Fix performance and undo

[rbdr/map] / Map / MapParser / Strategies / EdgeParserStrategy.swift

import Foundation

struct EdgeParserStrategy: MapParserStrategy {
  private let regex = MapParsingPatterns.edge

  func canHandle(line: String) -> Bool {
    let range = NSRange(location: 0, length: line.utf16.count)
    let matches = regex.matches(in: String(line), options: [], range: range)
    return matches.count > 0 && matches[0].numberOfRanges == 4
  }

  func handle(index: Int, line: String, vertices: [String: Vertex]) -> (Any.Type, Any) {
    let range = NSRange(location: 0, length: line.utf16.count)
    let matches = regex.matches(in: String(line), options: [], range: range)

    let match = matches[0]
    let arrowhead = String(line[Range(match.range(at: 2), in: line)!]) == ">"
    let vertexA = String(line[Range(match.range(at: 1), in: line)!])
    let vertexB = String(line[Range(match.range(at: 3), in: line)!])

    if let origin = vertices[vertexA] {
      if let destination = vertices[vertexB] {
        let edge = MapEdge(
          id: index, origin: origin.position, destination: destination.position,
          arrowhead: arrowhead)
        return (MapEdge.self, edge)
      }
    }

    return (NSObject.self, NSObject())  // No matching object
  }
}