//! Minimal code for drawing any level, based on traits from stockton-levels

use super::{DrawPass, IntoDrawPass};
use crate::{
    draw::{
        buffers::{
            draw_buffers::{DrawBuffers, INITIAL_INDEX_SIZE, INITIAL_VERT_SIZE},
            DedicatedLoadedImage, ModifiableBuffer,
        },
        builders::{
            pipeline::{
                CompletePipeline, PipelineSpecBuilder, VertexBufferSpec,
                VertexPrimitiveAssemblerSpec,
            },
            renderpass::RenderpassSpec,
            shader::ShaderDesc,
        },
        queue_negotiator::QueueNegotiator,
        target::SwapchainProperties,
        texture::{resolver::FsResolver, TexLoadQueue, TextureLoadConfig, TextureRepo},
    },
    error::{EnvironmentError, LevelError, LockPoisoned},
    types::*,
};
use hal::{
    buffer::SubRange,
    command::{ClearColor, ClearDepthStencil, ClearValue, RenderAttachmentInfo, SubpassContents},
    format::{Aspects, Format},
    image::{
        Filter, FramebufferAttachment, Layout, SubresourceRange, Usage, ViewCapabilities, WrapMode,
    },
    pass::{Attachment, AttachmentLoadOp, AttachmentOps, AttachmentStoreOp},
    pso::{
        BlendDesc, BlendOp, BlendState, ColorBlendDesc, ColorMask, Comparison, DepthStencilDesc,
        DepthTest, Face, Factor, FrontFace, InputAssemblerDesc, LogicOp, PolygonMode, Primitive,
        Rasterizer, ShaderStageFlags, State, VertexInputRate,
    },
};
use legion::{Entity, IntoQuery};
use shaderc::ShaderKind;
use stockton_levels::{
    features::MinRenderFeatures,
    parts::{data::Geometry, IsFace},
};
use stockton_types::{
    components::{CameraSettings, CameraVPMatrix, Transform},
    *,
};

use std::{
    array::IntoIter,
    convert::TryInto,
    iter::{empty, once},
    marker::PhantomData,
    path::Path,
    sync::{Arc, RwLock},
};

use anyhow::{Context, Result};

/// The Vertexes that go to the shader
#[derive(Debug, Clone, Copy)]
struct UvPoint(pub Vector3, pub i32, pub Vector2);

/// Draw a level
pub struct LevelDrawPass<'a, M> {
    pipeline: CompletePipeline,
    repo: TextureRepo,
    active_camera: Entity,
    draw_buffers: DrawBuffers<'a, UvPoint>,

    framebuffers: Vec<FramebufferT>,
    depth_buffers: Vec<DedicatedLoadedImage>,
    next_resources: usize,

    _d: PhantomData<M>,
}

impl<'a, M> DrawPass for LevelDrawPass<'a, M>
where
    M: for<'b> MinRenderFeatures<'b> + 'static,
{
    fn queue_draw(
        &mut self,
        session: &Session,
        img_view: &ImageViewT,
        cmd_buffer: &mut crate::types::CommandBufferT,
    ) -> anyhow::Result<()> {
        // We might have loaded more textures
        self.repo.process_responses();

        // Make sure we update the vertex buffers after they're written to, but before they're read from.
        self.draw_buffers
            .vertex_buffer
            .record_commit_cmds(cmd_buffer)?;
        self.draw_buffers
            .index_buffer
            .record_commit_cmds(cmd_buffer)?;

        // Get level & camera
        let mut query = <(&Transform, &CameraSettings, &CameraVPMatrix)>::query();
        let (camera_transform, camera_settings, camera_vp) = query
            .get(&session.world, self.active_camera)
            .context("Couldn't find camera components")?;
        let map_lock: Arc<RwLock<M>> = session.resources.get::<Arc<RwLock<M>>>().unwrap().clone();
        let map = map_lock.read().map_err(|_| LockPoisoned::Map)?;

        // Get framebuffer and depth buffer
        let fb = &self.framebuffers[self.next_resources];
        let db = &self.depth_buffers[self.next_resources];
        self.next_resources = (self.next_resources + 1) % self.framebuffers.len();

        unsafe {
            cmd_buffer.begin_render_pass(
                &self.pipeline.renderpass,
                fb,
                self.pipeline.render_area,
                vec![
                    RenderAttachmentInfo {
                        image_view: img_view,
                        clear_value: ClearValue {
                            color: ClearColor {
                                float32: [0.0, 0.0, 0.0, 1.0],
                            },
                        },
                    },
                    RenderAttachmentInfo {
                        image_view: &*db.image_view,
                        clear_value: ClearValue {
                            depth_stencil: ClearDepthStencil {
                                depth: 1.0,
                                stencil: 0,
                            },
                        },
                    },
                ]
                .into_iter(),
                SubpassContents::Inline,
            );
            cmd_buffer.bind_graphics_pipeline(&self.pipeline.pipeline);

            // VP Matrix
            let vp = &*(camera_vp.vp_matrix.data.as_slice() as *const [f32] as *const [u32]);

            cmd_buffer.push_graphics_constants(
                &self.pipeline.pipeline_layout,
                ShaderStageFlags::VERTEX,
                0,
                vp,
            );

            // Bind buffers
            cmd_buffer.bind_vertex_buffers(
                0,
                once((
                    self.draw_buffers.vertex_buffer.get_buffer(),
                    SubRange {
                        offset: 0,
                        size: None,
                    },
                )),
            );
            cmd_buffer.bind_index_buffer(
                self.draw_buffers.index_buffer.get_buffer(),
                SubRange {
                    offset: 0,
                    size: None,
                },
                hal::IndexType::U16,
            );
        }

        // Get visible faces
        let mut faces = map.get_visible(camera_transform, camera_settings);

        // Iterate over faces, copying them in and drawing groups that use the same texture chunk all at once.
        let face = faces.next();
        if let Some(face) = face {
            let mut face = map.get_face(face).ok_or(LevelError::BadReference)?;
            let mut current_chunk = face.texture_idx(&map) as usize / 8;
            let mut chunk_start = 0;

            let mut curr_vert_idx: usize = 0;
            let mut curr_idx_idx: usize = 0;
            loop {
                if current_chunk != face.texture_idx(&map) as usize / 8 {
                    // Last index was last of group, so draw it all if textures are loaded.
                    draw_or_queue(
                        current_chunk,
                        &mut self.repo,
                        cmd_buffer,
                        &*self.pipeline.pipeline_layout,
                        chunk_start as u32,
                        curr_idx_idx as u32,
                    )?;

                    // Next group of same-chunked faces starts here.
                    chunk_start = curr_idx_idx;
                    current_chunk = face.texture_idx(&map) as usize / 8;
                }

                match face.geometry(&map) {
                    Geometry::Vertices(v1, v2, v3) => {
                        for v in [v1, v2, v3] {
                            let uvp =
                                UvPoint(v.position, face.texture_idx(&map).try_into()?, v.tex);

                            self.draw_buffers.vertex_buffer[curr_vert_idx] = uvp;
                            curr_vert_idx += 1;
                        }
                        self.draw_buffers.index_buffer[curr_idx_idx] = (
                            curr_vert_idx as u16 - 3,
                            curr_vert_idx as u16 - 2,
                            curr_vert_idx as u16 - 1,
                        );
                        curr_idx_idx += 1;
                    }
                }

                if curr_vert_idx >= INITIAL_VERT_SIZE.try_into()?
                    || curr_idx_idx >= INITIAL_INDEX_SIZE.try_into()?
                {
                    println!("out of vertex buffer space!");
                    break;
                }

                match faces.next() {
                    Some(x) => face = map.get_face(x).ok_or(LevelError::BadReference)?,
                    None => break,
                };
            }

            // Draw the final group of chunks
            draw_or_queue(
                current_chunk,
                &mut self.repo,
                cmd_buffer,
                &*self.pipeline.pipeline_layout,
                chunk_start as u32,
                curr_idx_idx as u32,
            )?;
        }

        unsafe {
            cmd_buffer.end_render_pass();
        }

        Ok(())
    }

    fn deactivate(self, device_lock: &mut Arc<RwLock<DeviceT>>) -> Result<()> {
        unsafe {
            let mut device = device_lock.write().map_err(|_| LockPoisoned::Device)?;
            self.pipeline.deactivate(&mut device);
            self.draw_buffers.deactivate(&mut device);
            for fb in self.framebuffers.into_iter() {
                device.destroy_framebuffer(fb);
            }
            for db in self.depth_buffers.into_iter() {
                db.deactivate(&mut device);
            }
        }
        self.repo.deactivate(device_lock);

        Ok(())
    }
}

impl<'a, M> IntoDrawPass<LevelDrawPass<'a, M>> for Entity
where
    M: for<'b> MinRenderFeatures<'b> + 'static,
{
    fn init(
        self,
        session: &Session,
        adapter: &Adapter,
        device_lock: Arc<RwLock<DeviceT>>,
        queue_negotiator: &mut QueueNegotiator,
        swapchain_properties: &SwapchainProperties,
    ) -> Result<LevelDrawPass<'a, M>> {
        let spec = PipelineSpecBuilder::default()
            .rasterizer(Rasterizer {
                polygon_mode: PolygonMode::Fill,
                cull_face: Face::BACK,
                front_face: FrontFace::CounterClockwise,
                depth_clamping: false,
                depth_bias: None,
                conservative: true,
                line_width: State::Static(1.0),
            })
            .depth_stencil(DepthStencilDesc {
                depth: Some(DepthTest {
                    fun: Comparison::Less,
                    write: true,
                }),
                depth_bounds: false,
                stencil: None,
            })
            .blender(BlendDesc {
                logic_op: Some(LogicOp::Copy),
                targets: vec![ColorBlendDesc {
                    mask: ColorMask::ALL,
                    blend: Some(BlendState {
                        color: BlendOp::Add {
                            src: Factor::One,
                            dst: Factor::Zero,
                        },
                        alpha: BlendOp::Add {
                            src: Factor::One,
                            dst: Factor::Zero,
                        },
                    }),
                }],
            })
            .primitive_assembler(VertexPrimitiveAssemblerSpec::with_buffers(
                InputAssemblerDesc::new(Primitive::TriangleList),
                vec![VertexBufferSpec {
                    attributes: vec![Format::Rgb32Sfloat, Format::R32Sint, Format::Rg32Sfloat],
                    rate: VertexInputRate::Vertex,
                }],
            ))
            .shader_vertex(ShaderDesc {
                source: include_str!("../data/stockton.vert").to_string(),
                entry: "main".to_string(),
                kind: ShaderKind::Vertex,
            })
            .shader_fragment(ShaderDesc {
                source: include_str!("../data/stockton.frag").to_string(),
                entry: "main".to_string(),
                kind: ShaderKind::Fragment,
            })
            .push_constants(vec![(ShaderStageFlags::VERTEX, 0..64)])
            .renderpass(RenderpassSpec {
                colors: vec![Attachment {
                    format: Some(swapchain_properties.format),
                    samples: 1,
                    ops: AttachmentOps::new(AttachmentLoadOp::Clear, AttachmentStoreOp::Store),
                    stencil_ops: AttachmentOps::new(
                        AttachmentLoadOp::Clear,
                        AttachmentStoreOp::DontCare,
                    ),
                    layouts: Layout::ColorAttachmentOptimal..Layout::ColorAttachmentOptimal,
                }],
                depth: Some(Attachment {
                    format: Some(swapchain_properties.depth_format),
                    samples: 1,
                    ops: AttachmentOps::new(AttachmentLoadOp::Clear, AttachmentStoreOp::DontCare),
                    stencil_ops: AttachmentOps::new(
                        AttachmentLoadOp::DontCare,
                        AttachmentStoreOp::DontCare,
                    ),
                    layouts: Layout::Undefined..Layout::DepthStencilAttachmentOptimal,
                }),
                inputs: vec![],
                resolves: vec![],
                preserves: vec![],
            })
            .build()
            .context("Error building pipeline")?;

        let map_lock: Arc<RwLock<M>> = session.resources.get::<Arc<RwLock<M>>>().unwrap().clone();
        let repo = TextureRepo::new(
            device_lock.clone(),
            queue_negotiator
                .family::<TexLoadQueue>()
                .ok_or(EnvironmentError::NoSuitableFamilies)
                .context("Error finding texture queue")?,
            queue_negotiator
                .get_queue::<TexLoadQueue>()
                .ok_or(EnvironmentError::NoQueues)
                .context("Error finding texture queue")?,
            adapter,
            TextureLoadConfig {
                resolver: FsResolver::new(Path::new("textures"), map_lock),
                filter: Filter::Linear,
                wrap_mode: WrapMode::Tile,
            },
        )
        .context("Error creating texture repo")?;

        let (draw_buffers, pipeline, framebuffers, depth_buffers) = {
            let mut device = device_lock.write().map_err(|_| LockPoisoned::Device)?;
            let draw_buffers =
                DrawBuffers::new(&mut device, adapter).context("Error creating draw buffers")?;
            let pipeline = spec
                .build(
                    &mut device,
                    swapchain_properties.extent,
                    swapchain_properties,
                    once(&*repo.get_ds_layout()?),
                )
                .context("Error building pipeline")?;

            let mut framebuffers = Vec::with_capacity(swapchain_properties.image_count as usize);
            let mut depth_buffers = Vec::with_capacity(swapchain_properties.image_count as usize);
            let fat = FramebufferAttachment {
                usage: Usage::COLOR_ATTACHMENT,
                format: swapchain_properties.format,
                view_caps: ViewCapabilities::empty(),
            };
            let dat = FramebufferAttachment {
                usage: Usage::DEPTH_STENCIL_ATTACHMENT,
                format: swapchain_properties.depth_format,
                view_caps: ViewCapabilities::empty(),
            };
            for _i in 0..swapchain_properties.image_count {
                unsafe {
                    framebuffers.push(device.create_framebuffer(
                        &pipeline.renderpass,
                        IntoIter::new([fat.clone(), dat.clone()]),
                        swapchain_properties.extent,
                    )?);
                    depth_buffers.push(
                        DedicatedLoadedImage::new(
                            &mut device,
                            adapter,
                            swapchain_properties.depth_format,
                            Usage::DEPTH_STENCIL_ATTACHMENT,
                            SubresourceRange {
                                aspects: Aspects::DEPTH,
                                level_start: 0,
                                level_count: Some(1),
                                layer_start: 0,
                                layer_count: Some(1),
                            },
                            swapchain_properties.extent.width as usize,
                            swapchain_properties.extent.height as usize,
                        )
                        .context("Error creating depth buffer")?,
                    )
                }
            }

            (draw_buffers, pipeline, framebuffers, depth_buffers)
        };

        Ok(LevelDrawPass {
            pipeline,
            repo,
            draw_buffers,
            active_camera: self,
            _d: PhantomData,
            framebuffers,
            depth_buffers,
            next_resources: 0,
        })
    }

    fn find_aux_queues<'c>(
        adapter: &'c Adapter,
        queue_negotiator: &mut QueueNegotiator,
    ) -> Result<Vec<(&'c QueueFamilyT, Vec<f32>)>> {
        queue_negotiator.find(adapter, &TexLoadQueue)?;

        Ok(vec![queue_negotiator
            .family_spec::<TexLoadQueue>(&adapter.queue_families, 1)
            .ok_or(EnvironmentError::NoSuitableFamilies)?])
    }
}

fn draw_or_queue(
    current_chunk: usize,
    tex_repo: &mut TextureRepo,
    cmd_buffer: &mut CommandBufferT,
    pipeline_layout: &PipelineLayoutT,
    chunk_start: u32,
    curr_idx_idx: u32,
) -> Result<()> {
    if let Some(ds) = tex_repo.attempt_get_descriptor_set(current_chunk) {
        unsafe {
            cmd_buffer.bind_graphics_descriptor_sets(pipeline_layout, 0, once(ds), empty());
            cmd_buffer.draw_indexed(chunk_start * 3..(curr_idx_idx * 3) + 1, 0, 0..1);
        }
    } else {
        tex_repo.queue_load(current_chunk)?
    }

    Ok(())
}