ReadKeep/readeck/UI/BookmarkDetail/ImageViewerView.swift

import SwiftUI

struct ImageViewerView: View {
    let imageUrl: String
    @Environment(\.dismiss) private var dismiss
    @State private var scale: CGFloat = 1.0
    @State private var lastScale: CGFloat = 1.0
    @State private var offset: CGSize = .zero
    @State private var lastOffset: CGSize = .zero
    @State private var dragOffset: CGSize = .zero
    @State private var isDraggingToDismiss = false
    
    var body: some View {
        NavigationView {
            GeometryReader { geometry in
                ZStack {
                    Color.black
                        .ignoresSafeArea()
                    
                    AsyncImage(url: URL(string: imageUrl)) { image in
                        image
                            .resizable()
                            .scaledToFit()
                            .scaleEffect(scale)
                            .offset(offset)
                            .offset(dragOffset)
                            .opacity(isDraggingToDismiss ? 0.8 : 1.0)
                            .gesture(
                                SimultaneousGesture(
                                    MagnificationGesture()
                                        .onChanged { value in
                                            let delta = value / lastScale
                                            lastScale = value
                                            scale = min(max(scale * delta, 1), 4)
                                        }
                                        .onEnded { _ in
                                            lastScale = 1.0
                                            if scale < 1 {
                                                withAnimation(.spring()) {
                                                    scale = 1
                                                    offset = .zero
                                                }
                                            }
                                            if scale > 4 {
                                                scale = 4
                                            }
                                        },
                                    DragGesture()
                                        .onChanged { value in
                                            if scale > 1 {
                                                let newOffset = CGSize(
                                                    width: lastOffset.width + value.translation.width,
                                                    height: lastOffset.height + value.translation.height
                                                )
                                                offset = newOffset
                                            } else {
                                                // Dismiss gesture when not zoomed
                                                dragOffset = value.translation
                                                let dragDistance = sqrt(pow(value.translation.width, 2) + pow(value.translation.height, 2))
                                                if dragDistance > 50 {
                                                    isDraggingToDismiss = true
                                                }
                                            }
                                        }
                                        .onEnded { value in
                                            if scale <= 1 {
                                                lastOffset = offset
                                                let dragDistance = sqrt(pow(value.translation.width, 2) + pow(value.translation.height, 2))
                                                let velocity = sqrt(pow(value.velocity.width, 2) + pow(value.velocity.height, 2))
                                                
                                                if dragDistance > 100 || velocity > 500 {
                                                    dismiss()
                                                } else {
                                                    withAnimation(.spring()) {
                                                        dragOffset = .zero
                                                        isDraggingToDismiss = false
                                                    }
                                                }
                                            } else {
                                                lastOffset = offset
                                            }
                                        }
                                )
                            )
                            .onTapGesture(count: 2) {
                                withAnimation(.spring()) {
                                    if scale > 1 {
                                        scale = 1
                                        offset = .zero
                                        lastOffset = .zero
                                    } else {
                                        scale = 2
                                    }
                                }
                            }
                    } placeholder: {
                        ProgressView()
                            .scaleEffect(1.5)
                            .foregroundColor(.white)
                    }
                }
            }
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .navigationBarLeading) {
                    Button("Close") {
                        dismiss()
                    }
                    .foregroundColor(.white)
                }
            }
        }
    }
}

#Preview {
    ImageViewerView(imageUrl: "https://example.com/image.jpg")
}