MycLib/GeminiTest/Myc.Api.Gemini.pas

unit Myc.Api.Gemini;

interface

uses
    System.SysUtils,
    System.Classes,
    System.Net.HttpClient,
    System.Net.Mime,
    System.JSON,
    System.NetEncoding,
    System.Generics.Collections,
    System.SyncObjs,
    Myc.System.Quota; // Einbindung der Global Quota Unit

type
    // Represents usage statistics for a request
    TGeminiUsage = record
        PromptTokens: Integer;
        CandidatesTokens: Integer;
        TotalTokens: Integer;
    end;

    // Represents the result of a generation request
    TGeminiResult = record
        Text: string;
        IsThought: Boolean; // True if this part contains reasoning/thoughts
        Usage: TGeminiUsage;
    end;

    TChatRole = (User, Model);

    TChatItem = record
        Role: TChatRole;
        Text: string;
    end;

    // Callback for streaming: provides the new text delta and thought flag
    TStreamCallback = reference to procedure(const TextDelta: string; IsThought: Boolean);

    // Interface for a chat session (maintains history)
    IGeminiChat = interface
        ['{5C2F64C8-4D18-47C0-9513-332715053673}']
        function SendMessage(const Text: string): TGeminiResult;
        function SendMessageStream(const Text: string; const OnDelta: TStreamCallback): TGeminiResult;
        function GetHistory: TArray<TChatItem>;
    end;

    // Interface for the API Client
    IGeminiClient = interface
        ['{E6721670-3498-4660-848D-82F3B1A2B5E2}']
        // Standard Generation
        function GenerateContent(const Prompt: string): TGeminiResult; overload;
        function GenerateContent(const History: TArray<TChatItem>): TGeminiResult; overload;

        // Streaming Generation
        function GenerateContentStream(const Prompt: string; const OnDelta: TStreamCallback): TGeminiResult; overload;
        function GenerateContentStream(const History: TArray<TChatItem>; const OnDelta: TStreamCallback): TGeminiResult; overload;

        // Utilities
        function ListModels: TArray<string>;
        function StartChat: IGeminiChat;

        // Context Caching
        function CreateCache(const Content: string; const SysInstructions: string; const TTLSeconds: Integer = 300): string;
        procedure SetActiveCache(const CacheName: string);
        function GetActiveCache: string;

        // Configuration
        procedure SetSystemInstruction(const Value: string);
        function GetSystemInstruction: string;

        // Native Thinking / Reasoning
        procedure SetEnableThinking(const Value: Boolean);
        function GetEnableThinking: Boolean;

        property ActiveCacheName: string read GetActiveCache write SetActiveCache;
        property SystemInstruction: string read GetSystemInstruction write SetSystemInstruction;
        property EnableThinking: Boolean read GetEnableThinking write SetEnableThinking;
    end;

    // Implementation of the API Client
    TGeminiClient = class(TInterfacedObject, IGeminiClient)
    private
        class var
            FTotalUsage: TGeminiUsage;
    private
        FApiKey: string;
        FBaseUrl: string;
        FStreamUrl: string;
        FListUrl: string;
        FModelName: string;
        FActiveCacheName: string;
        FSystemInstruction: string;
        FEnableThinking: Boolean;

        function ParseResponse(const JsonStr: string): TGeminiResult;
        function ParseModels(const JsonStr: string): TArray<string>;
        function BuildJsonBody(const History: TArray<TChatItem>): TJSONObject;
        procedure ProcessStreamData(const Data: TBytes; var Buffer: string; const OnDelta: TStreamCallback; var TotalResult: TGeminiResult);
    public
        constructor Create(const AApiKey: string; const AModel: string = 'gemini-1.5-flash-001');

        function GenerateContent(const Prompt: string): TGeminiResult; overload;
        function GenerateContent(const History: TArray<TChatItem>): TGeminiResult; overload;

        function GenerateContentStream(const Prompt: string; const OnDelta: TStreamCallback): TGeminiResult; overload;
        function GenerateContentStream(const History: TArray<TChatItem>; const OnDelta: TStreamCallback): TGeminiResult; overload;

        function ListModels: TArray<string>;
        function StartChat: IGeminiChat;

        function CreateCache(const Content: string; const SysInstructions: string; const TTLSeconds: Integer = 300): string;
        procedure SetActiveCache(const CacheName: string);
        function GetActiveCache: string;

        procedure SetSystemInstruction(const Value: string);
        function GetSystemInstruction: string;

        procedure SetEnableThinking(const Value: Boolean);
        function GetEnableThinking: Boolean;

        // Static access to session-global usage (RAM only)
        class property TotalUsage: TGeminiUsage read FTotalUsage;
    end;

implementation

type
    // Internal Chat Session Implementation
    TChatSession = class(TInterfacedObject, IGeminiChat)
    private
        FClient: IGeminiClient;
        FHistory: TList<TChatItem>;
    public
        constructor Create(const Client: IGeminiClient);
        destructor Destroy; override;
        function SendMessage(const Text: string): TGeminiResult;
        function SendMessageStream(const Text: string; const OnDelta: TStreamCallback): TGeminiResult;
        function GetHistory: TArray<TChatItem>;
    end;

{ TGeminiClient }

constructor TGeminiClient.Create(const AApiKey: string; const AModel: string);
var
    LModel: string;
    encodedKey: string;
begin
    inherited Create;
    FApiKey := AApiKey.Trim;
    LModel := AModel.Trim;

    if LModel.IsEmpty then
        LModel := 'gemini-1.5-flash-001';

    FModelName := LModel;
    if not FModelName.StartsWith('models/') then
        FModelName := 'models/' + FModelName;

    encodedKey := TNetEncoding.URL.EncodeQuery(FApiKey);

    // Endpoint construction
    FBaseUrl := Format('https://generativelanguage.googleapis.com/v1beta/%s:generateContent?key=%s', [FModelName, encodedKey]);

    FStreamUrl := Format('https://generativelanguage.googleapis.com/v1beta/%s:streamGenerateContent?key=%s', [FModelName, encodedKey]);

    FListUrl := Format('https://generativelanguage.googleapis.com/v1beta/models?key=%s', [encodedKey]);

    FEnableThinking := False;
end;

// --- Property Setters/Getters ---

procedure TGeminiClient.SetEnableThinking(const Value: Boolean);
begin
    FEnableThinking := Value;
end;

function TGeminiClient.GetEnableThinking: Boolean;
begin
    Result := FEnableThinking;
end;

procedure TGeminiClient.SetActiveCache(const CacheName: string);
begin
    FActiveCacheName := CacheName;
end;

function TGeminiClient.GetActiveCache: string;
begin
    Result := FActiveCacheName;
end;

procedure TGeminiClient.SetSystemInstruction(const Value: string);
begin
    FSystemInstruction := Value;
end;

function TGeminiClient.GetSystemInstruction: string;
begin
    Result := FSystemInstruction;
end;

// --- Core Logic ---

function TGeminiClient.GenerateContent(const Prompt: string): TGeminiResult;
var
    item: TChatItem;
begin
    item.Role := TChatRole.User;
    item.Text := Prompt;
    Result := GenerateContent([item]);
end;

function TGeminiClient.GenerateContent(const History: TArray<TChatItem>): TGeminiResult;
var
    httpClient: THTTPClient;
    requestBody: TJSONObject;
    response: IHTTPResponse;
    stringStream: TStringStream;
begin
    Result.Text := '';
    Result.Usage := Default(TGeminiUsage);
    Result.IsThought := False;

    httpClient := THTTPClient.Create;
    requestBody := BuildJsonBody(History);
    try
        stringStream := TStringStream.Create(requestBody.ToString, TEncoding.UTF8);
        try
            httpClient.CustomHeaders['Content-Type'] := 'application/json';
            httpClient.ConnectionTimeout := 10000;
            httpClient.ResponseTimeout := 30000;

            try
                response := httpClient.Post(FBaseUrl, stringStream);
            except
                on E: Exception do
                begin
                    Result.Text := 'Error: Connection failed - ' + E.Message;
                    exit;
                end;
            end;

            if (response.StatusCode = 200) then
            begin
                Result := ParseResponse(response.ContentAsString(TEncoding.UTF8));

                // Update Usages
                if (Result.Usage.TotalTokens > 0) then
                begin
                    // RAM Counter
                    TInterlocked.Add(FTotalUsage.PromptTokens, Result.Usage.PromptTokens);
                    TInterlocked.Add(FTotalUsage.CandidatesTokens, Result.Usage.CandidatesTokens);
                    TInterlocked.Add(FTotalUsage.TotalTokens, Result.Usage.TotalTokens);

                    // Persistent System Counter
                    TGlobalQuota.AddTokens(Result.Usage.TotalTokens);
                end;
            end
            else
            begin
                Result.Text :=
                    Format('Error: %d - %s (%s)', [response.StatusCode, response.StatusText, response.ContentAsString(TEncoding.UTF8)]);
            end;
        finally
            stringStream.Free;
        end;
    finally
        httpClient.Free;
        requestBody.Free;
    end;
end;

function TGeminiClient.GenerateContentStream(const Prompt: string; const OnDelta: TStreamCallback): TGeminiResult;
var
    item: TChatItem;
begin
    item.Role := TChatRole.User;
    item.Text := Prompt;
    Result := GenerateContentStream([item], OnDelta);
end;

function TGeminiClient.GenerateContentStream(const History: TArray<TChatItem>; const OnDelta: TStreamCallback): TGeminiResult;
var
    httpClient: THTTPClient;
    requestBody: TJSONObject;
    stringStream: TStringStream;
    buffer: string;

    // Captured local variable for the result state to avoid E2555
    LFullResult: TGeminiResult;
begin
    // Init local result container
    LFullResult.Text := '';
    LFullResult.Usage := Default(TGeminiUsage);
    LFullResult.IsThought := False;
    buffer := '';

    httpClient := THTTPClient.Create;
    requestBody := BuildJsonBody(History);
    try
        stringStream := TStringStream.Create(requestBody.ToString, TEncoding.UTF8);
        try
            httpClient.CustomHeaders['Content-Type'] := 'application/json';
            httpClient.ConnectionTimeout := 10000;
            httpClient.ResponseTimeout := 60000;

            // Use ReceiveDataExCallback to access raw data chunks efficiently
            httpClient.ReceiveDataExCallback :=
                procedure(
                    const Sender: TObject;
                    AContentLength: Int64;
                    AReadCount: Int64;
                    AChunk: Pointer;
                    AChunkLength: Cardinal;
                    var AAbort: Boolean
                )
                var
                    LBytes: TBytes;
                begin
                    if AChunkLength > 0 then
                    begin
                        SetLength(LBytes, AChunkLength);
                        Move(AChunk^, LBytes[0], AChunkLength);

                        ProcessStreamData(LBytes, buffer, OnDelta, LFullResult);
                    end;
                end;

            try
                httpClient.Post(FStreamUrl, stringStream);
            except
                on E: Exception do
                begin
                    LFullResult.Text := LFullResult.Text + sLineBreak + '[Error: ' + E.Message + ']';
                end;
            end;

            // Update Usages
            if LFullResult.Usage.TotalTokens > 0 then
            begin
                // RAM Counter
                TInterlocked.Add(FTotalUsage.PromptTokens, LFullResult.Usage.PromptTokens);
                TInterlocked.Add(FTotalUsage.CandidatesTokens, LFullResult.Usage.CandidatesTokens);
                TInterlocked.Add(FTotalUsage.TotalTokens, LFullResult.Usage.TotalTokens);

                // Persistent System Counter
                TGlobalQuota.AddTokens(LFullResult.Usage.TotalTokens);
            end;

        finally
            stringStream.Free;
        end;
    finally
        httpClient.Free;
        requestBody.Free;
    end;

    Result := LFullResult;
end;

// --- JSON Body Construction ---

function TGeminiClient.BuildJsonBody(const History: TArray<TChatItem>): TJSONObject;
var
    contentsArray, partsArray: TJSONArray;
    contentObj, partObj: TJSONObject;
    sysObj, sysPart: TJSONObject;
    sysPartsArr: TJSONArray;
    item: TChatItem;
    genConfig, thinkConfig: TJSONObject;
begin
    Result := TJSONObject.Create;

    // 1. Caching Strategy
    if not FActiveCacheName.IsEmpty then
    begin
        Result.AddPair('cachedContent', FActiveCacheName);
    end
    else
    begin
        // 2. Dynamic System Instructions (only if no cache active)
        if not FSystemInstruction.IsEmpty then
        begin
            sysObj := TJSONObject.Create;

            sysPartsArr := TJSONArray.Create;
            sysPart := TJSONObject.Create;
            sysPart.AddPair('text', FSystemInstruction);
            sysPartsArr.Add(sysPart);

            sysObj.AddPair('parts', sysPartsArr);
            Result.AddPair('systemInstruction', sysObj);
        end;
    end;

    // 3. Native Thinking Configuration
    if FEnableThinking then
    begin
        thinkConfig := TJSONObject.Create;
        thinkConfig.AddPair('includeThoughts', TJSONTrue.Create);
        // 'thinkingLevel' omitted to use model default

        genConfig := TJSONObject.Create;
        genConfig.AddPair('thinkingConfig', thinkConfig);

        Result.AddPair('generationConfig', genConfig);
    end;

    // 4. Chat Contents
    contentsArray := TJSONArray.Create;

    for item in History do
    begin
        contentObj := TJSONObject.Create;

        // Delphi 13 inline if
        contentObj.AddPair(
            'role',
            if item.Role = TChatRole.User then 'user'
            else 'model'
        );

        partObj := TJSONObject.Create;
        partObj.AddPair('text', item.Text);

        partsArray := TJSONArray.Create;
        partsArray.Add(partObj);

        contentObj.AddPair('parts', partsArray);
        contentsArray.Add(contentObj);
    end;
    Result.AddPair('contents', contentsArray);
end;

// --- Response Parsing (Streaming) ---

procedure TGeminiClient.ProcessStreamData(
    const Data: TBytes;
    var Buffer: string;
    const OnDelta: TStreamCallback;
    var TotalResult: TGeminiResult
);
var
    chunkStr: string;
    jsonStart, jsonEnd: Integer;
    jsonSub: string;
    jsonObj: TJSONObject;
    candidates, parts: TJSONArray;
    part, usageObj: TJSONObject;
    deltaText: string;
    isDeltaThought: Boolean;
    braceCount, i: Integer;
    foundEnd: Boolean;
begin
    chunkStr := TEncoding.UTF8.GetString(Data);
    Buffer := Buffer + chunkStr;

    // Parse loop to extract complete JSON objects from buffer
    while True do
    begin
        jsonStart := Buffer.IndexOf('{');
        jsonEnd := -1;
        if jsonStart < 0 then
            break;

        // Brackets matching to find end of JSON object
        braceCount := 0;
        foundEnd := False;
        for i := jsonStart to Buffer.Length - 1 do
        begin
            if Buffer.Chars[i] = '{' then
                inc(braceCount)
            else if Buffer.Chars[i] = '}' then
                dec(braceCount);

            if (braceCount = 0) then
            begin
                jsonEnd := i;
                foundEnd := True;
                break;
            end;
        end;

        if not foundEnd then
            break; // Object incomplete

        jsonSub := Buffer.Substring(jsonStart, jsonEnd - jsonStart + 1);
        Buffer := Buffer.Substring(jsonEnd + 1);

        jsonObj := TJSONObject.ParseJSONValue(jsonSub) as TJSONObject;
        if Assigned(jsonObj) then
            try
                deltaText := '';
                isDeltaThought := False;

                candidates := jsonObj.GetValue('candidates') as TJSONArray;
                if (Assigned(candidates)) and (candidates.Count > 0) then
                begin
                    var cand := candidates.Items[0] as TJSONObject;
                    var content := cand.GetValue('content') as TJSONObject;
                    if Assigned(content) then
                    begin
                        parts := content.GetValue('parts') as TJSONArray;
                        if (Assigned(parts)) and (parts.Count > 0) then
                        begin
                            part := parts.Items[0] as TJSONObject;
                            deltaText := part.GetValue<string>('text');

                            // Check for Native Thinking flag "thought": true
                            part.TryGetValue<Boolean>('thought', isDeltaThought);
                        end;
                    end;
                end;

                usageObj := jsonObj.GetValue('usageMetadata') as TJSONObject;
                if Assigned(usageObj) then
                begin
                    usageObj.TryGetValue<Integer>('promptTokenCount', TotalResult.Usage.PromptTokens);
                    usageObj.TryGetValue<Integer>('candidatesTokenCount', TotalResult.Usage.CandidatesTokens);
                    usageObj.TryGetValue<Integer>('totalTokenCount', TotalResult.Usage.TotalTokens);
                end;

                if not deltaText.IsEmpty then
                begin
                    // Append to full text (including thoughts)
                    if not isDeltaThought then
                        TotalResult.Text := TotalResult.Text + deltaText;

                    // Fire callback
                    if Assigned(OnDelta) then
                        OnDelta(deltaText, isDeltaThought);
                end;
            finally
                jsonObj.Free;
            end;
    end;
end;

// --- Response Parsing (Synchronous) ---

function TGeminiClient.ParseResponse(const JsonStr: string): TGeminiResult;
var
    jsonObj: TJSONObject;
    candidates, parts: TJSONArray;
    candidate, content, part, usageObj: TJSONObject;
    isThought: Boolean;
begin
    Result.Text := '';
    Result.Usage := Default(TGeminiUsage);
    Result.IsThought := False;

    jsonObj := TJSONObject.ParseJSONValue(JsonStr) as TJSONObject;
    if not Assigned(jsonObj) then
        exit;

    try
        candidates := jsonObj.GetValue('candidates') as TJSONArray;
        if (Assigned(candidates)) and (candidates.Count > 0) then
        begin
            candidate := candidates.Items[0] as TJSONObject;
            content := candidate.GetValue('content') as TJSONObject;
            if Assigned(content) then
            begin
                parts := content.GetValue('parts') as TJSONArray;
                if (Assigned(parts)) and (parts.Count > 0) then
                begin
                    part := parts.Items[0] as TJSONObject;
                    Result.Text := part.GetValue<string>('text');

                    // Check for thought flag
                    if part.TryGetValue<Boolean>('thought', isThought) then
                        Result.IsThought := isThought;
                end;
            end;
        end;

        usageObj := jsonObj.GetValue('usageMetadata') as TJSONObject;
        if Assigned(usageObj) then
        begin
            usageObj.TryGetValue<Integer>('promptTokenCount', Result.Usage.PromptTokens);
            usageObj.TryGetValue<Integer>('candidatesTokenCount', Result.Usage.CandidatesTokens);
            usageObj.TryGetValue<Integer>('totalTokenCount', Result.Usage.TotalTokens);
        end;
    finally
        jsonObj.Free;
    end;
end;

// --- Model Listing ---

function TGeminiClient.ListModels: TArray<string>;
var
    httpClient: THTTPClient;
    response: IHTTPResponse;
begin
    SetLength(Result, 0);
    httpClient := THTTPClient.Create;
    try
        httpClient.ConnectionTimeout := 10000;
        try
            response := httpClient.Get(FListUrl);
            if (response.StatusCode = 200) then
                Result := ParseModels(response.ContentAsString(TEncoding.UTF8));
        except
            // Return empty array on error
        end;
    finally
        httpClient.Free;
    end;
end;

function TGeminiClient.ParseModels(const JsonStr: string): TArray<string>;
var
    jsonObj: TJSONObject;
    models, methods: TJSONArray;
    model: TJSONObject;
    i, j: Integer;
    modelName: string;
    canGen: Boolean;
    list: TList<string>;
begin
    SetLength(Result, 0);
    jsonObj := TJSONObject.ParseJSONValue(JsonStr) as TJSONObject;
    if not Assigned(jsonObj) then
        exit;

    list := TList<string>.Create;
    try
        models := jsonObj.GetValue('models') as TJSONArray;
        if Assigned(models) then
        begin
            for i := 0 to models.Count - 1 do
            begin
                model := models.Items[i] as TJSONObject;
                modelName := model.GetValue<string>('name');

                if modelName.StartsWith('models/') then
                    modelName := modelName.Substring(7);

                // Filter for Gemini models
                if not modelName.ToLower.Contains('gemini') then
                    continue;
                if modelName.ToLower.Contains('embedding') then
                    continue;
                if modelName.ToLower.Contains('robotics') then
                    continue;
                if modelName.ToLower.Contains('computer-use') then
                    continue;

                // Filter for Generation capabilities
                canGen := False;
                methods := model.GetValue('supportedGenerationMethods') as TJSONArray;
                if Assigned(methods) then
                    for j := 0 to methods.Count - 1 do
                        if (methods.Items[j].Value = 'generateContent') then
                        begin
                            canGen := True;
                            break;
                        end;

                if canGen then
                    list.Add(modelName);
            end;
        end;
        Result := list.ToArray;
    finally
        list.Free;
        jsonObj.Free;
    end;
end;

// --- Context Caching ---

function TGeminiClient.CreateCache(const Content: string; const SysInstructions: string; const TTLSeconds: Integer): string;
var
    httpClient: THTTPClient;
    requestBody: TJSONObject;
    contentsArray, partsArray: TJSONArray;
    contentObj, partObj, sysObj: TJSONObject;
    sysPartsArr: TJSONArray;
    sysPart: TJSONObject;
    response: IHTTPResponse;
    stringStream: TStringStream;
    cacheUrl: string;
    respJson: TJSONObject;
begin
    Result := '';
    cacheUrl := Format('https://generativelanguage.googleapis.com/v1beta/cachedContents?key=%s', [TNetEncoding.URL.EncodeQuery(FApiKey)]);

    httpClient := THTTPClient.Create;
    requestBody := TJSONObject.Create;
    try
        requestBody.AddPair('model', FModelName);

        partObj := TJSONObject.Create;
        partObj.AddPair('text', Content);

        partsArray := TJSONArray.Create;
        partsArray.Add(partObj);

        contentObj := TJSONObject.Create;
        contentObj.AddPair('parts', partsArray);
        contentObj.AddPair('role', 'user');

        contentsArray := TJSONArray.Create;
        contentsArray.Add(contentObj);
        requestBody.AddPair('contents', contentsArray);

        if not SysInstructions.IsEmpty then
        begin
            sysObj := TJSONObject.Create;

            sysPartsArr := TJSONArray.Create;
            sysPart := TJSONObject.Create;
            sysPart.AddPair('text', SysInstructions);
            sysPartsArr.Add(sysPart);

            sysObj.AddPair('parts', sysPartsArr);
            requestBody.AddPair('systemInstruction', sysObj);
        end;

        requestBody.AddPair('ttl', IntToStr(TTLSeconds) + 's');

        stringStream := TStringStream.Create(requestBody.ToString, TEncoding.UTF8);
        try
            httpClient.CustomHeaders['Content-Type'] := 'application/json';
            try
                response := httpClient.Post(cacheUrl, stringStream);
            except
                on E: Exception do
                    raise Exception.Create('Cache Creation Failed: ' + E.Message);
            end;

            // Success is 200 OK or 201 Created
            if (response.StatusCode = 200) or (response.StatusCode = 201) then
            begin
                respJson := TJSONObject.ParseJSONValue(response.ContentAsString(TEncoding.UTF8)) as TJSONObject;
                try
                    if Assigned(respJson) then
                        Result := respJson.GetValue<string>('name');
                finally
                    respJson.Free;
                end;
            end
            else
            begin
                raise Exception.CreateFmt('Cache Error %d: %s', [response.StatusCode, response.ContentAsString(TEncoding.UTF8)]);
            end;
        finally
            stringStream.Free;
        end;
    finally
        httpClient.Free;
        requestBody.Free;
    end;
end;

function TGeminiClient.StartChat: IGeminiChat;
begin
    Result := TChatSession.Create(Self);
end;

// --- TChatSession Implementation ---

constructor TChatSession.Create(const Client: IGeminiClient);
begin
    inherited Create;
    FClient := Client;
    FHistory := TList<TChatItem>.Create;
end;

destructor TChatSession.Destroy;
begin
    FHistory.Free;
    inherited;
end;

function TChatSession.SendMessage(const Text: string): TGeminiResult;
var
    item: TChatItem;
begin
    item.Role := TChatRole.User;
    item.Text := Text;
    FHistory.Add(item);

    Result := FClient.GenerateContent(FHistory.ToArray);

    if not Result.Text.IsEmpty and not Result.Text.StartsWith('Error') then
    begin
        item.Role := TChatRole.Model;
        item.Text := Result.Text;
        FHistory.Add(item);
    end;
end;

function TChatSession.SendMessageStream(const Text: string; const OnDelta: TStreamCallback): TGeminiResult;
var
    item: TChatItem;
begin
    item.Role := TChatRole.User;
    item.Text := Text;
    FHistory.Add(item);

    Result := FClient.GenerateContentStream(FHistory.ToArray, OnDelta);

    if not Result.Text.IsEmpty and not Result.Text.StartsWith('Error') then
    begin
        item.Role := TChatRole.Model;
        item.Text := Result.Text;
        FHistory.Add(item);
    end;
end;

function TChatSession.GetHistory: TArray<TChatItem>;
begin
    Result := FHistory.ToArray;
end;

end.