// 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 SwiftUI

struct MapMask: View {

  let mapSize: CGSize
  let vertexSize: CGSize
  let vertices: [Vertex]
  let labelPositions: [Int: CGPoint]
  let padding = CGFloat(5.0)

  var body: some View {
    ZStack(alignment: .topLeading) {
      ForEach(vertices, id: \.id) { vertex in
        ZStack(alignment: .topLeading) {
          Text(vertex.label.replacingOccurrences(of: "\\n", with: "\n"))
            .font(.Theme.Map.vertexLabel)
            .lineSpacing(
              Dimensions.LineHeight.Map.vertexLabel - Dimensions.FontSize.Map.vertexLabel
            )
            .foregroundColor(.white)
            .background(.white)
            .padding(.horizontal, 1.0)
            .clipShape(Capsule())
            .offset(
              CGSize(
                width: labelPositions[vertex.id]?.x
                  ?? (w(vertex.position.x) + vertexSize.width + padding),
                height: labelPositions[vertex.id]?.y ?? (h(vertex.position.y) + 7.0))
            )
            .blendMode(.destinationOut)
        }.zIndex(1)
      }
      Rectangle()
        .fill(.black)
    }.drawingGroup()
  }

  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))
  }
}

#Preview {
  MapMask(
    mapSize: CGSize(width: 400.0, height: 400.0), vertexSize: CGSize(width: 25.0, height: 25.0),
    vertices: [
      Vertex(id: 0, label: "A Circle", position: CGPoint(x: 50.0, y: 50.0)),
      Vertex(id: 1, label: "A Square", position: CGPoint(x: 10.0, y: 20.0), shape: .square),
      Vertex(id: 2, label: "A triangle", position: CGPoint(x: 25, y: 32.0), shape: .triangle),
      Vertex(id: 3, label: "An X", position: CGPoint(x: 70.0, y: 70.0), shape: .xMark)
    ],
    labelPositions: [:])
}