// 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 MapEditor: View {
  @Binding var document: MapDocument
  var url: URL?
  @State var selectedEvolution: StageType = .behavior
  @State var isSearching: Bool = false

  @AppStorage("viewStyle") var viewStyle: ViewStyle = .horizontal

  let zoomRange = Constants.kMinZoom...Constants.kMaxZoom
  @AppStorage("zoom") var zoom = 1.0
  @State var lastZoom = 1.0
  @State var searchTerm = ""
  @State var selectedTerm = 0

  var results: [Range<String.Index>] {
    if !isSearching || searchTerm.isEmpty {
      return []
    }
    let options: NSString.CompareOptions = [.caseInsensitive, .diacriticInsensitive]
    var searchRange = document.text.startIndex..<document.text.endIndex
    var ranges: [Range<String.Index>] = []

    while let range = document.text.range(of: searchTerm, options: options, range: searchRange) {
      ranges.append(range)
      searchRange = range.upperBound..<document.text.endIndex
    }

    return ranges

  }

  var body: some View {
    VStack(spacing: 0) {
      if isSearching {
        SearchBar(
          term: $searchTerm,
          onNext: {
            withAnimation {
              if results.count > 0 {
                selectedTerm = (selectedTerm + 1) % results.count
              }
            }
          },
          onPrevious: {
            withAnimation {
              if results.count > 0 {
                if selectedTerm == 0 {
                  selectedTerm = results.count - 1
                } else {
                  selectedTerm = (selectedTerm - 1) % results.count
                }
              }
            }
          },
          onSubmit: {

          },
          onDismiss: {
            withAnimation {
              isSearching = false
            }
          }
        )
        .onChange(
          of: searchTerm,
          {
            selectedTerm = 0
          })
        Divider()
      }
      adaptiveStack {
        ZStack(alignment: .topLeading) {
          MapTextEditor(document: $document, highlightRanges: results, selectedRange: selectedTerm)
            .background(Color.UI.background)
            .foregroundColor(Color.UI.foreground)
            .frame(minHeight: 96.0)
        }.padding(.top, 8.0).padding(.leading, 8.0).background(Color.UI.background).cornerRadius(
          5.0)
        GeometryReader { geometry in
          ScrollView([.horizontal, .vertical]) {
            MapRenderView(
              document: $document, evolution: $selectedEvolution, onDragVertex: onDragVertex
            ).scaleEffect(zoom, anchor: .center).frame(
              width: (Dimensions.mapSize.width + 2 * Dimensions.mapPadding) * zoom,
              height: (Dimensions.mapSize.height + 2 * Dimensions.mapPadding) * zoom)
          }.background(Color.UI.background)
            .gesture(
              MagnificationGesture()
                .onChanged { value in
                  let delta = value / lastZoom
                  lastZoom = value
                  zoom = min(max(zoom * delta, zoomRange.lowerBound), zoomRange.upperBound)
                }
                .onEnded { _ in
                  lastZoom = 1.0
                }
            )
        }
      }
      Divider()
      HStack {
        Spacer()
        Slider(
          value: $zoom, in: zoomRange, step: 0.1,
          label: {
            Text(formatZoom(zoom))
              .font(.Theme.smallControl)
          },
          minimumValueLabel: {
            Image(systemName: "minus.magnifyingglass")
              .font(.Theme.smallControl)
              .help("Zoom Out (⌘-)")
          },
          maximumValueLabel: {
            Image(systemName: "plus.magnifyingglass")
              .font(.Theme.smallControl)
              .help("Zoom In (⌘+)")
          }
        ).frame(width: 200).padding(.trailing, 10.0)
      }.padding(4.0)
    }.toolbar {
      HStack {
        EvolutionPicker(selectedEvolution: $selectedEvolution)
      }
    }.focusedSceneValue(\.isSearching, $isSearching)
      .focusedSceneValue(\.selectedEvolution, $selectedEvolution)
  }

  @ViewBuilder
  func adaptiveStack<Content: View>(@ViewBuilder content: () -> Content) -> some View {
    if viewStyle == .horizontal {
      VSplitView {
        content()
      }
    } else {
      HSplitView {
        content()
      }
    }
  }

  private func formatZoom(_ number: CGFloat) -> String {
    let formatter = NumberFormatter()
    formatter.numberStyle = .decimal
    formatter.maximumFractionDigits = 1
    formatter.minimumFractionDigits = 1
    return (formatter.string(from: NSNumber(value: number)) ?? "") + "x"
  }

  private func onDragVertex(vertex: Vertex, x: CGFloat, y: CGFloat) {
  }
}

#Preview {
  MapEditor(document: .constant(MapDocument()), url: URL(filePath: "test.png")!)
}