Add the Converse method to the back end interface

Adds Converse as a back end method, making it usable by library clients.

Author: jhrozek

pkg/backend/backend.go

@@ -14,18 +14,22 @@
 
 package backend
 
-import "context"
+import (
+	"context"
+)
 
 // Backend defines the interface for interacting with various LLM backends.
 type Backend interface {
+	Converse(ctx context.Context, prompt *Prompt) (PromptResponse, error)
 	Generate(ctx context.Context, prompt *Prompt) (string, error)
 	Embed(ctx context.Context, input string) ([]float32, error)
 }
 
 // Message represents a single role-based message in the conversation.
 type Message struct {
-	Role    string `json:"role"`
-	Content string `json:"content"`
+	Role    string         `json:"role"`
+	Content string         `json:"content"`
+	Fields  map[string]any `json:"fields,omitempty"`
 }
 
 // Parameters defines generation settings for LLM completions.
@@ -41,11 +45,17 @@ type Parameters struct {
 type Prompt struct {
 	Messages   []Message  `json:"messages"`
 	Parameters Parameters `json:"parameters"`
+	// ToolRegistry is a map of tool names to their corresponding wrapper functions.
+	Tools *ToolRegistry
 }
 
 // NewPrompt creates and returns a new Prompt.
 func NewPrompt() *Prompt {
-	return &Prompt{}
+	return &Prompt{
+		Messages:   make([]Message, 0),
+		Parameters: Parameters{},
+		Tools:      NewToolRegistry(),
+	}
 }
 
 // AddMessage adds a message with a specific role to the prompt.
@@ -54,8 +64,50 @@ func (p *Prompt) AddMessage(role, content string) *Prompt {
 	return p
 }
 
+// AppendMessage adds a message with a specific role to the prompt.
+func (p *Prompt) AppendMessage(msg Message) *Prompt {
+	p.Messages = append(p.Messages, msg)
+	return p
+}
+
 // SetParameters sets the generation parameters for the prompt.
 func (p *Prompt) SetParameters(params Parameters) *Prompt {
 	p.Parameters = params
 	return p
 }
+
+// AsMap returns the conversation's messages as a list of maps.
+func (p *Prompt) AsMap() ([]map[string]any, error) {
+	messageList := make([]map[string]any, 0, len(p.Messages))
+	for _, message := range p.Messages {
+		msgMap := map[string]any{
+			"role":    message.Role,
+			"content": message.Content,
+		}
+		for k, v := range message.Fields {
+			msgMap[k] = v
+		}
+		messageList = append(messageList, msgMap)
+	}
+
+	return messageList, nil
+}
+
+// FunctionCall represents a call to a function.
+type FunctionCall struct {
+	Name      string         `json:"name"`
+	Arguments map[string]any `json:"arguments"`
+	Result    any            `json:"result"`
+}
+
+// ToolCall represents a call to a tool.
+type ToolCall struct {
+	Function FunctionCall `json:"function"`
+}
+
+// PromptResponse represents a response from the AI in a conversation.
+type PromptResponse struct {
+	Role      string     `json:"role"`
+	Content   string     `json:"content"`
+	ToolCalls []ToolCall `json:"tool_calls"`
+}

pkg/backend/openai_backend_test.go

@@ -33,16 +33,18 @@ func TestGenerate(t *testing.T) {
 		Choices: []struct {
 			Index   int `json:"index"`
 			Message struct {
-				Role    string `json:"role"`
-				Content string `json:"content"`
+				Role      string           `json:"role"`
+				Content   string           `json:"content"`
+				ToolCalls []OpenAIToolCall `json:"tool_calls"`
 			} `json:"message"`
 			FinishReason string `json:"finish_reason"`
 		}{
 			{
 				Index: 0,
 				Message: struct {
-					Role    string `json:"role"`
-					Content string `json:"content"`
+					Role      string           `json:"role"`
+					Content   string           `json:"content"`
+					ToolCalls []OpenAIToolCall `json:"tool_calls"`
 				}{
 					Role:    "assistant",
 					Content: "This is a test response.",