mod bind_group;
mod debug_overlay;
mod pipeline;
mod shadow;
mod types;

pub use types::{DrawCall, Pipeline, Spotlight, SpotlightRaw, Uniforms, MAX_SPOTLIGHTS};

use crate::debug::DebugMode;
use crate::postprocess::{create_blit_pipeline, create_fullscreen_quad, LowResFramebuffer};
use crate::texture::{DitherTextures, FlowmapTexture};
use pipeline::{create_debug_lines_pipeline, create_main_pipeline, create_snow_clipmap_pipeline,
               create_wireframe_pipeline};
use std::cell::RefCell;

pub struct Renderer
{
    pub device: wgpu::Device,
    pub queue: wgpu::Queue,
    pub surface: wgpu::Surface<'static>,
    pub config: wgpu::SurfaceConfiguration,

    framebuffer: LowResFramebuffer,

    standard_pipeline: wgpu::RenderPipeline,
    snow_clipmap_pipeline: wgpu::RenderPipeline,
    wireframe_pipeline: Option<wgpu::RenderPipeline>,
    debug_lines_pipeline: Option<wgpu::RenderPipeline>,
    debug_overlay: Option<debug_overlay::DebugOverlay>,
    wireframe_supported: bool,

    uniform_buffer: wgpu::Buffer,
    bind_group_layout: wgpu::BindGroupLayout,
    bind_group: wgpu::BindGroup,

    quad_vb: wgpu::Buffer,
    quad_ib: wgpu::Buffer,
    quad_num_indices: u32,
    blit_pipeline: wgpu::RenderPipeline,
    blit_bind_group: wgpu::BindGroup,

    shadow_pipeline: Option<wgpu::RenderPipeline>,
    shadow_bind_group_layout: wgpu::BindGroupLayout,
    shadow_bind_group: Option<wgpu::BindGroup>,

    terrain_height_scale: f32,

    pub spotlights: Vec<Spotlight>,
    pub shadow_bias: f32,

    shadow_map_texture: wgpu::Texture,
    shadow_map_view: wgpu::TextureView,
    shadow_map_sampler: wgpu::Sampler,

    dither_textures: Option<DitherTextures>,
    flowmap_texture: Option<FlowmapTexture>,
    blue_noise_view: wgpu::TextureView,
    blue_noise_sampler: wgpu::Sampler,

    dummy_snow_light_view: wgpu::TextureView,
    dummy_snow_light_sampler: wgpu::Sampler,

    snow_light_accumulation: Option<crate::snow_light::SnowLightAccumulation>,
    snow_light_bound: bool,
}

impl Renderer
{
    pub async fn new(
        window: &sdl3::video::Window,
        render_scale: u32,
    ) -> Result<Self, Box<dyn std::error::Error>>
    {
        let instance = wgpu::Instance::new(&wgpu::InstanceDescriptor {
            backends: wgpu::Backends::VULKAN,
            ..Default::default()
        });

        let surface = unsafe {
            let target = wgpu::SurfaceTargetUnsafe::from_window(window)?;
            instance.create_surface_unsafe(target)?
        };

        let adapter = instance
            .request_adapter(&wgpu::RequestAdapterOptions {
                power_preference: wgpu::PowerPreference::HighPerformance,
                compatible_surface: Some(&surface),
                force_fallback_adapter: false,
            })
            .await
            .map_err(|_| "Failed to find adapter")?;

        let wireframe_supported =
            adapter.features().contains(wgpu::Features::POLYGON_MODE_LINE);
        let required_features = if wireframe_supported
        {
            wgpu::Features::POLYGON_MODE_LINE
        }
        else
        {
            wgpu::Features::empty()
        };
        let (device, queue) = adapter
            .request_device(&wgpu::DeviceDescriptor {
                required_features,
                ..Default::default()
            })
            .await?;

        let size = window.size();
        let config = wgpu::SurfaceConfiguration {
            usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
            format: surface.get_capabilities(&adapter).formats[0],
            width: size.0,
            height: size.1,
            present_mode: wgpu::PresentMode::Fifo,
            alpha_mode: wgpu::CompositeAlphaMode::Auto,
            view_formats: vec![],
            desired_maximum_frame_latency: 2,
        };

        surface.configure(&device, &config);

        let low_res_width = config.width / render_scale;
        let low_res_height = config.height / render_scale;

        let framebuffer =
            LowResFramebuffer::new(&device, low_res_width, low_res_height, config.format);

        let uniform_buffer = device.create_buffer(&wgpu::BufferDescriptor {
            label: Some("Uniform Buffer"),
            size: std::mem::size_of::<Uniforms>() as wgpu::BufferAddress,
            usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
            mapped_at_creation: false,
        });

        let dither_textures = match DitherTextures::load_octaves(&device, &queue)
        {
            Ok(textures) =>
            {
                println!("Loaded dither textures successfully");
                Some(textures)
            }
            Err(e) =>
            {
                eprintln!(
                    "Warning: Could not load dither textures: {}. Rendering may look incorrect.",
                    e
                );
                None
            }
        };

        let flowmap_texture =
            match FlowmapTexture::load(&device, &queue, "textures/terrain_flowmap.exr")
            {
                Ok(texture) =>
                {
                    println!("Loaded terrain flowmap successfully");
                    Some(texture)
                }
                Err(e) =>
                {
                    eprintln!(
                        "Warning: Could not load terrain flowmap: {}. Path lighting will not work.",
                        e
                    );
                    None
                }
            };

        let blue_noise_data = image::open("textures/blue_noise.png")
            .expect("Failed to load blue noise texture")
            .to_luma8();
        let blue_noise_size = blue_noise_data.dimensions();

        let blue_noise_texture = device.create_texture(&wgpu::TextureDescriptor {
            label: Some("Blue Noise"),
            size: wgpu::Extent3d {
                width: blue_noise_size.0,
                height: blue_noise_size.1,
                depth_or_array_layers: 1,
            },
            mip_level_count: 1,
            sample_count: 1,
            dimension: wgpu::TextureDimension::D2,
            format: wgpu::TextureFormat::R8Unorm,
            usage: wgpu::TextureUsages::TEXTURE_BINDING | wgpu::TextureUsages::COPY_DST,
            view_formats: &[],
        });

        queue.write_texture(
            wgpu::TexelCopyTextureInfo {
                texture: &blue_noise_texture,
                mip_level: 0,
                origin: wgpu::Origin3d::ZERO,
                aspect: wgpu::TextureAspect::All,
            },
            &blue_noise_data,
            wgpu::TexelCopyBufferLayout {
                offset: 0,
                bytes_per_row: Some(blue_noise_size.0),
                rows_per_image: Some(blue_noise_size.1),
            },
            wgpu::Extent3d {
                width: blue_noise_size.0,
                height: blue_noise_size.1,
                depth_or_array_layers: 1,
            },
        );

        let blue_noise_view =
            blue_noise_texture.create_view(&wgpu::TextureViewDescriptor::default());
        let blue_noise_sampler = device.create_sampler(&wgpu::SamplerDescriptor {
            label: Some("Blue Noise Sampler"),
            address_mode_u: wgpu::AddressMode::Repeat,
            address_mode_v: wgpu::AddressMode::Repeat,
            mag_filter: wgpu::FilterMode::Nearest,
            min_filter: wgpu::FilterMode::Nearest,
            ..Default::default()
        });

        let shadow_map_size = 4096;
        let shadow_map_texture = device.create_texture(&wgpu::TextureDescriptor {
            label: Some("Shadow Map"),
            size: wgpu::Extent3d {
                width: shadow_map_size,
                height: shadow_map_size,
                depth_or_array_layers: MAX_SPOTLIGHTS as u32,
            },
            mip_level_count: 1,
            sample_count: 1,
            dimension: wgpu::TextureDimension::D2,
            format: wgpu::TextureFormat::Depth32Float,
            usage: wgpu::TextureUsages::RENDER_ATTACHMENT | wgpu::TextureUsages::TEXTURE_BINDING,
            view_formats: &[],
        });

        let shadow_map_view = shadow_map_texture.create_view(&wgpu::TextureViewDescriptor {
            dimension: Some(wgpu::TextureViewDimension::D2Array),
            ..Default::default()
        });

        let shadow_map_sampler = device.create_sampler(&wgpu::SamplerDescriptor {
            label: Some("Shadow Map Sampler"),
            address_mode_u: wgpu::AddressMode::ClampToEdge,
            address_mode_v: wgpu::AddressMode::ClampToEdge,
            address_mode_w: wgpu::AddressMode::ClampToEdge,
            mag_filter: wgpu::FilterMode::Linear,
            min_filter: wgpu::FilterMode::Linear,
            mipmap_filter: wgpu::MipmapFilterMode::Nearest,
            compare: Some(wgpu::CompareFunction::LessEqual),
            ..Default::default()
        });

        let dummy_texture = device.create_texture(&wgpu::TextureDescriptor {
            label: Some("Dummy Snow Light"),
            size: wgpu::Extent3d {
                width: 1,
                height: 1,
                depth_or_array_layers: 1,
            },
            mip_level_count: 1,
            sample_count: 1,
            dimension: wgpu::TextureDimension::D2,
            format: wgpu::TextureFormat::R16Float,
            usage: wgpu::TextureUsages::TEXTURE_BINDING | wgpu::TextureUsages::COPY_DST,
            view_formats: &[],
        });

        queue.write_texture(
            wgpu::TexelCopyTextureInfo {
                texture: &dummy_texture,
                mip_level: 0,
                origin: wgpu::Origin3d::ZERO,
                aspect: wgpu::TextureAspect::All,
            },
            &[0u8; 2],
            wgpu::TexelCopyBufferLayout {
                offset: 0,
                bytes_per_row: Some(2),
                rows_per_image: Some(1),
            },
            wgpu::Extent3d {
                width: 1,
                height: 1,
                depth_or_array_layers: 1,
            },
        );
        let dummy_snow_light_view =
            dummy_texture.create_view(&wgpu::TextureViewDescriptor::default());
        let dummy_snow_light_sampler = device.create_sampler(&wgpu::SamplerDescriptor {
            label: Some("Snow Light Sampler"),
            address_mode_u: wgpu::AddressMode::ClampToEdge,
            address_mode_v: wgpu::AddressMode::ClampToEdge,
            mag_filter: wgpu::FilterMode::Linear,
            min_filter: wgpu::FilterMode::Linear,
            ..Default::default()
        });

        let bind_group_layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
            label: Some("Bind Group Layout"),
            entries: &[
                wgpu::BindGroupLayoutEntry {
                    binding: 0,
                    visibility: wgpu::ShaderStages::VERTEX | wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Buffer {
                        ty: wgpu::BufferBindingType::Uniform,
                        has_dynamic_offset: false,
                        min_binding_size: None,
                    },
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 1,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Texture {
                        sample_type: wgpu::TextureSampleType::Depth,
                        view_dimension: wgpu::TextureViewDimension::D2Array,
                        multisampled: false,
                    },
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 2,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Comparison),
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 3,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Texture {
                        sample_type: wgpu::TextureSampleType::Float { filterable: false },
                        view_dimension: wgpu::TextureViewDimension::D2Array,
                        multisampled: false,
                    },
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 4,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::NonFiltering),
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 5,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Texture {
                        sample_type: wgpu::TextureSampleType::Float { filterable: false },
                        view_dimension: wgpu::TextureViewDimension::D2,
                        multisampled: false,
                    },
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 6,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::NonFiltering),
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 7,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Texture {
                        sample_type: wgpu::TextureSampleType::Float { filterable: false },
                        view_dimension: wgpu::TextureViewDimension::D2,
                        multisampled: false,
                    },
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 8,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::NonFiltering),
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 9,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Texture {
                        sample_type: wgpu::TextureSampleType::Float { filterable: true },
                        view_dimension: wgpu::TextureViewDimension::D2,
                        multisampled: false,
                    },
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 10,
                    visibility: wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Filtering),
                    count: None,
                },
            ],
        });

        let bind_group = Self::create_bind_group_from_parts(
            &device,
            &bind_group_layout,
            &uniform_buffer,
            &shadow_map_view,
            &shadow_map_sampler,
            dither_textures.as_ref().expect("Dither textures required"),
            flowmap_texture.as_ref().expect("Flowmap texture required"),
            &blue_noise_view,
            &blue_noise_sampler,
            &dummy_snow_light_view,
            &dummy_snow_light_sampler,
        );

        let standard_pipeline = create_main_pipeline(
            &device,
            config.format,
            &bind_group_layout,
            wgpu::DepthBiasState::default(),
            "Standard Pipeline",
        );

        let snow_clipmap_pipeline =
            create_snow_clipmap_pipeline(&device, config.format, &bind_group_layout);

        let (quad_vb, quad_ib, quad_num_indices) = create_fullscreen_quad(&device);

        let blit_bind_group_layout =
            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
                label: Some("Blit Bind Group Layout"),
                entries: &[
                    wgpu::BindGroupLayoutEntry {
                        binding: 0,
                        visibility: wgpu::ShaderStages::FRAGMENT,
                        ty: wgpu::BindingType::Texture {
                            sample_type: wgpu::TextureSampleType::Float { filterable: true },
                            view_dimension: wgpu::TextureViewDimension::D2,
                            multisampled: false,
                        },
                        count: None,
                    },
                    wgpu::BindGroupLayoutEntry {
                        binding: 1,
                        visibility: wgpu::ShaderStages::FRAGMENT,
                        ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Filtering),
                        count: None,
                    },
                ],
            });

        let blit_bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
            label: Some("Blit Bind Group"),
            layout: &blit_bind_group_layout,
            entries: &[
                wgpu::BindGroupEntry {
                    binding: 0,
                    resource: wgpu::BindingResource::TextureView(&framebuffer.view),
                },
                wgpu::BindGroupEntry {
                    binding: 1,
                    resource: wgpu::BindingResource::Sampler(&framebuffer.sampler),
                },
            ],
        });

        let blit_pipeline = create_blit_pipeline(&device, config.format, &blit_bind_group_layout);

        let wireframe_pipeline = if wireframe_supported
        {
            Some(create_wireframe_pipeline(&device, config.format, &bind_group_layout))
        }
        else
        {
            None
        };

        let debug_lines_pipeline =
            Some(create_debug_lines_pipeline(&device, config.format, &bind_group_layout));

        let debug_overlay = Some(debug_overlay::DebugOverlay::new(&device, config.format));

        let shadow_bind_group_layout =
            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
                label: Some("Shadow Bind Group Layout"),
                entries: &[wgpu::BindGroupLayoutEntry {
                    binding: 0,
                    visibility: wgpu::ShaderStages::VERTEX | wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Buffer {
                        ty: wgpu::BufferBindingType::Uniform,
                        has_dynamic_offset: false,
                        min_binding_size: None,
                    },
                    count: None,
                }],
            });

        Ok(Self {
            device,
            queue,
            surface,
            config,
            framebuffer,
            standard_pipeline,
            snow_clipmap_pipeline,
            wireframe_pipeline,
            debug_lines_pipeline,
            debug_overlay,
            wireframe_supported,
            uniform_buffer,
            bind_group_layout,
            bind_group,
            quad_vb,
            quad_ib,
            quad_num_indices,
            blit_pipeline,
            blit_bind_group,
            shadow_pipeline: None,
            shadow_bind_group_layout,
            shadow_bind_group: None,
            terrain_height_scale: 10.0,
            spotlights: vec![Spotlight::new(
                glam::Vec3::new(0.0, 50.0, 0.0),
                glam::Vec3::new(-0.5, -1.0, 1.0).normalize(),
                0.4,
                1.0,
                100.0,
            )],
            shadow_bias: 0.005,
            shadow_map_texture,
            shadow_map_view,
            shadow_map_sampler,
            dither_textures,
            flowmap_texture,
            blue_noise_view,
            blue_noise_sampler,
            dummy_snow_light_view,
            dummy_snow_light_sampler,
            snow_light_accumulation: None,
            snow_light_bound: false,
        })
    }

    pub fn render(
        &mut self,
        view: &glam::Mat4,
        projection: &glam::Mat4,
        camera_position: glam::Vec3,
        player_position: glam::Vec3,
        draw_calls: &[DrawCall],
        time: f32,
        delta_time: f32,
        debug_mode: DebugMode,
    ) -> wgpu::SurfaceTexture
    {
        let light_view_projections = self.calculate_light_view_projections();

        if let Some(ref mut snow_light_accum) = self.snow_light_accumulation
        {
            let mut encoder = self
                .device
                .create_command_encoder(&wgpu::CommandEncoderDescriptor {
                    label: Some("Snow Light Accumulation Encoder"),
                });

            snow_light_accum.render(
                &mut encoder,
                &self.queue,
                &self.spotlights,
                delta_time,
                &light_view_projections,
                self.shadow_bias,
                self.terrain_height_scale,
            );

            self.queue.submit(std::iter::once(encoder.finish()));
        }

        if self.snow_light_accumulation.is_some() && !self.snow_light_bound
        {
            self.rebuild_bind_group_with_snow_light();
            self.snow_light_bound = true;
        }

        self.render_shadow_pass(draw_calls, &light_view_projections, player_position, time);

        let mut encoder = self
            .device
            .create_command_encoder(&wgpu::CommandEncoderDescriptor {
                label: Some("Render Encoder"),
            });

        for (i, draw_call) in draw_calls.iter().enumerate()
        {
            let uniforms = Uniforms::new(
                draw_call.model,
                *view,
                *projection,
                &light_view_projections,
                camera_position,
                player_position,
                self.terrain_height_scale,
                time,
                self.shadow_bias,
                draw_call.tile_scale,
                draw_call.enable_dissolve,
                draw_call.enable_snow_light,
                &self.spotlights,
                debug_mode.as_u32(),
            );
            self.queue
                .write_buffer(&self.uniform_buffer, 0, bytemuck::cast_slice(&[uniforms]));

            {
                let mut render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                    label: Some("3D Render Pass"),
                    color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                        view: &self.framebuffer.view,
                        resolve_target: None,
                        ops: wgpu::Operations {
                            load: if i == 0
                            {
                                wgpu::LoadOp::Clear(wgpu::Color {
                                    r: 0.2,
                                    g: 0.2,
                                    b: 0.2,
                                    a: 1.0,
                                })
                            }
                            else
                            {
                                wgpu::LoadOp::Load
                            },
                            store: wgpu::StoreOp::Store,
                        },
                        depth_slice: None,
                    })],
                    depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
                        view: &self.framebuffer.depth_view,
                        depth_ops: Some(wgpu::Operations {
                            load: if i == 0
                            {
                                wgpu::LoadOp::Clear(1.0)
                            }
                            else
                            {
                                wgpu::LoadOp::Load
                            },
                            store: wgpu::StoreOp::Store,
                        }),
                        stencil_ops: None,
                    }),
                    timestamp_writes: None,
                    occlusion_query_set: None,
                    multiview_mask: None,
                });

                let pipeline = match draw_call.pipeline
                {
                    Pipeline::Standard => &self.standard_pipeline,
                    Pipeline::SnowClipmap => &self.snow_clipmap_pipeline,
                    Pipeline::DebugLines => self
                        .debug_lines_pipeline
                        .as_ref()
                        .unwrap_or(&self.standard_pipeline),
                };
                render_pass.set_pipeline(pipeline);
                render_pass.set_bind_group(0, &self.bind_group, &[]);

                if let Some(ref displacement_bind_group) = draw_call.displacement_bind_group
                {
                    render_pass.set_bind_group(1, displacement_bind_group, &[]);
                }

                render_pass.set_vertex_buffer(0, draw_call.vertex_buffer.slice(..));

                if let Some(ref instance_buffer) = draw_call.instance_buffer
                {
                    render_pass.set_vertex_buffer(1, instance_buffer.slice(..));
                }

                render_pass
                    .set_index_buffer(draw_call.index_buffer.slice(..), wgpu::IndexFormat::Uint32);
                render_pass.draw_indexed(0..draw_call.num_indices, 0, 0..draw_call.num_instances);
            }
        }

        if debug_mode == DebugMode::Wireframe
        {
            if let Some(ref wireframe_pipeline) = self.wireframe_pipeline
            {
                for draw_call in draw_calls.iter()
                {
                    if matches!(draw_call.pipeline, Pipeline::SnowClipmap | Pipeline::DebugLines)
                    {
                        continue;
                    }

                    let uniforms = Uniforms::new(
                        draw_call.model,
                        *view,
                        *projection,
                        &light_view_projections,
                        camera_position,
                        player_position,
                        self.terrain_height_scale,
                        time,
                        self.shadow_bias,
                        draw_call.tile_scale,
                        draw_call.enable_dissolve,
                        draw_call.enable_snow_light,
                        &self.spotlights,
                        4,
                    );
                    self.queue.write_buffer(
                        &self.uniform_buffer,
                        0,
                        bytemuck::cast_slice(&[uniforms]),
                    );

                    {
                        let mut wire_pass =
                            encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                                label: Some("Wireframe Pass"),
                                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                                    view: &self.framebuffer.view,
                                    resolve_target: None,
                                    ops: wgpu::Operations {
                                        load: wgpu::LoadOp::Load,
                                        store: wgpu::StoreOp::Store,
                                    },
                                    depth_slice: None,
                                })],
                                depth_stencil_attachment: Some(
                                    wgpu::RenderPassDepthStencilAttachment {
                                        view: &self.framebuffer.depth_view,
                                        depth_ops: Some(wgpu::Operations {
                                            load: wgpu::LoadOp::Load,
                                            store: wgpu::StoreOp::Store,
                                        }),
                                        stencil_ops: None,
                                    },
                                ),
                                timestamp_writes: None,
                                occlusion_query_set: None,
                                multiview_mask: None,
                            });

                        wire_pass.set_pipeline(wireframe_pipeline);
                        wire_pass.set_bind_group(0, &self.bind_group, &[]);
                        wire_pass.set_vertex_buffer(0, draw_call.vertex_buffer.slice(..));

                        if let Some(ref instance_buffer) = draw_call.instance_buffer
                        {
                            wire_pass.set_vertex_buffer(1, instance_buffer.slice(..));
                        }

                        wire_pass.set_index_buffer(
                            draw_call.index_buffer.slice(..),
                            wgpu::IndexFormat::Uint32,
                        );
                        wire_pass.draw_indexed(
                            0..draw_call.num_indices,
                            0,
                            0..draw_call.num_instances,
                        );
                    }
                }
            }
        }

        if debug_mode == DebugMode::ShadowMap
        {
            if let Some(ref overlay) = self.debug_overlay
            {
                let shadow_view = &self.shadow_map_view;
                let framebuffer_view = &self.framebuffer.view;
                let quad_vb = &self.quad_vb;
                let quad_ib = &self.quad_ib;
                let quad_num = self.quad_num_indices;
                let device = &self.device;
                overlay.render_shadow_map(
                    &mut encoder,
                    framebuffer_view,
                    shadow_view,
                    quad_vb,
                    quad_ib,
                    quad_num,
                    device,
                );
            }
        }
        else if debug_mode == DebugMode::SnowLight
        {
            if let Some(ref overlay) = self.debug_overlay
            {
                let snow_light_view = self
                    .snow_light_accumulation
                    .as_ref()
                    .map(|s| s.read_view())
                    .unwrap_or(&self.dummy_snow_light_view);
                let framebuffer_view = &self.framebuffer.view;
                let quad_vb = &self.quad_vb;
                let quad_ib = &self.quad_ib;
                let quad_num = self.quad_num_indices;
                let device = &self.device;
                let sampler = &self.dummy_snow_light_sampler;
                overlay.render_snow_light(
                    &mut encoder,
                    framebuffer_view,
                    snow_light_view,
                    sampler,
                    quad_vb,
                    quad_ib,
                    quad_num,
                    device,
                );
            }
        }

        self.queue.submit(std::iter::once(encoder.finish()));

        let frame = match self.surface.get_current_texture()
        {
            Ok(frame) => frame,
            Err(_) =>
            {
                self.surface.configure(&self.device, &self.config);
                self.surface
                    .get_current_texture()
                    .expect("Failed to acquire next surface texture")
            }
        };

        let screen_view = frame
            .texture
            .create_view(&wgpu::TextureViewDescriptor::default());

        let mut blit_encoder =
            self.device
                .create_command_encoder(&wgpu::CommandEncoderDescriptor {
                    label: Some("Blit Encoder"),
                });

        {
            let mut blit_pass = blit_encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                label: Some("Blit Pass"),
                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                    view: &screen_view,
                    resolve_target: None,
                    ops: wgpu::Operations {
                        load: wgpu::LoadOp::Clear(wgpu::Color::BLACK),
                        store: wgpu::StoreOp::Store,
                    },
                    depth_slice: None,
                })],
                depth_stencil_attachment: None,
                timestamp_writes: None,
                occlusion_query_set: None,
                multiview_mask: None,
            });

            blit_pass.set_pipeline(&self.blit_pipeline);
            blit_pass.set_bind_group(0, &self.blit_bind_group, &[]);
            blit_pass.set_vertex_buffer(0, self.quad_vb.slice(..));
            blit_pass.set_index_buffer(self.quad_ib.slice(..), wgpu::IndexFormat::Uint16);
            blit_pass.draw_indexed(0..self.quad_num_indices, 0, 0..1);
        }

        self.queue.submit(std::iter::once(blit_encoder.finish()));
        frame
    }

    pub fn render_scale(&self) -> (u32, u32)
    {
        (
            self.config.width / self.framebuffer.width,
            self.config.height / self.framebuffer.height,
        )
    }

    pub fn set_terrain_data(&mut self)
    {
        let shadow_bind_group = self.device.create_bind_group(&wgpu::BindGroupDescriptor {
            label: Some("Shadow Bind Group"),
            layout: &self.shadow_bind_group_layout,
            entries: &[wgpu::BindGroupEntry {
                binding: 0,
                resource: self.uniform_buffer.as_entire_binding(),
            }],
        });

        let shadow_pipeline =
            pipeline::create_shadow_pipeline(&self.device, &self.shadow_bind_group_layout);

        self.shadow_bind_group = Some(shadow_bind_group);
        self.shadow_pipeline = Some(shadow_pipeline);
        self.terrain_height_scale = 1.0;
    }

    pub fn init_snow_light_accumulation(&mut self, terrain_min: glam::Vec2, terrain_max: glam::Vec2)
    {
        let snow_light_accumulation = crate::snow_light::SnowLightAccumulation::new(
            &self.device,
            terrain_min,
            terrain_max,
            512,
        );

        self.snow_light_accumulation = Some(snow_light_accumulation);
    }

    pub fn set_snow_depth(&mut self, snow_depth_view: &wgpu::TextureView)
    {
        println!("set_snow_depth() called");
        if let Some(ref mut snow_light_accum) = self.snow_light_accumulation
        {
            println!("Snow light accumulation exists, setting up bind groups");
            let snow_depth_sampler = self.device.create_sampler(&wgpu::SamplerDescriptor {
                label: Some("Snow Depth Sampler"),
                address_mode_u: wgpu::AddressMode::ClampToEdge,
                address_mode_v: wgpu::AddressMode::ClampToEdge,
                mag_filter: wgpu::FilterMode::Nearest,
                min_filter: wgpu::FilterMode::Nearest,
                ..Default::default()
            });

            match crate::texture::HeightmapTexture::load(
                &self.device,
                &self.queue,
                "textures/terrain_heightmap.exr",
            )
            {
                Ok(heightmap) =>
                {
                    snow_light_accum.set_heightmap(
                        &self.device,
                        &heightmap.view,
                        &heightmap.sampler,
                        &self.shadow_map_view,
                        &self.shadow_map_sampler,
                        snow_depth_view,
                        &snow_depth_sampler,
                    );
                }
                Err(e) =>
                {
                    eprintln!("Failed to load heightmap for snow depth setup: {}", e);
                }
            }
        }
    }

    pub fn aspect_ratio(&self) -> f32
    {
        self.config.width as f32 / self.config.height as f32
    }
}

thread_local! {
    static GLOBAL_RENDERER: RefCell<Option<Renderer>> = RefCell::new(None);
}

pub fn init(renderer: Renderer)
{
    GLOBAL_RENDERER.with(|r| *r.borrow_mut() = Some(renderer));
}

pub fn with_device<F, R>(f: F) -> R
where
    F: FnOnce(&wgpu::Device) -> R,
{
    GLOBAL_RENDERER.with(|r| {
        let renderer = r.borrow();
        let renderer = renderer.as_ref().expect("Renderer not set");
        f(&renderer.device)
    })
}

pub fn with_queue<F, R>(f: F) -> R
where
    F: FnOnce(&wgpu::Queue) -> R,
{
    GLOBAL_RENDERER.with(|r| {
        let renderer = r.borrow();
        let renderer = renderer.as_ref().expect("Renderer not set");
        f(&renderer.queue)
    })
}

pub fn set_terrain_data()
{
    GLOBAL_RENDERER.with(|r| {
        let mut renderer = r.borrow_mut();
        let renderer = renderer.as_mut().expect("Renderer not set");
        renderer.set_terrain_data();
    });
}

pub fn init_snow_light_accumulation(terrain_min: glam::Vec2, terrain_max: glam::Vec2)
{
    GLOBAL_RENDERER.with(|r| {
        let mut renderer = r.borrow_mut();
        let renderer = renderer.as_mut().expect("Renderer not set");
        renderer.init_snow_light_accumulation(terrain_min, terrain_max);
    });
}

pub fn set_snow_depth(snow_depth_view: &wgpu::TextureView)
{
    GLOBAL_RENDERER.with(|r| {
        let mut renderer = r.borrow_mut();
        let renderer = renderer.as_mut().expect("Renderer not set");
        renderer.set_snow_depth(snow_depth_view);
    });
}

pub fn aspect_ratio() -> f32
{
    GLOBAL_RENDERER.with(|r| {
        let renderer = r.borrow();
        let renderer = renderer.as_ref().expect("Renderer not set");
        renderer.aspect_ratio()
    })
}

pub fn render(
    view: &glam::Mat4,
    projection: &glam::Mat4,
    camera_position: glam::Vec3,
    player_position: glam::Vec3,
    draw_calls: &[DrawCall],
    time: f32,
    delta_time: f32,
    debug_mode: DebugMode,
) -> wgpu::SurfaceTexture
{
    GLOBAL_RENDERER.with(|r| {
        let mut renderer = r.borrow_mut();
        let renderer = renderer.as_mut().expect("Renderer not set");
        renderer.render(
            view,
            projection,
            camera_position,
            player_position,
            draw_calls,
            time,
            delta_time,
            debug_mode,
        )
    })
}

pub fn with_surface_format<F, R>(f: F) -> R
where
    F: FnOnce(wgpu::TextureFormat) -> R,
{
    GLOBAL_RENDERER.with(|r| {
        let renderer = r.borrow();
        let renderer = renderer.as_ref().expect("Renderer not set");
        f(renderer.config.format)
    })
}

pub fn set_shadow_bias(bias: f32)
{
    GLOBAL_RENDERER.with(|r| {
        let mut renderer = r.borrow_mut();
        let renderer = renderer.as_mut().expect("Renderer not set");
        renderer.shadow_bias = bias;
    });
}

pub fn update_spotlights(spotlights: Vec<Spotlight>)
{
    GLOBAL_RENDERER.with(|r| {
        let mut renderer = r.borrow_mut();
        let renderer = renderer.as_mut().expect("Renderer not set");
        renderer.spotlights = spotlights;
    });
}