TodosApp/Todos/Model/Task.swift

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

import Foundation
import SwiftData
import SwiftUI

@Model
final class Task: Codable, Ordered, Aggregate {
  typealias Element = SubTask

  var sortOrder: Int = 0
  var name: String
  var project: Project?
  var category: String = ""
  @Relationship(deleteRule: .cascade, inverse: \Tag.task)
  var tags: [Tag] = []
  @Relationship(deleteRule: .cascade, inverse: \SubTask.task)
  var subtasks: [SubTask] = []
  var notes: String = ""
  var status: Status = Status.todo

  init(name: String, parent: Project? = nil) {
    self.name = name
    self.project = parent
    self.category = parent?.category ?? ""
    self.sortOrder = parent?.tasks.count ?? 0
  }

  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
    }
  }

  func yaml(_ indent: Int = 0) -> String {
    let hdr = String(repeating: "  ", count: indent)
    let subhdr = hdr + "  # "
    var rval = hdr + "[\(status.rawValue)] \(name) "
    rval += "(\(tags.map(\.id).joined(separator: " ")))\n"
    if !notes.isEmpty {
      rval += subhdr + notes.replacingOccurrences(of: "\n", with: "\n" + subhdr) + "\n"
    }
    rval += subtasks.map({ $0.yaml(indent + 1) }).joined()
    return rval
  }

  enum CodingKeys: CodingKey { case name, category, tags, subtasks, notes, status }

  required init(from decoder: any Decoder) throws {
    let container = try decoder.container(keyedBy: CodingKeys.self)
    name = try container.decode(String.self, forKey: .name)
    category = try container.decode(String.self, forKey: .category)
    tags = try container.decode([Tag].self, forKey: .tags)
    subtasks = try container.decode([SubTask].self, forKey: .subtasks)
    notes = try container.decode(String.self, forKey: .notes)
    status = try container.decode(Status.self, forKey: .status)
    tags.forEach({ $0.task = self })
    for (index, item) in subtasks.enumerated() {
      item.task = self
      item.sortOrder = index
    }
  }

  func encode(to encoder: any Encoder) throws {
    var container = encoder.container(keyedBy: CodingKeys.self)
    try container.encode(name, forKey: .name)
    try container.encode(category, forKey: .category)
    try container.encode(tags, forKey: .tags)
    try container.encode(subtasks, forKey: .subtasks)
    try container.encode(notes, forKey: .notes)
    try container.encode(status, forKey: .status)
  }
}