会话持久化与恢复、模型级上下文窗口配置与自动获取

internal/bot/bot.go

@@ -13,6 +13,7 @@ import (
 	"github.com/openai/openai-go/shared/constant"
 	"github.com/tidwall/gjson"
 	"myaibot/internal/config"
+	"myaibot/internal/store"
 	"myaibot/internal/tools"
 	"myaibot/internal/tools/builtin"
 )
@@ -43,7 +44,7 @@ func New(cfg *config.Config) (*Bot, error) {
 		systemPrompt: cfg.SystemPrompt,
 		toolRegistry: tools.NewRegistry(builtin.NewTimeTool(), builtin.NewCalculatorTool(), builtin.NewRandomTool()),
 	}
-	b.provider = config.FindProvider(cfg.DefaultProvider)
+	b.provider = config.FindProviderIn(cfg, cfg.DefaultProvider)
 	b.model = cfg.DefaultModel
 	b.toolProvider, b.toolModel = b.provider, b.model
 	if cfg.ToolModel != "" {
@@ -126,6 +127,62 @@ func (b *Bot) Tools() []string {
 	return b.toolRegistry.List()
 }
 
+func (b *Bot) ContextWindow() int64 {
+	if m := config.FindModel(b.provider, b.model); m != nil {
+		return m.ContextWindow
+	}
+	return 0
+}
+
+func (b *Bot) SessionMessages() []store.Message {
+	out := make([]store.Message, 0, len(b.history)+1)
+	out = append(out, store.Message{Role: "system", Content: b.systemPrompt})
+	for _, msg := range b.history {
+		var role, content string
+		switch {
+		case msg.OfUser != nil:
+			role, content = "user", msg.OfUser.Content.OfString.Value
+		case msg.OfAssistant != nil:
+			role, content = "assistant", msg.OfAssistant.Content.OfString.Value
+		case msg.OfSystem != nil:
+			role, content = "system", msg.OfSystem.Content.OfString.Value
+		default:
+			continue
+		}
+		if content == "" {
+			continue
+		}
+		out = append(out, store.Message{Role: role, Content: content})
+	}
+	return out
+}
+
+func (b *Bot) RestoreSession(s *store.Session) {
+	if s == nil {
+		return
+	}
+	if s.SystemPrompt != "" {
+		b.systemPrompt = s.SystemPrompt
+	}
+	var history []openai.ChatCompletionMessageParamUnion
+	for _, m := range s.Messages {
+		switch m.Role {
+		case "user":
+			history = append(history, openai.UserMessage(m.Content))
+		case "assistant":
+			history = append(history, openai.AssistantMessage(m.Content))
+		case "system":
+			if b.systemPrompt == "" || m.Content != b.systemPrompt {
+				b.systemPrompt = m.Content
+			}
+		}
+	}
+	if len(history) > maxHistory {
+		history = history[len(history)-maxHistory:]
+	}
+	b.history = history
+}
+
 func (b *Bot) ContextDump() string {
 	var sb strings.Builder
 	sb.WriteString("[系统] " + b.systemPrompt + "\n")

internal/bot/session_test.go

@@ -0,0 +1,87 @@
+package bot
+
+import (
+	"testing"
+
+	"github.com/openai/openai-go"
+
+	"myaibot/internal/config"
+	"myaibot/internal/store"
+)
+
+func newTestBot(t *testing.T) *Bot {
+	t.Helper()
+	t.Chdir(t.TempDir())
+	for _, name := range []string{"get_current_time", "calculate", "random_number"} {
+		if err := config.WriteDefaultToolConfig(name, map[string]any{"enabled": true, "prompt": "p"}); err != nil {
+			t.Fatalf("写入工具配置失败: %v", err)
+		}
+	}
+	cfg := &config.Config{
+		BotName:         "test",
+		SystemPrompt:    "测试系统提示",
+		DefaultProvider: "p",
+		DefaultModel:    "m",
+		Providers: []config.Provider{
+			{Name: "p", BaseURL: "x", Models: []config.ModelConfig{{Name: "m"}}},
+		},
+	}
+	b, err := New(cfg)
+	if err != nil {
+		t.Fatalf("New 出错: %v", err)
+	}
+	return b
+}
+
+func TestSessionRoundtrip(t *testing.T) {
+	b := newTestBot(t)
+	b.history = append(b.history,
+		openai.UserMessage("你好"),
+		openai.AssistantMessage("你好！有什么可以帮你？"),
+	)
+	msgs := b.SessionMessages()
+	if len(msgs) != 3 {
+		t.Fatalf("SessionMessages 数量 = %d, want 3", len(msgs))
+	}
+	if msgs[0].Role != "system" || msgs[0].Content != "测试系统提示" {
+		t.Errorf("首条应为系统提示: %+v", msgs[0])
+	}
+
+	restored := &Bot{}
+	restored.RestoreSession(&store.Session{Messages: msgs})
+	if restored.systemPrompt != "测试系统提示" {
+		t.Errorf("systemPrompt 未恢复: %q", restored.systemPrompt)
+	}
+	if len(restored.history) != 2 {
+		t.Fatalf("history 数量 = %d, want 2", len(restored.history))
+	}
+	if u := restored.history[0].OfUser; u == nil || u.Content.OfString.Value != "你好" {
+		t.Errorf("用户消息未还原: %+v", restored.history[0])
+	}
+	if a := restored.history[1].OfAssistant; a == nil || a.Content.OfString.Value != "你好！有什么可以帮你？" {
+		t.Errorf("助手消息未还原: %+v", restored.history[1])
+	}
+}
+
+func TestRestoreSessionOverridesPrompt(t *testing.T) {
+	b := newTestBot(t)
+	b.RestoreSession(&store.Session{
+		SystemPrompt: "会话覆盖的系统提示",
+		Messages:     []store.Message{{Role: "user", Content: "hi"}},
+	})
+	if b.systemPrompt != "会话覆盖的系统提示" {
+		t.Errorf("systemPrompt 未覆盖: %q", b.systemPrompt)
+	}
+}
+
+func TestRestoreTrimsHistory(t *testing.T) {
+	b := newTestBot(t)
+	var msgs []store.Message
+	for i := 0; i < maxHistory+10; i++ {
+		msgs = append(msgs, store.Message{Role: "user", Content: "m"})
+	}
+	b.RestoreSession(&store.Session{Messages: msgs})
+	if len(b.history) != maxHistory {
+		t.Errorf("history 应截断到 %d, got %d", maxHistory, len(b.history))
+	}
+}

internal/cli/cli.go

@@ -1,18 +1,35 @@
 package cli
 
 import (
+	"database/sql"
 	"fmt"
+	"strconv"
 	"strings"
 
 	"myaibot/internal/bot"
+	"myaibot/internal/store"
 )
 
 type Handler struct {
 	bot *bot.Bot
+	db  *sql.DB
 }
 
-func New(b *bot.Bot) *Handler {
-	return &Handler{bot: b}
+func New(b *bot.Bot, db *sql.DB) *Handler {
+	return &Handler{bot: b, db: db}
+}
+
+func formatWindow(n int64) string {
+	switch {
+	case n <= 0:
+		return "未配置"
+	case n >= 1048576:
+		return fmt.Sprintf("%dM tokens", n/1048576)
+	case n >= 1024:
+		return fmt.Sprintf("%dK tokens", n/1024)
+	default:
+		return fmt.Sprintf("%d tokens", n)
+	}
 }
 
 func (h *Handler) Handle(input string) bool {
@@ -30,6 +47,8 @@ func (h *Handler) Handle(input string) bool {
 		fmt.Println("  /effort <low|high|max>  设置思考强度")
 		fmt.Println("  /context           打印当前聊天上下文")
 		fmt.Println("  /tools             列出可用工具")
+		fmt.Println("  /sessions          列出历史会话")
+		fmt.Println("  /session <id>      切换到历史会话，如 /session 3")
 		fmt.Println("  /info              显示当前供应商、模型和思考配置")
 		fmt.Println("  /exit              退出")
 	case "/models":
@@ -74,6 +93,40 @@ func (h *Handler) Handle(input string) bool {
 		for _, t := range h.bot.Tools() {
 			fmt.Println("  " + t)
 		}
+	case "/sessions":
+		list, err := store.ListSessions(h.db)
+		if err != nil {
+			fmt.Printf("⚠️  %v\n", err)
+			return true
+		}
+		if len(list) == 0 {
+			fmt.Println("暂无历史会话")
+			return true
+		}
+		for _, s := range list {
+			fmt.Printf("  #%d  %s  (%d 条消息)\n", s.ID, s.CreatedAt.Format("2006-01-02 15:04:05"), s.MessageCount)
+		}
+	case "/session":
+		if len(args) == 0 {
+			fmt.Println("用法: /session <id>，如 /session 3")
+			return true
+		}
+		id, err := strconv.ParseInt(args[0], 10, 64)
+		if err != nil || id <= 0 {
+			fmt.Printf("无效的会话 id: %s\n", args[0])
+			return true
+		}
+		sess, err := store.LoadSession(h.db, id)
+		if err != nil {
+			fmt.Printf("⚠️  %v\n", err)
+			return true
+		}
+		if sess == nil {
+			fmt.Printf("会话 #%d 不存在\n", id)
+			return true
+		}
+		h.bot.RestoreSession(sess)
+		fmt.Printf("已切换到会话 #%d (%d 条消息)\n", id, len(sess.Messages))
 	case "/info":
 		provider, model := h.bot.Current()
 		thinking, effort := h.bot.ThinkingConfig()
@@ -85,6 +138,7 @@ func (h *Handler) Handle(input string) bool {
 			effort = "high(默认)"
 		}
 		fmt.Printf("供应商: %s, 模型: %s, 思考模式: %s, 思考强度: %s\n", provider, model, thinking, effort)
+		fmt.Printf("上下文窗口: %s\n", formatWindow(h.bot.ContextWindow()))
 		fmt.Printf("工具调用AI: %s\n图片识别AI: %s\n", tool, vision)
 	default:
 		fmt.Printf("未知命令: %s，输入 /help 查看命令列表\n", cmd)

internal/cli/complete.go

@@ -2,7 +2,7 @@ package cli
 
 import "strings"
 
-var commands = []string{"/exit", "/quit", "/help", "/models", "/use", "/think", "/effort", "/context", "/tools", "/info"}
+var commands = []string{"/exit", "/quit", "/help", "/models", "/use", "/think", "/effort", "/context", "/tools", "/sessions", "/session", "/info"}
 
 func Complete(line string, models []string) []string {
 	fields := strings.Fields(line)

internal/config/config.go

@@ -1,12 +1,16 @@
 package config
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
+	"sort"
 	"strings"
 
+	"github.com/openai/openai-go"
+	"github.com/openai/openai-go/option"
 	"gopkg.in/yaml.v3"
 )
 
@@ -16,13 +20,43 @@ const (
 	toolConfigDir = "data/tools"
 )
 
+type ModelConfig struct {
+	Name          string `yaml:"name"`
+	ContextWindow int64  `yaml:"context_window"`
+}
+
+// UnmarshalYAML 兼容两种格式：
+//
+//	models: [deepseek-v4-flash, deepseek-v4-pro]   # 字符串列表（旧格式）
+//	models:
+//	  - name: deepseek-v4-flash
+//	    context_window: 1048576                    # 对象列表
+func (m *ModelConfig) UnmarshalYAML(node *yaml.Node) error {
+	switch node.Kind {
+	case yaml.ScalarNode:
+		m.Name = node.Value
+		return nil
+	case yaml.MappingNode:
+		type raw ModelConfig
+		var r raw
+		if err := node.Decode(&r); err != nil {
+			return err
+		}
+		*m = ModelConfig(r)
+		return nil
+	default:
+		return fmt.Errorf("模型配置必须是字符串或对象")
+	}
+}
+
 type Provider struct {
-	Name            string   `yaml:"name"`
-	APIKey          string   `yaml:"api_key"`
-	BaseURL         string   `yaml:"base_url"`
-	Models          []string `yaml:"models"`
-	Thinking        string   `yaml:"thinking"`
-	ReasoningEffort string   `yaml:"reasoning_effort"`
+	Name            string        `yaml:"name"`
+	APIKey          string        `yaml:"api_key"`
+	BaseURL         string        `yaml:"base_url"`
+	Models          []ModelConfig `yaml:"models"`
+	AutoFetchModels bool          `yaml:"auto_fetch_models"`
+	Thinking        string        `yaml:"thinking"`
+	ReasoningEffort string        `yaml:"reasoning_effort"`
 }
 
 type Config struct {
@@ -110,17 +144,17 @@ func migrateLegacy(path string, data []byte) error {
 		Name:    "openai",
 		APIKey:  legacy.APIKey,
 		BaseURL: legacy.BaseURL,
-		Models:  []string{legacy.Model},
+		Models:  []ModelConfig{{Name: legacy.Model}},
 	}
 	if p.BaseURL == "" {
 		p.BaseURL = "https://api.openai.com/v1"
 	}
-	if len(p.Models) == 0 || p.Models[0] == "" {
-		p.Models = []string{"gpt-4o-mini"}
+	if len(p.Models) == 0 || p.Models[0].Name == "" {
+		p.Models = []ModelConfig{{Name: "gpt-4o-mini"}}
 	}
 	cfg.Providers = []Provider{p}
 	cfg.DefaultProvider = p.Name
-	cfg.DefaultModel = p.Models[0]
+	cfg.DefaultModel = p.Models[0].Name
 	return writeFile(path, cfg)
 }
 
@@ -183,13 +217,16 @@ func validate(c *Config) error {
 		if p.BaseURL == "" {
 			return fmt.Errorf("供应商 %s 缺少 base_url", p.Name)
 		}
-		if len(p.Models) == 0 {
+		if len(p.Models) == 0 && !p.AutoFetchModels {
 			return fmt.Errorf("供应商 %s 未配置 models", p.Name)
 		}
 		for _, m := range p.Models {
-			if m == "" {
+			if m.Name == "" {
 				return fmt.Errorf("供应商 %s 包含空模型名", p.Name)
 			}
+			if m.ContextWindow < 0 {
+				return fmt.Errorf("供应商 %s 的模型 %s context_window 无效: %d（不能为负数）", p.Name, m.Name, m.ContextWindow)
+			}
 		}
 		if p.Thinking != "" && !contains([]string{"enabled", "disabled"}, p.Thinking) {
 			return fmt.Errorf("供应商 %s 的 thinking 无效: %q（可选 enabled/disabled）", p.Name, p.Thinking)
@@ -201,17 +238,17 @@ func validate(c *Config) error {
 	if _, ok := names[c.DefaultProvider]; !ok {
 		return fmt.Errorf("default_provider %q 不存在", c.DefaultProvider)
 	}
-	if _, _, err := ResolveModel(c.DefaultModel); err != nil {
-		return fmt.Errorf("default_model 无效: %w", err)
+	if err := validateModelRef("default_model", c.DefaultModel, c); err != nil {
+		return err
 	}
 	if c.ToolModel != "" {
-		if _, _, err := ResolveModel(c.ToolModel); err != nil {
-			return fmt.Errorf("tool_model 无效: %w", err)
+		if err := validateModelRef("tool_model", c.ToolModel, c); err != nil {
+			return err
 		}
 	}
 	if c.VisionModel != "" {
-		if _, _, err := ResolveModel(c.VisionModel); err != nil {
-			return fmt.Errorf("vision_model 无效: %w", err)
+		if err := validateModelRef("vision_model", c.VisionModel, c); err != nil {
+			return err
 		}
 	}
 	d := c.Database
@@ -224,36 +261,69 @@ func validate(c *Config) error {
 	return nil
 }
 
+// validateModelRef 校验模型引用；若引用指向启用了 auto_fetch_models 的供应商，
+// 则跳过存在性校验（模型列表将在启动时从 API 拉取）。
+func validateModelRef(field, id string, c *Config) error {
+	if _, _, err := ResolveModelIn(c, id); err == nil {
+		return nil
+	}
+	providerName, _, hasProvider := strings.Cut(id, "/")
+	if !hasProvider {
+		providerName = c.DefaultProvider
+	}
+	if p := FindProviderIn(c, providerName); p != nil && p.AutoFetchModels {
+		return nil
+	}
+	return fmt.Errorf("%s 无效: 模型 %q 不存在", field, id)
+}
+
 func FindProvider(name string) *Provider {
-	for i := range cfg.Providers {
-		if cfg.Providers[i].Name == name {
-			return &cfg.Providers[i]
+	return FindProviderIn(cfg, name)
+}
+
+func FindProviderIn(c *Config, name string) *Provider {
+	for i := range c.Providers {
+		if c.Providers[i].Name == name {
+			return &c.Providers[i]
+		}
+	}
+	return nil
+}
+
+func FindModel(p *Provider, name string) *ModelConfig {
+	for i := range p.Models {
+		if p.Models[i].Name == name {
+			return &p.Models[i]
 		}
 	}
 	return nil
 }
 
 func ResolveModel(id string) (*Provider, string, error) {
+	return ResolveModelIn(cfg, id)
+}
+
+func ResolveModelIn(c *Config, id string) (*Provider, string, error) {
 	if id == "" {
-		id = cfg.DefaultModel
+		id = c.DefaultModel
 	}
 	if providerName, modelName, ok := strings.Cut(id, "/"); ok {
-		p := FindProvider(providerName)
+		p := FindProviderIn(c, providerName)
 		if p == nil {
 			return nil, "", fmt.Errorf("供应商 %q 不存在", providerName)
 		}
-		if !contains(p.Models, modelName) {
+		if FindModel(p, modelName) == nil {
 			return nil, "", fmt.Errorf("供应商 %s 没有模型 %q", p.Name, modelName)
 		}
 		return p, modelName, nil
 	}
 	var found *Provider
-	for i := range cfg.Providers {
-		if contains(cfg.Providers[i].Models, id) {
+	for i := range c.Providers {
+		if FindModel(&c.Providers[i], id) != nil {
 			if found != nil {
 				return nil, "", fmt.Errorf("模型 %q 在多个供应商中存在，请使用 provider/model 格式指定", id)
 			}
-			found = &cfg.Providers[i]
+			found = &c.Providers[i]
 		}
 	}
 	if found == nil {
@@ -267,7 +337,7 @@ func AllModels() []string {
 	for i := range cfg.Providers {
 		p := &cfg.Providers[i]
 		for _, m := range p.Models {
-			out = append(out, p.Name+"/"+m)
+			out = append(out, p.Name+"/"+m.Name)
 		}
 	}
 	return out
@@ -293,13 +363,19 @@ func writeDefault(path string) error {
 				Name:    "openai",
 				APIKey:  "",
 				BaseURL: "https://api.openai.com/v1",
-				Models:  []string{"gpt-4o-mini", "gpt-4o"},
+				Models: []ModelConfig{
+					{Name: "gpt-4o-mini", ContextWindow: 128000},
+					{Name: "gpt-4o", ContextWindow: 128000},
+				},
 			},
 			{
 				Name:    "deepseek",
 				APIKey:  "",
 				BaseURL: "https://api.deepseek.com/v1",
-				Models:  []string{"deepseek-chat", "deepseek-reasoner"},
+				Models: []ModelConfig{
+					{Name: "deepseek-v4-flash", ContextWindow: 1048576},
+					{Name: "deepseek-v4-pro", ContextWindow: 1048576},
+				},
 			},
 		},
 		DefaultProvider: "openai",
@@ -359,3 +435,59 @@ func WriteDefaultToolConfig(name string, defaults map[string]any) error {
 func ToolConfigPath(name string) string {
 	return filepath.Join(toolConfigDir, name+".yaml")
 }
+
+// Save 将配置写回 data/config.yaml。
+func Save(c *Config) error {
+	path := filepath.Join(configDir, configFile)
+	return writeFile(path, c)
+}
+
+// ModelsEqual 比较两个模型的名称与上下文窗口是否完全一致。
+func ModelsEqual(a, b []ModelConfig) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i].Name != b[i].Name || a[i].ContextWindow != b[i].ContextWindow {
+			return false
+		}
+	}
+	return true
+}
+
+// FetchModels 从供应商 API 拉取模型列表并合并进 p.Models。
+// 已配置模型的 context_window 保留，新模型默认 0。
+func FetchModels(ctx context.Context, p *Provider) error {
+	if p.APIKey == "" {
+		return errors.New("未配置 api_key")
+	}
+	client := openai.NewClient(
+		option.WithAPIKey(p.APIKey),
+		option.WithBaseURL(p.BaseURL),
+	)
+	page, err := client.Models.List(ctx)
+	if err != nil {
+		return fmt.Errorf("请求模型列表失败: %w", err)
+	}
+	ids := make([]string, 0, len(page.Data))
+	seen := make(map[string]bool, len(page.Data))
+	for _, m := range page.Data {
+		if m.ID == "" || seen[m.ID] {
+			continue
+		}
+		seen[m.ID] = true
+		ids = append(ids, m.ID)
+	}
+	sort.Strings(ids)
+
+	existing := make(map[string]int64, len(p.Models))
+	for _, m := range p.Models {
+		existing[m.Name] = m.ContextWindow
+	}
+	merged := make([]ModelConfig, 0, len(ids))
+	for _, id := range ids {
+		merged = append(merged, ModelConfig{Name: id, ContextWindow: existing[id]})
+	}
+	p.Models = merged
+	return nil
+}

internal/config/config_test.go

@@ -8,7 +8,7 @@ import (
 )
 
 func TestApplyDatabaseDefaults(t *testing.T) {
-	c := &Config{Providers: []Provider{{Name: "p", BaseURL: "x", Models: []string{"m"}}}}
+	c := &Config{Providers: []Provider{{Name: "p", BaseURL: "x", Models: []ModelConfig{{Name: "m"}}}}}
 	changed := applyDefaults(c)
 	if !changed {
 		t.Error("缺失字段应返回 changed=true")
@@ -28,7 +28,7 @@ func TestApplyDefaultsNoChange(t *testing.T) {
 		LogLevel:        "debug",
 		SystemPrompt:    "sp",
 		DefaultProvider: "p",
-		Providers:       []Provider{{Name: "p", BaseURL: "x", Models: []string{"m"}}},
+		Providers:       []Provider{{Name: "p", BaseURL: "x", Models: []ModelConfig{{Name: "m"}}}},
 		Database:        DatabaseConfig{Driver: "mysql", File: "f", Host: "h", Port: 3307, Name: "n"},
 	}
 	if applyDefaults(c) {
@@ -38,7 +38,7 @@ func TestApplyDefaultsNoChange(t *testing.T) {
 
 func TestApplyMySQLDefaults(t *testing.T) {
 	c := &Config{
-		Providers: []Provider{{Name: "p", BaseURL: "x", Models: []string{"m"}}},
+		Providers: []Provider{{Name: "p", BaseURL: "x", Models: []ModelConfig{{Name: "m"}}}},
 		Database:  DatabaseConfig{Driver: "mysql", Name: "memory"},
 	}
 	changed := applyDefaults(c)
@@ -117,7 +117,7 @@ func TestValidateDatabase(t *testing.T) {
 	c := &Config{
 		DefaultProvider: "p",
 		DefaultModel:    "m",
-		Providers:       []Provider{{Name: "p", BaseURL: "x", Models: []string{"m"}}},
+		Providers:       []Provider{{Name: "p", BaseURL: "x", Models: []ModelConfig{{Name: "m"}}}},
 		Database:        DatabaseConfig{Driver: "oracle"},
 	}
 	cfg = c

internal/config/models_test.go

@@ -0,0 +1,149 @@
+package config
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"gopkg.in/yaml.v3"
+)
+
+func TestModelConfigUnmarshalStringList(t *testing.T) {
+	var p struct {
+		Models []ModelConfig `yaml:"models"`
+	}
+	err := yaml.Unmarshal([]byte("models:\n    - deepseek-v4-flash\n    - deepseek-v4-pro\n"), &p)
+	if err != nil {
+		t.Fatalf("解析失败: %v", err)
+	}
+	if len(p.Models) != 2 || p.Models[0].Name != "deepseek-v4-flash" || p.Models[1].Name != "deepseek-v4-pro" {
+		t.Errorf("字符串列表解析异常: %+v", p.Models)
+	}
+}
+
+func TestModelConfigUnmarshalObjectList(t *testing.T) {
+	var p struct {
+		Models []ModelConfig `yaml:"models"`
+	}
+	err := yaml.Unmarshal([]byte("models:\n    - name: deepseek-v4-flash\n      context_window: 1048576\n    - name: deepseek-v4-pro\n"), &p)
+	if err != nil {
+		t.Fatalf("解析失败: %v", err)
+	}
+	if len(p.Models) != 2 {
+		t.Fatalf("数量 = %d, want 2", len(p.Models))
+	}
+	if p.Models[0].Name != "deepseek-v4-flash" || p.Models[0].ContextWindow != 1048576 {
+		t.Errorf("对象列表解析异常: %+v", p.Models[0])
+	}
+	if p.Models[1].Name != "deepseek-v4-pro" || p.Models[1].ContextWindow != 0 {
+		t.Errorf("缺省 context_window 应为 0: %+v", p.Models[1])
+	}
+}
+
+func TestValidateContextWindow(t *testing.T) {
+	base := &Config{
+		DefaultProvider: "p",
+		DefaultModel:    "m",
+		Database:        DatabaseConfig{Driver: "sqlite3"},
+		Providers: []Provider{{
+			Name: "p", BaseURL: "x",
+			Models: []ModelConfig{{Name: "m", ContextWindow: -1}},
+		}},
+	}
+	cfg = base
+	if err := validate(base); err == nil {
+		t.Error("负 context_window 应报错")
+	}
+	base.Providers[0].Models[0].ContextWindow = 0
+	if err := validate(base); err != nil {
+		t.Errorf("context_window 0 不应报错: %v", err)
+	}
+}
+
+func TestValidateAutoFetch(t *testing.T) {
+	c := &Config{
+		DefaultProvider: "p",
+		DefaultModel:    "m",
+		Database:        DatabaseConfig{Driver: "sqlite3"},
+		Providers: []Provider{{
+			Name: "p", BaseURL: "x",
+			AutoFetchModels: true,
+		}},
+	}
+	cfg = c
+	if err := validate(c); err != nil {
+		t.Errorf("auto_fetch 空 models 不应报错: %v", err)
+	}
+	c.Providers[0].AutoFetchModels = false
+	if err := validate(c); err == nil {
+		t.Error("非 auto_fetch 空 models 应报错")
+	}
+}
+
+func TestValidateAutoFetchDefaultModel(t *testing.T) {
+	c := &Config{
+		DefaultProvider: "p",
+		DefaultModel:    "future-model",
+		Database:        DatabaseConfig{Driver: "sqlite3"},
+		Providers: []Provider{{
+			Name: "p", BaseURL: "x",
+			AutoFetchModels: true,
+		}},
+	}
+	cfg = c
+	if err := validate(c); err != nil {
+		t.Errorf("auto_fetch 时 default_model 应跳过存在性校验: %v", err)
+	}
+}
+
+func TestFetchModels(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/models" {
+			t.Errorf("请求路径 = %q, want /models", r.URL.Path)
+		}
+		w.Header().Set("Content-Type", "application/json")
+		w.Write([]byte(`{"object":"list","data":[
+			{"id":"deepseek-v4-pro","object":"model","owned_by":"deepseek"},
+			{"id":"deepseek-v4-flash","object":"model","owned_by":"deepseek"}
+		]}`))
+	}))
+	defer srv.Close()
+
+	p := &Provider{
+		Name:    "deepseek",
+		APIKey:  "sk-test",
+		BaseURL: srv.URL,
+		Models:  []ModelConfig{{Name: "deepseek-v4-flash", ContextWindow: 1048576}},
+	}
+	if err := FetchModels(context.Background(), p); err != nil {
+		t.Fatalf("FetchModels 出错: %v", err)
+	}
+	if len(p.Models) != 2 {
+		t.Fatalf("模型数量 = %d, want 2", len(p.Models))
+	}
+	if p.Models[0].Name != "deepseek-v4-flash" || p.Models[0].ContextWindow != 1048576 {
+		t.Errorf("已有模型应保留 context_window: %+v", p.Models[0])
+	}
+	if p.Models[1].Name != "deepseek-v4-pro" || p.Models[1].ContextWindow != 0 {
+		t.Errorf("新模型 context_window 应为 0: %+v", p.Models[1])
+	}
+}
+
+func TestFetchModelsNoAPIKey(t *testing.T) {
+	if err := FetchModels(context.Background(), &Provider{Name: "p"}); err == nil {
+		t.Error("无 api_key 应报错")
+	}
+}
+
+func TestModelsEqual(t *testing.T) {
+	a := []ModelConfig{{Name: "x", ContextWindow: 1}}
+	b := []ModelConfig{{Name: "x", ContextWindow: 1}}
+	if !ModelsEqual(a, b) {
+		t.Error("相同列表应相等")
+	}
+	b[0].ContextWindow = 2
+	if ModelsEqual(a, b) {
+		t.Error("不同列表应不相等")
+	}
+}

internal/store/session.go

@@ -0,0 +1,142 @@
+package store
+
+import (
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"time"
+)
+
+type Message struct {
+	Role    string `json:"role"`
+	Content string `json:"content"`
+}
+
+type Session struct {
+	ID           int64
+	CreatedAt    time.Time
+	Provider     string
+	Model        string
+	SystemPrompt string
+	Messages     []Message
+}
+
+type SessionSummary struct {
+	ID           int64
+	CreatedAt    time.Time
+	MessageCount int
+}
+
+const createSessionsSQLite = `
+CREATE TABLE IF NOT EXISTS sessions (
+    id            INTEGER PRIMARY KEY AUTOINCREMENT,
+    created_at    DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    provider      TEXT NOT NULL DEFAULT '',
+    model         TEXT NOT NULL DEFAULT '',
+    system_prompt TEXT NOT NULL DEFAULT '',
+    messages      TEXT NOT NULL,
+    message_count INTEGER NOT NULL DEFAULT 0
+)`
+
+const createSessionsMySQL = `
+CREATE TABLE IF NOT EXISTS sessions (
+    id            BIGINT AUTO_INCREMENT PRIMARY KEY,
+    created_at    DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    provider      VARCHAR(255) NOT NULL DEFAULT '',
+    model         VARCHAR(255) NOT NULL DEFAULT '',
+    system_prompt TEXT NOT NULL,
+    messages      LONGTEXT NOT NULL,
+    message_count INT NOT NULL DEFAULT 0
+)`
+
+func Migrate(db *sql.DB, driver string) error {
+	var ddl string
+	switch driver {
+	case "sqlite3":
+		ddl = createSessionsSQLite
+	case "mysql":
+		ddl = createSessionsMySQL
+	default:
+		return fmt.Errorf("不支持的数据库驱动: %s", driver)
+	}
+	if _, err := db.Exec(ddl); err != nil {
+		return fmt.Errorf("创建 sessions 表失败: %w", err)
+	}
+	return nil
+}
+
+func SaveSession(db *sql.DB, s *Session) (int64, error) {
+	if s.Messages == nil {
+		s.Messages = []Message{}
+	}
+	data, err := json.Marshal(s.Messages)
+	if err != nil {
+		return 0, fmt.Errorf("序列化消息失败: %w", err)
+	}
+	res, err := db.Exec(
+		"INSERT INTO sessions (provider, model, system_prompt, messages, message_count) VALUES (?, ?, ?, ?, ?)",
+		s.Provider, s.Model, s.SystemPrompt, string(data), len(s.Messages),
+	)
+	if err != nil {
+		return 0, fmt.Errorf("保存会话失败: %w", err)
+	}
+	return res.LastInsertId()
+}
+
+func LoadLatestSession(db *sql.DB) (*Session, error) {
+	return loadSession(db, "SELECT id, created_at, provider, model, system_prompt, messages FROM sessions ORDER BY id DESC LIMIT 1")
+}
+
+func LoadSession(db *sql.DB, id int64) (*Session, error) {
+	return loadSession(db, "SELECT id, created_at, provider, model, system_prompt, messages FROM sessions WHERE id = ?", id)
+}
+
+func loadSession(db *sql.DB, query string, args ...any) (*Session, error) {
+	row := db.QueryRow(query, args...)
+	var (
+		s        Session
+		created  string
+		messages string
+	)
+	if err := row.Scan(&s.ID, &created, &s.Provider, &s.Model, &s.SystemPrompt, &messages); err != nil {
+		if err == sql.ErrNoRows {
+			return nil, nil
+		}
+		return nil, fmt.Errorf("读取会话失败: %w", err)
+	}
+	s.CreatedAt = parseTime(created)
+	if err := json.Unmarshal([]byte(messages), &s.Messages); err != nil {
+		return nil, fmt.Errorf("解析会话消息失败: %w", err)
+	}
+	return &s, nil
+}
+
+func ListSessions(db *sql.DB) ([]SessionSummary, error) {
+	rows, err := db.Query("SELECT id, created_at, message_count FROM sessions ORDER BY id DESC")
+	if err != nil {
+		return nil, fmt.Errorf("查询会话列表失败: %w", err)
+	}
+	defer rows.Close()
+	var out []SessionSummary
+	for rows.Next() {
+		var (
+			sm SessionSummary
+			t  string
+		)
+		if err := rows.Scan(&sm.ID, &t, &sm.MessageCount); err != nil {
+			return nil, fmt.Errorf("读取会话列表失败: %w", err)
+		}
+		sm.CreatedAt = parseTime(t)
+		out = append(out, sm)
+	}
+	return out, rows.Err()
+}
+
+func parseTime(s string) time.Time {
+	for _, layout := range []string{time.RFC3339, "2006-01-02 15:04:05"} {
+		if t, err := time.ParseInLocation(layout, s, time.Local); err == nil {
+			return t
+		}
+	}
+	return time.Time{}
+}

internal/store/session_test.go

@@ -0,0 +1,99 @@
+package store
+
+import (
+	"database/sql"
+	"path/filepath"
+	"testing"
+
+	"myaibot/internal/config"
+)
+
+func openTestDB(t *testing.T) *sql.DB {
+	t.Helper()
+	cfg := &config.DatabaseConfig{
+		Driver: "sqlite3",
+		File:   filepath.Join(t.TempDir(), "memory.db"),
+	}
+	db, err := Open(cfg)
+	if err != nil {
+		t.Fatalf("Open 出错: %v", err)
+	}
+	t.Cleanup(func() { Close(db) })
+	if err := Migrate(db, "sqlite3"); err != nil {
+		t.Fatalf("Migrate 出错: %v", err)
+	}
+	return db
+}
+
+func TestSessionRoundtrip(t *testing.T) {
+	db := openTestDB(t)
+	first := &Session{
+		Provider: "deepseek",
+		Model:    "deepseek-v4-flash",
+		Messages: []Message{{Role: "user", Content: "你好"}, {Role: "assistant", Content: "你好！"}},
+	}
+	id1, err := SaveSession(db, first)
+	if err != nil {
+		t.Fatalf("SaveSession 出错: %v", err)
+	}
+	second := &Session{
+		Provider: "deepseek",
+		Model:    "deepseek-v4-flash",
+		Messages: []Message{{Role: "user", Content: "现在几点"}},
+	}
+	id2, err := SaveSession(db, second)
+	if err != nil {
+		t.Fatalf("SaveSession 出错: %v", err)
+	}
+	if id2 <= id1 {
+		t.Errorf("id2 (%d) 应大于 id1 (%d)", id2, id1)
+	}
+
+	latest, err := LoadLatestSession(db)
+	if err != nil {
+		t.Fatalf("LoadLatestSession 出错: %v", err)
+	}
+	if latest == nil || latest.ID != id2 {
+		t.Errorf("最新会话应为 #%d, got %+v", id2, latest)
+	}
+	if len(latest.Messages) != 1 || latest.Messages[0].Content != "现在几点" {
+		t.Errorf("消息还原异常: %+v", latest.Messages)
+	}
+
+	byID, err := LoadSession(db, id1)
+	if err != nil {
+		t.Fatalf("LoadSession 出错: %v", err)
+	}
+	if byID == nil || len(byID.Messages) != 2 {
+		t.Errorf("按 id 加载异常: %+v", byID)
+	}
+
+	list, err := ListSessions(db)
+	if err != nil {
+		t.Fatalf("ListSessions 出错: %v", err)
+	}
+	if len(list) != 2 {
+		t.Errorf("列表数量 = %d, want 2", len(list))
+	}
+	if list[0].ID != id2 || list[0].MessageCount != 1 {
+		t.Errorf("列表首条应为最新会话: %+v", list[0])
+	}
+}
+
+func TestLoadSessionMissing(t *testing.T) {
+	db := openTestDB(t)
+	sess, err := LoadSession(db, 999)
+	if err != nil {
+		t.Fatalf("LoadSession 出错: %v", err)
+	}
+	if sess != nil {
+		t.Errorf("不存在的会话应返回 nil, got %+v", sess)
+	}
+	latest, err := LoadLatestSession(db)
+	if err != nil {
+		t.Fatalf("LoadLatestSession 出错: %v", err)
+	}
+	if latest != nil {
+		t.Errorf("空库最新会话应为 nil, got %+v", latest)
+	}
+}