129 lines
4.5 KiB
Swift
129 lines
4.5 KiB
Swift
import Foundation
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@MainActor
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final class PrivateChatViewModel: ObservableObject {
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@Published private(set) var messages: [MessageItem] = []
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@Published private(set) var isInitialLoading: Bool = false
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@Published private(set) var isLoadingMore: Bool = false
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@Published var errorMessage: String?
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private let chatService: ChatService
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private let chatId: String
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private let pageSize: Int
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private var hasMore: Bool = true
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private var didLoadInitially: Bool = false
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init(chatId: String, chatService: ChatService = ChatService(), pageSize: Int = 30) {
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self.chatId = chatId
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self.chatService = chatService
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self.pageSize = pageSize
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}
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func loadInitialHistory(force: Bool = false) {
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if !force && didLoadInitially { return }
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guard !isInitialLoading else { return }
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isInitialLoading = true
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errorMessage = nil
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hasMore = true
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chatService.fetchPrivateChatHistory(chatId: chatId, beforeMessageId: nil, limit: pageSize) { [weak self] result in
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guard let self else { return }
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switch result {
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case .success(let data):
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self.hasMore = data.hasMore
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self.messages = Self.merge(existing: [], newMessages: data.items)
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self.didLoadInitially = true
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case .failure(let error):
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self.errorMessage = self.message(for: error)
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}
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self.isInitialLoading = false
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}
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}
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func refresh() {
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didLoadInitially = false
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loadInitialHistory(force: true)
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}
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func loadMoreIfNeeded(for message: MessageItem) {
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guard didLoadInitially, !isInitialLoading, hasMore, !isLoadingMore else { return }
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guard let first = messages.first, first.id == message.id else { return }
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isLoadingMore = true
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chatService.fetchPrivateChatHistory(chatId: chatId, beforeMessageId: message.id, limit: pageSize) { [weak self] result in
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guard let self else { return }
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switch result {
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case .success(let data):
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self.hasMore = data.hasMore
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if !data.items.isEmpty {
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self.messages = Self.merge(existing: self.messages, newMessages: data.items)
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}
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case .failure(let error):
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self.errorMessage = self.message(for: error)
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}
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self.isLoadingMore = false
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}
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}
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private func message(for error: Error) -> String {
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if let chatError = error as? ChatServiceError {
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return chatError.errorDescription ?? NSLocalizedString("Не удалось загрузить историю чата.", comment: "")
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}
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if let networkError = error as? NetworkError {
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switch networkError {
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case .unauthorized:
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return NSLocalizedString("Сессия истекла. Войдите снова.", comment: "")
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case .invalidURL, .noResponse:
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return NSLocalizedString("Ошибка соединения с сервером.", comment: "")
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case .network(let underlying):
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return String(format: NSLocalizedString("Ошибка сети: %@", comment: ""), underlying.localizedDescription)
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case .server(let statusCode, _):
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return String(format: NSLocalizedString("Ошибка сервера (%@).", comment: ""), "\(statusCode)")
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}
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}
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return NSLocalizedString("Неизвестная ошибка. Попробуйте позже.", comment: "")
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}
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private static func merge(existing: [MessageItem], newMessages: [MessageItem]) -> [MessageItem] {
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var combined: [MessageItem] = []
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combined.reserveCapacity(existing.count + newMessages.count)
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var seen: Set<String> = []
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for message in newMessages {
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if seen.insert(message.id).inserted {
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combined.append(message)
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}
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}
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for message in existing {
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if seen.insert(message.id).inserted {
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combined.append(message)
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}
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}
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combined.sort(by: compare)
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return combined
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}
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private static func compare(lhs: MessageItem, rhs: MessageItem) -> Bool {
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if let lhsDate = lhs.createdAt, let rhsDate = rhs.createdAt, lhsDate != rhsDate {
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return lhsDate < rhsDate
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}
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if let lhsId = Int(lhs.messageId), let rhsId = Int(rhs.messageId), lhsId != rhsId {
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return lhsId < rhsId
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}
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return lhs.messageId < rhs.messageId
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}
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}
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