//
//  BookmarksView.swift
//  Ferrite
//
//  Created by Brian Dashore on 9/2/22.
//

import SwiftUI

struct BookmarksView: View {
    @Environment(\.verticalSizeClass) var verticalSizeClass

    @EnvironmentObject var navModel: NavigationViewModel
    @EnvironmentObject var debridManager: DebridManager

    let backgroundContext = PersistenceController.shared.backgroundContext

    @Binding var searchText: String

    @State private var viewTask: Task<Void, Never>?
    @State private var bookmarkPredicate: NSPredicate?

    var body: some View {
        DynamicFetchRequest(
            predicate: bookmarkPredicate,
            sortDescriptors: [NSSortDescriptor(keyPath: \Bookmark.orderNum, ascending: true)]
        ) { (bookmarks: FetchedResults<Bookmark>) in
            List {
                    if !bookmarks.isEmpty {
                        ForEach(bookmarks, id: \.self) { bookmark in
                            SearchResultButtonView(result: bookmark.toSearchResult(), existingBookmark: bookmark)
                        }
                        .onDelete { offsets in
                            for index in offsets {
                                if let bookmark = bookmarks[safe: index] {
                                    PersistenceController.shared.delete(bookmark, context: backgroundContext)
                                    NotificationCenter.default.post(name: .didDeleteBookmark, object: bookmark)
                                }
                            }
                        }
                        .onMove { source, destination in
                            var changedBookmarks = bookmarks.map { $0 }

                            changedBookmarks.move(fromOffsets: source, toOffset: destination)

                            for reverseIndex in stride(from: changedBookmarks.count - 1, through: 0, by: -1) {
                                changedBookmarks[reverseIndex].orderNum = Int16(reverseIndex)
                            }

                            PersistenceController.shared.save()
                        }
                    }
            }
            .listStyle(.insetGrouped)
            .inlinedList(inset: Application.shared.osVersion.majorVersion > 14 ? 15 : -25)
            .backport.onAppear {
                if debridManager.enabledDebrids.count > 0 {
                    viewTask = Task {
                        let magnets = bookmarks.compactMap {
                            if let magnetHash = $0.magnetHash {
                                return Magnet(hash: magnetHash, link: $0.magnetLink)
                            } else {
                                return nil
                            }
                        }
                        await debridManager.populateDebridIA(magnets)
                    }
                }
            }
            .onDisappear {
                viewTask?.cancel()
            }
        }
        .backport.onAppear {
            applyPredicate()
        }
        .onChange(of: searchText) { _ in
            applyPredicate()
        }
    }

    func applyPredicate() {
        bookmarkPredicate = searchText.isEmpty ? nil : NSPredicate(format: "title CONTAINS[cd] %@", searchText)
    }
}