extern "C"
{
#include "dxc.h"
#include "arena.h"
#include "string.h"
}

#pragma clang diagnostic ignored "-Wlanguage-extension-token"
#include <Windows.h>
#include <atlbase.h>
#include <dxcapi.h>
#include <d3d12shader.h>

#pragma comment(lib, "d3dcompiler")
#pragma comment(lib, "dxcompiler")

/* https://github.com/microsoft/DirectXShaderCompiler/wiki/Using-dxc.exe-and-dxcompiler.dll */
struct dxc_compile_result dxc_compile(struct arena *arena, string shader_source, i32 num_args, struct string *args)
{
    __prof;
    struct arena_temp scratch = scratch_begin(arena);
    struct dxc_compile_result res = ZI;

    wchar_t **wstr_args = arena_push_array(scratch.arena, wchar_t *, num_args);
    for (i32 i = 0; i < num_args; ++i) {
        wstr_args[i] = wstr_from_string(scratch.arena, args[i]);
    }

    DxcBuffer dxc_src_buffer = ZI;
    dxc_src_buffer.Ptr = shader_source.text;
    dxc_src_buffer.Size = shader_source.len;
    dxc_src_buffer.Encoding = DXC_CP_UTF8;

    /* Init compiler */
    CComPtr<IDxcUtils> dxc_utils;
    CComPtr<IDxcCompiler3> dxc_compiler;
    CComPtr<IDxcIncludeHandler> dxc_include_handler;
    DxcCreateInstance(CLSID_DxcUtils, IID_PPV_ARGS(&dxc_utils));
    DxcCreateInstance(CLSID_DxcCompiler, IID_PPV_ARGS(&dxc_compiler));
    dxc_utils->CreateDefaultIncludeHandler(&dxc_include_handler);

    /* Compile */
    CComPtr<IDxcResult> compile_results = 0;
    dxc_compiler->Compile(&dxc_src_buffer, (LPCWSTR *)wstr_args, num_args, dxc_include_handler, IID_PPV_ARGS(&compile_results));

    /* Copy errors */
    CComPtr<IDxcBlobUtf8> dxc_errors = 0;
    compile_results->GetOutput(DXC_OUT_ERRORS, IID_PPV_ARGS(&dxc_errors), 0);
    if (dxc_errors != 0) {
        res.errors = string_copy(arena, STRING(dxc_errors->GetStringLength(), (u8 *)dxc_errors->GetBufferPointer()));
    }

    /* Get status */
    HRESULT dxc_hr = 0;
    compile_results->GetStatus(&dxc_hr);
    res.success = SUCCEEDED(dxc_hr);

    /* Copy shader output */
    if (res.success) {
        CComPtr<IDxcBlob> dxc_shader = 0;
        compile_results->GetOutput(DXC_OUT_OBJECT, IID_PPV_ARGS(&dxc_shader), 0);
        if (dxc_shader != 0) {
            res.dxc = string_copy(arena, STRING(dxc_shader->GetBufferSize(), (u8 *)dxc_shader->GetBufferPointer()));
        }
    }

    scratch_end(scratch);
    return res;
}