//
//  RotateController.swift
//  Todos
//
//  Created by Sam Jaffe on 3/13/26.
//

import Foundation

final class RotateController {
  static func ymd(_ date: Date) -> String { RotateController().ymd(date) }
  func ymd(_ date: Date) -> String {
    date.formatted(.iso8601.year().month().day())
  }

  func saveAndRotate(_ items: [Project], _ date: inout Date,
                     _ tracking: inout RotateTracking) {
    SaveController().save(items, onDate: ymd(date))
    tracking.summary = summarize(items)
    rotate(items, &tracking)
    date = Date()
  }

  func summarize(_ items: [Project]) -> String? {
    var summary = ""
    for item in items {
      item.tasks.filter(isComplete).map(\.name).forEach { name in
        summary += "- \(item.name) > \(name)\n"
      }
      for task in item.tasks {
        task.subtasks.filter(isComplete).map(\.name).forEach { name in
          summary += "- \(item.name) > \(task.name) > \(name)\n"
        }
      }
    }
    return summary.isEmpty ? nil : summary
  }

  private func rotate(_ items: [Project], _ tracking: inout RotateTracking) {
    for item in items {
      cleanStatuses(&item.tasks)
      for task in item.tasks {
        cleanStatuses(&task.subtasks)
      }
    }
  }

  private func isComplete<T: Filterable>(_ arg: T) -> Bool {
    arg.status == .complete
  }

  private func cleanStatuses<T: Filterable>(_ items: inout [T]) {
    items.removeAll(where: isComplete)
    for var item in items where item.status == .inProgress {
      item.status = .todo
    }
  }
}