// The MIT License (MIT)
//
// Copyright (c) 2020–2022 Alexander Grebenyuk (github.com/kean).

import SwiftUI
import Pulse

struct ImageViewer: View {
    let viewModel: ImagePreviewViewModel

    var body: some View {
        VStack(spacing: 16) {
            Image(uxImage: viewModel.image)
                .resizable()
                .aspectRatio(contentMode: .fit)
                .frame(maxWidth: viewModel.image.size.width, maxHeight: viewModel.image.size.height)
                .border(Color.separator, width: 1)

            KeyValueSectionView(viewModel: viewModel.info)
                .hiddenTitle()

            Spacer()
        }.padding()
    }
}

struct ImagePreviewViewModel {
    let image: UXImage
    let info: KeyValueSectionViewModel

    init(image: UXImage, data: Data, context: FileViewerViewModel.Context) {
        func intValue(for key: String) -> Int? {
            context.metadata?[key].flatMap { Int($0) }
        }

        let isShowingOriginal = Int64(data.count) == context.originalSize
        let originalImageSize: CGSize?
        if isShowingOriginal {
            originalImageSize = image.size
        } else if context.isResponse {
            if let width = intValue(for: "ResponsePixelWidth"),
               let height = intValue(for: "ResponsePixelHeight") {
                originalImageSize = CGSize(width: width, height: height)
            } else {
                originalImageSize = nil
            }
        } else {
            if let width = intValue(for: "RequestPixelWidth"),
               let height = intValue(for: "RequestPixelHeight") {
                originalImageSize = CGSize(width: width, height: height)
            } else {
                originalImageSize = nil
            }
        }

        var info: [(String, String?)] = [
            ("Resolution", originalImageSize.map { "\(Int($0.width)) × \(Int($0.height)) px" }),
            ("Size", ByteCountFormatter.string(fromByteCount: context.originalSize)),
            ("Type", context.contentType?.rawValue),
            ("Displayed", isShowingOriginal ? "original image" : "preview (original not saved)")
        ]
        if !isShowingOriginal {
            info.append(("Preview Size (Decompressed)", ByteCountFormatter.string(fromByteCount: Int64(data.count))))
        }

        self.image = image
        self.info = KeyValueSectionViewModel(title: "Image", color: .pink, items: info)
    }
}