mod app;
pub use app::App;
use app::AppData;

use ::anyhow::{anyhow, Result};
use ::log::*;
use ::std::collections::HashSet;
use ::std::ffi::CStr;
use ::std::os::raw::c_void;
use ::vulkanalia::prelude::v1_0::*;
use ::vulkanalia::window as vk_window;
use ::winit::window::Window;

pub const VALIDATION_ENABLED: bool = cfg!(debug_assertions);
pub const VALIDATION_LAYER: vk::ExtensionName =
    vk::ExtensionName::from_bytes(b"VK_LAYER_KHRONOS_validation");

pub fn create_app(window: &Window) -> Result<App> {
    Ok(unsafe { App::create(&window)? })
}

extern "system" fn debug_callback(
    severity: vk::DebugUtilsMessageSeverityFlagsEXT,
    type_: vk::DebugUtilsMessageTypeFlagsEXT,
    data: *const vk::DebugUtilsMessengerCallbackDataEXT,
    _: *mut c_void,
) -> vk::Bool32 {
    let data = unsafe { *data };
    let message = unsafe { CStr::from_ptr(data.message) }.to_string_lossy();

    if severity >= vk::DebugUtilsMessageSeverityFlagsEXT::ERROR {
        error!("({:?}) {}", type_, message);
    } else if severity >= vk::DebugUtilsMessageSeverityFlagsEXT::WARNING {
        warn!("({:?}) {}", type_, message);
    } else if severity >= vk::DebugUtilsMessageSeverityFlagsEXT::INFO {
        debug!("({:?}) {}", type_, message);
    } else {
        trace!("({:?}) {}", type_, message);
    }

    vk::FALSE
}

pub(crate) unsafe fn create_instance(
    window: &Window,
    entry: &Entry,
    data: &mut AppData,
) -> 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 available_layers = entry
        .enumerate_instance_layer_properties()?
        .iter()
        .map(|l| l.layer_name)
        .collect::<HashSet<_>>();

    if VALIDATION_ENABLED && !available_layers.contains(&VALIDATION_LAYER) {
        return Err(anyhow!("Validation layer requested but not supported."));
    }

    let layers = if VALIDATION_ENABLED {
        vec![VALIDATION_LAYER.as_ptr()]
    } else {
        Vec::new()
    };

    let mut extensions = vk_window::get_required_instance_extensions(window)
        .iter()
        .map(|e| e.as_ptr())
        .collect::<Vec<_>>();
    if VALIDATION_ENABLED {
        extensions.push(vk::EXT_DEBUG_UTILS_EXTENSION.name.as_ptr());
    }

    // 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 mut info = vk::InstanceCreateInfo::builder()
        .application_info(&application_info)
        .enabled_layer_names(&layers)
        .enabled_extension_names(&extensions)
        .flags(flags);

    let mut debug_info = vk::DebugUtilsMessengerCreateInfoEXT::builder()
        .message_severity(vk::DebugUtilsMessageSeverityFlagsEXT::all())
        .message_type(vk::DebugUtilsMessageTypeFlagsEXT::all())
        .user_callback(Some(debug_callback));

    if VALIDATION_ENABLED {
        info = info.push_next(&mut debug_info);
    }

    let instance = entry.create_instance(&info, None)?;

    Ok(instance)
}