import SwiftUI

@MainActor
@Observable
final class FrontPageViewModel {
    private static let redditHomeURL = URL(string: "https://www.reddit.com")!

    private(set) var redditLoadURL = redditHomeURL
    static let postGeneratorItem = SidebarNavItem(
        title: "Post Generator",
        subtitle: "Generate engaging posts",
        iconKind: .postGenerator
    )
    var selectedNavItem: SidebarNavItem? = postGeneratorItem
    var isRedditActive = false
    var isSettingsActive = false
    var isHistoryActive = false
    var isPaywallPresented = false
    var authErrorMessage: String?
    var hasOpenedReddit = false
    private(set) var redditReloadTrigger = 0
    private(set) var redditGoBackTrigger = 0
    var redditCanGoBack = false

    static let historyItem = SidebarNavItem(
        title: "History",
        subtitle: "Saved AI responses",
        iconKind: .history
    )

    static let settingsItem = SidebarNavItem(
        title: "Settings",
        subtitle: "Manage app preferences",
        iconKind: .settings
    )

    func openReddit(at url: URL? = nil) {
        hasOpenedReddit = true
        selectedNavItem = nil
        isSettingsActive = false
        isHistoryActive = false
        setRedditActive(true)

        guard let url else { return }

        redditLoadURL = url
        if RedditWebAuthHelper.isRedditHomeURL(url) {
            redditCanGoBack = false
        }
        redditReloadTrigger += 1
    }

    func showAuthError(_ message: String) {
        authErrorMessage = message
    }

    func clearAuthError() {
        authErrorMessage = nil
    }

    func goBackInReddit() {
        guard redditCanGoBack else { return }
        redditGoBackTrigger += 1
    }

    func updateRedditCanGoBack(_ canGoBack: Bool) {
        redditCanGoBack = canGoBack
    }

    func openSettings() {
        selectedNavItem = nil
        setRedditActive(false)
        isSettingsActive = true
        isHistoryActive = false
    }

    func openHistory() {
        selectedNavItem = nil
        setRedditActive(false)
        isSettingsActive = false
        isHistoryActive = true
    }

    func selectNavItem(_ item: SidebarNavItem) {
        selectedNavItem = item
        setRedditActive(false)
        isSettingsActive = false
        isHistoryActive = false
    }

    func deactivateRedditForPremiumGate() {
        setRedditActive(false)
    }

    private func setRedditActive(_ active: Bool) {
        isRedditActive = active
        RedditWebViewStore.shared.setRedditPageActive(active)
    }

    func showPaywall() {
        isPaywallPresented = true
        RedditWebViewStore.shared.setPaywallPresented(true)
    }

    func dismissPaywall() {
        isPaywallPresented = false
        RedditWebViewStore.shared.setPaywallPresented(false)
    }

    let createItems: [SidebarNavItem] = [
        postGeneratorItem,
        SidebarNavItem(title: "Title Optimizer", subtitle: "Create viral titles", iconKind: .titleOptimizer),
        SidebarNavItem(title: "Comment Writer", subtitle: "Write smart replies", iconKind: .commentWriter),
    ]

}