// 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 StagesPreferencesView: View {
  @AppStorage("customStages") private var customStagesData: Data = UserPreferences.Defaults
    .customStages
  @State private var customStages: [CustomStage] = []
  @State private var showingHelpPopover = false

  var body: some View {
    VStack(alignment: .leading, spacing: Dimensions.Spacing.regular) {
      Table(customStages) {
        TableColumn("preferences.stages.column.name") { customStage in
          TextField(
            "preferences.stages.placeholder.name",
            text: Binding(
              get: { customStage.name },
              set: { newValue in
                updateStageName(customStage.id, newValue)
              }
            )
          )
          .textFieldStyle(.plain)
        }
        .width(120)

        TableColumn("preferences.stages.column.stage_i") { customStage in
          TextField(
            "preferences.stages.placeholder.stage_i",
            text: Binding(
              get: { customStage.stage.i },
              set: { newValue in
                updateStageValue(customStage.id, \.i, newValue)
              }
            )
          )
          .textFieldStyle(.plain)
        }

        TableColumn("preferences.stages.column.stage_ii") { customStage in
          TextField(
            "preferences.stages.placeholder.stage_ii",
            text: Binding(
              get: { customStage.stage.ii },
              set: { newValue in
                updateStageValue(customStage.id, \.ii, newValue)
              }
            )
          )
          .textFieldStyle(.plain)
        }

        TableColumn("preferences.stages.column.stage_iii") { customStage in
          TextField(
            "preferences.stages.placeholder.stage_iii",
            text: Binding(
              get: { customStage.stage.iii },
              set: { newValue in
                updateStageValue(customStage.id, \.iii, newValue)
              }
            )
          )
          .textFieldStyle(.plain)
        }

        TableColumn("preferences.stages.column.stage_iv") { customStage in
          TextField(
            "preferences.stages.placeholder.stage_iv",
            text: Binding(
              get: { customStage.stage.iv },
              set: { newValue in
                updateStageValue(customStage.id, \.iv, newValue)
              }
            )
          )
          .textFieldStyle(.plain)
        }

        TableColumn("") { customStage in
          Button(action: { removeStage(customStage.id) }) {
            Image(systemName: "minus")
          }
          .buttonStyle(.borderless)
        }
        .width(30)
      }
      .tableStyle(.bordered(alternatesRowBackgrounds: true))

      HStack(spacing: Dimensions.Spacing.regular) {
        Spacer()
        Button(action: { showingHelpPopover = true }) {
          Image(systemName: "questionmark.circle")
        }
        .buttonStyle(.borderless)
        .popover(isPresented: $showingHelpPopover, arrowEdge: .bottom) {
          Text("preferences.stages.explanation")
            .font(.Theme.Body.regular)
            .kerning(Dimensions.Kerning.body)
            .lineSpacing(Dimensions.LineHeight.body - Dimensions.FontSize.body)
            .frame(width: 300)
            .padding(Dimensions.Spacing.regular)
        }
        Button(action: addStage) {
          Image(systemName: "plus")
        }
      }
    }
    .padding(.vertical, Dimensions.Spacing.loose)
    .padding(.horizontal, Dimensions.Spacing.indulgent)
    .onAppear {
      loadStages()
    }
  }

  private func loadStages() {
    if let decoded = try? JSONDecoder().decode([CustomStage].self, from: customStagesData) {
      customStages = decoded
    }
  }

  private func saveStages() {
    if let encoded = try? JSONEncoder().encode(customStages) {
      customStagesData = encoded
    }
  }

  private func addStage() {
    customStages.append(CustomStage.placeholderDefault())
    saveStages()
  }

  private func removeStage(_ id: UUID) {
    customStages.removeAll { $0.id == id }
    saveStages()
  }

  private func updateStageName(_ id: UUID, _ newName: String) {
    if let index = customStages.firstIndex(where: { $0.id == id }) {
      customStages[index].name = newName
      saveStages()
    }
  }

  private func updateStageValue(
    _ id: UUID, _ keyPath: WritableKeyPath<Stage, String>, _ value: String
  ) {
    if let index = customStages.firstIndex(where: { $0.id == id }) {
      customStages[index].stage[keyPath: keyPath] = value
      saveStages()
    }
  }
}

#Preview {
  StagesPreferencesView()
}