#include <gtest/gtest.h>

#include <XCEngine/Rendering/Passes/BuiltinPostProcessPassPlan.h>

#include <vector>

namespace {

using XCEngine::Rendering::Passes::BuildBuiltinPostProcessPassPlan;
using XCEngine::Rendering::Passes::BuiltinPostProcessPassPlanInput;
using XCEngine::Rendering::Passes::BuiltinPostProcessPassStep;

TEST(BuiltinPostProcessPassPlan_Test, ReturnsInvalidPlanWhenNoBuiltinEffectIsAvailable) {
    const auto plan = BuildBuiltinPostProcessPassPlan({});

    EXPECT_FALSE(plan.valid);
    EXPECT_TRUE(plan.steps.empty());
}

TEST(BuiltinPostProcessPassPlan_Test, BuildsGridOnlyPlanWhenNothingIsSelected) {
    BuiltinPostProcessPassPlanInput input = {};
    input.hasGridOverlay = true;

    const auto plan = BuildBuiltinPostProcessPassPlan(input);

    ASSERT_TRUE(plan.valid);
    EXPECT_EQ(
        plan.steps,
        (std::vector<BuiltinPostProcessPassStep>{
            BuiltinPostProcessPassStep::ColorToRenderTarget,
            BuiltinPostProcessPassStep::InfiniteGrid,
            BuiltinPostProcessPassStep::ColorToShaderResource
        }));
}

TEST(BuiltinPostProcessPassPlan_Test, BuildsGridAndSelectionOutlinePlanWhenObjectIdShaderViewExists) {
    BuiltinPostProcessPassPlanInput input = {};
    input.hasGridOverlay = true;
    input.hasSelection = true;
    input.hasObjectIdShaderView = true;

    const auto plan = BuildBuiltinPostProcessPassPlan(input);

    ASSERT_TRUE(plan.valid);
    EXPECT_EQ(
        plan.steps,
        (std::vector<BuiltinPostProcessPassStep>{
            BuiltinPostProcessPassStep::ColorToRenderTarget,
            BuiltinPostProcessPassStep::InfiniteGrid,
            BuiltinPostProcessPassStep::SelectionOutline,
            BuiltinPostProcessPassStep::ColorToShaderResource
        }));
}

TEST(BuiltinPostProcessPassPlan_Test, SkipsSelectionOutlineWhenObjectIdShaderViewIsMissingAndGridExists) {
    BuiltinPostProcessPassPlanInput input = {};
    input.hasGridOverlay = true;
    input.hasSelection = true;

    const auto plan = BuildBuiltinPostProcessPassPlan(input);

    ASSERT_TRUE(plan.valid);
    EXPECT_EQ(
        plan.steps,
        (std::vector<BuiltinPostProcessPassStep>{
            BuiltinPostProcessPassStep::ColorToRenderTarget,
            BuiltinPostProcessPassStep::InfiniteGrid,
            BuiltinPostProcessPassStep::ColorToShaderResource
        }));
}

TEST(BuiltinPostProcessPassPlan_Test, BuildsDebugMaskPlanFromObjectIdShaderView) {
    BuiltinPostProcessPassPlanInput input = {};
    input.hasGridOverlay = true;
    input.hasSelection = true;
    input.debugSelectionMask = true;
    input.hasObjectIdShaderView = true;

    const auto plan = BuildBuiltinPostProcessPassPlan(input);

    ASSERT_TRUE(plan.valid);
    EXPECT_EQ(
        plan.steps,
        (std::vector<BuiltinPostProcessPassStep>{
            BuiltinPostProcessPassStep::ColorToRenderTarget,
            BuiltinPostProcessPassStep::SelectionMaskDebug,
            BuiltinPostProcessPassStep::ColorToShaderResource
        }));
}

TEST(BuiltinPostProcessPassPlan_Test, DebugMaskPlanFallsBackToTransitionsWhenGridExistsButObjectIdShaderViewIsMissing) {
    BuiltinPostProcessPassPlanInput input = {};
    input.hasGridOverlay = true;
    input.hasSelection = true;
    input.debugSelectionMask = true;

    const auto plan = BuildBuiltinPostProcessPassPlan(input);

    ASSERT_TRUE(plan.valid);
    EXPECT_EQ(
        plan.steps,
        (std::vector<BuiltinPostProcessPassStep>{
            BuiltinPostProcessPassStep::ColorToRenderTarget,
            BuiltinPostProcessPassStep::ColorToShaderResource
        }));
}

TEST(BuiltinPostProcessPassPlan_Test, BuildsSelectionOnlyOutlinePlanWhenGridOverlayIsUnavailable) {
    BuiltinPostProcessPassPlanInput input = {};
    input.hasSelection = true;
    input.hasObjectIdShaderView = true;

    const auto plan = BuildBuiltinPostProcessPassPlan(input);

    ASSERT_TRUE(plan.valid);
    EXPECT_EQ(
        plan.steps,
        (std::vector<BuiltinPostProcessPassStep>{
            BuiltinPostProcessPassStep::ColorToRenderTarget,
            BuiltinPostProcessPassStep::SelectionOutline,
            BuiltinPostProcessPassStep::ColorToShaderResource
        }));
}

TEST(BuiltinPostProcessPassPlan_Test, BuildsDebugMaskWithoutGridWhenObjectIdShaderViewExists) {
    BuiltinPostProcessPassPlanInput input = {};
    input.hasSelection = true;
    input.debugSelectionMask = true;
    input.hasObjectIdShaderView = true;

    const auto plan = BuildBuiltinPostProcessPassPlan(input);

    ASSERT_TRUE(plan.valid);
    EXPECT_EQ(
        plan.steps,
        (std::vector<BuiltinPostProcessPassStep>{
            BuiltinPostProcessPassStep::ColorToRenderTarget,
            BuiltinPostProcessPassStep::SelectionMaskDebug,
            BuiltinPostProcessPassStep::ColorToShaderResource
        }));
}

} // namespace