// Copyright (c) 2016 The vulkano developers
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or https://opensource.org/licenses/MIT>,
// at your option. All files in the project carrying such
// notice may not be copied, modified, or distributed except
// according to those terms.

use crate::check_errors;
pub use crate::extensions::{
    ExtensionRestriction, ExtensionRestrictionError, SupportedExtensionsError,
};
use crate::instance::loader;
use crate::instance::loader::LoadingError;
use std::ffi::CStr;
use std::ptr;

macro_rules! instance_extensions {
    (
        $($member:ident => {
            doc: $doc:expr,
            raw: $raw:expr,
            requires_core: $requires_core:expr,
            requires_instance_extensions: [$($requires_instance_extension:ident),*]$(,)?
        },)*
    ) => (
        extensions! {
            InstanceExtensions,
            $($member => {
                doc: $doc,
                raw: $raw,
                requires_core: $requires_core,
                requires_device_extensions: [],
                requires_instance_extensions: [$($requires_instance_extension),*],
            },)*
        }

        impl InstanceExtensions {
            /// Checks enabled extensions against the instance version and each other.
            pub(super) fn check_requirements(
                &self,
                supported: &InstanceExtensions,
                api_version: crate::Version,
            ) -> Result<(), crate::extensions::ExtensionRestrictionError> {
                $(
                    if self.$member {
                        if !supported.$member {
                            return Err(crate::extensions::ExtensionRestrictionError {
                                extension: stringify!($member),
                                restriction: crate::extensions::ExtensionRestriction::NotSupported,
                            });
                        }

                        if api_version < $requires_core {
                            return Err(crate::extensions::ExtensionRestrictionError {
                                extension: stringify!($member),
                                restriction: crate::extensions::ExtensionRestriction::RequiresCore($requires_core),
                            });
                        } else {
                            $(
                                if !self.$requires_instance_extension {
                                    return Err(crate::extensions::ExtensionRestrictionError {
                                        extension: stringify!($member),
                                        restriction: crate::extensions::ExtensionRestriction::RequiresInstanceExtension(stringify!($requires_instance_extension)),
                                    });
                                }
                            )*
                        }
                    }
                )*
                Ok(())
            }
        }
    );
}

pub use crate::autogen::InstanceExtensions;
pub(crate) use instance_extensions;

impl InstanceExtensions {
    /// See the docs of supported_by_core().
    pub fn supported_by_core_raw() -> Result<Self, SupportedExtensionsError> {
        InstanceExtensions::supported_by_core_raw_with_loader(loader::auto_loader()?)
    }

    /// Returns an `InstanceExtensions` object with extensions supported by the core driver.
    pub fn supported_by_core() -> Result<Self, LoadingError> {
        match InstanceExtensions::supported_by_core_raw() {
            Ok(l) => Ok(l),
            Err(SupportedExtensionsError::LoadingError(e)) => Err(e),
            Err(SupportedExtensionsError::OomError(e)) => panic!("{:?}", e),
        }
    }

    /// Same as `supported_by_core`, but allows specifying a loader.
    pub fn supported_by_core_with_loader<L>(
        ptrs: &loader::FunctionPointers<L>,
    ) -> Result<Self, LoadingError>
    where
        L: loader::Loader,
    {
        match InstanceExtensions::supported_by_core_raw_with_loader(ptrs) {
            Ok(l) => Ok(l),
            Err(SupportedExtensionsError::LoadingError(e)) => Err(e),
            Err(SupportedExtensionsError::OomError(e)) => panic!("{:?}", e),
        }
    }

    /// See the docs of supported_by_core().
    pub fn supported_by_core_raw_with_loader<L>(
        ptrs: &loader::FunctionPointers<L>,
    ) -> Result<Self, SupportedExtensionsError>
    where
        L: loader::Loader,
    {
        let fns = ptrs.fns();

        let properties: Vec<ash::vk::ExtensionProperties> = unsafe {
            let mut num = 0;
            check_errors(fns.v1_0.enumerate_instance_extension_properties(
                ptr::null(),
                &mut num,
                ptr::null_mut(),
            ))?;

            let mut properties = Vec::with_capacity(num as usize);
            check_errors(fns.v1_0.enumerate_instance_extension_properties(
                ptr::null(),
                &mut num,
                properties.as_mut_ptr(),
            ))?;
            properties.set_len(num as usize);
            properties
        };

        Ok(Self::from(properties.iter().map(|property| unsafe {
            CStr::from_ptr(property.extension_name.as_ptr())
        })))
    }
}

#[cfg(test)]
mod tests {
    use crate::instance::InstanceExtensions;
    use std::ffi::CString;

    #[test]
    fn empty_extensions() {
        let i: Vec<CString> = (&InstanceExtensions::none()).into();
        assert!(i.iter().next().is_none());
    }
}