unit Myc.Data.Types.Tuple;

interface

uses
    System.SysUtils,
    Myc.Data.Types;

type
    // Implements the singleton tuple data type.
    TDataTupleType = class(TInterfacedObject, IDataType, IDataTupleType)
    strict private
        class var
            FSingleton: IDataTupleType;
        class constructor CreateClass;
    private
        function GetName: String;
        function GetKind: TDataKind;
    public
        function CreateValue(const AItems: array of IDataValue): IDataTupleValue;
        class property Singleton: IDataTupleType read FSingleton;
    end;

implementation

uses
    System.Rtti;

type
    // Implements the simple tuple data value.
    TDataTupleValue = class(TInterfacedObject, IDataValue, IDataTupleValue)
    private
        FItems: TArray<IDataValue>;
        function GetDataType: IDataType;
        function GetAsString: string;
        function AsTValue: TValue;
        function GetItemCount: Integer;
        function GetItem(Idx: Integer): IDataValue;
    public
        constructor Create(const AItems: array of IDataValue);
    end;

    // Optimized singleton implementation for a tuple with 0 elements.
    TDataTupleValue0 = class(TInterfacedObject, IDataValue, IDataTupleValue)
    strict private
        class var
            FSingleton: IDataTupleValue;
            FEmptyTValue: TValue;
        class constructor CreateClass;
    private
        function GetDataType: IDataType;
        function GetAsString: string;
        function AsTValue: TValue;
        function GetItemCount: Integer;
        function GetItem(Idx: Integer): IDataValue;
    public
        class property Singleton: IDataTupleValue read FSingleton;
    end;

    // Optimized implementation for a tuple with 1 element.
    TDataTupleValue1 = class(TInterfacedObject, IDataValue, IDataTupleValue)
    private
        FItem0: IDataValue;
        function GetDataType: IDataType;
        function GetAsString: string;
        function AsTValue: TValue;
        function GetItemCount: Integer;
        function GetItem(Idx: Integer): IDataValue;
    public
        constructor Create(const AItems: array of IDataValue);
    end;

    // Optimized implementation for a tuple with 2 elements.
    TDataTupleValue2 = class(TInterfacedObject, IDataValue, IDataTupleValue)
    private
        FItem0, FItem1: IDataValue;
        function GetDataType: IDataType;
        function GetAsString: string;
        function AsTValue: TValue;
        function GetItemCount: Integer;
        function GetItem(Idx: Integer): IDataValue;
    public
        constructor Create(const AItems: array of IDataValue);
    end;

    // Optimized implementation for a tuple with 3 elements.
    TDataTupleValue3 = class(TInterfacedObject, IDataValue, IDataTupleValue)
    private
        FItem0, FItem1, FItem2: IDataValue;
        function GetDataType: IDataType;
        function GetAsString: string;
        function AsTValue: TValue;
        function GetItemCount: Integer;
        function GetItem(Idx: Integer): IDataValue;
    public
        constructor Create(const AItems: array of IDataValue);
    end;

    // Optimized implementation for a tuple with 4 elements.
    TDataTupleValue4 = class(TInterfacedObject, IDataValue, IDataTupleValue)
    private
        FItem0, FItem1, FItem2, FItem3: IDataValue;
        function GetDataType: IDataType;
        function GetAsString: string;
        function AsTValue: TValue;
        function GetItemCount: Integer;
        function GetItem(Idx: Integer): IDataValue;
    public
        constructor Create(const AItems: array of IDataValue);
    end;

    // Optimized implementation for a tuple with 5 elements.
    TDataTupleValue5 = class(TInterfacedObject, IDataValue, IDataTupleValue)
    private
        FItem0, FItem1, FItem2, FItem3, FItem4: IDataValue;
        function GetDataType: IDataType;
        function GetAsString: string;
        function AsTValue: TValue;
        function GetItemCount: Integer;
        function GetItem(Idx: Integer): IDataValue;
    public
        constructor Create(const AItems: array of IDataValue);
    end;

{ TDataTupleValue (generic implementation for N > 5 elements) }

constructor TDataTupleValue.Create(const AItems: array of IDataValue);
var
    i: Integer;
begin
    inherited Create;
    SetLength(FItems, Length(AItems));
    for i := 0 to High(AItems) do
        FItems[i] := AItems[i];
end;

function TDataTupleValue.GetDataType: IDataType;
begin
    Result := TDataTupleType.Singleton;
end;

function TDataTupleValue.GetAsString: string;
var
    sb: TStringBuilder;
    i: Integer;
begin
    sb := TStringBuilder.Create;
    try
        sb.Append('(');
        for i := 0 to High(FItems) do
        begin
            sb.Append(FItems[i].AsString);
            if (i < High(FItems)) then
                sb.Append(', ');
        end;
        sb.Append(')');
        Result := sb.ToString;
    finally
        sb.Free;
    end;
end;

function TDataTupleValue.AsTValue: TValue;
var
    tvalueArray: TArray<TValue>;
    i: Integer;
begin
    SetLength(tvalueArray, Length(FItems));
    for i := 0 to High(FItems) do
        tvalueArray[i] := FItems[i].AsTValue;
    Result := TValue.From<TArray<TValue>>(tvalueArray);
end;

function TDataTupleValue.GetItem(Idx: Integer): IDataValue;
begin
    Result := FItems[Idx];
end;

function TDataTupleValue.GetItemCount: Integer;
begin
    Result := Length(FItems);
end;

{ TDataTupleValue0 }

class constructor TDataTupleValue0.CreateClass;
var
    emptyArray: TArray<TValue>;
begin
    FSingleton := TDataTupleValue0.Create;
    SetLength(emptyArray, 0);
    FEmptyTValue := TValue.From<TArray<TValue>>(emptyArray);
end;

function TDataTupleValue0.GetAsString: string;
begin
    Result := '()';
end;

function TDataTupleValue0.AsTValue: TValue;
begin
    Result := FEmptyTValue;
end;

function TDataTupleValue0.GetDataType: IDataType;
begin
    Result := TDataTupleType.Singleton;
end;

function TDataTupleValue0.GetItem(Idx: Integer): IDataValue;
begin
    raise EArgumentException.Create('Index out of bounds');
end;

function TDataTupleValue0.GetItemCount: Integer;
begin
    Result := 0;
end;

{ TDataTupleValue1 }

constructor TDataTupleValue1.Create(const AItems: array of IDataValue);
begin
    inherited Create;
    FItem0 := AItems[0];
end;

function TDataTupleValue1.GetAsString: string;
begin
    Result := '(' + FItem0.AsString + ')';
end;

function TDataTupleValue1.AsTValue: TValue;
var
    tvalueArray: TArray<TValue>;
begin
    SetLength(tvalueArray, 1);
    tvalueArray[0] := FItem0.AsTValue;
    Result := TValue.From<TArray<TValue>>(tvalueArray);
end;

function TDataTupleValue1.GetDataType: IDataType;
begin
    Result := TDataTupleType.Singleton;
end;

function TDataTupleValue1.GetItem(Idx: Integer): IDataValue;
begin
    case Idx of
        0: Result := FItem0;
    else
        raise EArgumentException.Create('Index out of bounds');
    end;
end;

function TDataTupleValue1.GetItemCount: Integer;
begin
    Result := 1;
end;

{ TDataTupleValue2 }

constructor TDataTupleValue2.Create(const AItems: array of IDataValue);
begin
    inherited Create;
    FItem0 := AItems[0];
    FItem1 := AItems[1];
end;

function TDataTupleValue2.GetAsString: string;
begin
    Result := '(' + FItem0.AsString + ', ' + FItem1.AsString + ')';
end;

function TDataTupleValue2.AsTValue: TValue;
var
    tvalueArray: TArray<TValue>;
begin
    SetLength(tvalueArray, 2);
    tvalueArray[0] := FItem0.AsTValue;
    tvalueArray[1] := FItem1.AsTValue;
    Result := TValue.From<TArray<TValue>>(tvalueArray);
end;

function TDataTupleValue2.GetDataType: IDataType;
begin
    Result := TDataTupleType.Singleton;
end;

function TDataTupleValue2.GetItem(Idx: Integer): IDataValue;
begin
    case Idx of
        0: Result := FItem0;
        1: Result := FItem1;
    else
        raise EArgumentException.Create('Index out of bounds');
    end;
end;

function TDataTupleValue2.GetItemCount: Integer;
begin
    Result := 2;
end;

{ TDataTupleValue3 }

constructor TDataTupleValue3.Create(const AItems: array of IDataValue);
begin
    inherited Create;
    FItem0 := AItems[0];
    FItem1 := AItems[1];
    FItem2 := AItems[2];
end;

function TDataTupleValue3.GetAsString: string;
var
    sb: TStringBuilder;
begin
    sb := TStringBuilder.Create;
    try
        sb.Append('(');
        sb.Append(FItem0.AsString);
        sb.Append(', ');
        sb.Append(FItem1.AsString);
        sb.Append(', ');
        sb.Append(FItem2.AsString);
        sb.Append(')');
        Result := sb.ToString;
    finally
        sb.Free;
    end;
end;

function TDataTupleValue3.AsTValue: TValue;
var
    tvalueArray: TArray<TValue>;
begin
    SetLength(tvalueArray, 3);
    tvalueArray[0] := FItem0.AsTValue;
    tvalueArray[1] := FItem1.AsTValue;
    tvalueArray[2] := FItem2.AsTValue;
    Result := TValue.From<TArray<TValue>>(tvalueArray);
end;

function TDataTupleValue3.GetDataType: IDataType;
begin
    Result := TDataTupleType.Singleton;
end;

function TDataTupleValue3.GetItem(Idx: Integer): IDataValue;
begin
    case Idx of
        0: Result := FItem0;
        1: Result := FItem1;
        2: Result := FItem2;
    else
        raise EArgumentException.Create('Index out of bounds');
    end;
end;

function TDataTupleValue3.GetItemCount: Integer;
begin
    Result := 3;
end;

{ TDataTupleValue4 }

constructor TDataTupleValue4.Create(const AItems: array of IDataValue);
begin
    inherited Create;
    FItem0 := AItems[0];
    FItem1 := AItems[1];
    FItem2 := AItems[2];
    FItem3 := AItems[3];
end;

function TDataTupleValue4.GetAsString: string;
var
    sb: TStringBuilder;
begin
    sb := TStringBuilder.Create;
    try
        sb.Append('(');
        sb.Append(FItem0.AsString);
        sb.Append(', ');
        sb.Append(FItem1.AsString);
        sb.Append(', ');
        sb.Append(FItem2.AsString);
        sb.Append(', ');
        sb.Append(FItem3.AsString);
        sb.Append(')');
        Result := sb.ToString;
    finally
        sb.Free;
    end;
end;

function TDataTupleValue4.AsTValue: TValue;
var
    tvalueArray: TArray<TValue>;
begin
    SetLength(tvalueArray, 4);
    tvalueArray[0] := FItem0.AsTValue;
    tvalueArray[1] := FItem1.AsTValue;
    tvalueArray[2] := FItem2.AsTValue;
    tvalueArray[3] := FItem3.AsTValue;
    Result := TValue.From<TArray<TValue>>(tvalueArray);
end;

function TDataTupleValue4.GetDataType: IDataType;
begin
    Result := TDataTupleType.Singleton;
end;

function TDataTupleValue4.GetItem(Idx: Integer): IDataValue;
begin
    case Idx of
        0: Result := FItem0;
        1: Result := FItem1;
        2: Result := FItem2;
        3: Result := FItem3;
    else
        raise EArgumentException.Create('Index out of bounds');
    end;
end;

function TDataTupleValue4.GetItemCount: Integer;
begin
    Result := 4;
end;

{ TDataTupleValue5 }

constructor TDataTupleValue5.Create(const AItems: array of IDataValue);
begin
    inherited Create;
    FItem0 := AItems[0];
    FItem1 := AItems[1];
    FItem2 := AItems[2];
    FItem3 := AItems[3];
    FItem4 := AItems[4];
end;

function TDataTupleValue5.GetAsString: string;
var
    sb: TStringBuilder;
begin
    sb := TStringBuilder.Create;
    try
        sb.Append('(');
        sb.Append(FItem0.AsString);
        sb.Append(', ');
        sb.Append(FItem1.AsString);
        sb.Append(', ');
        sb.Append(FItem2.AsString);
        sb.Append(', ');
        sb.Append(FItem3.AsString);
        sb.Append(', ');
        sb.Append(FItem4.AsString);
        sb.Append(')');
        Result := sb.ToString;
    finally
        sb.Free;
    end;
end;

function TDataTupleValue5.AsTValue: TValue;
var
    tvalueArray: TArray<TValue>;
begin
    SetLength(tvalueArray, 5);
    tvalueArray[0] := FItem0.AsTValue;
    tvalueArray[1] := FItem1.AsTValue;
    tvalueArray[2] := FItem2.AsTValue;
    tvalueArray[3] := FItem3.AsTValue;
    tvalueArray[4] := FItem4.AsTValue;
    Result := TValue.From<TArray<TValue>>(tvalueArray);
end;

function TDataTupleValue5.GetDataType: IDataType;
begin
    Result := TDataTupleType.Singleton;
end;

function TDataTupleValue5.GetItem(Idx: Integer): IDataValue;
begin
    case Idx of
        0: Result := FItem0;
        1: Result := FItem1;
        2: Result := FItem2;
        3: Result := FItem3;
        4: Result := FItem4;
    else
        raise EArgumentException.Create('Index out of bounds');
    end;
end;

function TDataTupleValue5.GetItemCount: Integer;
begin
    Result := 5;
end;

{ TDataTupleType }

class constructor TDataTupleType.CreateClass;
begin
    FSingleton := TDataTupleType.Create;
end;

function TDataTupleType.CreateValue(const AItems: array of IDataValue): IDataTupleValue;
begin
    // Use optimized implementations for tuples with 0 to 5 elements.
    case Length(AItems) of
        0: Result := TDataTupleValue0.Singleton;
        1: Result := TDataTupleValue1.Create(AItems);
        2: Result := TDataTupleValue2.Create(AItems);
        3: Result := TDataTupleValue3.Create(AItems);
        4: Result := TDataTupleValue4.Create(AItems);
        5: Result := TDataTupleValue5.Create(AItems);
    else
        // Use the generic implementation for tuples with more than 5 elements.
        Result := TDataTupleValue.Create(AItems);
    end;
end;

function TDataTupleType.GetName: String;
begin
    Result := 'Tuple';
end;

function TDataTupleType.GetKind: TDataKind;
begin
    Result := dkTuple;
end;

end.