//
//  ProjectPanelView.swift
//  Todos
//
//  Created by Sam Jaffe on 2/28/26.
//

import SwiftUI
import SwiftData

struct ProjectPanelView: View {
  @Environment(\.modelContext) private var modelContext
  @AppStorage(UserDefaultsKeys.Category) var allGroups = CodableArray<Category>()

  @Bindable var item: Project
  @State private var empty = Category()

  @State private var showDialogue = false
  @State private var move = false
  @State private var taskFilter = ""
  @State private var statuses = StatusList()

  var body: some View {
    HStack {
      TextField("", text: $item.name)
        .font(.title)
        .padding(.leading, 10)
      Spacer()
      Button(action: addItem) {
        Image(systemName: "plus")
      }
      .help("New Task")
      .padding(.trailing, 10)
      if move {
        Label("", systemImage: "arrow.up.arrow.down")
          .foregroundStyle(.red)
          .font(.title2)
          .help("Re-ordering mode is enabled, text fields will be unresponsive")
      }
      if !taskFilter.isEmpty {
        Label("", systemImage: "text.magnifyingglass")
          .foregroundStyle(.blue)
          .font(.title2)
          .help("Only showing text matching '\(taskFilter)'")
      }
      if !statuses.all {
        Label("", systemImage: "exclamationmark.magnifyingglass")
          .foregroundStyle(.blue)
          .font(.title2)
          .help(statuses.description)
      }
      Button {
        showDialogue = !showDialogue
      } label: {
        Label("", systemImage: "ellipsis.circle")
          .foregroundStyle(.gray)
          .font(.title)
      }
      .buttonStyle(.borderless)
      .popover(isPresented: $showDialogue) {
        List{
          HStack {
            Label("", systemImage: "arrow.up.arrow.down")
            Toggle("Move Tasks", isOn: $move)
          }
          HStack {
            Label("", systemImage: "magnifyingglass")
            TextField("Filter Tasks", text: $taskFilter)
          }
          StatusChecklist(statuses: $statuses)
        }
      }
      Text("")
    }
    HStack(alignment: .top) {
      TextField("Project Notes", text: $item.notes, axis: .vertical)
        .padding(.leading, 20)
      if let grp = $allGroups.first(where: { $0.name.wrappedValue == item.category }) {
        ColorPicker("", selection: grp.color).disabled(true).scaledToFit()
      }
      Picker("", selection: $item.category) {
        Text(empty.name).tag("")
        ForEach(allGroups) { group in
          Text(group.name)
        }
      }.help("Default category for new Tasks")
    }
    List {
      ForEach(selected($item.tasks), id: \.id) { task in
        TaskView(task: task)
          .swipeActions {
            Button("Delete", systemImage: "trash", role: .destructive) {
              deleteItem(item: task.wrappedValue, from: item)
            }
          }

        ForEach(selected(task.subtasks), id: \.id) { subtask in
          SubTaskView(task: subtask)
            .swipeActions {
              Button("Delete", systemImage: "trash", role: .destructive) {
                deleteItem(item: subtask.wrappedValue, from: task.wrappedValue)
              }
            }
        }
        .onMove(perform: { moveItem(task.wrappedValue, $0, $1) })
        .moveDisabled(!move)
      }
      .onMove(perform: { moveItem(item, $0, $1) })
      .moveDisabled(!move)
    }
  }
  
  private func selected<T : Ordered & Filterable>(_ items: Binding<[T]>) -> [Binding<T>] {
    return items.sorted(by: T.less).filter({
      statuses.test($0.wrappedValue.status) &&
        (taskFilter.isEmpty || $0.wrappedValue.containsText(taskFilter))
    })
  }

  private func addItem() {
    withAnimation {
      let newTask = Task(name: "New Task", parent: item)
      modelContext.insert(newTask)
      item.tasks.append(newTask)
    }
  }

  private func moveItem(_ within: any Aggregate, _ fromOffsets: IndexSet, _ toOffset: Int) {
    withAnimation {
      within.move(fromOffsets: fromOffsets, toOffset: toOffset)
    }
  }

  private func deleteItem<T: Aggregate>(item: T.Element, from: T) where T.Element: PersistentModel {
    withAnimation {
      from.remove(item)
      modelContext.delete(item)
    }
  }
}

#Preview {
  @Previewable @State var item = Project()
  ProjectPanelView(item: item)
}