task 355: add terminal flamegraph layout renderer

1 files changed, 99 insertions, 0 deletions

diff --git a/internal/tui/flamegraph/renderer.go b/internal/tui/flamegraph/renderer.go
new file mode 100644
index 0000000..6cace44
--- /dev/null
+++ b/internal/tui/flamegraph/renderer.go
@@ -0,0 +1,99 @@
+package flamegraph
+
+import (
+	"hash/fnv"
+	"image/color"
+	"math"
+	"strings"
+)
+
+const pathSeparator = "\x1f"
+
+// BuildTerminalLayout converts a live trie snapshot into terminal frame cells.
+func BuildTerminalLayout(snapshot *snapshotNode, width, height int) []tuiFrame {
+	if snapshot == nil || width <= 0 || height <= 0 {
+		return nil
+	}
+	rootTotal := snapshotTotal(snapshot)
+	if rootTotal == 0 {
+		return nil
+	}
+
+	rootName := frameName(snapshot.Name, 0)
+	frames := make([]tuiFrame, 0, len(snapshot.Children)+1)
+	collectTerminalLayout(&frames, snapshot, rootTotal, width, height, 0, 0, rootName)
+	return frames
+}
+
+func collectTerminalLayout(out *[]tuiFrame, node *snapshotNode, rootTotal uint64, width, height, depth, col int, path string) {
+	if node == nil || depth >= height {
+		return
+	}
+	total := snapshotTotal(node)
+	frameWidth := int(math.Floor(float64(width) * (float64(total) / float64(rootTotal))))
+	if frameWidth < 1 {
+		return
+	}
+
+	name := frameName(node.Name, depth)
+	*out = append(*out, tuiFrame{
+		Name:    name,
+		Col:     col,
+		Row:     depth,
+		Width:   frameWidth,
+		Total:   total,
+		Percent: 100 * float64(total) / float64(rootTotal),
+		Fill:    terminalFrameColor(name),
+		Depth:   depth,
+		Path:    path,
+	})
+
+	cursor := col
+	for _, child := range node.Children {
+		childTotal := snapshotTotal(child)
+		childWidth := int(math.Floor(float64(width) * (float64(childTotal) / float64(rootTotal))))
+		if childWidth < 1 {
+			continue
+		}
+		childName := frameName(child.Name, depth+1)
+		childPath := strings.Join([]string{path, childName}, pathSeparator)
+		collectTerminalLayout(out, child, rootTotal, width, height, depth+1, cursor, childPath)
+		cursor += childWidth
+	}
+}
+
+func snapshotTotal(node *snapshotNode) uint64 {
+	if node == nil {
+		return 0
+	}
+	total := node.Value
+	for _, child := range node.Children {
+		total += snapshotTotal(child)
+	}
+	if node.Total > total {
+		return node.Total
+	}
+	return total
+}
+
+func frameName(name string, depth int) string {
+	if name != "" {
+		return name
+	}
+	if depth == 0 {
+		return "root"
+	}
+	return "(unknown)"
+}
+
+func terminalFrameColor(name string) color.Color {
+	hasher := fnv.New32a()
+	_, _ = hasher.Write([]byte(name))
+	h := hasher.Sum32()
+	return color.RGBA{
+		R: uint8(200 + int(h%35)),
+		G: uint8(80 + int((h>>8)%120)),
+		B: uint8(40 + int((h>>16)%90)),
+		A: 255,
+	}
+}