import SwiftUI

#if canImport(UIKit)
import UIKit
#elseif canImport(AppKit)
import AppKit
#endif

/// Lädt ein authentifiziertes Image vom Cardecky-Media-Endpoint und
/// rendert es. Streamt erst beim ersten Mal, danach aus dem
/// MediaCache (LRU 200 MB).
struct RemoteImage: View {
    let mediaId: String
    let contentMode: ContentMode

    @Environment(\.mediaCache) private var mediaCache
    @State private var image: PlatformImage?
    @State private var failed = false

    init(mediaId: String, contentMode: ContentMode = .fit) {
        self.mediaId = mediaId
        self.contentMode = contentMode
    }

    var body: some View {
        Group {
            if let image {
                imageView(image)
            } else if failed {
                ContentUnavailableView("Bild konnte nicht geladen werden", systemImage: "photo.badge.exclamationmark")
                    .foregroundStyle(CardsTheme.mutedForeground)
            } else {
                ProgressView()
                    .tint(CardsTheme.primary)
            }
        }
        .task(id: mediaId) {
            await load()
        }
    }

    @ViewBuilder
    private func imageView(_ image: PlatformImage) -> some View {
        #if canImport(UIKit)
        Image(uiImage: image).resizable().aspectRatio(contentMode: contentMode)
        #elseif canImport(AppKit)
        Image(nsImage: image).resizable().aspectRatio(contentMode: contentMode)
        #endif
    }

    private func load() async {
        guard let cache = mediaCache else { failed = true; return }
        do {
            let data = try await cache.data(for: mediaId)
            if let img = PlatformImage(data: data) {
                image = img
            } else {
                failed = true
            }
        } catch {
            failed = true
        }
    }
}

#if canImport(UIKit)
typealias PlatformImage = UIImage
#elseif canImport(AppKit)
typealias PlatformImage = NSImage
#endif