#include <Engine/Shader/ShaderUtils.hpp>
#include <Nazara/Core/File.hpp>
#include <Nazara/Core/StringExt.hpp>
#include <Nazara/Shader/ShaderBuilder.hpp>
#include <Nazara/Shader/ShaderLangParser.hpp>
#include <catch2/catch.hpp>
#include <cctype>

TEST_CASE("branching", "[Shader]")
{
	WHEN("using a simple branch")
	{
		std::string_view nzslSource = R"(
struct inputStruct
{
	value: f32
}

external
{
	[set(0), binding(0)] data: uniform[inputStruct]
}

[entry(frag)]
fn main()
{
	let value: f32;
	if (data.value > 0.0)
		value = 1.0;
	else
		value = 0.0;
}
)";

		Nz::ShaderAst::StatementPtr shader = Nz::ShaderLang::Parse(nzslSource);

		ExpectGLSL(*shader, R"(
void main()
{
	float value;
	if (data.value > (0.000000))
	{
		value = 1.000000;
	}
	else
	{
		value = 0.000000;
	}
	
}
)");

		ExpectNZSL(*shader, R"(
[entry(frag)]
fn main()
{
	let value: f32;
	if (data.value > (0.000000))
	{
		value = 1.000000;
	}
	else
	{
		value = 0.000000;
	}
	
}
)");

		ExpectSpirV(*shader, R"(
OpFunction
OpLabel
OpVariable
OpAccessChain
OpLoad
OpFOrdGreaterThanEqual
OpSelectionMerge
OpBranchConditional
OpLabel
OpStore
OpBranch
OpLabel
OpStore
OpBranch
OpLabel
OpReturn
OpFunctionEnd)");
	}

	WHEN("discarding in a branch")
	{
		std::string_view nzslSource = R"(
struct inputStruct
{
	value: f32
}

external
{
	[set(0), binding(0)] data: uniform[inputStruct]
}

[entry(frag)]
fn main()
{
	if (data.value > 0.0)
		discard;
}
)";

		Nz::ShaderAst::StatementPtr shader = Nz::ShaderLang::Parse(nzslSource);

		ExpectGLSL(*shader, R"(
void main()
{
	if (data.value > (0.000000))
	{
		discard;
	}
	
}
)");

		ExpectNZSL(*shader, R"(
[entry(frag)]
fn main()
{
	if (data.value > (0.000000))
	{
		discard;
	}
	
}
)");

		ExpectSpirV(*shader, R"(
OpFunction
OpLabel
OpAccessChain
OpLoad
OpFOrdGreaterThanEqual
OpSelectionMerge
OpBranchConditional
OpLabel
OpKill
OpLabel
OpBranch
OpLabel
OpReturn
OpFunctionEnd)");
	}

	
	WHEN("using a complex branch")
	{
		std::string_view nzslSource = R"(
struct inputStruct
{
	value: f32
}

external
{
	[set(0), binding(0)] data: uniform[inputStruct]
}

[entry(frag)]
fn main()
{
	let value: f32;
	if (data.value > 3.0)
		value = 3.0;
	else if (data.value > 2.0)
		value = 2.0;
	else if (data.value > 1.0)
		value = 1.0;
	else
		value = 0.0;
}
)";

		Nz::ShaderAst::StatementPtr shader = Nz::ShaderLang::Parse(nzslSource);

		ExpectGLSL(*shader, R"(
void main()
{
	float value;
	if (data.value > (3.000000))
	{
		value = 3.000000;
	}
	else if (data.value > (2.000000))
	{
		value = 2.000000;
	}
	else if (data.value > (1.000000))
	{
		value = 1.000000;
	}
	else
	{
		value = 0.000000;
	}
	
}
)");

		ExpectNZSL(*shader, R"(
[entry(frag)]
fn main()
{
	let value: f32;
	if (data.value > (3.000000))
	{
		value = 3.000000;
	}
	else if (data.value > (2.000000))
	{
		value = 2.000000;
	}
	else if (data.value > (1.000000))
	{
		value = 1.000000;
	}
	else
	{
		value = 0.000000;
	}
	
}
)");

		ExpectSpirV(*shader, R"(
OpFunction
OpLabel
OpVariable
OpAccessChain
OpLoad
OpFOrdGreaterThanEqual
OpSelectionMerge
OpBranchConditional
OpLabel
OpStore
OpBranch
OpLabel
OpAccessChain
OpLoad
OpFOrdGreaterThanEqual
OpSelectionMerge
OpBranchConditional
OpLabel
OpStore
OpBranch
OpLabel
OpAccessChain
OpLoad
OpFOrdGreaterThanEqual
OpSelectionMerge
OpBranchConditional
OpLabel
OpStore
OpBranch
OpLabel
OpStore
OpBranch
OpLabel
OpBranch
OpLabel
OpBranch
OpLabel
OpReturn
OpFunctionEnd)");
	}
}