// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.

use deno_core::error::AnyError;
use deno_core::op;
use deno_core::OpState;
use deno_core::Resource;
use deno_core::ResourceId;
use serde::Deserialize;
use std::borrow::Cow;

use super::error::WebGpuResult;

pub(crate) struct WebGpuBindGroupLayout(pub(crate) wgpu_core::id::BindGroupLayoutId);
impl Resource for WebGpuBindGroupLayout {
    fn name(&self) -> Cow<str> {
        "webGPUBindGroupLayout".into()
    }
}

pub(crate) struct WebGpuBindGroup(pub(crate) wgpu_core::id::BindGroupId);
impl Resource for WebGpuBindGroup {
    fn name(&self) -> Cow<str> {
        "webGPUBindGroup".into()
    }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct GpuBufferBindingLayout {
    r#type: GpuBufferBindingType,
    has_dynamic_offset: bool,
    min_binding_size: u64,
}

#[derive(Deserialize)]
#[serde(rename_all = "kebab-case")]
enum GpuBufferBindingType {
    Uniform,
    Storage,
    ReadOnlyStorage,
}

impl From<GpuBufferBindingType> for wgpu_types::BufferBindingType {
    fn from(binding_type: GpuBufferBindingType) -> Self {
        match binding_type {
            GpuBufferBindingType::Uniform => wgpu_types::BufferBindingType::Uniform,
            GpuBufferBindingType::Storage => {
                wgpu_types::BufferBindingType::Storage { read_only: false }
            }
            GpuBufferBindingType::ReadOnlyStorage => {
                wgpu_types::BufferBindingType::Storage { read_only: true }
            }
        }
    }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct GpuSamplerBindingLayout {
    r#type: wgpu_types::SamplerBindingType,
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct GpuTextureBindingLayout {
    sample_type: GpuTextureSampleType,
    view_dimension: wgpu_types::TextureViewDimension,
    multisampled: bool,
}

#[derive(Deserialize)]
#[serde(rename_all = "kebab-case")]
enum GpuTextureSampleType {
    Float,
    UnfilterableFloat,
    Depth,
    Sint,
    Uint,
}

impl From<GpuTextureSampleType> for wgpu_types::TextureSampleType {
    fn from(sample_type: GpuTextureSampleType) -> Self {
        match sample_type {
            GpuTextureSampleType::Float => {
                wgpu_types::TextureSampleType::Float { filterable: true }
            }
            GpuTextureSampleType::UnfilterableFloat => {
                wgpu_types::TextureSampleType::Float { filterable: false }
            }
            GpuTextureSampleType::Depth => wgpu_types::TextureSampleType::Depth,
            GpuTextureSampleType::Sint => wgpu_types::TextureSampleType::Sint,
            GpuTextureSampleType::Uint => wgpu_types::TextureSampleType::Uint,
        }
    }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct GpuStorageTextureBindingLayout {
    access: GpuStorageTextureAccess,
    format: wgpu_types::TextureFormat,
    view_dimension: wgpu_types::TextureViewDimension,
}

#[derive(Deserialize)]
#[serde(rename_all = "kebab-case")]
enum GpuStorageTextureAccess {
    WriteOnly,
}

impl From<GpuStorageTextureAccess> for wgpu_types::StorageTextureAccess {
    fn from(access: GpuStorageTextureAccess) -> Self {
        match access {
            GpuStorageTextureAccess::WriteOnly => wgpu_types::StorageTextureAccess::WriteOnly,
        }
    }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct GpuBindGroupLayoutEntry {
    binding: u32,
    visibility: u32,
    #[serde(flatten)]
    binding_type: GpuBindingType,
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
enum GpuBindingType {
    Buffer(GpuBufferBindingLayout),
    Sampler(GpuSamplerBindingLayout),
    Texture(GpuTextureBindingLayout),
    StorageTexture(GpuStorageTextureBindingLayout),
}

impl From<GpuBindingType> for wgpu_types::BindingType {
    fn from(binding_type: GpuBindingType) -> wgpu_types::BindingType {
        match binding_type {
            GpuBindingType::Buffer(buffer) => wgpu_types::BindingType::Buffer {
                ty: buffer.r#type.into(),
                has_dynamic_offset: buffer.has_dynamic_offset,
                min_binding_size: std::num::NonZeroU64::new(buffer.min_binding_size),
            },
            GpuBindingType::Sampler(sampler) => wgpu_types::BindingType::Sampler(sampler.r#type),
            GpuBindingType::Texture(texture) => wgpu_types::BindingType::Texture {
                sample_type: texture.sample_type.into(),
                view_dimension: texture.view_dimension,
                multisampled: texture.multisampled,
            },
            GpuBindingType::StorageTexture(storage_texture) => {
                wgpu_types::BindingType::StorageTexture {
                    access: storage_texture.access.into(),
                    format: storage_texture.format,
                    view_dimension: storage_texture.view_dimension,
                }
            }
        }
    }
}

#[op]
pub fn op_webgpu_create_bind_group_layout(
    state: &mut OpState,
    device_rid: ResourceId,
    label: Option<String>,
    entries: Vec<GpuBindGroupLayoutEntry>,
) -> Result<WebGpuResult, AnyError> {
    let instance = state.borrow::<super::Instance>();
    let device_resource = state
        .resource_table
        .get::<super::WebGpuDevice>(device_rid)?;
    let device = device_resource.0;

    let entries = entries
        .into_iter()
        .map(|entry| {
            wgpu_types::BindGroupLayoutEntry {
                binding: entry.binding,
                visibility: wgpu_types::ShaderStages::from_bits(entry.visibility).unwrap(),
                ty: entry.binding_type.into(),
                count: None, // native-only
            }
        })
        .collect::<Vec<_>>();

    let descriptor = wgpu_core::binding_model::BindGroupLayoutDescriptor {
        label: label.map(Cow::from),
        entries: Cow::from(entries),
    };

    gfx_put!(device => instance.device_create_bind_group_layout(
    device,
    &descriptor,
    std::marker::PhantomData
  ) => state, WebGpuBindGroupLayout)
}

#[op]
pub fn op_webgpu_create_pipeline_layout(
    state: &mut OpState,
    device_rid: ResourceId,
    label: Option<String>,
    bind_group_layouts: Vec<u32>,
) -> Result<WebGpuResult, AnyError> {
    let instance = state.borrow::<super::Instance>();
    let device_resource = state
        .resource_table
        .get::<super::WebGpuDevice>(device_rid)?;
    let device = device_resource.0;

    let bind_group_layouts = bind_group_layouts
        .into_iter()
        .map(|rid| {
            let bind_group_layout = state.resource_table.get::<WebGpuBindGroupLayout>(rid)?;
            Ok(bind_group_layout.0)
        })
        .collect::<Result<Vec<_>, AnyError>>()?;

    let descriptor = wgpu_core::binding_model::PipelineLayoutDescriptor {
        label: label.map(Cow::from),
        bind_group_layouts: Cow::from(bind_group_layouts),
        push_constant_ranges: Default::default(),
    };

    gfx_put!(device => instance.device_create_pipeline_layout(
    device,
    &descriptor,
    std::marker::PhantomData
  ) => state, super::pipeline::WebGpuPipelineLayout)
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct GpuBindGroupEntry {
    binding: u32,
    kind: String,
    resource: ResourceId,
    offset: Option<u64>,
    size: Option<u64>,
}

#[op]
pub fn op_webgpu_create_bind_group(
    state: &mut OpState,
    device_rid: ResourceId,
    label: Option<String>,
    layout: ResourceId,
    entries: Vec<GpuBindGroupEntry>,
) -> Result<WebGpuResult, AnyError> {
    let instance = state.borrow::<super::Instance>();
    let device_resource = state
        .resource_table
        .get::<super::WebGpuDevice>(device_rid)?;
    let device = device_resource.0;

    let entries = entries
        .into_iter()
        .map(|entry| {
            Ok(wgpu_core::binding_model::BindGroupEntry {
                binding: entry.binding,
                resource: match entry.kind.as_str() {
                    "GPUSampler" => {
                        let sampler_resource = state
                            .resource_table
                            .get::<super::sampler::WebGpuSampler>(entry.resource)?;
                        wgpu_core::binding_model::BindingResource::Sampler(sampler_resource.0)
                    }
                    "GPUTextureView" => {
                        let texture_view_resource =
                            state
                                .resource_table
                                .get::<super::texture::WebGpuTextureView>(entry.resource)?;
                        wgpu_core::binding_model::BindingResource::TextureView(
                            texture_view_resource.0,
                        )
                    }
                    "GPUBufferBinding" => {
                        let buffer_resource = state
                            .resource_table
                            .get::<super::buffer::WebGpuBuffer>(entry.resource)?;
                        wgpu_core::binding_model::BindingResource::Buffer(
                            wgpu_core::binding_model::BufferBinding {
                                buffer_id: buffer_resource.0,
                                offset: entry.offset.unwrap_or(0),
                                size: std::num::NonZeroU64::new(entry.size.unwrap_or(0)),
                            },
                        )
                    }
                    _ => unreachable!(),
                },
            })
        })
        .collect::<Result<Vec<_>, AnyError>>()?;

    let bind_group_layout = state.resource_table.get::<WebGpuBindGroupLayout>(layout)?;

    let descriptor = wgpu_core::binding_model::BindGroupDescriptor {
        label: label.map(Cow::from),
        layout: bind_group_layout.0,
        entries: Cow::from(entries),
    };

    gfx_put!(device => instance.device_create_bind_group(
    device,
    &descriptor,
    std::marker::PhantomData
  ) => state, WebGpuBindGroup)
}
