use anyhow::Result;
use cgmath::{Matrix4, Vector2, Vector4};
use vulkan_rs::prelude::*;

use std::{
    sync::{Arc, Mutex},
    time::Duration,
};

use super::{pipeline::SingleColorPipeline, rfactor_data::RenderObject};
use crate::write_log;

#[derive(Clone)]
pub struct PositionOnlyVertex {
    pub position: Vector4<f32>,
}

impl PositionOnlyVertex {
    ///
    /// corners[0]  -  bottom left
    /// corners[1]  -  top left
    /// corners[2]  -  top right
    /// corners[3]  -  bottom right
    ///
    pub fn from_2d_corners(ortho: Matrix4<f32>, corners: [Vector2<f32>; 4]) -> [Self; 6] {
        [
            Self {
                position: ortho * corners[0].extend(0.0).extend(1.0),
            },
            Self {
                position: ortho * corners[1].extend(0.0).extend(1.0),
            },
            Self {
                position: ortho * corners[2].extend(0.0).extend(1.0),
            },
            Self {
                position: ortho * corners[2].extend(0.0).extend(1.0),
            },
            Self {
                position: ortho * corners[3].extend(0.0).extend(1.0),
            },
            Self {
                position: ortho * corners[0].extend(0.0).extend(1.0),
            },
        ]
    }
}

pub struct Rendering {
    swapchain: Arc<Swapchain>,
    pipeline: SingleColorPipeline,
    render_target: RenderTarget,
    command_buffer: Arc<CommandBuffer>,

    queue: Arc<Mutex<Queue>>,
}

impl Rendering {
    pub fn new(
        device: Arc<Device>,
        queue: Arc<Mutex<Queue>>,
        swapchain: Arc<Swapchain>,
    ) -> Result<Self> {
        crate::write_log!("-> Rendering ctor: begin");
        let vk_images = swapchain.vk_images()?;
        write_log!(format!(
            "-> Rendering ctor: vk images ({})",
            vk_images.len()
        ));
        let images = match swapchain.wrap_images(&vk_images, &queue, true) {
            Ok(images) => images,
            Err(err) => {
                write_log!(format!("-> Rendering ctor: failed wrapper: {:?}", err));
                return Err(err);
            }
        };
        write_log!("-> Rendering ctor: wrapped images");

        let render_target = RenderTarget::builder()
            .add_sub_pass(
                SubPass::builder(swapchain.width(), swapchain.height())
                    .set_prepared_targets(&images, 0, [0.0, 0.0, 0.0, 1.0], false)
                    .build(&device, &queue)?,
            )
            .build(&device)?;

        write_log!("-> Rendering ctor: created render_target");

        write_log!(format!(
            "-> Rendering swapchain extents ({}, {})",
            swapchain.width(),
            swapchain.height(),
        ));

        Ok(Self {
            swapchain,
            pipeline: SingleColorPipeline::new(device.clone(), render_target.render_pass())?,
            render_target,
            command_buffer: CommandBuffer::new_primary().build(device.clone(), queue.clone())?,

            queue,
        })
    }

    pub fn swapchain(&self) -> &Arc<Swapchain> {
        &self.swapchain
    }

    pub fn single_color_pipeline(&self) -> &SingleColorPipeline {
        &self.pipeline
    }

    pub fn render(
        &mut self,
        swapchain: Arc<Swapchain>,
        objects: &[&dyn RenderObject],
    ) -> Result<()> {
        let image_index = self.swapchain.current_index();

        let viewport = [VkViewport {
            x: 0.0,
            y: 0.0,
            width: swapchain.width() as f32,
            height: swapchain.height() as f32,
            minDepth: 0.0,
            maxDepth: 1.0,
        }];

        let scissor = [VkRect2D {
            offset: VkOffset2D { x: 0, y: 0 },
            extent: VkExtent2D {
                width: swapchain.width(),
                height: swapchain.height(),
            },
        }];

        {
            let mut recorder = self.command_buffer.begin(VkCommandBufferBeginInfo::new(
                VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT
                    | VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT,
            ))?;

            self.render_target
                .begin(&recorder, VK_SUBPASS_CONTENTS_INLINE, image_index as usize);

            recorder.bind_pipeline(self.pipeline.pipeline())?;
            recorder.set_scissor(&scissor);
            recorder.set_viewport(&viewport);

            write_log!(format!("-> Rendering {} objects", objects.len()));

            for object in objects {
                let buffer = object.buffer();

                recorder.bind_descriptor_sets_minimal(&[object.descriptor()]);
                recorder.bind_vertex_buffer(buffer);
                recorder.draw_complete_single_instance(buffer.size() as u32);
            }

            self.render_target.end(&recorder);
        }

        let queue = self.queue.lock().unwrap();
        queue.minimal_submit(Duration::from_secs(10), &[self.command_buffer.clone()])?;

        Ok(())
    }
}