import Foundation
import Postbox
import TelegramApi
import SwiftSignalKit

import SyncCore

extension StickerPackReference {
    init(_ stickerPackInfo: StickerPackCollectionInfo) {
        self = .id(id: stickerPackInfo.id.id, accessHash: stickerPackInfo.accessHash)
    }
    
    var apiInputStickerSet: Api.InputStickerSet {
        switch self {
            case let .id(id, accessHash):
                return .inputStickerSetID(id: id, accessHash: accessHash)
            case let .name(name):
                return .inputStickerSetShortName(shortName: name)
            case .animatedEmoji:
                return .inputStickerSetAnimatedEmoji
            case .dice:
                return .inputStickerSetDice
        }
    }
}

public enum LoadedStickerPack {
    case fetching
    case none
    case result(info: StickerPackCollectionInfo, items: [ItemCollectionItem], installed: Bool)
}

func updatedRemoteStickerPack(postbox: Postbox, network: Network, reference: StickerPackReference) -> Signal<(StickerPackCollectionInfo, [ItemCollectionItem])?, NoError> {
    return network.request(Api.functions.messages.getStickerSet(stickerset: reference.apiInputStickerSet))
        |> map(Optional.init)
        |> `catch` { _ -> Signal<Api.messages.StickerSet?, NoError> in
            return .single(nil)
        }
        |> mapToSignal { result -> Signal<(StickerPackCollectionInfo, [ItemCollectionItem])?, NoError> in
            guard let result = result else {
                return .single(nil)
            }
            
            let info: StickerPackCollectionInfo
            var items: [ItemCollectionItem] = []
            switch result {
            case let .stickerSet(set, packs, documents):
                let namespace: ItemCollectionId.Namespace
                switch set {
                    case let .stickerSet(flags, _, _, _, _, _, _, _, _, _):
                        if (flags & (1 << 3)) != 0 {
                            namespace = Namespaces.ItemCollection.CloudMaskPacks
                        } else {
                            namespace = Namespaces.ItemCollection.CloudStickerPacks
                        }
                }
                info = StickerPackCollectionInfo(apiSet: set, namespace: namespace)
                var indexKeysByFile: [MediaId: [MemoryBuffer]] = [:]
                for pack in packs {
                    switch pack {
                        case let .stickerPack(text, fileIds):
                            let key = ValueBoxKey(text).toMemoryBuffer()
                            for fileId in fileIds {
                                let mediaId = MediaId(namespace: Namespaces.Media.CloudFile, id: fileId)
                                if indexKeysByFile[mediaId] == nil {
                                    indexKeysByFile[mediaId] = [key]
                                } else {
                                    indexKeysByFile[mediaId]!.append(key)
                                }
                            }
                    }
                }
                
                for apiDocument in documents {
                    if let file = telegramMediaFileFromApiDocument(apiDocument), let id = file.id {
                        let fileIndexKeys: [MemoryBuffer]
                        if let indexKeys = indexKeysByFile[id] {
                            fileIndexKeys = indexKeys
                        } else {
                            fileIndexKeys = []
                        }
                        items.append(StickerPackItem(index: ItemCollectionItemIndex(index: Int32(items.count), id: id.id), file: file, indexKeys: fileIndexKeys))
                    }
                }
            }
            
            return postbox.transaction { transaction -> (StickerPackCollectionInfo, [ItemCollectionItem])? in
                if transaction.getItemCollectionInfo(collectionId: info.id) != nil {
                    transaction.replaceItemCollectionItems(collectionId: info.id, items: items)
                }
                cacheStickerPack(transaction: transaction, info: info, items: items)
                
                return (info, items)
            }
        }
}

public func loadedStickerPack(postbox: Postbox, network: Network, reference: StickerPackReference, forceActualized: Bool) -> Signal<LoadedStickerPack, NoError> {
    return cachedStickerPack(postbox: postbox, network: network, reference: reference, forceRemote: forceActualized)
    |> map { result -> LoadedStickerPack in
        switch result {
            case .none:
                return .none
            case .fetching:
                return .fetching
            case let .result(info, items, installed):
                return .result(info: info, items: items, installed: installed)
        }
    }
}