//
//  EQNGenericPickerViewController.swift
//  Earthquake Network
//
//  Created by Busi Andrea on 13/09/2020.
//  Copyright © 2020 Earthquake Network. All rights reserved.
//

import Foundation

/// Protocollo per rappresentare elementi nel picker generico
protocol PickerRepresentable {
    var pickerTitle: String { get }
}


class EQNGenericPickerViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
    
    typealias DoneCompletion = (PickerRepresentable) -> Void
    var onCompletion: DoneCompletion?
    var onCancel: (() -> Void)?
    
    // MARK: - Properties
    
    private var selectedIndex: Int?
    private var items = [PickerRepresentable]()
        
    private lazy var pickerView: UIPickerView = {
        let picker = UIPickerView(frame: .zero)
        picker.delegate = self
        picker.dataSource = self
        return picker
    }()
    
    private lazy var toolbar: UIToolbar = {
        let toolbar = UIToolbar()
        toolbar.barStyle = .default
        toolbar.isTranslucent = true
        
        let doneButton = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(doneTapped(_:)))
        let spaceButton = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
        let cancelButton = UIBarButtonItem(barButtonSystemItem: .cancel, target: self, action: #selector(cancelTapped(_:)))
        
        toolbar.setItems([cancelButton, spaceButton, doneButton], animated: false)
        return toolbar
    }()
    
    // MARK: - View Lifecycle
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = .clear
        toolbar.translatesAutoresizingMaskIntoConstraints = false
        pickerView.translatesAutoresizingMaskIntoConstraints = false
        
        view.addSubview(pickerView)
        view.addSubview(toolbar)
        
        pickerView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true
        pickerView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
        pickerView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
        
        toolbar.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        toolbar.trailingAnchor.constraint(equalTo: pickerView.trailingAnchor).isActive = true
        toolbar.leadingAnchor.constraint(equalTo: pickerView.leadingAnchor).isActive = true
    }
    
    // MARK: - Public
    
    public func configure(with items: [PickerRepresentable], selectedIndex: Int? = nil, completion: @escaping DoneCompletion) {
        self.onCompletion = completion
        self.items = items
        self.selectedIndex = items.count > 0 ? 1 : nil
        self.pickerView.reloadAllComponents()
        
        if let selectedIndex = selectedIndex, 0..<items.count ~= selectedIndex {
            self.selectedIndex = selectedIndex
            self.pickerView.selectRow(selectedIndex, inComponent: 0, animated: false)
        }
    }
    
    // MARK: - Actions
    
    @objc func doneTapped(_ sender: Any) {
        guard let index = selectedIndex else {
            return
        }
        onCompletion?(items[index])
    }
    
    @objc func cancelTapped(_ sender: Any) {
        onCancel?()
    }
    
    // MARK: - UIPickerViewDataSource
    
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        1
    }
    
    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        items.count
    }
    
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        items[row].pickerTitle
    }
    
    // MARK: - UIPickerViewDataDelegate
    
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        selectedIndex = row
    }
}