ItemDetailView.swift

//
//  ItemDetailView.swift
//  To-Do-List-Demo
//
//  Created by Nelson Lai on 2026/6/25.
//

import SwiftUI

struct ItemDetailView: View {
    @Environment(\.dismiss) private var dismiss
    @Bindable var item: Item

    @State private var subject = ""
    @State private var itemDescription = ""

    private var trimmedSubject: String {
        subject.trimmingCharacters(in: .whitespacesAndNewlines)
    }

    private var trimmedDescription: String {
        itemDescription.trimmingCharacters(in: .whitespacesAndNewlines)
    }

    private var canSave: Bool {
        !trimmedSubject.isEmpty
    }

    var body: some View {
        Form {
            Section("Subject") {
                TextField("Enter subject", text: $subject)
            }
            Section("Description") {
                TextField("Enter description", text: $itemDescription, axis: .vertical)
                    .lineLimit(3...6)
            }
            Section("Created") {
                Text(item.timestamp, format: Date.FormatStyle(date: .complete, time: .standard))
            }
        }
        .navigationTitle(trimmedSubject.isEmpty ? item.subject : trimmedSubject)
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .cancellationAction) {
                Button("Cancel") {
                    dismiss()
                }
            }
            ToolbarItem(placement: .confirmationAction) {
                Button("Save") {
                    saveChanges()
                    dismiss()
                }
                .disabled(!canSave)
            }
        }
        .onAppear {
            loadFromItem()
        }
    }

    private func loadFromItem() {
        subject = item.subject
        itemDescription = item.itemDescription
    }

    private func saveChanges() {
        item.subject = trimmedSubject
        item.itemDescription = trimmedDescription
    }
}