import SwiftUI

struct MapVertices: View {

  @Environment(\.colorScheme) var colorScheme

  let mapSize: CGSize
  let vertexSize: CGSize
  let vertices: [Vertex]
  let padding = CGFloat(4.0)

  var color: MapColor {
    MapColor.colorForScheme(colorScheme)
  }

  var body: some View {
    ForEach(vertices, id: \.id) { vertex in
      getVertexShape(vertex).fill(color.foreground)
      Text(vertex.label).foregroundColor(color.secondary).offset(
        CGSize(
          width: w(vertex.position.x) + vertexSize.width + padding,
          height: h(vertex.position.y)))
    }
  }

  func h(_ dimension: CGFloat) -> CGFloat {
    max(0.0, min(mapSize.height, dimension * mapSize.height / 100.0))
  }

  func w(_ dimension: CGFloat) -> CGFloat {
    max(0.0, min(mapSize.width, dimension * mapSize.width / 100.0))
  }

  func getVertexShape(_ vertex: Vertex) -> Path {
    switch vertex.shape {
    case .circle:
      return Path { path in
        path.addEllipse(
          in: CGRect(
            origin: CGPoint(x: w(vertex.position.x), y: h(vertex.position.y)), size: vertexSize
          ))
      }
    case .square:
      return Path { path in
        path.addRect(
          CGRect(
            x: w(vertex.position.x), y: h(vertex.position.y), width: vertexSize.width,
            height: vertexSize.height
          ))
      }
    case .triangle:
      return Path { path in
        path.move(to: CGPoint(x: w(vertex.position.x), y: h(vertex.position.y) + vertexSize.height))
        path.addLine(
          to: CGPoint(
            x: w(vertex.position.x) + vertexSize.width, y: h(vertex.position.y) + vertexSize.height)
        )
        path.addLine(
          to: CGPoint(x: w(vertex.position.x) + vertexSize.width / 2.0, y: h(vertex.position.y)))
        path.addLine(
          to: CGPoint(x: w(vertex.position.x), y: h(vertex.position.y) + vertexSize.height))
        path.closeSubpath()
      }
    case .x:
      return Path { path in
        path.move(to: CGPoint(x: w(vertex.position.x), y: h(vertex.position.y)))
        path.addLine(
          to: CGPoint(
            x: w(vertex.position.x) + vertexSize.width, y: h(vertex.position.y) + vertexSize.height)
        )
        path.closeSubpath()
        path.move(to: CGPoint(x: w(vertex.position.x) + vertexSize.width, y: h(vertex.position.y)))
        path.addLine(
          to: CGPoint(x: w(vertex.position.x), y: h(vertex.position.y) + vertexSize.height))
        path.closeSubpath()
      }.strokedPath(StrokeStyle(lineWidth: 5.0, lineCap: .butt))
    }
  }
}

struct MapVertices_Previews: PreviewProvider {
  static var previews: some View {
    MapVertices(
      mapSize: CGSize(width: 400.0, height: 400.0), vertexSize: CGSize(width: 25.0, height: 25.0),
      vertices: [
        Vertex(id: 0, label: "A", position: CGPoint(x: 50.0, y: 50.0)),
        Vertex(id: 0, label: "A", position: CGPoint(x: 10.0, y: 20.0)),
      ])
  }
}