use crate::globaluniform::{AtlasArray, AtlasImageLocation, SpriteData, SpriteDataArray};
use anyhow::Result;
use bytemuck::Zeroable;
use galactica_content::Content;
use galactica_packer::SpriteAtlasImage;
use galactica_util::constants::ASSET_CACHE;
use image::GenericImageView;
use std::{fs::File, io::Read, num::NonZeroU32, path::Path};
use wgpu::BindGroupLayout;

pub(crate) struct RawTexture {
	pub(crate) view: wgpu::TextureView,
}

impl RawTexture {
	pub(crate) fn from_bytes(
		device: &wgpu::Device,
		queue: &wgpu::Queue,
		bytes: &[u8],
		label: &str,
	) -> Result<Self> {
		let img = image::load_from_memory(bytes)?;
		Self::from_image(device, queue, &img, Some(label))
	}

	pub(crate) fn from_image(
		device: &wgpu::Device,
		queue: &wgpu::Queue,
		img: &image::DynamicImage,
		label: Option<&str>,
	) -> Result<Self> {
		let rgba = img.to_rgba8();
		let dimensions = img.dimensions();

		let size = wgpu::Extent3d {
			width: dimensions.0,
			height: dimensions.1,
			depth_or_array_layers: 1,
		};

		let texture = device.create_texture(&wgpu::TextureDescriptor {
			label,
			size,
			mip_level_count: 1,
			sample_count: 1,
			dimension: wgpu::TextureDimension::D2,
			format: wgpu::TextureFormat::Rgba8UnormSrgb,
			usage: wgpu::TextureUsages::TEXTURE_BINDING | wgpu::TextureUsages::COPY_DST,
			view_formats: &[],
		});

		let view = texture.create_view(&Default::default());

		queue.write_texture(
			wgpu::ImageCopyTexture {
				aspect: wgpu::TextureAspect::All,
				texture: &texture,
				mip_level: 0,
				origin: wgpu::Origin3d::ZERO,
			},
			&rgba,
			wgpu::ImageDataLayout {
				offset: 0,
				bytes_per_row: Some(4 * dimensions.0),
				rows_per_image: Some(dimensions.1),
			},
			size,
		);

		Ok(Self { view })
	}
}

#[derive(Debug, Clone)]
pub struct Texture {
	pub index: u32,          // Index in texture array
	pub len: u32,            // Number of frames
	pub frame_duration: f32, // Frames per second
	pub aspect: f32,         // width / height
	pub repeat: u32,         // How to re-play this texture
	pub location: Vec<SpriteAtlasImage>,
}

pub struct TextureArray {
	pub bind_group: wgpu::BindGroup,
	pub bind_group_layout: BindGroupLayout,
	pub image_locations: AtlasArray,
	pub sprite_data: SpriteDataArray,
}

impl TextureArray {
	pub fn new(device: &wgpu::Device, queue: &wgpu::Queue, ct: &Content) -> Result<Self> {
		// Load all textures
		let mut texture_data = Vec::new();

		for a in ct.atlas_files() {
			println!("opening {a}");
			let p = Path::new(ASSET_CACHE);
			let mut f = File::open(p.join(a))?;
			let mut bytes = Vec::new();
			f.read_to_end(&mut bytes)?;
			texture_data.push(RawTexture::from_bytes(
				&device,
				&queue,
				&bytes,
				&format!("Atlas `{a}`"),
			)?);
		}

		let mut image_locations = AtlasArray::zeroed();
		let mut sprite_data = SpriteDataArray::zeroed();

		println!("sending to gpu");
		let mut image_counter = 0;
		let mut sprite_counter = 0;
		for t in &ct.sprites {
			sprite_data.data[sprite_counter] = SpriteData {
				frame_count: t.frames.len() as u32,
				repeatmode: t.repeat.as_int(),
				aspect: t.aspect,
				frame_duration: t.frame_duration,
				first_frame: image_counter,
				_padding: Default::default(),
			};
			sprite_counter += 1;

			// Insert texture location data
			for path in &t.frames {
				let image = ct.get_image(&path);
				image_locations.data[image_counter as usize] = AtlasImageLocation {
					xpos: image.x,
					ypos: image.y,
					width: image.w,
					height: image.h,
					atlas_texture: image.atlas,
					_padding: Default::default(),
				};
				image_counter += 1;
			}
		}

		let sampler = device.create_sampler(&wgpu::SamplerDescriptor {
			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::Nearest,
			mipmap_filter: wgpu::FilterMode::Nearest,
			..Default::default()
		});

		let bind_group_layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
			label: Some("TextureArray bind group layout"),
			entries: &[
				// Texture data
				wgpu::BindGroupLayoutEntry {
					binding: 0,
					visibility: wgpu::ShaderStages::VERTEX_FRAGMENT,
					ty: wgpu::BindingType::Texture {
						multisampled: false,
						view_dimension: wgpu::TextureViewDimension::D2,
						sample_type: wgpu::TextureSampleType::Float { filterable: true },
					},
					count: NonZeroU32::new(texture_data.len() as u32),
				},
				// Texture sampler
				wgpu::BindGroupLayoutEntry {
					binding: 1,
					visibility: wgpu::ShaderStages::VERTEX_FRAGMENT,
					ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Filtering),
					count: NonZeroU32::new(1),
				},
			],
		});

		let views: Vec<&wgpu::TextureView> = texture_data.iter().map(|x| &x.view).collect();
		let bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
			label: Some("TextureArray bind group"),
			layout: &bind_group_layout,
			entries: &[
				wgpu::BindGroupEntry {
					binding: 0,
					resource: wgpu::BindingResource::TextureViewArray(&views),
				},
				wgpu::BindGroupEntry {
					binding: 1,
					resource: wgpu::BindingResource::SamplerArray(&[&sampler]),
				},
			],
		});

		return Ok(Self {
			bind_group,
			bind_group_layout,
			image_locations,
			sprite_data,
		});
	}
}