Initial commit: CarrotAssistant backend (Go + Gin + SQLite, OpenAI-compatible agent runtime)

internal/server/agentkit.go

@@ -0,0 +1,122 @@
+package server
+
+import (
+	"errors"
+	"fmt"
+
+	"gorm.io/gorm"
+
+	"code.littlelan.cn/CarrotAssistant/backend/internal/agent"
+	"code.littlelan.cn/CarrotAssistant/backend/internal/llm"
+	"code.littlelan.cn/CarrotAssistant/backend/internal/skill"
+	"code.littlelan.cn/CarrotAssistant/backend/internal/store"
+)
+
+// resolveLLMConfig builds the llm.Config for an App: looks up the App's
+// ModelConfig (or errors), decrypts the API key, and returns a ready client.
+func (d Deps) resolveLLMConfig(app *store.App) (llm.Config, error) {
+	if app.ModelConfigID == nil {
+		return llm.Config{}, errors.New("应用未配置模型")
+	}
+	var mc store.ModelConfig
+	if err := d.DB.First(&mc, "id = ?", *app.ModelConfigID).Error; err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return llm.Config{}, errors.New("应用的模型配置不存在")
+		}
+		return llm.Config{}, err
+	}
+	apiKey, err := d.Crypto.Decrypt(mc.APIKeyEncrypted)
+	if err != nil {
+		return llm.Config{}, fmt.Errorf("解密 api key: %w", err)
+	}
+	return llm.Config{
+		BaseURL:   mc.BaseURL,
+		APIKey:    apiKey,
+		Model:     mc.DefaultModel,
+		MaxTokens: mc.MaxTokens,
+	}, nil
+}
+
+// loadPublishedSkill returns the currently-published skill for an app plus its
+// parsed content. Returns an error if none is published (the agent cannot run
+// without one).
+func (d Deps) loadPublishedSkill(app *store.App) (*store.Skill, *skill.Skill, error) {
+	var row store.Skill
+	err := d.DB.Where("app_id = ? AND status = ?", app.ID, "published").
+		Order("id DESC").First(&row).Error
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, nil, errors.New("应用尚未发布任何 skill")
+		}
+		return nil, nil, err
+	}
+	content, err := skill.NewManager(d.SkillsDir).Load(&row)
+	if err != nil {
+		return nil, nil, fmt.Errorf("读取 skill 文件: %w", err)
+	}
+	return &row, content, nil
+}
+
+// sessionHistory loads a session's messages and converts them to llm.Message
+// form, prefixed with the skill's system prompt. The returned slice is ready
+// to hand to agent.NewRunner.
+func (d Deps) sessionHistory(sessionID string, sk *skill.Skill) ([]llm.Message, error) {
+	var msgs []store.Message
+	if err := d.DB.Where("session_id = ?", sessionID).Order("id ASC").Find(&msgs).Error; err != nil {
+		return nil, err
+	}
+	out := make([]llm.Message, 0, len(msgs)+1)
+	// System prompt first; never replay it from storage.
+	out = append(out, llm.Message{Role: llm.RoleSystem, Content: sk.SystemPrompt})
+	for _, m := range msgs {
+		out = append(out, toLLMMessage(m))
+	}
+	return out, nil
+}
+
+// toLLMMessage converts a stored message back into llm.Message, rehydrating
+// tool calls from the JSON column.
+func toLLMMessage(m store.Message) llm.Message {
+	msg := llm.Message{
+		Role:       llm.Role(m.Role),
+		Content:    m.Content,
+		ToolCallID: m.ToolCallID,
+	}
+	if len(m.ToolCalls) > 0 {
+		var calls []llm.ToolCall
+		// Best-effort decode; a corrupt column should never break the chat.
+		_ = jsonUnmarshal(m.ToolCalls, &calls)
+		msg.ToolCalls = calls
+	}
+	return msg
+}
+
+// persistMessage stores one message row. Used after each assistant turn /
+// tool result so the conversation survives across requests.
+func (d Deps) persistMessage(sessionID string, m llm.Message) error {
+	row := store.Message{
+		SessionID:  sessionID,
+		Role:       string(m.Role),
+		Content:    m.Content,
+		ToolCallID: m.ToolCallID,
+	}
+	if len(m.ToolCalls) > 0 {
+		// Store the calls array directly; toLLMMessage decodes []ToolCall.
+		row.ToolCalls = jsonRaw(m.ToolCalls)
+	}
+	if err := d.DB.Create(&row).Error; err != nil {
+		return err
+	}
+	return d.DB.Model(&store.Session{}).Where("id = ?", sessionID).
+		UpdateColumn("message_count", gorm.Expr("message_count + 1")).Error
+}
+
+// newRunner assembles an agent.Runner for an app + session.
+func (d Deps) newRunner(app *store.App, sk *skill.Skill, history []llm.Message, onEvent func(agent.Event)) (*agent.Runner, error) {
+	cfg, err := d.resolveLLMConfig(app)
+	if err != nil {
+		return nil, err
+	}
+	client := llm.New(cfg)
+	return agent.NewRunner(client, sk, history, onEvent), nil
+}