fix: fallback on invalid ai table output

internal/ai/service.go

@@ -268,6 +268,7 @@ func (s *Service) AnalyzeTable(ctx context.Context, input TableAnalysisInput) (T
 	if err != nil {
 		return TableAnalysisResult{}, err
 	}
+	usage := usageFromResponse(resp)
 	var out struct {
 		Title          string        `json:"title"`
 		Summary        string        `json:"summary"`
@@ -277,18 +278,152 @@ func (s *Service) AnalyzeTable(ctx context.Context, input TableAnalysisInput) (T
 		Interpretation string        `json:"interpretation"`
 	}
 	if err := json.Unmarshal([]byte(ExtractJSONObject(resp.Content)), &out); err != nil {
-		return TableAnalysisResult{}, fmt.Errorf("%w: %v", ErrBadOutput, err)
+		return fallbackTableAnalysis(input, usage, "AI 输出格式异常，已使用兜底解读。"), nil
 	}
 	out.Title = firstNonEmpty(out.Title, input.Topic, input.FileName, "智能解读报告")
 	if strings.TrimSpace(out.Interpretation) == "" {
-		return TableAnalysisResult{}, ErrBadOutput
+		return fallbackTableAnalysis(input, usage, "AI 输出缺少核心解读，已使用兜底解读。"), nil
 	}
 	return TableAnalysisResult{
 		Title: out.Title, Metrics: out.Metrics, Preview: out.Preview, Alerts: out.Alerts,
-		Interpretation: strings.TrimSpace(out.Interpretation), Summary: strings.TrimSpace(out.Summary), Usage: usageFromResponse(resp),
+		Interpretation: strings.TrimSpace(out.Interpretation), Summary: strings.TrimSpace(out.Summary), Usage: usage,
 	}, nil
 }
 
+func fallbackTableAnalysis(input TableAnalysisInput, usage Usage, reason string) TableAnalysisResult {
+	title := firstNonEmpty(input.Topic, input.FileName, "智能表格解读报告")
+	preview := fallbackTablePreview(input.Profile)
+	metrics := fallbackTableMetrics(input, preview)
+	alerts := []TableAlert{{
+		Level:       "warning",
+		Title:       "已启用兜底解读",
+		Description: reason,
+	}}
+	if !input.Profile.Parsed {
+		alerts = append(alerts, TableAlert{
+			Level:       "warning",
+			Title:       "表格内容未解析",
+			Description: firstNonEmpty(input.Profile.Message, "当前无法读取表格内容，仅基于文件元信息生成解读。"),
+		})
+	}
+	interpretation := fallbackTableInterpretation(input, preview, reason)
+	return TableAnalysisResult{
+		Title:          title,
+		Summary:        excerptPlain(interpretation, 120),
+		Metrics:        metrics,
+		Preview:        preview,
+		Alerts:         alerts,
+		Interpretation: interpretation,
+		Usage:          usage,
+	}
+}
+
+func fallbackTablePreview(profile TableProfile) TablePreview {
+	var columns []struct {
+		Name string `json:"name"`
+		Type string `json:"type"`
+	}
+	_ = decodeProfileAny(profile.Columns, &columns)
+	names := make([]string, 0, len(columns))
+	for _, column := range columns {
+		if name := strings.TrimSpace(column.Name); name != "" {
+			names = append(names, name)
+		}
+	}
+	var rows [][]string
+	_ = decodeProfileAny(profile.SampleRows, &rows)
+	if len(rows) > 5 {
+		rows = rows[:5]
+	}
+	return TablePreview{Columns: names, Rows: rows, TotalRows: profile.RowCount}
+}
+
+func fallbackTableMetrics(input TableAnalysisInput, preview TablePreview) []TableMetric {
+	metrics := []TableMetric{
+		{Name: "文件类型", Value: strings.ToUpper(input.FileType), ChangeText: "来自上传元信息", Trend: "flat"},
+		{Name: "文件大小", Value: fmt.Sprintf("%d bytes", input.FileSize), ChangeText: "来自上传元信息", Trend: "flat"},
+	}
+	if input.Profile.Parsed {
+		metrics = append(metrics,
+			TableMetric{Name: "数据行数", Value: fmt.Sprintf("%d", preview.TotalRows), ChangeText: "来自表格解析", Trend: "flat"},
+			TableMetric{Name: "字段数", Value: fmt.Sprintf("%d", len(preview.Columns)), ChangeText: "来自表格解析", Trend: "flat"},
+		)
+	} else {
+		metrics = append(metrics, TableMetric{Name: "解析状态", Value: "未解析", ChangeText: firstNonEmpty(input.Profile.Message, "source file is not available locally"), Trend: "flat"})
+	}
+	var stats map[string]struct {
+		Count int     `json:"count"`
+		Sum   float64 `json:"sum"`
+		Avg   float64 `json:"avg"`
+		Min   float64 `json:"min"`
+		Max   float64 `json:"max"`
+	}
+	if err := decodeProfileAny(input.Profile.Stats, &stats); err == nil {
+		for name, stat := range stats {
+			if len(metrics) >= 6 {
+				break
+			}
+			metrics = append(metrics, TableMetric{
+				Name:       name,
+				Value:      fmt.Sprintf("平均 %.2f", stat.Avg),
+				ChangeText: fmt.Sprintf("样本 %d，范围 %.2f-%.2f", stat.Count, stat.Min, stat.Max),
+				Trend:      "flat",
+			})
+		}
+	}
+	return metrics
+}
+
+func fallbackTableInterpretation(input TableAnalysisInput, preview TablePreview, reason string) string {
+	var b strings.Builder
+	b.WriteString(reason)
+	b.WriteString("\n\n")
+	b.WriteString("文件《")
+	b.WriteString(firstNonEmpty(input.FileName, input.FileID, "未命名文件"))
+	b.WriteString("》已进入智能表格解读流程。")
+	if input.Profile.Parsed {
+		b.WriteString(fmt.Sprintf("当前已解析到 %d 行数据、%d 个字段。", preview.TotalRows, len(preview.Columns)))
+		if len(preview.Columns) > 0 {
+			b.WriteString("字段包括：")
+			b.WriteString(strings.Join(preview.Columns, "、"))
+			b.WriteString("。")
+		}
+		b.WriteString("建议结合字段含义继续查看数值分布、异常值和业务口径。")
+	} else {
+		b.WriteString("当前未能读取表格内容，报告仅基于文件名、类型和大小生成。")
+		if msg := strings.TrimSpace(input.Profile.Message); msg != "" {
+			b.WriteString("未解析原因：")
+			b.WriteString(msg)
+			b.WriteString("。")
+		}
+		b.WriteString("建议确认文件已上传完成、格式正确后重新发起解读。")
+	}
+	return b.String()
+}
+
+func decodeProfileAny(value any, target any) error {
+	if value == nil {
+		return nil
+	}
+	data, err := json.Marshal(value)
+	if err != nil {
+		return err
+	}
+	return json.Unmarshal(data, target)
+}
+
+func excerptPlain(value string, maxRunes int) string {
+	value = strings.TrimSpace(value)
+	if maxRunes <= 0 {
+		return ""
+	}
+	runes := []rune(value)
+	if len(runes) <= maxRunes {
+		return value
+	}
+	return string(runes[:maxRunes])
+}
+
 func (s *Service) SummarizeMeeting(ctx context.Context, input MeetingSummaryInput) (MeetingSummaryResult, error) {
 	if s == nil || s.client == nil {
 		return MeetingSummaryResult{}, ErrNotConfigured

internal/ai/service_test.go

@@ -0,0 +1,29 @@
+package ai
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestFallbackTableAnalysisUnparsedProfile(t *testing.T) {
+	result := fallbackTableAnalysis(TableAnalysisInput{
+		Topic:    "销售分析",
+		FileID:   "file1",
+		FileName: "sales.xlsx",
+		FileType: "xlsx",
+		FileSize: 5149,
+		Profile:  TableProfile{Parsed: false, Message: "source file is not available locally"},
+	}, Usage{Model: "deepseek-flash"}, "AI 输出格式异常，已使用兜底解读。")
+	if result.Title != "销售分析" {
+		t.Fatalf("Title=%q, want 销售分析", result.Title)
+	}
+	if strings.TrimSpace(result.Interpretation) == "" {
+		t.Fatal("Interpretation is empty")
+	}
+	if len(result.Alerts) < 2 {
+		t.Fatalf("Alerts len=%d, want at least 2", len(result.Alerts))
+	}
+	if got := result.Metrics[len(result.Metrics)-1].Value; got != "未解析" {
+		t.Fatalf("last metric value=%q, want 未解析", got)
+	}
+}