#include "PlanetDataManager.h"
#include "ComputePointActor.h"

#include "HttpModule.h"
#include "Interfaces/IHttpResponse.h"
#include "Dom/JsonObject.h"
#include "Dom/JsonValue.h"
#include "Serialization/JsonReader.h"
#include "Serialization/JsonSerializer.h"
#include "Misc/FileHelper.h"
#include "Misc/Paths.h"
#include "Engine/World.h"

// Cesium coordinate conversion
#include "CesiumGeoreference.h"

APlanetDataManager::APlanetDataManager()
{
    PrimaryActorTick.bCanEverTick = false;
}

void APlanetDataManager::BeginPlay()
{
    Super::BeginPlay();

    // Build default mock path if not overridden
    if (MockDataPath.IsEmpty())
    {
        MockDataPath = FPaths::ProjectContentDir() / TEXT("Data/mock_compute_points.json");
    }

    FetchAllData();
}

void APlanetDataManager::FetchAllData()
{
    // Clear previous actors
    for (AComputePointActor* Point : SpawnedPoints)
    {
        if (IsValid(Point)) Point->Destroy();
    }
    SpawnedPoints.Empty();

    if (bUseLocalMockData)
    {
        LoadMockComputePoints();
    }
    else
    {
        FetchComputePoints();
    }
}

// ---------------------------------------------------------------------------
// Phase A: local JSON file
// ---------------------------------------------------------------------------

void APlanetDataManager::LoadMockComputePoints()
{
    FString JsonStr;
    if (!FFileHelper::LoadFileToString(JsonStr, *MockDataPath))
    {
        UE_LOG(LogTemp, Error, TEXT("PlanetDataManager: cannot read mock file: %s"), *MockDataPath);
        return;
    }
    TArray<FComputePoint> Points = ParseComputePointsJson(JsonStr);
    UE_LOG(LogTemp, Log, TEXT("PlanetDataManager: loaded %d points from mock file"), Points.Num());
    SpawnComputePoints(Points);
}

// ---------------------------------------------------------------------------
// Phase B: HTTP request
// ---------------------------------------------------------------------------

void APlanetDataManager::FetchComputePoints()
{
    const FString Url = BackendBaseUrl + TEXT("/api/v1/ue/compute-points");
    TSharedRef<IHttpRequest, ESPMode::ThreadSafe> Req = FHttpModule::Get().CreateRequest();
    Req->SetURL(Url);
    Req->SetVerb(TEXT("GET"));
    Req->SetHeader(TEXT("Content-Type"), TEXT("application/json"));
    Req->OnProcessRequestComplete().BindUObject(
        this, &APlanetDataManager::OnComputePointsResponse);
    Req->ProcessRequest();
    UE_LOG(LogTemp, Log, TEXT("PlanetDataManager: GET %s"), *Url);
}

void APlanetDataManager::OnComputePointsResponse(FHttpRequestPtr Request,
                                                   FHttpResponsePtr Response,
                                                   bool bSuccess)
{
    if (!bSuccess || !Response.IsValid())
    {
        UE_LOG(LogTemp, Error,
               TEXT("PlanetDataManager: HTTP request failed. Is the backend running at %s?"),
               *BackendBaseUrl);
        return;
    }
    if (Response->GetResponseCode() != 200)
    {
        UE_LOG(LogTemp, Error, TEXT("PlanetDataManager: HTTP %d from %s"),
               Response->GetResponseCode(), *Request->GetURL());
        return;
    }

    TArray<FComputePoint> Points = ParseComputePointsJson(Response->GetContentAsString());
    UE_LOG(LogTemp, Log, TEXT("PlanetDataManager: received %d compute points"), Points.Num());
    SpawnComputePoints(Points);
}

// ---------------------------------------------------------------------------
// JSON parser
// ---------------------------------------------------------------------------

TArray<FComputePoint> APlanetDataManager::ParseComputePointsJson(const FString& JsonStr)
{
    TArray<FComputePoint> Result;

    TSharedPtr<FJsonObject> Root;
    TSharedRef<TJsonReader<>> Reader = TJsonReaderFactory<>::Create(JsonStr);
    if (!FJsonSerializer::Deserialize(Reader, Root) || !Root.IsValid())
    {
        UE_LOG(LogTemp, Error, TEXT("PlanetDataManager: JSON parse failed"));
        return Result;
    }

    const TArray<TSharedPtr<FJsonValue>>* Items;
    if (!Root->TryGetArrayField(TEXT("items"), Items))
    {
        UE_LOG(LogTemp, Error, TEXT("PlanetDataManager: no 'items' array in JSON"));
        return Result;
    }

    for (const TSharedPtr<FJsonValue>& Val : *Items)
    {
        const TSharedPtr<FJsonObject>* ObjPtr;
        if (!Val->TryGetObject(ObjPtr)) continue;
        const TSharedPtr<FJsonObject>& Obj = *ObjPtr;

        FComputePoint Pt;
        Obj->TryGetStringField(TEXT("id"),      Pt.Id);
        Obj->TryGetStringField(TEXT("name"),    Pt.Name);
        Obj->TryGetStringField(TEXT("country"), Pt.Country);
        Obj->TryGetStringField(TEXT("city"),    Pt.City);

        double Lat, Lon;
        if (!Obj->TryGetNumberField(TEXT("latitude"),  Lat)) continue;
        if (!Obj->TryGetNumberField(TEXT("longitude"), Lon)) continue;
        Pt.Latitude  = (float)Lat;
        Pt.Longitude = (float)Lon;

        int32 Rank;
        if (Obj->TryGetNumberField(TEXT("rank"), Rank)) Pt.Rank = Rank;

        double Rmax;
        if (Obj->TryGetNumberField(TEXT("rmax_tflops"), Rmax)) Pt.RmaxTFlops = (float)Rmax;
        double Rpeak;
        if (Obj->TryGetNumberField(TEXT("rpeak_tflops"), Rpeak)) Pt.RpeakTFlops = (float)Rpeak;
        int32 Cores;
        if (Obj->TryGetNumberField(TEXT("cores"), Cores)) Pt.Cores = Cores;
        double Power;
        if (Obj->TryGetNumberField(TEXT("power_kw"), Power)) Pt.PowerKw = (float)Power;

        Result.Add(Pt);
    }

    return Result;
}

// ---------------------------------------------------------------------------
// Spawn actors
// ---------------------------------------------------------------------------

void APlanetDataManager::SpawnComputePoints(const TArray<FComputePoint>& Points)
{
    if (!ComputePointClass)
    {
        UE_LOG(LogTemp, Warning,
               TEXT("PlanetDataManager: ComputePointClass not set — set it in the Details Panel"));
        return;
    }

    UWorld* World = GetWorld();
    if (!World) return;

    // Find the CesiumGeoreference in the level
    ACesiumGeoreference* Georeference = ACesiumGeoreference::GetDefaultGeoreference(World);
    if (!Georeference)
    {
        UE_LOG(LogTemp, Error,
               TEXT("PlanetDataManager: no CesiumGeoreference in level. Add a CesiumGeoreference actor."));
        return;
    }

    for (const FComputePoint& Pt : Points)
    {
        // Convert geographic coordinates to Unreal world coordinates
        // Altitude is PointAltitudeMeters above sea level
        FVector WorldPos = Georeference->TransformLongitudeLatitudeHeightPositionToUnreal(
            FVector(Pt.Longitude, Pt.Latitude, PointAltitudeMeters)
        );

        FActorSpawnParameters Params;
        Params.SpawnCollisionHandlingOverride =
            ESpawnActorCollisionHandlingMethod::AlwaysSpawn;

        AComputePointActor* Actor = World->SpawnActor<AComputePointActor>(
            ComputePointClass, WorldPos, FRotator::ZeroRotator, Params);

        if (Actor)
        {
            Actor->SetPointData(Pt);
            SpawnedPoints.Add(Actor);
        }
    }

    OnComputePointsLoaded.Broadcast(SpawnedPoints.Num());
    UE_LOG(LogTemp, Log, TEXT("PlanetDataManager: spawned %d compute point actors"),
           SpawnedPoints.Num());
}