//
//  ActiveAppsTimelineProvider.swift
//  AltStore
//
//  Created by Magesh K on 10/01/25.
//  Copyright © 2025 SideStore. All rights reserved.
//

import WidgetKit

protocol WidgetInfo{
    var ID: Int? { get }
}

@available(iOS 17, *)
class ActiveAppsTimelineProvider<T:  WidgetInfo>: AppsTimelineProviderBase<WidgetInfo> {
    public struct WidgetData: WidgetInfo {
        let ID: Int?
    }

    private let defaultDataHolder = PaginationDataHolder(
        itemsPerPage: ActiveAppsWidget.Constants.MAX_ROWS_PER_PAGE
    )
    
    let widgetKind: String
    
    init(widgetKind: String){
        self.widgetKind = widgetKind
    }
    
    deinit{
        // if this provider goes out of scope, clear all entries
        PageInfoManager.shared.clearAll()
    }
    
    override func getUpdatedData(_ apps: [AppSnapshot], _ context: WidgetInfo?) -> [AppSnapshot] {
        var apps = apps
        
        // if simulator, get the 10 simulated entries based on first entry
        #if targetEnvironment(simulator)
        apps = getSimulatedData(apps: apps)
        #endif
        
        // always first page since this is never updated
        var currentPageApps = defaultDataHolder.currentPage(inItems: apps)

        guard let widgetInfo = context,
              let widgetID = widgetInfo.ID else
        {
            return currentPageApps
        }
        
        let navEvent = getPageInfo(widgetID: widgetID)
        guard var navEvent = navEvent,
              let direction = navEvent.direction else
        {
            // when widget is edited for new ID than the current,
            // buttons were never triggered for this ID,
            // hence nav-event or direction wasn't set yet
            updatePageInfo(
                widgetID: widgetID,
                navEvent: NavigationEvent(direction: nil, consumed: true, dataHolder: PaginationDataHolder(other: defaultDataHolder))
            )
            return currentPageApps
        }

        let dataHolder = navEvent.dataHolder!

        // process navigation request only if event wasn't consumed yet
        if !navEvent.consumed {
            switch (direction){
                case Direction.up:
                    currentPageApps = dataHolder.prevPage(inItems: apps, whenUnavailable: .current)!
                case Direction.down:
                    currentPageApps = dataHolder.nextPage(inItems: apps, whenUnavailable: .current)!
            }
            // mark the event as consumed
            // this prevents duplicate getUpdatedData() requests for same navigation event
            navEvent.consumed = true
        }else{
            // since the event was consumed, get the current page as-is for this dataholder
            currentPageApps = dataHolder.currentPage(inItems: apps)
        }
        
        // put back the data
        updatePageInfo(widgetID: widgetID, navEvent: navEvent)
        return currentPageApps
    }
    
    
    private func getPageInfo(widgetID: Int) -> NavigationEvent?{
        return PageInfoManager.shared.getPageInfo(forWidgetKind: widgetKind, forWidgetID: widgetID)
    }

    private func updatePageInfo(widgetID: Int, navEvent: NavigationEvent?) {
        PageInfoManager.shared.setPageInfo(forWidgetKind: widgetKind, forWidgetID: widgetID, value: navEvent)
    }
}

/// TimelineProvider for WidgetAppIntentConfiguration widget type
@available(iOS 17, *)
extension ActiveAppsTimelineProvider: AppIntentTimelineProvider {
    
    typealias Intent = WidgetUpdateIntent

    func snapshot(for intent: Intent, in context: Context) async -> AppsEntry<WidgetInfo> {
        // system retains the previously configured ID value and posts the same here
        let widgetData = WidgetData(ID: intent.ID)
        
        let bundleIDs = await super.fetchActiveAppBundleIDs()
        let snapshot = await self.snapshot(for: bundleIDs, in: widgetData)
        
        return snapshot
    }
    
    func timeline(for intent: Intent, in context: Context) async -> Timeline<AppsEntry<WidgetInfo>> {
        // system retains the previously configured ID value and posts the same here
        let widgetData = WidgetData(ID: intent.ID)

        let bundleIDs = await self.fetchActiveAppBundleIDs()
        let timeline = await self.timeline(for: bundleIDs, in: widgetData)

        return timeline
    }
}