//

// BookmarksStateValidation.swift

// DuckDuckGo

//

// Copyright © 2024 DuckDuckGo. All rights reserved.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

//

import Foundation

import CoreData

import Bookmarks

import Persistence

public protocol BookmarksStateValidation {

func validateInitialState(context: NSManagedObjectContext,

validationError: BookmarksStateValidator.ValidationError) -> Bool

func validateBookmarksStructure(context: NSManagedObjectContext)

}

public class BookmarksStateValidator: BookmarksStateValidation {

enum Constants {

static let bookmarksDBIsInitialized = "bookmarksDBIsInitialized"

}

public enum ValidationError {

case bookmarksStructureLost

case bookmarksStructureNotRecovered

case bookmarksStructureBroken(additionalParams: [String: String])

case validatorError(Error)

}

let keyValueStore: KeyValueStoring

let errorHandler: (ValidationError) -> Void

public init(keyValueStore: KeyValueStoring,

errorHandler: @escaping (ValidationError) -> Void) {

self.keyValueStore = keyValueStore

self.errorHandler = errorHandler

}

public func validateInitialState(context: NSManagedObjectContext,

validationError: ValidationError) -> Bool {

guard keyValueStore.object(forKey: Constants.bookmarksDBIsInitialized) != nil else { return true }

let fetch = BookmarkEntity.fetchRequest()

do {

let count = try context.count(for: fetch)

if count == 0 {

errorHandler(validationError)

return false

}

} catch {

errorHandler(.validatorError(error))

}

return true

}

public func validateBookmarksStructure(context: NSManagedObjectContext) {

let isMarkedAsInitialized = keyValueStore.object(forKey: Constants.bookmarksDBIsInitialized) != nil

if isMarkedAsInitialized == false {

keyValueStore.set(true, forKey: Constants.bookmarksDBIsInitialized)

}

let rootUUIDs = [BookmarkEntity.Constants.rootFolderID,

FavoritesFolderID.unified.rawValue,

FavoritesFolderID.mobile.rawValue,

FavoritesFolderID.desktop.rawValue]

let request = BookmarkEntity.fetchRequest()

request.predicate = NSPredicate(format: "%K IN %@", #keyPath(BookmarkEntity.uuid), rootUUIDs)

do {

let roots = try context.fetch(request)

if roots.count != rootUUIDs.count {

var additionalParams = [String: String]()

for uuid in rootUUIDs {

additionalParams[uuid] = "\(roots.filter({ $0.uuid == uuid }).count)"

}

additionalParams["is-marked-as-initialized"] = isMarkedAsInitialized ? "true" : "false"

errorHandler(.bookmarksStructureBroken(additionalParams: additionalParams))

}

} catch {

errorHandler(.validatorError(error))

}

}

}