RSSuper/iOS/RSSuper/ViewModels/FeedViewModel.swift

//
//  FeedViewModel.swift
//  RSSuper
//
//  ViewModel for feed state management
//

import Foundation
import Combine

/// State enum for feed data
enum FeedState {
    case idle
    case loading
    case success([FeedItem])
    case error(String)
}

/// ViewModel for managing feed state
class FeedViewModel: ObservableObject {
    @Published var feedState: FeedState = .idle
    @Published var unreadCount: Int = 0
    @Published var feedItems: [FeedItem] = []
    
    private let feedService: FeedServiceProtocol
    private var cancellables = Set<AnyCancellable>()
    private var currentSubscriptionId: String?
    
    init(feedService: FeedServiceProtocol = FeedService()) {
        self.feedService = feedService
    }
    
    deinit {
        cancellables.forEach { $0.cancel() }
    }
    
    /// Load feed items for a subscription
    func loadFeedItems(subscriptionId: String) {
        currentSubscriptionId = subscriptionId
        feedState = .loading
        
        Task { [weak self] in
            guard let self = self else { return }
            
            let items = self.feedService.getFeedItems(subscriptionId: subscriptionId)
            
            DispatchQueue.main.async {
                self.feedItems = items
                self.feedState = .success(items)
                self.unreadCount = items.filter { !$0.read }.count
            }
        }
    }
    
    /// Load unread count
    func loadUnreadCount(subscriptionId: String) {
        let items = feedService.getFeedItems(subscriptionId: subscriptionId)
        unreadCount = items.filter { !$0.read }.count
    }
    
    /// Mark an item as read
    func markAsRead(itemId: String, isRead: Bool) {
        let success = feedService.markItemAsRead(itemId: itemId)
        
        if success {
            if let index = feedItems.firstIndex(where: { $0.id == itemId }) {
                var updatedItem = feedItems[index]
                updatedItem.read = isRead
                feedItems[index] = updatedItem
            }
        }
    }
    
    /// Mark an item as starred
    func markAsStarred(itemId: String, isStarred: Bool) {
        let success = feedService.markItemAsStarred(itemId: itemId)
        
        if success {
            if let index = feedItems.firstIndex(where: { $0.id == itemId }) {
                var updatedItem = feedItems[index]
                updatedItem.starred = isStarred
                feedItems[index] = updatedItem
            }
        }
    }
    
    /// Refresh feed
    func refresh(subscriptionId: String) {
        loadFeedItems(subscriptionId: subscriptionId)
        loadUnreadCount(subscriptionId: subscriptionId)
    }
}