import SwiftUI
import AppKit
import UniformTypeIdentifiers

// MARK: - File shelf
//
// Drop files on the notch → "На полку": they wait in the top-left slot of the home
// view. Drag an icon out to put the file anywhere, click to open it, right-click to
// reveal or remove. The shelf keeps references (paths), not copies, and survives restarts;
// files that no longer exist are dropped silently.

struct ShelfItem: Identifiable, Codable, Equatable {
    var id = UUID()
    var path: String
    var addedAt = Date()

    var url: URL { URL(fileURLWithPath: path) }
    var name: String { url.lastPathComponent }
}

@MainActor
final class FileShelf: ObservableObject {
    static let shared = FileShelf()
    static let maxItems = 12
    private let key = "fileShelf"

    @Published private(set) var items: [ShelfItem] = []

    private init() {
        if let data = UserDefaults.standard.data(forKey: key),
           let saved = try? JSONDecoder().decode([ShelfItem].self, from: data) {
            items = saved.filter { FileManager.default.fileExists(atPath: $0.path) }
        }
    }

    func add(_ urls: [URL]) {
        for url in urls where !items.contains(where: { $0.path == url.path }) {
            items.insert(ShelfItem(path: url.path), at: 0)
        }
        if items.count > Self.maxItems { items = Array(items.prefix(Self.maxItems)) }
        save()
    }

    func remove(_ item: ShelfItem) {
        items.removeAll { $0.id == item.id }
        save()
    }

    func clear() {
        items = []
        save()
    }

    /// Drops entries whose file was moved or deleted.
    func prune() {
        let alive = items.filter { FileManager.default.fileExists(atPath: $0.path) }
        if alive != items { items = alive; save() }
    }

    private func save() {
        if let data = try? JSONEncoder().encode(items) {
            UserDefaults.standard.set(data, forKey: key)
        }
    }
}

// MARK: - Shelf pill (home view, top-left slot)

struct ShelfPill: View {
    @ObservedObject private var shelf = FileShelf.shared

    var body: some View {
        ZStack {
            if shelf.items.isEmpty {
                RoundedRectangle(cornerRadius: 14, style: .continuous)
                    .strokeBorder(Color.white.opacity(0.08), style: StrokeStyle(lineWidth: 1, dash: [4, 4]))
                Text("полка · брось файл на чёлку")
                    .font(.system(size: 10.5))
                    .foregroundColor(Color(hex: "#4A4E55"))
            } else {
                RoundedRectangle(cornerRadius: 14, style: .continuous)
                    .fill(Color(hex: "#0E0F11"))
                RoundedRectangle(cornerRadius: 14, style: .continuous)
                    .stroke(Color.white.opacity(0.10), lineWidth: 1)
                HStack(spacing: 6) {
                    ScrollView(.horizontal, showsIndicators: false) {
                        HStack(spacing: 4) {
                            ForEach(shelf.items) { item in
                                ShelfIcon(item: item)
                            }
                        }
                        .padding(.horizontal, 2)
                    }
                    Button {
                        shelf.clear()
                        SoundEngine.shared.play("close")
                    } label: {
                        Image(systemName: "xmark")
                            .font(.system(size: 8, weight: .bold))
                            .foregroundColor(Color(hex: "#5F646D"))
                            .frame(width: 16, height: 16)
                            .background(Circle().fill(Color.white.opacity(0.06)))
                    }
                    .buttonStyle(.plain)
                    .help("Очистить полку")
                }
                .padding(.horizontal, 8)
            }
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .onAppear { shelf.prune() }
    }
}

struct ShelfIcon: View {
    let item: ShelfItem
    @State private var isHovered = false

    var body: some View {
        Image(nsImage: NSWorkspace.shared.icon(forFile: item.path))
            .resizable()
            .interpolation(.high)
            .frame(width: 28, height: 28)
            .padding(2)
            .background(RoundedRectangle(cornerRadius: 6).fill(Color.white.opacity(isHovered ? 0.10 : 0)))
            .scaleEffect(isHovered ? 1.08 : 1)
            .onHover { h in withAnimation(.easeOut(duration: 0.12)) { isHovered = h } }
            .help(item.name)
            .onTapGesture { NSWorkspace.shared.open(item.url) }
            .onDrag {
                SoundEngine.shared.play("pop")
                return NSItemProvider(contentsOf: item.url) ?? NSItemProvider()
            }
            .contextMenu {
                Button("Открыть") { NSWorkspace.shared.open(item.url) }
                Button("Показать в Finder") { NSWorkspace.shared.activateFileViewerSelecting([item.url]) }
                Divider()
                Button("Убрать с полки") { FileShelf.shared.remove(item) }
            }
    }
}