Take the turn management out of GeminiClient (#42)

1 files changed, 102 insertions, 310 deletions

diff --git a/packages/cli/src/core/gemini-client.ts b/packages/cli/src/core/gemini-client.ts
index be338754..19dba40f 100644
--- a/packages/cli/src/core/gemini-client.ts
+++ b/packages/cli/src/core/gemini-client.ts
@@ -15,31 +15,17 @@ import {
   Content,
 } from '@google/genai';
 import { CoreSystemPrompt } from './prompts.js';
-import {
-  type ToolCallEvent,
-  type ToolCallConfirmationDetails,
-  ToolCallStatus,
-} from '../ui/types.js';
 import process from 'node:process';
 import { toolRegistry } from '../tools/tool-registry.js';
-import { ToolResult } from '../tools/tools.js';
 import { getFolderStructure } from '../utils/getFolderStructure.js';
 import { GeminiEventType, GeminiStream } from './gemini-stream.js';
 import { Config } from '../config/config.js';
-
-type ToolExecutionOutcome = {
-  callId: string;
-  name: string;
-  args: Record<string, never>;
-  result?: ToolResult;
-  error?: Error;
-  confirmationDetails?: ToolCallConfirmationDetails;
-};
+import { Turn } from './turn.js';
 
 export class GeminiClient {
   private config: Config;
   private ai: GoogleGenAI;
-  private defaultHyperParameters: GenerateContentConfig = {
+  private generateContentConfig: GenerateContentConfig = {
     temperature: 0,
     topP: 1,
   };
@@ -50,14 +36,9 @@ export class GeminiClient {
     this.ai = new GoogleGenAI({ apiKey: config.getApiKey() });
   }
 
-  async startChat(): Promise<Chat> {
-    const tools = toolRegistry.getToolSchemas();
-    const model = this.config.getModel();
-
-    // --- Get environmental information ---
+  private async getEnvironment(): Promise<Part> {
     const cwd = process.cwd();
     const today = new Date().toLocaleDateString(undefined, {
-      // Use locale-aware date formatting
       weekday: 'long',
       year: 'numeric',
       month: 'long',
@@ -65,33 +46,37 @@ export class GeminiClient {
     });
     const platform = process.platform;
 
-    // --- Format information into a conversational multi-line string ---
     const folderStructure = await getFolderStructure(cwd);
-    // --- End folder structure formatting ---)
-    const initialContextText = `
-Okay, just setting up the context for our chat.
-Today is ${today}.
-My operating system is: ${platform}
-I'm currently working in the directory: ${cwd}
-${folderStructure}
-        `.trim();
 
-    const initialContextPart: Part = { text: initialContextText };
-    // --- End environmental information formatting ---
+    const context = `
+  Okay, just setting up the context for our chat.
+  Today is ${today}.
+  My operating system is: ${platform}
+  I'm currently working in the directory: ${cwd}
+  ${folderStructure}
+          `.trim();
+
+    return { text: context };
+  }
+
+  async startChat(): Promise<Chat> {
+    const envPart = await this.getEnvironment();
+    const model = this.config.getModel();
+    const tools = toolRegistry.getToolSchemas();
 
     try {
       const chat = this.ai.chats.create({
         model,
         config: {
           systemInstruction: CoreSystemPrompt,
-          ...this.defaultHyperParameters,
+          ...this.generateContentConfig,
           tools,
         },
         history: [
           // --- Add the context as a single part in the initial user message ---
           {
             role: 'user',
-            parts: [initialContextPart], // Pass the single Part object in an array
+            parts: [envPart], // Pass the single Part object in an array
           },
           // --- Add an empty model response to balance the history ---
           {
@@ -109,308 +94,113 @@ ${folderStructure}
     }
   }
 
-  addMessageToHistory(chat: Chat, message: Content): void {
-    const history = chat.getHistory();
-    history.push(message);
-  }
-
   async *sendMessageStream(
     chat: Chat,
     request: PartListUnion,
     signal?: AbortSignal,
   ): GeminiStream {
-    let currentMessageToSend: PartListUnion = request;
     let turns = 0;
 
     try {
       while (turns < this.MAX_TURNS) {
         turns++;
-        const resultStream = await chat.sendMessageStream({
-          message: currentMessageToSend,
-        });
-        let functionResponseParts: Part[] = [];
-        let pendingToolCalls: Array<{
-          callId: string;
-          name: string;
-          args: Record<string, never>;
-        }> = [];
-        let yieldedTextInTurn = false;
-        const chunksForDebug = [];
-
-        for await (const chunk of resultStream) {
-          chunksForDebug.push(chunk);
-          if (signal?.aborted) {
-            const abortError = new Error(
-              'Request cancelled by user during stream.',
-            );
-            abortError.name = 'AbortError';
-            throw abortError;
-          }
-
-          const functionCalls = chunk.functionCalls;
-          if (functionCalls && functionCalls.length > 0) {
-            for (const call of functionCalls) {
-              const callId =
-                call.id ??
-                `${call.name}-${Date.now()}-${Math.random().toString(16).slice(2)}`;
-              const name = call.name || 'undefined_tool_name';
-              const args = (call.args || {}) as Record<string, never>;
+        // A turn either yields a text response or returns
+        // function responses to be used in the next turn.
+        // This callsite is responsible to handle the buffered
+        // function responses and use it on the next turn.
+        const turn = new Turn(chat);
+        const resultStream = turn.run(request, signal);
 
-              pendingToolCalls.push({ callId, name, args });
-              const evtValue: ToolCallEvent = {
-                type: 'tool_call',
-                status: ToolCallStatus.Pending,
-                callId,
-                name,
-                args,
-                resultDisplay: undefined,
-                confirmationDetails: undefined,
-              };
-              yield {
-                type: GeminiEventType.ToolCallInfo,
-                value: evtValue,
-              };
-            }
-          } else {
-            const text = chunk.text;
-            if (text) {
-              yieldedTextInTurn = true;
-              yield {
-                type: GeminiEventType.Content,
-                value: text,
-              };
-            }
-          }
+        for await (const event of resultStream) {
+          yield event;
+        }
+        const fnResponses = turn.getFunctionResponses();
+        if (fnResponses.length > 0) {
+          request = fnResponses;
+          continue; // use the responses in the next turn
         }
 
-        if (pendingToolCalls.length > 0) {
-          const toolPromises: Array<Promise<ToolExecutionOutcome>> =
-            pendingToolCalls.map(async (pendingToolCall) => {
-              const tool = toolRegistry.getTool(pendingToolCall.name);
-
-              if (!tool) {
-                // Directly return error outcome if tool not found
-                return {
-                  ...pendingToolCall,
-                  error: new Error(
-                    `Tool "${pendingToolCall.name}" not found or is not registered.`,
-                  ),
-                };
-              }
-
-              try {
-                const confirmation = await tool.shouldConfirmExecute(
-                  pendingToolCall.args,
-                );
-                if (confirmation) {
-                  return {
-                    ...pendingToolCall,
-                    confirmationDetails: confirmation,
-                  };
-                }
-              } catch (error) {
-                return {
-                  ...pendingToolCall,
-                  error: new Error(
-                    `Tool failed to check tool confirmation: ${error}`,
-                  ),
-                };
-              }
-
-              try {
-                const result = await tool.execute(pendingToolCall.args);
-                return { ...pendingToolCall, result };
-              } catch (error) {
-                return {
-                  ...pendingToolCall,
-                  error: new Error(`Tool failed to execute: ${error}`),
-                };
-              }
-            });
-          const toolExecutionOutcomes: ToolExecutionOutcome[] =
-            await Promise.all(toolPromises);
-
-          for (const executedTool of toolExecutionOutcomes) {
-            const { callId, name, args, result, error, confirmationDetails } =
-              executedTool;
-
-            if (error) {
-              const errorMessage = error?.message || String(error);
-              yield {
-                type: GeminiEventType.Content,
-                value: `[Error invoking tool ${name}: ${errorMessage}]`,
-              };
-            } else if (
-              result &&
-              typeof result === 'object' &&
-              result !== null &&
-              'error' in result
-            ) {
-              const errorMessage = String(result.error);
-              yield {
-                type: GeminiEventType.Content,
-                value: `[Error executing tool ${name}: ${errorMessage}]`,
-              };
-            } else {
-              const status = confirmationDetails
-                ? ToolCallStatus.Confirming
-                : ToolCallStatus.Invoked;
-              const evtValue: ToolCallEvent = {
-                type: 'tool_call',
-                status,
-                callId,
-                name,
-                args,
-                resultDisplay: result?.returnDisplay,
-                confirmationDetails,
-              };
-              yield {
-                type: GeminiEventType.ToolCallInfo,
-                value: evtValue,
-              };
-            }
-          }
-
-          pendingToolCalls = [];
-
-          const waitingOnConfirmations =
-            toolExecutionOutcomes.filter(
-              (outcome) => outcome.confirmationDetails,
-            ).length > 0;
-          if (waitingOnConfirmations) {
-            // Stop processing content, wait for user.
-            // TODO: Kill token processing once API supports signals.
-            break;
-          }
-
-          functionResponseParts = toolExecutionOutcomes.map(
-            (executedTool: ToolExecutionOutcome): Part => {
-              const { name, result, error } = executedTool;
-              const output = { output: result?.llmContent };
-              let toolOutcomePayload: Record<string, unknown>;
-
-              if (error) {
-                const errorMessage = error?.message || String(error);
-                toolOutcomePayload = {
-                  error: `Invocation failed: ${errorMessage}`,
-                };
-                console.error(
-                  `[Turn ${turns}] Critical error invoking tool ${name}:`,
-                  error,
-                );
-              } else if (
-                result &&
-                typeof result === 'object' &&
-                result !== null &&
-                'error' in result
-              ) {
-                toolOutcomePayload = output;
-                console.warn(
-                  `[Turn ${turns}] Tool ${name} returned an error structure:`,
-                  result.error,
-                );
-              } else {
-                toolOutcomePayload = output;
-              }
-
-              return {
-                functionResponse: {
-                  name,
-                  id: executedTool.callId,
-                  response: toolOutcomePayload,
-                },
-              };
-            },
-          );
-          currentMessageToSend = functionResponseParts;
-        } else if (yieldedTextInTurn) {
-          const history = chat.getHistory();
-          const checkPrompt = `Analyze *only* the content and structure of your immediately preceding response (your last turn in the conversation history). Based *strictly* on that response, determine who should logically speak next: the 'user' or the 'model' (you).
+        const history = chat.getHistory();
+        const checkPrompt = `Analyze *only* the content and structure of your immediately preceding response (your last turn in the conversation history). Based *strictly* on that response, determine who should logically speak next: the 'user' or the 'model' (you).
 
-**Decision Rules (apply in order):**
+  **Decision Rules (apply in order):**
 
-1.  **Model Continues:** If your last response explicitly states an immediate next action *you* intend to take (e.g., "Next, I will...", "Now I'll process...", "Moving on to analyze...", indicates an intended tool call that didn't execute), OR if the response seems clearly incomplete (cut off mid-thought without a natural conclusion), then the **'model'** should speak next.
-2.  **Question to User:** If your last response ends with a direct question specifically addressed *to the user*, then the **'user'** should speak next.
-3.  **Waiting for User:** If your last response completed a thought, statement, or task *and* does not meet the criteria for Rule 1 (Model Continues) or Rule 2 (Question to User), it implies a pause expecting user input or reaction. In this case, the **'user'** should speak next.
+  1.  **Model Continues:** If your last response explicitly states an immediate next action *you* intend to take (e.g., "Next, I will...", "Now I'll process...", "Moving on to analyze...", indicates an intended tool call that didn't execute), OR if the response seems clearly incomplete (cut off mid-thought without a natural conclusion), then the **'model'** should speak next.
+  2.  **Question to User:** If your last response ends with a direct question specifically addressed *to the user*, then the **'user'** should speak next.
+  3.  **Waiting for User:** If your last response completed a thought, statement, or task *and* does not meet the criteria for Rule 1 (Model Continues) or Rule 2 (Question to User), it implies a pause expecting user input or reaction. In this case, the **'user'** should speak next.
 
-**Output Format:**
+  **Output Format:**
 
-Respond *only* in JSON format according to the following schema. Do not include any text outside the JSON structure.
+  Respond *only* in JSON format according to the following schema. Do not include any text outside the JSON structure.
 
-\`\`\`json
-{
-  "type": "object",
-  "properties": {
-    "reasoning": {
+  \`\`\`json
+  {
+    "type": "object",
+    "properties": {
+      "reasoning": {
+          "type": "string",
+          "description": "Brief explanation justifying the 'next_speaker' choice based *strictly* on the applicable rule and the content/structure of the preceding turn."
+      },
+      "next_speaker": {
         "type": "string",
-        "description": "Brief explanation justifying the 'next_speaker' choice based *strictly* on the applicable rule and the content/structure of the preceding turn."
+        "enum": ["user", "model"],
+        "description": "Who should speak next based *only* on the preceding turn and the decision rules."
+      }
     },
-    "next_speaker": {
-      "type": "string",
-      "enum": ["user", "model"],
-      "description": "Who should speak next based *only* on the preceding turn and the decision rules."
-    }
-  },
-  "required": ["next_speaker", "reasoning"]
-\`\`\`
-}`;
+    "required": ["next_speaker", "reasoning"]
+  \`\`\`
+  }`;
 
-          // Schema Idea
-          const responseSchema: SchemaUnion = {
-            type: Type.OBJECT,
-            properties: {
-              reasoning: {
-                type: Type.STRING,
-                description:
-                  "Brief explanation justifying the 'next_speaker' choice based *strictly* on the applicable rule and the content/structure of the preceding turn.",
-              },
-              next_speaker: {
-                type: Type.STRING,
-                enum: ['user', 'model'], // Enforce the choices
-                description:
-                  'Who should speak next based *only* on the preceding turn and the decision rules',
-              },
+        // Schema Idea
+        const responseSchema: SchemaUnion = {
+          type: Type.OBJECT,
+          properties: {
+            reasoning: {
+              type: Type.STRING,
+              description:
+                "Brief explanation justifying the 'next_speaker' choice based *strictly* on the applicable rule and the content/structure of the preceding turn.",
+            },
+            next_speaker: {
+              type: Type.STRING,
+              enum: ['user', 'model'], // Enforce the choices
+              description:
+                'Who should speak next based *only* on the preceding turn and the decision rules',
             },
-            required: ['reasoning', 'next_speaker'],
-          };
+          },
+          required: ['reasoning', 'next_speaker'],
+        };
 
-          try {
-            // Use the new generateJson method, passing the history and the check prompt
-            const parsedResponse = await this.generateJson(
-              [
-                ...history,
-                {
-                  role: 'user',
-                  parts: [{ text: checkPrompt }],
-                },
-              ],
-              responseSchema,
-            );
+        try {
+          // Use the new generateJson method, passing the history and the check prompt
+          const parsedResponse = await this.generateJson(
+            [
+              ...history,
+              {
+                role: 'user',
+                parts: [{ text: checkPrompt }],
+              },
+            ],
+            responseSchema,
+          );
 
-            // Safely extract the next speaker value
-            const nextSpeaker: string | undefined =
-              typeof parsedResponse?.next_speaker === 'string'
-                ? parsedResponse.next_speaker
-                : undefined;
+          // Safely extract the next speaker value
+          const nextSpeaker: string | undefined =
+            typeof parsedResponse?.next_speaker === 'string'
+              ? parsedResponse.next_speaker
+              : undefined;
 
-            if (nextSpeaker === 'model') {
-              currentMessageToSend = { text: 'alright' }; // Or potentially a more meaningful continuation prompt
-            } else {
-              // 'user' should speak next, or value is missing/invalid. End the turn.
-              break;
-            }
-          } catch (error) {
-            console.error(
-              `[Turn ${turns}] Failed to get or parse next speaker check:`,
-              error,
-            );
-            // If the check fails, assume user should speak next to avoid infinite loops
+          if (nextSpeaker === 'model') {
+            request = { text: 'alright' }; // Or potentially a more meaningful continuation prompt
+          } else {
+            // 'user' should speak next, or value is missing/invalid. End the turn.
             break;
           }
-        } else {
-          console.warn(
-            `[Turn ${turns}] No text or function calls received from Gemini. Ending interaction.`,
+        } catch (error) {
+          console.error(
+            `[Turn ${turns}] Failed to get or parse next speaker check:`,
+            error,
           );
+          // If the check fails, assume user should speak next to avoid infinite loops
           break;
         }
       }
@@ -426,6 +216,8 @@ Respond *only* in JSON format according to the following schema. Do not include
         };
       }
     } catch (error: unknown) {
+      // TODO(jbd): There is so much of packing/unpacking of error types.
+      // Figure out a way to remove the redundant work.
       if (error instanceof Error && error.name === 'AbortError') {
         console.log('Gemini stream request aborted by user.');
         throw error;
@@ -457,7 +249,7 @@ Respond *only* in JSON format according to the following schema. Do not include
       const result = await this.ai.models.generateContent({
         model,
         config: {
-          ...this.defaultHyperParameters,
+          ...this.generateContentConfig,
           systemInstruction: CoreSystemPrompt,
           responseSchema: schema,
           responseMimeType: 'application/json',