Record chunking metadata in process runs

internal/core/chunking/summary.go

@@ -0,0 +1,84 @@
+package chunking
+
+// Summary provides a concise overview of chunking results for reports
+type Summary struct {
+	ChunkCount           int  `json:"chunk_count"`
+	MinEstimatedTokens   int  `json:"min_estimated_chunk_tokens"`
+	MaxEstimatedTokens   int  `json:"max_estimated_chunk_tokens"`
+	TotalEstimatedTokens int  `json:"total_estimated_transcript_tokens"`
+	TargetSections       *int `json:"target_sections,omitempty"`
+	MaxSectionTokens     int  `json:"max_section_tokens"`
+	MinSectionTokens     int  `json:"min_section_tokens"`
+}
+
+// ChunkSummary represents a single chunk's metadata for diagnostics
+type ChunkSummary struct {
+	Index           int `json:"index"`
+	StartSegmentID  int `json:"start_segment_id"`
+	EndSegmentID    int `json:"end_segment_id"`
+	EstimatedTokens int `json:"estimated_tokens"`
+	SegmentCount    int `json:"segment_count"`
+}
+
+// DetailedSummary provides per-chunk details for diagnostics
+type DetailedSummary struct {
+	Summary `json:",inline"`
+	Chunks  []ChunkSummary `json:"chunks"`
+}
+
+// ComputeSummary creates a Summary from sections and config
+func ComputeSummary(sections []Section, config ChunkingConfig) Summary {
+	if len(sections) == 0 {
+		return Summary{
+			ChunkCount:       0,
+			MaxSectionTokens: config.MaxSectionTokens,
+			MinSectionTokens: config.MinSectionTokens,
+			TargetSections:   config.TargetSections,
+		}
+	}
+
+	minTokens := sections[0].EstimatedTokens
+	maxTokens := sections[0].EstimatedTokens
+	totalTokens := 0
+
+	for _, sec := range sections {
+		if sec.EstimatedTokens < minTokens {
+			minTokens = sec.EstimatedTokens
+		}
+		if sec.EstimatedTokens > maxTokens {
+			maxTokens = sec.EstimatedTokens
+		}
+		totalTokens += sec.EstimatedTokens
+	}
+
+	return Summary{
+		ChunkCount:           len(sections),
+		MinEstimatedTokens:   minTokens,
+		MaxEstimatedTokens:   maxTokens,
+		TotalEstimatedTokens: totalTokens,
+		TargetSections:       config.TargetSections,
+		MaxSectionTokens:     config.MaxSectionTokens,
+		MinSectionTokens:     config.MinSectionTokens,
+	}
+}
+
+// ComputeDetailedSummary creates a DetailedSummary from sections and config
+func ComputeDetailedSummary(sections []Section, config ChunkingConfig) DetailedSummary {
+	summary := ComputeSummary(sections, config)
+
+	chunks := make([]ChunkSummary, len(sections))
+	for i, sec := range sections {
+		chunks[i] = ChunkSummary{
+			Index:           sec.Index,
+			StartSegmentID:  sec.StartSegmentID,
+			EndSegmentID:    sec.EndSegmentID,
+			EstimatedTokens: sec.EstimatedTokens,
+			SegmentCount:    len(sec.Segments),
+		}
+	}
+
+	return DetailedSummary{
+		Summary: summary,
+		Chunks:  chunks,
+	}
+}