//
//  ContentView.swift
//  Listomania
//
//  Created by Jack Newcombe on 05/06/2019.
//  Copyright © 2019 Jack Newcombe. All rights reserved.
//

import SwiftUI

let dateFormatter = DateFormatter()

struct NoteItem: Codable, Hashable, Identifiable {
    let id: Int
    let text: String
    private let date = Date()
    var dateText: String {
        dateFormatter.dateFormat = "MMM d yyyy, h:mm a"
        return dateFormatter.string(from: date)
    }
}

struct ContentView : View {

    @State var items: [NoteItem] = {
        guard let data = UserDefaults.standard.data(forKey: "notes") else { return [] }
        if let json = try? JSONDecoder().decode([NoteItem].self, from: data) {
            return json
        }
        return []
    }()

    @State var taskText: String = ""

    @State var showAlert = false

    @State var itemToDelete: NoteItem?

    var alert: Alert {
        Alert(title: Text("Hey!"),
              message: Text("Are you sure you want to delete this item?"),
              primaryButton: .destructive(Text("Delete"), onTrigger: deleteNote),
              secondaryButton: .cancel())
    }

    var inputView: some View {
        HStack {
            TextField($taskText, placeholder: Text("Write a note ..."))
                .padding(EdgeInsets(top: 0, leading: 16, bottom: 0, trailing: 16))
                .clipped()
            Button(action: didTapAddTask, label: { Text("Add") }).padding(8)
        }
    }

    var body: some View {
        VStack {
            inputView
            Divider()
            List(items) { item in
                VStack(alignment: .leading) {
                    Text(item.dateText).font(.headline)
                    Text(item.text).lineLimit(nil).multilineTextAlignment(.leading)
                }
                .longPressAction({
                    self.itemToDelete = item
                    self.showAlert = true
                })
            }
            .presentation($showAlert) { alert }
        }
    }

    func didTapAddTask() {
        let id = items.reduce(0) { max($0.id, $1.id) } + 1
        items.insert(NoteItem(id: id, text: taskText), at: 0)
        taskText = ""
        save()
    }

    func deleteNote() {
        guard let itemToDelete = itemToDelete else { return }
        items = items.filter { $0 != itemToDelete }
        save()
    }

    func save() {
        guard let data = try? JSONEncoder().encode(items) else { return }
        UserDefaults.standard.set(data, forKey: "notes")
    }
}

#if DEBUG
struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}
#endif