import SwiftUI

struct LocalView: View {
    @ObservedObject var appState: AppState
    @ObservedObject private var localManager = LocalWallpapersManager.shared
    @State private var selectedWallpaper: LocalWallpaper?
    @State private var showingDeleteConfirmation = false
    @State private var wallpaperToDelete: LocalWallpaper?
    
    var body: some View {
        VStack(spacing: 0) {
            // Header
            HStack {
                Text("Local Wallpapers")
                    .font(.headline)
                
                Spacer()
                
                if !localManager.wallpapers.isEmpty {
                    Text("\(localManager.wallpapers.count) items")
                        .font(.caption)
                        .foregroundColor(.secondary)
                }
                
                Button {
                    localManager.scanFolder(path: appState.saveFolderPath)
                } label: {
                    Image(systemName: "arrow.clockwise")
                }
                .buttonStyle(.plain)
                .disabled(localManager.isLoading)
            }
            .padding()
            
            Divider()
            
            // Content
            if localManager.isLoading && localManager.wallpapers.isEmpty {
                LoadingState()
            } else if !appState.saveToFolderEnabled {
                EmptyState(
                    icon: "folder.badge.questionmark",
                    text: "Enable 'Save wallpapers locally' in Settings to view local wallpapers"
                )
            } else if localManager.wallpapers.isEmpty {
                EmptyState(
                    icon: "photo.on.rectangle.angled",
                    text: "No wallpapers found in your save folder"
                )
            } else {
                LocalWallpaperGrid(
                    wallpapers: localManager.wallpapers,
                    onSetWallpaper: { wallpaper in
                        Task {
                            await appState.setLocalWallpaper(wallpaper)
                        }
                    },
                    onDeleteWallpaper: { wallpaper in
                        wallpaperToDelete = wallpaper
                        showingDeleteConfirmation = true
                    }
                )
            }
        }
        .alert("Delete Wallpaper?", isPresented: $showingDeleteConfirmation, presenting: wallpaperToDelete) { wallpaper in
            Button("Cancel", role: .cancel) {}
            Button("Delete", role: .destructive) {
                localManager.deleteWallpaper(wallpaper)
            }
        } message: { wallpaper in
            Text("This will permanently delete '\(wallpaper.filename)' from your save folder.")
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .top)
        .onAppear {
            if appState.saveToFolderEnabled {
                localManager.scanFolder(path: appState.saveFolderPath)
            }
        }
    }
}

// MARK: - Local Wallpaper Grid

struct LocalWallpaperGrid: View {
    let wallpapers: [LocalWallpaper]
    let onSetWallpaper: (LocalWallpaper) -> Void
    let onDeleteWallpaper: (LocalWallpaper) -> Void
    
    var body: some View {
        ScrollView {
            LazyVGrid(columns: [GridItem(.adaptive(minimum: 140), spacing: 12)], spacing: 12) {
                ForEach(wallpapers) { wallpaper in
                    LocalWallpaperItem(
                        wallpaper: wallpaper,
                        onSet: { onSetWallpaper(wallpaper) },
                        onDelete: { onDeleteWallpaper(wallpaper) }
                    )
                }
            }
            .padding(12)
        }
    }
}

// MARK: - Local Wallpaper Item

struct LocalWallpaperItem: View {
    let wallpaper: LocalWallpaper
    let onSet: () -> Void
    let onDelete: () -> Void
    
    @State private var isHovering = false
    @State private var image: NSImage?
    @State private var isLoadingImage = true
    
    var body: some View {
        Button(action: onSet) {
            ZStack {
                if let image = image {
                    Image(nsImage: image)
                        .resizable()
                        .aspectRatio(contentMode: .fill)
                        .clipped()
                } else if isLoadingImage {
                    Rectangle()
                        .fill(Color.gray.opacity(0.2))
                        .overlay(ProgressView())
                } else {
                    Rectangle()
                        .fill(Color.gray.opacity(0.1))
                        .overlay(
                            VStack {
                                Image(systemName: "photo")
                                    .foregroundColor(.gray)
                                Text(wallpaper.filename)
                                    .font(.caption2)
                                    .foregroundColor(.secondary)
                                    .lineLimit(1)
                            }
                        )
                }
            }
            .frame(maxWidth: .infinity, minHeight: 100, maxHeight: 100)
            .cornerRadius(8)
            .overlay(
                RoundedRectangle(cornerRadius: 8)
                    .stroke(isHovering ? Color.accentColor : Color.clear, lineWidth: 2)
            )
            .shadow(radius: isHovering ? 4 : 0)
            .overlay(
                // Action Buttons
                HStack {
                    // Delete button
                    Button {
                        onDelete()
                    } label: {
                        Image(systemName: "trash")
                            .foregroundColor(.white)
                            .shadow(radius: 2)
                            .font(.system(size: 14, weight: .bold))
                            .padding(6)
                            .background(Color.red.opacity(0.7))
                            .clipShape(Circle())
                    }
                    .buttonStyle(.plain)
                    .padding(6)
                    
                    Spacer()
                    
                    // Resolution badge
                    Text(wallpaper.resolution)
                        .font(.caption2)
                        .padding(.horizontal, 6)
                        .padding(.vertical, 2)
                        .background(Color.black.opacity(0.6))
                        .foregroundColor(.white)
                        .cornerRadius(4)
                        .padding(6)
                }
                .opacity(isHovering ? 1 : 0)
                .animation(.easeInOut(duration: 0.15), value: isHovering),
                alignment: .top
            )
            .scaleEffect(isHovering ? 1.02 : 1.0)
            .animation(.spring(response: 0.3), value: isHovering)
        }
        .buttonStyle(.plain)
        .onHover { isHovering = $0 }
        .help("\(wallpaper.resolution) • \(formatFileSize(wallpaper.fileSize))")
        .onAppear {
            loadImage()
        }
    }
    
    private func loadImage() {
        isLoadingImage = true
        
        DispatchQueue.global(qos: .userInitiated).async {
            let loadedImage = NSImage(contentsOf: self.wallpaper.url)
            DispatchQueue.main.async {
                self.image = loadedImage
                self.isLoadingImage = false
            }
        }
    }
    
    private func formatFileSize(_ bytes: Int64) -> String {
        let formatter = ByteCountFormatter()
        formatter.allowedUnits = [.useKB, .useMB, .useGB]
        formatter.countStyle = .file
        return formatter.string(fromByteCount: bytes)
    }
}

// MARK: - Loading State

struct LoadingState: View {
    var body: some View {
        VStack(spacing: 16) {
            ProgressView()
            Text("Loading wallpapers...")
                .foregroundColor(.secondary)
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
}