//
// Swiftfin is subject to the terms of the Mozilla Public
// License, v2.0. If a copy of the MPL was not distributed with this
// file, you can obtain one at https://mozilla.org/MPL/2.0/.
//
// Copyright (c) 2025 Jellyfin & Jellyfin Contributors
//

import SwiftUI

@MainActor
final class TabCoordinator: ObservableObject {

    struct SelectedEvent {
        let isRoot: Bool
        let isRepeat: Bool
    }

    typealias TabData = (
        item: TabItem,
        coordinator: NavigationCoordinator,
        publisher: TabItemSelectedPublisher
    )

    @Published
    var selectedTabID: String! = nil {
        didSet {
            guard let tab = tabs.first(property: \.item.id, equalTo: selectedTabID) else { return }

            tab.publisher.send(
                .init(
                    isRoot: tab.coordinator.path.isEmpty,
                    isRepeat: oldValue == selectedTabID
                )
            )
        }
    }

    @Published
    var tabs: [TabData] = []

    private let sessionManager: SessionManager

    init(sessionManager: SessionManager) {
        self.sessionManager = sessionManager
        refreshTabs()
    }

    func refreshTabs() {
        let newTabs = buildTabs()

        // Preserve navigation coordinators for existing tabs
        let preservedTabs = newTabs.map { newTab in
            if let existingTab = tabs.first(where: { $0.item.id == newTab.id }) {
                return (newTab, existingTab.coordinator, existingTab.publisher)
            } else {
                let coordinator = NavigationCoordinator()
                let publisher = TabItemSelectedPublisher()
                return (newTab, coordinator, publisher)
            }
        }

        tabs = preservedTabs

        // Reset selected tab if it no longer exists
        if let selectedID = selectedTabID, !tabs.contains(where: { $0.item.id == selectedID }) {
            selectedTabID = tabs.first?.item.id
        }
    }

    private func buildTabs() -> [TabItem] {
        var tabItems: [TabItem] = []

        // Add Jellyfin tabs if JF session is active
        if sessionManager.hasJellyfinProvider {
            #if os(iOS)
            tabItems.append(TabItem.home)
            tabItems.append(TabItem.search)
            tabItems.append(TabItem.media)
            #else
            tabItems.append(TabItem.home)
            tabItems.append(TabItem.library(
                title: L10n.tvShows,
                systemName: "tv",
                filters: .init(itemTypes: [.series])
            ))
            tabItems.append(TabItem.library(
                title: L10n.movies,
                systemName: "film",
                filters: .init(itemTypes: [.movie])
            ))
            tabItems.append(TabItem.search)
            tabItems.append(TabItem.media)
            #endif
        }

        // Add Xtream tab if XC session is active
        if sessionManager.hasXtreamProvider {
            tabItems.append(TabItem.xtream)
        }

        // Always add settings on tvOS (if JF is active)
        #if !os(iOS)
        if sessionManager.hasJellyfinProvider {
            tabItems.append(TabItem.settings)
        }
        #endif

        return tabItems
    }
}