import CoreGraphics
import Foundation

struct MapParser {
  static func parse(content: String) -> ParsedMap {

    let parsers = [
      AnyMapParserStrategy(NoteParserStrategy()),
      AnyMapParserStrategy(VertexParserStrategy()),
      AnyMapParserStrategy(EdgeParserStrategy()),
      AnyMapParserStrategy(BlockerParserStrategy()),
      AnyMapParserStrategy(OpportunityParserStrategy()),
      AnyMapParserStrategy(StageParserStrategy()),
      AnyMapParserStrategy(GroupParserStrategy()),
    ]
    let builder = MapBuilder()

    let lines = content.split(whereSeparator: \.isNewline)

    for (index, line) in lines.enumerated() {
      for parser in parsers {
        if parser.canHandle(line: String(line)) {
          let (type, object) = parser.handle(
            index: index, line: String(line), vertices: builder.vertices)
          builder.addObjectToMap(type: type, object: object)
          break
        }
      }
    }

    return builder.build()
  }
}

// MARK: - Types

struct MapParsingPatterns {
  static let vertex = try! NSRegularExpression(
    pattern:
      "^([^\\(\\[\\]]*?)[\\s]*\\([\\s]*([0-9]+.?[0-9]*)[\\s]*,[\\s]*([0-9]+.?[0-9]*)[\\s]*\\)[\\s]*(?:\\[(.*?)\\])?[\\s]*$",
    options: [.caseInsensitive, .anchorsMatchLines])
  static let edge = try! NSRegularExpression(
    pattern: "^(.+?)[\\s]*-([->])[\\s]*(.+)", options: [.caseInsensitive, .anchorsMatchLines])
  static let blocker = try! NSRegularExpression(
    pattern: "^\\[(Blocker)\\][\\s]*(.+)", options: [.caseInsensitive, .anchorsMatchLines])
  static let opportunity = try! NSRegularExpression(
    pattern: "^\\[(Evolution)\\][\\s]*(.+)[\\s]+([-+])[\\s]*([0-9]+.?[0-9]*)",
    options: [.caseInsensitive, .anchorsMatchLines])
  static let note = try! NSRegularExpression(
    pattern:
      "^\\[(Note)\\][\\s]*\\([\\s]*([0-9]+.?[0-9]*)[\\s]*,[\\s]*([0-9]+.?[0-9]*)[\\s]*\\)[\\s]*(.*)",
    options: [.caseInsensitive, .anchorsMatchLines])
  static let stage = try! NSRegularExpression(
    pattern: "^\\[(I{1,3})\\][\\s]*([0-9]+.?[0-9]*)",
    options: [.caseInsensitive, .anchorsMatchLines])
  static let group = try! NSRegularExpression(
    pattern: "^\\[(Group)\\][\\s]*(.+)", options: [.caseInsensitive, .anchorsMatchLines])
}

struct ParsedMap {
  let vertices: [Vertex]
  let edges: [MapEdge]
  let blockers: [Blocker]
  let opportunities: [Opportunity]
  let notes: [Note]
  let stages: [CGFloat]
  let groups: [[Vertex]]

  static let empty: ParsedMap = ParsedMap(
    vertices: [], edges: [], blockers: [], opportunities: [], notes: [], stages: defaultDimensions,
    groups: [])
}

struct Vertex: Identifiable, Hashable {
  let id: Int
  let label: String
  let position: CGPoint
  var shape: VertexShape = .circle
}

struct Note {
  let id: Int
  let position: CGPoint
  let text: String
}

enum VertexShape: String {
  case circle
  case square
  case triangle
  case x
}

struct MapEdge {
  let id: Int
  let origin: CGPoint
  let destination: CGPoint
  let arrowhead: Bool
}

struct Blocker {
  let id: Int
  let position: CGPoint
}

struct Opportunity {
  let id: Int
  let origin: CGPoint
  let destination: CGPoint
}

struct StageDimensions {
  let index: Int
  let dimensions: CGFloat
}

private let defaultDimensions: [CGFloat] = [
  25.0,
  50.0,
  75.0,
]

// MARK: - MapParserStrategy protocol

protocol MapParserStrategy {
  func canHandle(line: String) -> Bool
  func handle(index: Int, line: String, vertices: [String: Vertex]) -> (Any.Type, Any)
}

struct AnyMapParserStrategy: MapParserStrategy {

  private let base: MapParserStrategy

  init<T: MapParserStrategy>(_ base: T) {
    self.base = base
  }

  func canHandle(line: String) -> Bool {
    return base.canHandle(line: line)
  }
  func handle(index: Int, line: String, vertices: [String: Vertex]) -> (Any.Type, Any) {
    return base.handle(index: index, line: line, vertices: vertices)
  }
}

// MARK: - Map Builder

class MapBuilder {
  var vertices: [String: Vertex] = [:]
  private var edges: [MapEdge] = []
  private var blockers: [Blocker] = []
  private var opportunities: [Opportunity] = []
  private var notes: [Note] = []
  private var stages: [CGFloat] = defaultDimensions
  private var groups: [[Vertex]] = []

  func addObjectToMap(type: Any.Type, object: Any) {
    if type == Vertex.self {
      let vertex = object as! Vertex
      vertices[vertex.label] = vertex
    }

    if type == MapEdge.self {
      let edge = object as! MapEdge
      edges.append(edge)
    }

    if type == Blocker.self {
      let blocker = object as! Blocker
      blockers.append(blocker)
    }

    if type == Opportunity.self {
      let opportunity = object as! Opportunity
      opportunities.append(opportunity)
    }

    if type == Note.self {
      let note = object as! Note
      notes.append(note)
    }

    if type == StageDimensions.self {
      let stageDimensions = object as! StageDimensions
      stages[stageDimensions.index] = stageDimensions.dimensions
    }

    if type == [Vertex].self {
      let group = object as! [Vertex]
      groups.append(group)
    }
  }

  func build() -> ParsedMap {
    let mappedVertices = vertices.map { label, vertex in return vertex }
    return ParsedMap(
      vertices: mappedVertices, edges: edges, blockers: blockers, opportunities: opportunities,
      notes: notes,
      stages: stages, groups: groups)
  }
}