe {
            self.SetComputeRootConstantBufferView(root_index, buffer_location);
        }
    }

    pub fn set_compute_root_shader_resource_view(
        &self,
        root_index: RootIndex,
        buffer_location: GpuAddress,
    ) {
        unsafe {
            self.SetComputeRootShaderResourceView(root_index, buffer_location);
        }
    }

    pub fn set_compute_root_unordered_access_view(
        &self,
        root_index: RootIndex,
        buffer_location: GpuAddress,
    ) {
        unsafe {
            self.SetComputeRootUnorderedAccessView(root_index, buffer_location);
        }
    }

    pub fn set_compute_root_constant(
        &self,
        root_index: RootIndex,
        value: u32,
        dest_offset_words: u32,
    ) {
        unsafe {
            self.SetComputeRoot32BitConstant(root_index, value, dest_offset_words);
        }
    }

    pub fn set_graphics_root_descriptor_table(
        &self,
        root_index: RootIndex,
        base_descriptor: GpuDescriptor,
    ) {
        unsafe {
            self.SetGraphicsRootDescriptorTable(root_index, base_descriptor);
        }
    }

    pub fn set_graphics_root_constant_buffer_view(
        &self,
        root_index: RootIndex,
        buffer_location: GpuAddress,
    ) {
        unsafe {
            self.SetGraphicsRootConstantBufferView(root_index, buffer_location);
        }
    }

    pub fn set_graphics_root_shader_resource_view(
        &self,
        root_index: RootIndex,
        buffer_location: GpuAddress,
    ) {
        unsafe {
            self.SetGraphicsRootShaderResourceView(root_index, buffer_location);
        }
    }

    pub fn set_graphics_root_unordered_access_view(
        &self,
        root_index: RootIndex,
        buffer_location: GpuAddress,
    ) {
        unsafe {
            self.SetGraphicsRootUnorderedAccessView(root_index, buffer_location);
        }
    }

    pub fn set_graphics_root_constant(
        &self,
        root_index: RootIndex,
        value: u32,
        dest_offset_words: u32,
    ) {
        unsafe {
            self.SetGraphicsRoot32BitConstant(root_index, value, dest_offset_words);
        }
    }

    pub fn resource_barrier(&self, barriers: &[ResourceBarrier]) {
        unsafe {
            self.ResourceBarrier(barriers.len() as _, barriers.as_ptr() as _) // matches representation
        }
    }
}