v0.1.0 initial commit

tui/tree_builder.go

@@ -0,0 +1,67 @@
+package tui
+
+// TreeBuilder helps construct flattened visible node list from hierarchical data
+type TreeBuilder struct {
+	nodes     []TreeNode
+	expansion *TreeExpansion
+}
+
+// NewTreeBuilder creates a builder with expansion state
+func NewTreeBuilder(expansion *TreeExpansion) *TreeBuilder {
+	return &TreeBuilder{
+		expansion: expansion,
+	}
+}
+
+// Reset clears accumulated nodes
+func (b *TreeBuilder) Reset() {
+	b.nodes = b.nodes[:0]
+}
+
+// Add adds a node if visible (parent expanded)
+// parentExpanded should be true for root-level nodes
+func (b *TreeBuilder) Add(node TreeNode, parentExpanded bool) {
+	if !parentExpanded {
+		return
+	}
+	node.Expanded = b.expansion.IsExpanded(node.Key)
+	b.nodes = append(b.nodes, node)
+}
+
+// Nodes returns accumulated visible nodes
+func (b *TreeBuilder) Nodes() []TreeNode {
+	return b.nodes
+}
+
+// MarkLastSiblings sets IsLast flag on nodes that are last at their depth
+// Call after all nodes added, before rendering
+func (b *TreeBuilder) MarkLastSiblings() {
+	n := len(b.nodes)
+	if n == 0 {
+		return
+	}
+
+	// Track last seen index at each depth
+	depthLast := make(map[int]int)
+
+	for i := 0; i < n; i++ {
+		depth := b.nodes[i].Depth
+		depthLast[depth] = i
+
+		// When we see a node, all deeper nodes before it are "last" at their levels
+		// Actually we need to mark when depth decreases or changes
+	}
+
+	// Simpler approach: scan backwards, mark last at each depth transition
+	for i := n - 1; i >= 0; i-- {
+		depth := b.nodes[i].Depth
+
+		// Check if next node (i+1) is at same or lesser depth
+		if i == n-1 {
+			b.nodes[i].IsLast = true
+		} else {
+			nextDepth := b.nodes[i+1].Depth
+			b.nodes[i].IsLast = nextDepth <= depth
+		}
+	}
+}