//
//  FeedItemViewController.swift
//  ReviewsFeed
//
//  Created by Dmitrii Ivanov on 21/07/2020.
//  Copyright © 2020 ING. All rights reserved.
//

import ReviewsUIKit
import SwiftUI
import UIKit

final class FeedItemViewController: UIViewController {
    
    // MARK: Constants
    private let item: Review
    
    // MARK: Properties
    private lazy var appVersionController = {
        UIHostingController(rootView: FakeLabel(
            systemIcon: .Icon.info,
            title: item.rating.appVersion
        ))
    }()

    private lazy var authorController = {
        UIHostingController(rootView: FakeLabel(
            systemIcon: .Icon.person,
            title: item.author
        ))
    }()

    private lazy var starRatingController = {
        UIHostingController(rootView: StarRating(
            item.rating.stars,
            of: .Rating.total
        ))
    }()
    
    // MARK: Outlets
    private lazy var appVersionView = {
        guard let view = appVersionController.view else {
            fatalError("The StarRating component must be initialised")
        }
        
        view.translatesAutoresizingMaskIntoConstraints = false
        
        return view
    }()

    private lazy var authorView = {
        guard let view = authorController.view else {
            fatalError("The StarRating component must be initialised")
        }
        
        view.translatesAutoresizingMaskIntoConstraints = false
        
        return view
    }()

    private lazy var commentLabel = {
        let label = UILabel()
        
        label.font = UIFont.preferredFont(forTextStyle: .body)
        label.numberOfLines = 0
        label.translatesAutoresizingMaskIntoConstraints = false
        label.text = item.comment
        
        return label
    }()
    
    private lazy var ratingView = {
        let stack = UIStackView()
        
        stack.axis = .horizontal
        stack.backgroundColor = .clear
        stack.distribution = .fillProportionally
        stack.translatesAutoresizingMaskIntoConstraints = false
        
        stack.addArrangedSubview(starRatingView)
        stack.addArrangedSubview(appVersionView)

        return stack
    }()

    private lazy var scrollView = {
        let scroll = UIScrollView()
        
        scroll.backgroundColor = .clear
        scroll.showsVerticalScrollIndicator = true
        scroll.translatesAutoresizingMaskIntoConstraints = false
        
        return scroll
    }()
    
    private lazy var stackView = {
        let stack = UIStackView()
        
        stack.axis = .vertical
        stack.alignment = .leading
        stack.backgroundColor = .clear
        stack.distribution = .fill
        stack.spacing = 16
        stack.translatesAutoresizingMaskIntoConstraints = false
        
        return stack
    }()
    
    private lazy var starRatingView = {
        guard let view = starRatingController.view else {
            fatalError("The StarRating component must be initialised")
        }
        
        view.translatesAutoresizingMaskIntoConstraints = false
        
        return view
    }()
    
    private lazy var titleLabel = {
        let label = UILabel()

        label.font = UIFont.preferredFont(forTextStyle: .headline)
        label.numberOfLines = 0
        label.translatesAutoresizingMaskIntoConstraints = false
        label.text = item.title

        return label
    }()

    // MARK: Initialisers
    init(_ item: Review) {
        self.item = item
        
        super.init(nibName: nil, bundle: nil)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    // MARK: UIViewController
    override func viewDidLoad() {
        super.viewDidLoad()

        addChild(appVersionController)
        addChild(authorController)
        addChild(starRatingController)
        
        setView()
        setNavigationBar()
        setLayout()
        
        appVersionController.didMove(toParent: self)
        authorController.didMove(toParent: self)
        starRatingController.didMove(toParent: self)
    }
    
}

// MARK: - Helpers
private extension FeedItemViewController {
    
    // MARK: Functions
    func setLayout() {
        let scrollContentGuide = scrollView.contentLayoutGuide
        let scrollFrameGuide = scrollView.frameLayoutGuide

        NSLayoutConstraint.activate([
            scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            scrollView.topAnchor.constraint(equalTo: view.topAnchor),
            scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),

            stackView.bottomAnchor.constraint(equalTo: scrollContentGuide.bottomAnchor, constant: -16),
            stackView.leadingAnchor.constraint(equalTo: scrollContentGuide.leadingAnchor),
            stackView.topAnchor.constraint(equalTo: scrollContentGuide.topAnchor, constant: 8),
            stackView.trailingAnchor.constraint(equalTo: scrollContentGuide.trailingAnchor),
            stackView.leadingAnchor.constraint(equalTo: scrollFrameGuide.leadingAnchor),
            stackView.trailingAnchor.constraint(equalTo: scrollFrameGuide.trailingAnchor),

            authorView.leadingAnchor.constraint(equalTo: stackView.leadingAnchor, constant: 16),
            
            ratingView.leadingAnchor.constraint(equalTo: stackView.leadingAnchor, constant: 16),

            titleLabel.leadingAnchor.constraint(equalTo: stackView.leadingAnchor, constant: 16),
            titleLabel.trailingAnchor.constraint(equalTo: stackView.trailingAnchor, constant: -16),

            commentLabel.leadingAnchor.constraint(equalTo: stackView.leadingAnchor, constant: 16),
            commentLabel.trailingAnchor.constraint(equalTo: stackView.trailingAnchor, constant: -16),
        ])
    }
    
    func setNavigationBar() {
        navigationController?.navigationBar.prefersLargeTitles = true
        navigationController?.navigationBar.isTranslucent = true
        
        navigationItem.title = "# \(String(item.id))"
    }

    func setView() {
        view.backgroundColor = .systemBackground

        view.addSubview(scrollView)
        
        scrollView.addSubview(stackView)

        stackView.addArrangedSubview(authorView)
        stackView.addArrangedSubview(ratingView)
        stackView.addArrangedSubview(titleLabel)
        stackView.addArrangedSubview(commentLabel)
    }
    
}

// MARK: - Previews
@available(iOS 17.0, *)
#Preview("Feed Item with a review") {
    UINavigationController(rootViewController: FeedItemViewController(.init(
        author: "Some author name here...",
        comment: "Some long, explanatory review comment goes here...",
        id: 1,
        rating: .init(stars: 3, appVersion: "v1.0.0"),
        title: "Some review title goes here..."
    )))
}