damus/damus/Views/Video/DamusVideoPlayer.swift

//
//  VideoPlayerView.swift
//  damus
//
//  Created by William Casarin on 2023-04-05.
//

import SwiftUI

struct DamusVideoPlayer: View {
    var url: URL
    @ObservedObject var model: VideoPlayerModel
    @Binding var video_size: CGSize?
    
    var mute_icon: String {
        if model.has_audio == false || model.muted {
            return "speaker.slash"
        } else {
            return "speaker"
        }
    }
    
    var mute_icon_color: Color {
        switch self.model.has_audio {
        case .none:
            return .white
        case .some(let has_audio):
            return has_audio ? .white : .red
        }
    }
    
    var MuteIcon: some View {
        ZStack {
            Circle()
                .opacity(0.2)
                .frame(width: 32, height: 32)
                .foregroundColor(.black)
            
            Image(systemName: mute_icon)
                .padding()
                .foregroundColor(mute_icon_color)
        }
    }
    
    var body: some View {
        GeometryReader { geo in
            let localFrame = geo.frame(in: .local)
            let localCenter = CGPoint(x: localFrame.midX, y: localFrame.midY)
            let globalCenter = geo.frame(in: .global).origin.applying(.init(translationX: localCenter.x, y: localCenter.y))
            let centerY = globalCenter.y

            ZStack(alignment: .bottomTrailing) {
                VideoPlayer(url: url, model: model)
                if model.has_audio == true {
                    MuteIcon
                        .zIndex(11.0)
                        .onTapGesture {
                            self.model.muted = !self.model.muted
                        }
                }
            }
            .onChange(of: model.size) { size in
                guard let size else {
                    return
                }
                video_size = size
            }
            .onChange(of: centerY) { _ in
                let screenHeight = UIScreen.main.bounds.height
                let screenMidY = screenHeight / 2
                let tol = 0.20 * screenHeight /// tolerance - can vary  to taste ie.,  %  of screen height of a centered box in which video plays
                model.play = centerY > screenMidY - tol && centerY < screenMidY + tol /// video plays when inside tolerance box
            }
        }
    }
}
struct DamusVideoPlayer_Previews: PreviewProvider {
    @StateObject static var model: VideoPlayerModel = VideoPlayerModel()
    
    static var previews: some View {
        DamusVideoPlayer(url: URL(string: "http://cdn.jb55.com/s/zaps-build.mp4")!, model: model, video_size: .constant(nil))
    }
}