// SPDX-FileCopyrightText: 2025 The Project Pterodactyl Developers
//
// SPDX-License-Identifier: MPL-2.0

import Foundation
import LanguageServerProtocol

extension SyntaxTree {
	public final class Cursor {
		public let lineMap: LineMap
		public let node: SyntaxTree.Child
		public let utf16Offset: Int

		public private(set) lazy var children: [Cursor] = {
			var children: [Cursor] = []
			var utf16Offset = utf16Offset
			for childNode in node.children {
				children.append(Self(lineMap: lineMap, node: childNode, utf16Offset: utf16Offset))
				utf16Offset += childNode.utf16Length
			}

			return children
		}()

		public var utf16Range: Range<Int> {
			utf16Offset..<utf16Offset + node.utf16Length
		}

		init(lineMap: LineMap, node: SyntaxTree.Child, utf16Offset: Int) {
			self.lineMap = lineMap
			self.node = node
			self.utf16Offset = utf16Offset
		}
	}
}

extension SyntaxTree.Cursor {
	public func firstChild<T>(mapping: (SyntaxTree.Cursor) -> T?) -> T? {
		for child in children {
			if let result = mapping(child) {
				return result
			} else {
				continue
			}
		}
		return nil
	}
	
	public func children<T>(mapping: (SyntaxTree.Cursor) -> T?) -> [T] {
		children.compactMap(mapping)
	}
}