//
//  AudioMixerViewController.swift
//  XIONControlPanel
//

import UIKit
import WebKit

final class AudioMixerViewController: UIViewController, WKNavigationDelegate
{
    static let controlsWidth: CGFloat = 54.0

    var closeHandler: (() -> Void)?

    private static let mixerURL = URL(string: "http://avmotu.localdomain/#touch-console")!
    private static let accentColor = UIColor(red: 0.0, green: 0.95, blue: 0.95, alpha: 1.0)

    private let _panelView = UIView(frame: .zero)
    private let _webView = WKWebView(frame: .zero, configuration: WKWebViewConfiguration())
    private let _closeButton = UIButton(type: .custom)
    private let _refreshButton = UIButton(type: .custom)
    private let _loadingProgressView = UIProgressView(progressViewStyle: .bar)
    private var _progressObservation: NSKeyValueObservation?

    override func loadView()
    {
        view = UIView(frame: .zero)
        view.backgroundColor = .clear
        view.clipsToBounds = false
    }

    override func viewDidLoad()
    {
        super.viewDidLoad()

        _panelView.backgroundColor = .black
        _panelView.layer.borderColor = Self.accentColor.withAlphaComponent(0.65).cgColor
        _panelView.layer.borderWidth = 1.0
        _panelView.layer.shadowColor = UIColor.black.cgColor
        _panelView.layer.shadowOpacity = 0.95
        _panelView.layer.shadowRadius = 116.0
        _panelView.layer.shadowOffset = CGSize(width: -10.0, height: 0.0)
        view.addSubview(_panelView)

        _webView.navigationDelegate = self
        _webView.isOpaque = false
        _webView.backgroundColor = .black
        _webView.scrollView.backgroundColor = .black
        _webView.allowsBackForwardNavigationGestures = false
        _panelView.addSubview(_webView)

        _configureControlTab(_closeButton, accessibilityLabel: "Close Mixer")
        _closeButton.setTitle("X", for: .normal)
        _closeButton.titleLabel?.font = UIFont(name: "Orbitron-Medium", size: 18.0)
        _closeButton.accessibilityIdentifier = "audio.close"
        _closeButton.addTarget(self, action: #selector(_close), for: .touchUpInside)
        view.addSubview(_closeButton)

        _configureControlTab(_refreshButton, accessibilityLabel: "Refresh Mixer")
        let refreshImage = UIImage(
            systemName: "arrow.clockwise",
            withConfiguration: UIImage.SymbolConfiguration(pointSize: 20.0, weight: .medium)
        )
        _refreshButton.setImage(refreshImage, for: .normal)
        _refreshButton.tintColor = Self.accentColor
        _refreshButton.accessibilityIdentifier = "audio.refresh"
        _refreshButton.addTarget(self, action: #selector(_refresh), for: .touchUpInside)
        view.addSubview(_refreshButton)

        _loadingProgressView.progressTintColor = Self.accentColor
        _loadingProgressView.trackTintColor = UIColor(white: 0.15, alpha: 1.0)
        _panelView.addSubview(_loadingProgressView)

        _progressObservation = _webView.observe(
            \.estimatedProgress,
            options: [.new]
        ) { [weak self] webView, _ in
            guard let self else { return }
            let progress = Float(webView.estimatedProgress)
            self._loadingProgressView.setProgress(progress, animated: true)
            self._loadingProgressView.isHidden = progress >= 1.0
        }

        _loadMixer()
    }

    override func viewDidLayoutSubviews()
    {
        super.viewDidLayoutSubviews()

        let contentFrame = CGRect(
            x: Self.controlsWidth,
            y: 0.0,
            width: max(0.0, view.bounds.width - Self.controlsWidth),
            height: view.bounds.height
        )
        _panelView.frame = contentFrame
        _panelView.layer.shadowPath = UIBezierPath(rect: _panelView.bounds).cgPath
        _webView.frame = _panelView.bounds
        _loadingProgressView.frame = CGRect(
            x: 1.0,
            y: 1.0,
            width: max(0.0, _panelView.bounds.width - 2.0),
            height: 2.0
        )

        let tabHeight: CGFloat = 54.0
        let tabSpacing: CGFloat = 5.0
        let tabTop: CGFloat = 16.0
        _closeButton.frame = CGRect(
            x: 0.0,
            y: tabTop,
            width: Self.controlsWidth + 1.0,
            height: tabHeight
        )
        _refreshButton.frame = CGRect(
            x: 0.0,
            y: _closeButton.frame.maxY + tabSpacing,
            width: Self.controlsWidth + 1.0,
            height: tabHeight
        )

        view.bringSubviewToFront(_closeButton)
        view.bringSubviewToFront(_refreshButton)
    }

    private func _configureControlTab(_ button: UIButton, accessibilityLabel: String)
    {
        button.backgroundColor = UIColor(white: 0.2, alpha: 1.0)
        button.setTitleColor(Self.accentColor, for: .normal)
        button.accessibilityTraits = .button
        button.accessibilityLabel = accessibilityLabel
        button.layer.borderColor = Self.accentColor.withAlphaComponent(0.65).cgColor
        button.layer.borderWidth = 1.0
    }

    private func _loadMixer()
    {
        _loadingProgressView.isHidden = false
        _loadingProgressView.progress = 0.0
        let request = URLRequest(
            url: Self.mixerURL,
            cachePolicy: .reloadIgnoringLocalCacheData,
            timeoutInterval: 30.0
        )
        _webView.load(request)
    }

    @objc private func _close()
    {
        closeHandler?()
    }

    @objc private func _refresh()
    {
        if _webView.url == nil {
            _loadMixer()
        } else {
            _webView.reload()
        }
    }
}