package dirtree

import "strings"

// FlattenTree returns []*Node consistent with each node's `Expanded` state
func FlattenTree(node *Node, expandAll bool) []*Node {
	lines := make([]*Node, 0)
	var flatten func(n *Node)
	flatten = func(node *Node) {
		lines = append(lines, node)
		if node.isDir && (node.Expanded || expandAll) {
			for _, child := range node.children {
				flatten(child)
			}
		}
	}
	flatten(node)
	return lines
}

type TreeFormat struct {
	Space    string
	Span     string
	Node     string
	NodeLast string
}

var (
	Standard = TreeFormat{
		Space:    "    ",
		Span:     "│   ",
		Node:     "├── ",
		NodeLast: "└── ",
	}
	Compact = TreeFormat{
		Space:    "  ",
		Span:     "│ ",
		Node:     "├ ",
		NodeLast: "└ ",
	}
)

func RenderNodes(displayNodes []*Node, format TreeFormat, cursor int, renderNode func(*Node) string) string {
	var sb strings.Builder
	levelIsLast := make(map[int]bool)
	for i, node := range displayNodes {
		// Cursor indicator
		if cursor >= 0 {
			if i == cursor {
				sb.WriteString("> ")
			} else {
				sb.WriteString("  ")
			}
		}

		// Tree structure
		if node.depth > 0 {
			for d := 1; d < node.depth; d++ {
				if levelIsLast[d] {
					sb.WriteString(format.Space)
				} else {
					sb.WriteString(format.Span)
				}
			}

			// Find if this node is the last among its siblings
			isLast := node.parent.children[len(node.parent.children)-1] == node
			levelIsLast[node.depth] = isLast

			if isLast {
				sb.WriteString(format.NodeLast)
			} else {
				sb.WriteString(format.Node)
			}
		}

		// Render the node
		sb.WriteString(renderNode(node))
		sb.WriteString("\n")
	}
	return sb.String()
}