/*
 Copyright (C) 2024 Rubén Beltrán del Río

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program. If not, see https://map.tranquil.systems.
 */
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
  }
}