use anyhow::{anyhow, Result};
use vulkanalia::loader::{LibloadingLoader, LIBRARY};
use vulkanalia::prelude::v1_0::*;
use vulkanalia::window as vk_window;
use winit::window::Window;

unsafe fn create_instance(window: &Window, entry: &Entry) -> Result<Instance> {
    let application_info = vk::ApplicationInfo::builder()
        .application_name(b"Vulkan Tutorial\0")
        .application_version(vk::make_version(1, 0, 0))
        .engine_name(b"No Engine\0")
        .engine_version(vk::make_version(1, 0, 0))
        .api_version(vk::make_version(1, 0, 0));

    let mut extensions = vk_window::get_required_instance_extensions(window)
        .iter()
        .map(|e| e.as_ptr())
        .collect::<Vec<_>>();

    // Compatibility extension for macOS
    let flags = if entry
        .enumerate_instance_extension_properties(None)?
        .iter()
        .any(|e| e.extension_name == vk::KHR_PORTABILITY_ENUMERATION_EXTENSION.name)
    {
        extensions.push(vk::KHR_PORTABILITY_ENUMERATION_EXTENSION.name.as_ptr());
        vk::InstanceCreateFlags::ENUMERATE_PORTABILITY_KHR
    } else {
        vk::InstanceCreateFlags::empty()
    };

    let info = vk::InstanceCreateInfo::builder()
        .application_info(&application_info)
        .enabled_extension_names(&extensions)
        .flags(flags);

    Ok(entry.create_instance(&info, None)?)
}

/// Our Vulkan app.
#[derive(Clone, Debug)]
pub struct App {
    entry: Entry,
    instance: Instance,
}

impl App {
    /// Creates our Vulkan app.
    pub unsafe fn create(window: &Window) -> Result<Self> {
        let loader = LibloadingLoader::new(LIBRARY)?;
        let entry = Entry::new(loader).map_err(|b| anyhow!("{}", b))?;
        let instance = create_instance(window, &entry)?;

        Ok(Self { entry, instance })
    }

    /// Renders a frame for our Vulkan app.
    pub unsafe fn render(&mut self, window: &Window) -> Result<()> {
        Ok(())
    }

    /// Destroys our Vulkan app.
    pub unsafe fn destroy(&mut self) {
        self.instance.destroy_instance(None);
    }
}

/// The Vulkan handles and associated properties used by our Vulkan app.
#[derive(Clone, Debug, Default)]
pub struct AppData {}