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

import SwiftUI
import SwiftData

struct ContentView: View {
  @Environment(\.modelContext) private var modelContext
  @AppStorage(UserDefaultsKeys.WeekStart) private var weekStart = Date()
  let inPreview = ProcessInfo.processInfo.environment["XCODE_RUNNING_FOR_PREVIEWS"] == "1"
  
  @Binding var isMoveMode: Bool
  @Query private var items: [Project]
  @State private var selection: Project?

  var body: some View {
    NavigationSplitView {
      List(selection: $selection) {
        ForEach(items, id: \.self) { item in
          NavigationLink(value: item) {
            ProjectSidebarView(name: Bindable(item).name)
          } .contextMenu {
            Button(action: { deleteItem(item: item) }) {
              Label("Delete", systemImage: "trash")
            }
          }
        }
        .onDelete(perform: deleteItems)
      }
      .navigationSplitViewColumnWidth(min: 180, ideal: 200)
      .toolbar {
        ToolbarItem {
          Button(action: addItem) {
            Label("New Project", systemImage: "plus")
          }
        }
      }
    } detail: {
      if let selection = selection {
        ProjectPanelView(item: selection, isMoveMode: $isMoveMode)
      } else {
        let header = items.isEmpty ? "Create a New Project" : "Select a project from the sidebar"
        ContentUnavailableView(header, systemImage: "doc.text.image.fill")
      }
    }
    .onAppear(perform: autosave)
  }

  private func addItem() {
    withAnimation {
      let newItem = Project(timestamp: Date())
      modelContext.insert(newItem)
    }
  }
  
  private func autosave() {
    if inPreview {
      // This isn't great, but we shouldn't be running this in a preview
      // environment in the first place, so w/e.
      return
    }
    
    let now = Date()
    let sunday = Calendar.current.nextDate(after: weekStart,
                                           matching: DateComponents(weekday: 1),
                                           matchingPolicy: .nextTime)

    if now <= sunday! {
      return
    }
    
    let ymd = weekStart.formatted(.iso8601.year().month().day())
    SaveController.save(items, to: SaveController.filename(date: ymd))
    weekStart = now
    cleanup()
  }
  
  private func cleanup() {
    for item in items {
      item.tasks.removeAll(where: { $0.status == .Complete })
      for task in item.tasks {
        if task.status == .InProgress {
          task.status = .Todo
        }

        task.subtasks.removeAll(where: { $0.status == .Complete })
        for subtask in task.subtasks {
          if subtask.status == .InProgress {
            subtask.status = .Todo
          }
        }
      }
    }
  }
  
  private func deleteItem(item: Project) {
    if let selection = selection, selection == item {
      self.selection = nil
    }
    withAnimation {
      modelContext.delete(item)
    }
  }

  private func deleteItems(offsets: IndexSet) {
    if let selection = selection, offsets.contains(where: { items[$0] == selection }) {
      self.selection = nil
    }
    withAnimation {
      for index in offsets {
        modelContext.delete(items[index])
      }
    }
  }
}

#Preview {
  @Previewable @State var isMoveMode = false
  ContentView(isMoveMode: $isMoveMode)
      .modelContainer(for: Project.self, inMemory: true)
}