#include "StringDecoder.h"


void UlxLuaValues::Empty()
{
    Serialized.clear();
    Types.Empty();
    Data.Empty();
    Cursor = 0;
}

bool UlxLuaValues::Initialize(std::string_view data)
{
    Empty();
    Serialized = data;
    const char *SerializedChar = &Serialized[0];
    
    FlxStreamBuffer Decoder(Serialized);

    while (!Decoder.empty())
    {
        SimpleDynamicTag Tag = Decoder.read_simple_dynamic_tag();

        int64 Pos = Decoder.total_reads();
        ELxLuaValueType Type;
        switch (Tag)
        {
            case SimpleDynamicTag::BOOLEAN: Type=ELxLuaValueType::Boolean; Decoder.read_bool(); break;
            case SimpleDynamicTag::NUMBER:  Type=ELxLuaValueType::Float;   Decoder.read_double(); break;
            case SimpleDynamicTag::STRING:  Type=ELxLuaValueType::String;  Decoder.read_string_view(); break;
            case SimpleDynamicTag::TOKEN:   Type=ELxLuaValueType::Name;    Decoder.read_string_view(); break;
            case SimpleDynamicTag::VECTOR:  Type=ELxLuaValueType::Vector;  Decoder.read_fvector(); break;
            default: {
                Empty();
                return false;
            }
        }
        int64 Pos2 = Decoder.total_reads();
        Types.Add(Type);
        Data.Add(std::string_view(SerializedChar + Pos, Pos2 - Pos));
    }
    return true;
}

bool UlxLuaValues::CheckType(ELxLuaValueType Type, ELxLuaValueType Desired)
{
    if (Type != Desired)
    {
        FString TypeName = StaticEnum<ELxLuaValueType>()->GetDisplayNameTextByValue(int64(Type)).ToString();
        FString DesiredName = StaticEnum<ELxLuaValueType>()->GetDisplayNameTextByValue(int64(Desired)).ToString();
        UE_LOG(LogBlueprint, Error, TEXT("Expected a value of type %s, but found %s instead."), *DesiredName, *TypeName);
        return false;
    }
    return true;
}

ELxLuaValueType UlxLuaValues::GetType(int n) const
{
    if (n < 0) return ELxLuaValueType::None;
    if (n >= Types.Num()) return ELxLuaValueType::None;
    return Types[Cursor];
}

//
// Get the Nth value in the array.  Array bounds-checking
// is handled by 'GetType', which returns 'None' for out-of-bounds
// accesses.
//

FString UlxLuaValues::GetString(int n) const
{
    if (!CheckType(GetType(n), ELxLuaValueType::String)) return FString();
    FlxStreamBuffer Decoder(Data[n]);
    return Decoder.read_fstring();
}

FName UlxLuaValues::GetName(int n) const
{
    if (!CheckType(GetType(n), ELxLuaValueType::Name)) return FName();
    FlxStreamBuffer Decoder(Data[n]);
    return Decoder.read_fname();
}

double UlxLuaValues::GetFloat(int n) const
{
    if (!CheckType(GetType(n), ELxLuaValueType::Float)) return 0.0;
    FlxStreamBuffer Decoder(Data[n]);
    return Decoder.read_double();
}

int UlxLuaValues::GetInt(int n) const
{
    if (!CheckType(GetType(n), ELxLuaValueType::Float)) return 0;
    FlxStreamBuffer Decoder(Data[n]);
    return int(Decoder.read_double());
}

FVector UlxLuaValues::GetVector(int n) const
{
    if (!CheckType(GetType(n), ELxLuaValueType::Vector)) return FVector();
    FlxStreamBuffer Decoder(Data[n]);
    return Decoder.read_fvector();
}

FVector2D UlxLuaValues::GetVector2D(int n) const
{
    if (!CheckType(GetType(n), ELxLuaValueType::Vector)) return FVector2D();
    FlxStreamBuffer Decoder(Data[n]);
    FVector v = Decoder.read_fvector();
    return FVector2D(v.X, v.Y);
}

bool UlxLuaValues::GetBoolean(int n) const
{
    if (!CheckType(GetType(n), ELxLuaValueType::Boolean)) return false;
    FlxStreamBuffer Decoder(Data[n]);
    return Decoder.read_bool();
}