use crate::{RenderCoreCreateInfo, prelude::*, renderbackend::RenderBackend};

use super::windowsystemintegration::WindowSystemIntegration;

use crate::Result;
use ecs::World;
// use ui::prelude::*;
use vulkan_rs::prelude::*;

use std::sync::{
    Arc, Mutex, RwLock,
    atomic::{AtomicUsize, Ordering::SeqCst},
};
use std::time::Duration;
use std::u64;

pub struct VulkanWindowRenderCore {
    device: Arc<Device>,

    // driver provided images
    swapchain: Arc<Swapchain>,
    _surface: Arc<Surface>,

    format: VkFormat,

    image_available_sem: RwLock<Arc<Semaphore>>,
    render_finished_sem: Arc<Semaphore>,
    render_fence: Arc<Fence>,

    render_backend: RenderBackend,

    current_image_index: AtomicUsize,

    wsi: Arc<WindowSystemIntegration>,
}

impl VulkanWindowRenderCore {
    pub fn new(
        wsi: Arc<WindowSystemIntegration>,
        device: &Arc<Device>,
        queue: &Arc<Mutex<Queue>>,
        create_info: RenderCoreCreateInfo,
    ) -> Result<(Self, TargetMode<()>)> {
        // check swapchain extension
        if !device.enabled_extensions().swapchain {
            return Err(anyhow::Error::msg("Swapchain Extension must be enabled"));
        }

        let surface = wsi.surface();

        if (surface.capabilities(device)?.supportedUsageFlagBits & VK_IMAGE_USAGE_TRANSFER_DST_BIT)
            == 0
        {
            return Err(anyhow::Error::msg(format!(
                "Surface capability not met: {:?}",
                VK_IMAGE_USAGE_TRANSFER_DST_BIT
            )));
        }

        let usage = create_info.usage | RenderBackend::required_image_usage();

        // create swapchain
        let swapchain = Swapchain::new(
            device.clone(),
            &surface,
            create_info.vsync,
            2,
            usage,
            create_info.format,
            1,
            wsi.window_size(),
        )?;

        let swapchain_images = swapchain.wrap_images(&swapchain.vk_images()?, queue, false)?;

        let render_sem = Semaphore::new(device.clone())?;
        let image_sem = Semaphore::new(device.clone())?;
        let fence = Fence::builder().build(device.clone())?;

        let images = TargetMode::Mono(swapchain_images);

        let render_backend = RenderBackend::new(device, queue, images)?;

        let window_render_core = VulkanWindowRenderCore {
            device: device.clone(),

            format: swapchain.format(),

            swapchain,
            _surface: surface,

            render_finished_sem: render_sem,
            image_available_sem: RwLock::new(image_sem),
            render_fence: fence,

            render_backend,

            current_image_index: AtomicUsize::new(0),

            wsi,
        };

        Ok((window_render_core, TargetMode::Mono(())))
    }

    fn aquire_next_image_index(&mut self, world: &mut World) -> Result<()> {
        // there was a bug that a windows never reacted after it was minimized
        // with this timeout, the window has 250ms delay
        #[cfg(target_os = "windows")]
        const ACQUIRE_IMAGE_TIME_OUT: u64 = 1_000_000_000 / 4;

        #[cfg(target_os = "linux")]
        const ACQUIRE_IMAGE_TIME_OUT: u64 = u64::MAX;

        let resize_mut = unsafe { remove_life_time_mut(self) };
        let mut semaphore = self.image_available_sem.write().unwrap();

        loop {
            match self
                .swapchain
                .acquire_next_image(ACQUIRE_IMAGE_TIME_OUT, &*semaphore)?
            {
                OutOfDate::Ok(index) => {
                    self.current_image_index.store(index as usize, SeqCst);
                    break;
                }
                OutOfDate::OutOfDate => {
                    let (w, h) = self.wsi.window_size();
                    resize_mut.resize(world, w, h)?;

                    *semaphore = Semaphore::new(self.device.clone())?;
                }
                OutOfDate::TimeOut => {
                    break;
                }
            }
        }

        Ok(())
    }
}

impl VulkanWindowRenderCore {
    pub fn format(&self) -> VkFormat {
        self.format
    }

    pub fn resize(&mut self, world: &mut World, w: u32, h: u32) -> Result<()> {
        self.swapchain.recreate((w, h))?;

        let swapchain_images = self.swapchain.wrap_images(
            &self.swapchain.vk_images()?,
            self.render_backend.queue(),
            false,
        )?;

        self.render_backend.resize(
            world,
            TargetMode::Mono(swapchain_images),
            self.swapchain.width(),
            self.swapchain.height(),
        )?;

        Ok(())
    }

    pub fn next_frame(&mut self, world: &mut World) -> Result<bool> {
        self.aquire_next_image_index(world)?;

        let command_buffer = self.render_backend.render(
            world,
            TargetMode::Mono(self.current_image_index.load(SeqCst)),
        )?;

        let submits = &[SubmitInfo::default()
            .add_wait_semaphore(
                &*self.image_available_sem.read().unwrap(),
                VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
            )
            .add_command_buffer(command_buffer)
            .add_signal_semaphore(&self.render_finished_sem)];

        if let OutOfDate::OutOfDate = {
            let queue_lock = self.render_backend.queue().lock().unwrap();

            queue_lock.submit(Some(&self.render_fence), submits)?;

            queue_lock.present(
                &[&self.swapchain],
                &[self.current_image_index.load(SeqCst) as u32],
                &[&self.render_finished_sem],
            )?
        } {
            let (w, h) = self.wsi.window_size();
            self.resize(world, w, h)?;
            self.render_fence.reset();
            return Ok(true);
        }

        // make sure command_buffer is ready
        self.render_backend.device().wait_for_fences(
            &[&self.render_fence],
            true,
            Duration::from_secs(10),
        )?;
        self.render_fence.reset();

        Ok(true)
    }

    pub fn set_clear_color(&self, color: [f32; 4]) {
        self.render_backend.set_clear_color(color);
    }

    // post process handling
    pub fn add_render_routine<T: TScene>(&mut self, priority: u32) {
        self.render_backend.add_render_routine::<T>(priority);
    }

    pub fn remove_render_routine<T: TScene>(&mut self) {
        self.render_backend.remove_render_routine::<T>();
    }

    // getter
    pub fn image_count(&self) -> usize {
        self.render_backend.image_count()
    }

    pub fn images(&self) -> TargetMode<Vec<Arc<Image>>> {
        self.render_backend.images()
    }

    pub fn width(&self) -> u32 {
        self.swapchain.width()
    }

    pub fn height(&self) -> u32 {
        self.swapchain.height()
    }

    pub fn transformations(&self) -> Option<(VRTransformations, VRTransformations)> {
        None
    }
}

impl std::fmt::Debug for VulkanWindowRenderCore {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "VulkanWindowRenderCore {{ }}")
    }
}