//
//  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"

  @Query(sort: \Project.sortOrder) private var items: [Project]
  @State private var selection: Project?

  var body: some View {
    NavigationSplitView {
      List(selection: $selection) {
        ForEach(items, id: \.uuid) { item in
          NavigationLink(value: item) {
            Text(item.name)
          }.swipeActions(content: {
            Button("Delete", systemImage: "trash", role: .destructive) {
              deleteItem(item: item)
            }
          })
        }
        .onMove(perform: reOrder)
      }
      .navigationSplitViewColumnWidth(min: 180, ideal: 200)
      .toolbar {
        ToolbarItem {
          Button(action: addItem) {
            Label("New Project", systemImage: "plus")
          }
        }
      }
    } detail: {
      if let selection = selection {
        ProjectPanelView(item: selection)
      } 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(sortOrder: items.count)
      modelContext.insert(newItem)
    }
  }

  @MainActor
  private func reOrder(fromOffsets: IndexSet, toOffset: Int) {
    var tmp = items.sorted(by: Project.less)
    tmp.move(fromOffsets: fromOffsets, toOffset: toOffset)
    for (index, item) in tmp.enumerated() {
      item.sortOrder = index
    }
    try? self.modelContext.save()
  }

  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, toUrl: 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 where subtask.status == .inProgress {
          subtask.status = .todo
        }
      }
    }
  }

  private func deleteItem(item: Project) {
    if let selection = selection, selection == item {
      self.selection = nil
    }
    withAnimation {
      modelContext.delete(item)
    }
  }
}

#Preview {
  ContentView()
    .modelContainer(for: Project.self, inMemory: true)
}