feat(ingestion): add wiki page merge logic

ingestion/internal/wiki/merge.go

@@ -0,0 +1,120 @@
+// ingestion/internal/wiki/merge.go
+package wiki
+
+import (
+	"fmt"
+	"strings"
+)
+
+var bulletSections = map[string]bool{
+	"Related Concepts":                  true,
+	"Related Entities":                  true,
+	"Sources":                           true,
+	"Key Claims":                        true,
+	"Entities Mentioned":                true,
+	"Concepts Introduced or Reinforced": true,
+	"Chapters":                          true,
+}
+
+var appendSections = map[string]bool{
+	"Evolving Notes":        true,
+	"Updates":               true,
+	"Open Questions Raised": true,
+	"Open Questions":        true,
+}
+
+type section struct {
+	heading string
+	content string
+}
+
+// Merge combines two Page values with the same path.
+// Frontmatter is taken from a. Sections are merged by strategy:
+// bullet sections union unique lines, append sections concatenate,
+// all others keep a's version. Sections in b not present in a are appended.
+func Merge(a, b Page) Page {
+	fmA, secsA := parseSections(a.Content)
+	_, secsB := parseSections(b.Content)
+
+	idx := make(map[string]int, len(secsA))
+	for i, s := range secsA {
+		idx[s.heading] = i
+	}
+
+	for _, sB := range secsB {
+		i, exists := idx[sB.heading]
+		if !exists {
+			idx[sB.heading] = len(secsA)
+			secsA = append(secsA, sB)
+			continue
+		}
+		sA := secsA[i]
+		switch {
+		case bulletSections[sB.heading]:
+			secsA[i].content = mergeBullets(sA.content, sB.content)
+		case appendSections[sB.heading]:
+			secsA[i].content = strings.TrimRight(sA.content, "\n") + "\n\n" + strings.TrimLeft(sB.content, "\n")
+		}
+	}
+
+	return Page{Path: a.Path, Content: rebuildContent(fmA, secsA)}
+}
+
+func parseSections(markdown string) (frontmatter string, sections []section) {
+	lines := strings.Split(markdown, "\n")
+	i := 0
+
+	if i < len(lines) && strings.TrimSpace(lines[i]) == "---" {
+		i++
+		var fmLines []string
+		for i < len(lines) {
+			if strings.TrimSpace(lines[i]) == "---" {
+				i++
+				break
+			}
+			fmLines = append(fmLines, lines[i])
+			i++
+		}
+		frontmatter = fmt.Sprintf("---\n%s\n---\n", strings.Join(fmLines, "\n"))
+	}
+
+	var cur *section
+	for ; i < len(lines); i++ {
+		line := lines[i]
+		if strings.HasPrefix(line, "## ") {
+			if cur != nil {
+				sections = append(sections, *cur)
+			}
+			cur = &section{heading: strings.TrimPrefix(line, "## ")}
+		} else if cur != nil {
+			cur.content += line + "\n"
+		}
+	}
+	if cur != nil {
+		sections = append(sections, *cur)
+	}
+	return
+}
+
+func rebuildContent(frontmatter string, sections []section) string {
+	var sb strings.Builder
+	sb.WriteString(frontmatter)
+	for _, sec := range sections {
+		fmt.Fprintf(&sb, "\n## %s\n\n%s", sec.heading, sec.content)
+	}
+	return sb.String()
+}
+
+func mergeBullets(a, b string) string {
+	seen := make(map[string]bool)
+	var lines []string
+	for _, line := range strings.Split(a+b, "\n") {
+		trimmed := strings.TrimSpace(line)
+		if trimmed == "" || seen[trimmed] {
+			continue
+		}
+		seen[trimmed] = true
+		lines = append(lines, line)
+	}
+	return strings.Join(lines, "\n") + "\n"
+}

ingestion/internal/wiki/merge_test.go

@@ -0,0 +1,55 @@
+// ingestion/internal/wiki/merge_test.go
+package wiki
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMerge_BulletSectionsUnion(t *testing.T) {
+	a := Page{Path: "wiki/concepts/foo.md", Content: "---\ntitle: Foo\n---\n\n## Related Concepts\n\n- [[bar|Bar]]\n"}
+	b := Page{Path: "wiki/concepts/foo.md", Content: "---\ntitle: Foo\n---\n\n## Related Concepts\n\n- [[bar|Bar]]\n- [[baz|Baz]]\n"}
+
+	got := Merge(a, b)
+	assert.Contains(t, got.Content, "[[bar|Bar]]")
+	assert.Contains(t, got.Content, "[[baz|Baz]]")
+	assert.Equal(t, 1, strings.Count(got.Content, "[[bar|Bar]]"))
+}
+
+func TestMerge_AppendSections(t *testing.T) {
+	a := Page{Path: "wiki/concepts/foo.md", Content: "---\ntitle: Foo\n---\n\n## Evolving Notes\n\nFirst note.\n"}
+	b := Page{Path: "wiki/concepts/foo.md", Content: "---\ntitle: Foo\n---\n\n## Evolving Notes\n\nSecond note.\n"}
+
+	got := Merge(a, b)
+	assert.Contains(t, got.Content, "First note.")
+	assert.Contains(t, got.Content, "Second note.")
+}
+
+func TestMerge_KeepFirstForOtherSections(t *testing.T) {
+	a := Page{Path: "wiki/concepts/foo.md", Content: "---\ntitle: Foo\n---\n\n## Definition\n\nFirst definition.\n"}
+	b := Page{Path: "wiki/concepts/foo.md", Content: "---\ntitle: Foo\n---\n\n## Definition\n\nSecond definition.\n"}
+
+	got := Merge(a, b)
+	assert.Contains(t, got.Content, "First definition.")
+	assert.NotContains(t, got.Content, "Second definition.")
+}
+
+func TestMerge_NewSectionFromB(t *testing.T) {
+	a := Page{Path: "wiki/concepts/foo.md", Content: "---\ntitle: Foo\n---\n\n## Definition\n\nA thing.\n"}
+	b := Page{Path: "wiki/concepts/foo.md", Content: "---\ntitle: Foo\n---\n\n## Why It Matters\n\nBecause reasons.\n"}
+
+	got := Merge(a, b)
+	assert.Contains(t, got.Content, "A thing.")
+	assert.Contains(t, got.Content, "Because reasons.")
+}
+
+func TestMerge_KeepsFrontmatterFromA(t *testing.T) {
+	a := Page{Path: "p.md", Content: "---\ntitle: A\nlast_updated: 2026-01-01\n---\n\n## Definition\n\nA.\n"}
+	b := Page{Path: "p.md", Content: "---\ntitle: B\nlast_updated: 2026-06-01\n---\n\n## Definition\n\nB.\n"}
+
+	got := Merge(a, b)
+	assert.Contains(t, got.Content, "title: A")
+	assert.NotContains(t, got.Content, "title: B")
+}