import Foundation
import UIKit
import Postbox
import TelegramCore
import SwiftSignalKit
import TelegramUIPreferences

private struct WebSearchRecentQueryItemId {
    public let rawValue: MemoryBuffer
    
    var value: String {
        return String(data: self.rawValue.makeData(), encoding: .utf8) ?? ""
    }
    
    init(_ rawValue: MemoryBuffer) {
        self.rawValue = rawValue
    }
    
    init?(_ value: String) {
        if let data = value.data(using: .utf8) {
            self.rawValue = MemoryBuffer(data: data)
        } else {
            return nil
        }
    }
}

public final class RecentWebSearchQueryItem: Codable {
    init() {
    }
    
    public init(from decoder: Decoder) throws {
    }
    
    public func encode(to encoder: Encoder) throws {
    }
}

func addRecentWebSearchQuery(engine: TelegramEngine, string: String) -> Signal<Never, NoError> {
    if let itemId = WebSearchRecentQueryItemId(string) {
        return engine.orderedLists.addOrMoveToFirstPosition(collectionId: ApplicationSpecificOrderedItemListCollectionId.webSearchRecentQueries, id: itemId.rawValue, item: RecentWebSearchQueryItem(), removeTailIfCountExceeds: 100)
    } else {
        return .complete()
    }
}

func removeRecentWebSearchQuery(engine: TelegramEngine, string: String) -> Signal<Never, NoError> {
    if let itemId = WebSearchRecentQueryItemId(string) {
        return engine.orderedLists.removeItem(collectionId: ApplicationSpecificOrderedItemListCollectionId.webSearchRecentQueries, id: itemId.rawValue)
    } else {
        return .complete()
    }
}

func clearRecentWebSearchQueries(engine: TelegramEngine) -> Signal<Never, NoError> {
    return engine.orderedLists.clear(collectionId: ApplicationSpecificOrderedItemListCollectionId.webSearchRecentQueries)
}

func webSearchRecentQueries(postbox: Postbox) -> Signal<[String], NoError> {
    return postbox.combinedView(keys: [.orderedItemList(id: ApplicationSpecificOrderedItemListCollectionId.webSearchRecentQueries)])
    |> mapToSignal { view -> Signal<[String], NoError> in
        var result: [String] = []
        if let view = view.views[.orderedItemList(id: ApplicationSpecificOrderedItemListCollectionId.webSearchRecentQueries)] as? OrderedItemListView {
            for item in view.items {
                let value = WebSearchRecentQueryItemId(item.id).value
                result.append(value)
            }
        }
        return .single(result)
    }
}