refactor: 重构llm包

backend/internal/llm/context.go

@@ -0,0 +1,58 @@
+package llm
+
+import "github.com/tmc/langchaingo/llms"
+
+type MessageBuilder struct {
+	messages []llms.MessageContent
+}
+
+func NewMessageBuilder() *MessageBuilder {
+	return &MessageBuilder{
+		messages: make([]llms.MessageContent, 0),
+	}
+}
+
+func (b *MessageBuilder) WithSystemPrompt(prompt string) *MessageBuilder {
+	b.messages = append(b.messages, llms.TextParts(llms.ChatMessageTypeSystem, prompt))
+	return b
+}
+
+func (b *MessageBuilder) WithMessages(msgs []llms.MessageContent) *MessageBuilder {
+	b.messages = append(b.messages, msgs...)
+	return b
+}
+
+func (b *MessageBuilder) AppendAIMessage(content string, toolCalls []llms.ToolCall) *MessageBuilder {
+	parts := []llms.ContentPart{}
+	if content != "" {
+		parts = append(parts, llms.TextPart(content))
+	}
+	for _, tc := range toolCalls {
+		parts = append(parts, tc)
+	}
+	b.messages = append(b.messages, llms.MessageContent{
+		Role:  llms.ChatMessageTypeAI,
+		Parts: parts,
+	})
+	return b
+}
+
+func (b *MessageBuilder) AppendToolResult(toolCallID, name, result string) *MessageBuilder {
+	b.messages = append(b.messages, llms.MessageContent{
+		Role: llms.ChatMessageTypeTool,
+		Parts: []llms.ContentPart{
+			llms.ToolCallResponse{
+				ToolCallID: toolCallID,
+				Name:       name,
+				Content:    result,
+			},
+		},
+	})
+	return b
+}
+
+func (b *MessageBuilder) Build() []llms.MessageContent {
+	result := make([]llms.MessageContent, len(b.messages))
+	copy(result, b.messages)
+	return result
+}