TodosApp/Todos/ViewModel/Aggregate.swift

//
//  Aggregate.swift
//  Todos
//
//  Created by Sam Jaffe on 3/5/26.
//

import Foundation
import SwiftUI

protocol Aggregate {
  associatedtype Element

  func move(fromOffsets: IndexSet, toOffset: Int)
  func remove(_ item: Element)
  func reindex()
}

extension Project : Aggregate {
  typealias Element = Task

  func move(fromOffsets: IndexSet, toOffset: Int) {
    tasks.move(fromOffsets: fromOffsets, toOffset: toOffset)
    reindex()
  }

  func remove(_ item: Element) {
    tasks.removeAll(where: { $0.id == item.id })
    reindex()
  }

  func reindex() {
    for (index, item) in tasks.enumerated() {
      item.sortOrder = index
    }
  }
}

extension Task : Aggregate {
  typealias Element = SubTask

  func move(fromOffsets: IndexSet, toOffset: Int) {
    subtasks.move(fromOffsets: fromOffsets, toOffset: toOffset)
    reindex()
  }

  func remove(_ item: Element) {
    subtasks.removeAll(where: { $0.id == item.id })
    reindex()
  }

  func reindex() {
    for (index, item) in subtasks.enumerated() {
      item.sortOrder = index
    }
  }
}