//! Macros utilizing the [OpenGL API and Extension Registry].
//!
//! [OpenGL API and Extension Registry]: https://github.com/KhronosGroup/OpenGL-Registry
#![cfg_attr(test, feature(test))]
#![deny(clippy::all, clippy::pedantic, missing_docs)]
use once_cell::sync::Lazy;
use opengl_registry::Registry;
use proc_macro::TokenStream;

use crate::repeat::for_each_opengl_command_impl;

mod iter;
mod repeat;
mod str;
mod token_stream;

const OPENGL_CMD_IDENT_REPLACE: &str = "gl_command";
const OPENGL_CMD_RET_TYPE_REPLACE: &str = "gl_command_ret_type";
const OPENGL_CMD_ARGS_REPLACE: &str = "gl_command_args";
const OPENGL_CMD_ARG_NAMES_REPLACE: &str = "gl_command_arg_names";
const OPENGL_CMD_ARG_TYPES_REPLACE: &str = "gl_command_arg_types";

static OPENGL_REGISTRY: Lazy<Registry> = Lazy::new(|| Registry::retrieve().unwrap());

/// Repeats the input for each command in the [OpenGL API and Extension Registry].
///
/// # Replacements
/// This macro will replace some specific identifiers **prefixed with a hashtag**.
///
/// ### The following identifiers will be replaced
///
/// **`gl_command`**<br>
/// Will be replaced by the full command name. For example, `glViewport`.
///
/// **`gl_command_ret_type`**<br>
/// Will be replaced by the command return type. For example, `GLuint`.
///
/// **`gl_command_args`**<br>
/// Will be replaced by the command arguments formatted as `name: type`, seperated by
/// comma.
///
/// **`gl_command_arg_names`**<br>
/// Will be replaced by the command argument names, seperated by comma.
///
/// **`gl_command_arg_types`**<br>
/// Will be replaced by the command argument types, seperated by comma.
///
/// # Examples
/// ```
/// # use opengl_registry_macros::for_each_opengl_command;
/// for_each_opengl_command! {
///     fn #gl_command()
///     {
///         println!("Hello from {}", stringify!(#gl_command));
///     }
/// }
/// ```
///
/// Would expand to the following if the only OpenGL commands were `glCreateShader` and
/// `glBindBuffer`.
///
/// ```
/// fn glCreateShader()
/// {
///     println!("Hello from {}", stringify!(glCreateShader));
/// }
/// fn glBindBuffer()
/// {
///     println!("Hello from {}", stringify!(glBindBuffer));
/// }
/// ```
///
/// [OpenGL API and Extension Registry]: https://github.com/KhronosGroup/OpenGL-Registry
#[proc_macro]
pub fn for_each_opengl_command(input_stream: TokenStream) -> TokenStream
{
    for_each_opengl_command_impl(&input_stream.into(), &OPENGL_REGISTRY).into()
}