//
//  BGTask.swift
//  Reflect (iOS)
//
//  Created by Trey Tartt on 1/12/22.
//

import Foundation
import BackgroundTasks

class BGTask {
    static let updateDBMissingID = "com.88oakapps.reflect.dbUpdateMissing"
    static let weatherRetryID = "com.88oakapps.reflect.weatherRetry"
    static let weeklyDigestID = "com.88oakapps.reflect.weeklyDigest"

    @MainActor
    class func runFillInMissingDatesTask(task: BGProcessingTask) {
        BGTask.scheduleBackgroundProcessing()

        task.expirationHandler = {
            task.setTaskCompleted(success: false)
        }

        DataController.shared.fillInMissingDates()

        // Catch up on any side effects from widget/watch votes
        MoodLogger.shared.processPendingSideEffects()

        task.setTaskCompleted(success: true)
    }
    
    @MainActor
    class func runWeatherRetryTask(task: BGProcessingTask) {
        BGTask.scheduleWeatherRetry()

        task.expirationHandler = {
            task.setTaskCompleted(success: false)
        }

        Task {
            await WeatherManager.shared.retryPendingWeatherFetches()
            task.setTaskCompleted(success: true)
        }
    }

    class func scheduleWeatherRetry() {
        let request = BGProcessingTaskRequest(identifier: BGTask.weatherRetryID)
        request.requiresNetworkConnectivity = true
        request.requiresExternalPower = false
        request.earliestBeginDate = Date(timeIntervalSinceNow: 15 * 60)

        do {
            try BGTaskScheduler.shared.submit(request)
        } catch {
            print("Could not schedule weather retry: \(error)")
        }
    }

    @MainActor
    class func runWeeklyDigestTask(task: BGProcessingTask) {
        BGTask.scheduleWeeklyDigest()

        task.expirationHandler = {
            task.setTaskCompleted(success: false)
        }

        if #available(iOS 26, *) {
            Task {
                guard !IAPManager.shared.shouldShowPaywall else {
                    task.setTaskCompleted(success: true)
                    return
                }

                do {
                    let digest = try await FoundationModelsDigestService.shared.generateWeeklyDigest()

                    // Send local notification with the headline
                    let personalityPack = UserDefaultsStore.personalityPackable()
                    LocalNotification.scheduleDigestNotification(headline: digest.headline, personalityPack: personalityPack)

                    task.setTaskCompleted(success: true)
                } catch {
                    print("Weekly digest generation failed: \(error)")
                    task.setTaskCompleted(success: false)
                }
            }
        } else {
            task.setTaskCompleted(success: true)
        }
    }

    class func scheduleWeeklyDigest() {
        let request = BGProcessingTaskRequest(identifier: BGTask.weeklyDigestID)
        request.requiresNetworkConnectivity = false
        request.requiresExternalPower = false

        // Schedule for next Sunday at 7 PM
        let calendar = Calendar.current
        var components = calendar.dateComponents([.yearForWeekOfYear, .weekOfYear], from: Date())
        components.weekday = 1 // Sunday
        components.hour = 19
        components.minute = 0

        var nextSunday = calendar.date(from: components) ?? Date()
        if nextSunday <= Date() {
            nextSunday = calendar.date(byAdding: .weekOfYear, value: 1, to: nextSunday)!
        }

        request.earliestBeginDate = nextSunday

        do {
            try BGTaskScheduler.shared.submit(request)
        } catch {
            print("Could not schedule weekly digest: \(error)")
        }
    }

    class func scheduleBackgroundProcessing() {
        let request = BGProcessingTaskRequest(identifier: BGTask.updateDBMissingID)
        request.requiresNetworkConnectivity = false
        request.requiresExternalPower = false
        
        var runDate = Calendar.current.date(byAdding: .day, value: 1, to: Date())
        runDate = Calendar.current.date(bySettingHour: 0, minute: 1, second: 0, of: runDate!)
        request.earliestBeginDate = runDate
        
        do {
            try BGTaskScheduler.shared.submit(request)
        } catch {
            print("Could not schedule image fetch: \(error)")
        }
    }
}