#include <UnitTest/WorldUnitTest.h>

#if JULIET_DEBUG

#include <Core/Common/CoreUtils.h>
#include <Core/Common/serialization.h>
#include <Core/HAL/IO/IOStream.h>
#include <Core/Logging/LogManager.h>
#include <Core/Logging/LogTypes.h>
#include <Core/Memory/MemoryArena.h>
#include <Core/Thread/ThreadContext.h>
#include <Data/World.h>
#include <Entity/entity_types.h>

namespace UnitTest
{
    internal void TestEntityAllocationAndWiring()
    {
        Log(LogLevel::Message, LogCategory::Game, "[UnitTest] Running TestEntityAllocationAndWiring...");

        TempArena tempArena = scratch_begin(nullptr, 0);

        World testWorld{};
        InitWorld(&testWorld, tempArena.Arena);

        InitEntityManager(&testWorld);
        EntityManager& manager = *testWorld.EntityManager;

        // 1. Allocate Inert Entity via AllocateEntity
        Entity* base_entity = allocate_entity(manager, Inert::kind);
        Assert(base_entity != nullptr);
        Assert(base_entity->ID == 0); // Pure memory allocator leaves ID unassigned (0) until MakeEntity or deserialization
        base_entity->ID = ++EntityManager::ID;
        Assert(base_entity->ID > 0);
        Assert(base_entity->derived_kind == Inert::kind);
        Assert(base_entity->derived != nullptr);
        Assert(base_entity->is_dirty == true);

        // 2. Validate mutual back-pointer wiring
        auto* derived = reinterpret_cast<EntityTemplate*>(base_entity->derived);
        Assert(derived->base == base_entity);

        // 3. DownCast verification
        Inert* inert = DownCast<Inert>(base_entity);
        Assert(inert != nullptr);
        Assert(inert->base == base_entity);

        // 4. Validate typed array tracking
        typed_entity_array& inert_array = manager.by_type[ENTITY(Inert)];
        Assert(inert_array.count == 1);
        Assert(inert_array.array == derived);

        ShutdownEntityManager();
        ShutdownWorld(&testWorld);

        scratch_end(tempArena);
        Log(LogLevel::Message, LogCategory::Game, "[UnitTest] PASSED: TestEntityAllocationAndWiring");
    }

    internal void TestInPlaceDeserialization()
    {
        Log(LogLevel::Message, LogCategory::Game, "[UnitTest] Running TestInPlaceDeserialization...");
        TempArena tempArena = scratch_begin(nullptr, 0);
        World     testWorld{};
        InitWorld(&testWorld, tempArena.Arena);
        InitEntityManager(&testWorld);
        EntityManager& manager = *testWorld.EntityManager;
        // 1. In-memory .jasset text fixture (no streams or files needed)
        String     asset_content = ConstString("; class\n"
                                                   "Inert\n"
                                                   "; version\n"
                                                   "1\n"
                                                   "; class_version\n"
                                                   "1\n"
                                                   "; id\n"
                                                   "42\n"
                                                   "; position\n"
                                                   "12.5 -44.0 108.2 1.0\n"
                                                   "; MeshInstance\n"
                                                   "42\n");
        ByteBuffer buffer        = { .Data = reinterpret_cast<Byte*>(asset_content.Str), .Size = asset_content.Size };
        // 2. Tokenize into Archive
        Archive load_ar = {};
        load_ar.arena   = tempArena.Arena;
        load_ar.loading = true;
        load_ar.base    = tokenize_archive(tempArena.Arena, buffer);
        // 3. Deserialize in-place
        Entity* loaded_base = deserialize_entity(load_ar, manager);
        // 4. Verify in-place allocations and values
        Assert(loaded_base != nullptr);
        Assert(loaded_base->ID == 42);
        Assert(EntityManager::ID > 42); // Generator counter advanced past loaded ID
        Assert(loaded_base->position.x == 12.5f);
        Assert(loaded_base->position.y == -44.0f);
        Assert(loaded_base->position.z == 108.2f);
        Assert(loaded_base->is_dirty == false);
        Inert* loaded_inert = DownCast<Inert>(loaded_base);
        Assert(loaded_inert != nullptr);
        Assert(loaded_inert->base == loaded_base);
        Assert(loaded_inert->MeshInstance == 42);
        ShutdownEntityManager();
        ShutdownWorld(&testWorld);
        scratch_end(tempArena);
        Log(LogLevel::Message, LogCategory::Game, "[UnitTest] PASSED: TestInPlaceDeserialization");
    }

    internal void TestDirtyTrackingLifecycle()
    {
        Log(LogLevel::Message, LogCategory::Game, "[UnitTest] Running TestDirtyTrackingLifecycle...");

        TempArena tempArena = scratch_begin(nullptr, 0);

        World testWorld{};
        InitWorld(&testWorld, tempArena.Arena);
        InitEntityManager(&testWorld);
        EntityManager& manager = *testWorld.EntityManager;

        Entity* entity = allocate_entity(manager, Inert::kind);
        Assert(entity->is_dirty == true);

        // Simulate save
        entity->is_dirty = false;
        Assert(entity->is_dirty == false);

        // Simulate mutation
        entity->position.x += 1.0f;
        entity->is_dirty = true;
        Assert(entity->is_dirty == true);

        ShutdownEntityManager();
        ShutdownWorld(&testWorld);

        scratch_end(tempArena);
        Log(LogLevel::Message, LogCategory::Game, "[UnitTest] PASSED: TestDirtyTrackingLifecycle");
    }

    void WorldUnitTest()
    {
        Log(LogLevel::Message, LogCategory::Game, "==================================================");
        Log(LogLevel::Message, LogCategory::Game, "Starting Entity Allocation & Lifecycle Unit Tests");
        Log(LogLevel::Message, LogCategory::Game, "==================================================");

        TestEntityAllocationAndWiring();
        TestInPlaceDeserialization();
        // TestSwapAndPopPointerFixup(); // Deferred to Entity_Removal_Brainstorm.md
        TestDirtyTrackingLifecycle();

        Log(LogLevel::Message, LogCategory::Game, "==================================================");
        Log(LogLevel::Message, LogCategory::Game, "All Entity Lifecycle Unit Tests PASSED Successfully");
        Log(LogLevel::Message, LogCategory::Game, "==================================================");
    }
} // namespace UnitTest

#endif