import CoreData
import Foundation
import Swinject

protocol DeterminationStorage {
    func fetchLastDeterminationObjectID(predicate: NSPredicate) async -> [NSManagedObjectID]
    func getForecastIDs(for determinationID: NSManagedObjectID, in context: NSManagedObjectContext) async -> [NSManagedObjectID]
    func getForecastValueIDs(for forecastID: NSManagedObjectID, in context: NSManagedObjectContext) async -> [NSManagedObjectID]
    func getOrefDeterminationNotYetUploadedToNightscout(_ determinationIds: [NSManagedObjectID]) async -> Determination?
}

final class BaseDeterminationStorage: DeterminationStorage, Injectable {
    private let viewContext = CoreDataStack.shared.persistentContainer.viewContext
    private let backgroundContext = CoreDataStack.shared.newTaskContext()

    init(resolver: Resolver) {
        injectServices(resolver)
    }

    func fetchLastDeterminationObjectID(predicate: NSPredicate) async -> [NSManagedObjectID] {
        let results = await CoreDataStack.shared.fetchEntitiesAsync(
            ofType: OrefDetermination.self,
            onContext: backgroundContext,
            predicate: predicate,
            key: "deliverAt",
            ascending: false,
            fetchLimit: 1
        )
        return await backgroundContext.perform {
            results.map(\.objectID)
        }
    }

    func getForecastIDs(for determinationID: NSManagedObjectID, in context: NSManagedObjectContext) async -> [NSManagedObjectID] {
        await context.perform {
            do {
                guard let determination = try context.existingObject(with: determinationID) as? OrefDetermination,
                      let forecastSet = determination.forecasts as? Set<NSManagedObject>
                else {
                    return []
                }
                let forecasts = Array(forecastSet)
                return forecasts.map(\.objectID) as [NSManagedObjectID]
            } catch {
                debugPrint(
                    "Failed \(DebuggingIdentifiers.failed) to fetch Forecast IDs for OrefDetermination with ID \(determinationID): \(error.localizedDescription)"
                )
                return []
            }
        }
    }

    func getForecastValueIDs(for forecastID: NSManagedObjectID, in context: NSManagedObjectContext) async -> [NSManagedObjectID] {
        await context.perform {
            do {
                guard let forecast = try context.existingObject(with: forecastID) as? Forecast,
                      let forecastValueSet = forecast.forecastValues
                else {
                    return []
                }
                let forecastValues = forecastValueSet.sorted(by: { $0.index < $1.index })
                return forecastValues.map(\.objectID)
            } catch {
                debugPrint(
                    "Failed \(DebuggingIdentifiers.failed) to fetch Forecast Value IDs with ID \(forecastID): \(error.localizedDescription)"
                )
                return []
            }
        }
    }

    // Convert NSDecimalNumber to Decimal
    func decimal(from nsDecimalNumber: NSDecimalNumber?) -> Decimal {
        nsDecimalNumber?.decimalValue ?? 0.0
    }

    // Convert NSSet to array of Ints for Predictions
    func parseForecastValues(ofType _: String, from determinationID: NSManagedObjectID) async -> [Int]? {
        let forecastIDs = await getForecastIDs(for: determinationID, in: backgroundContext)

        var forecastValuesList: [Int] = []

        for forecastID in forecastIDs {
            let forecastValueIDs = await getForecastValueIDs(for: forecastID, in: backgroundContext)

            await backgroundContext.perform {
                for forecastValueID in forecastValueIDs {
                    if let forecastValue = try? self.backgroundContext.existingObject(with: forecastValueID) as? ForecastValue {
                        let forecastValueInt = Int(forecastValue.value)
                        forecastValuesList.append(forecastValueInt)
                    }
                }
            }
        }

        return forecastValuesList
    }

    func getOrefDeterminationNotYetUploadedToNightscout(_ determinationIds: [NSManagedObjectID]) async -> Determination? {
        var result: Determination?

        guard let determinationId = determinationIds.first else {
            print("No determination ID found.")
            return nil
        }

        print("Using context: \(backgroundContext)")
        print("Determination ID: \(determinationId)")

        let predictions = Predictions(
            iob: await parseForecastValues(ofType: "iob", from: determinationId),
            zt: await parseForecastValues(ofType: "zt", from: determinationId),
            cob: await parseForecastValues(ofType: "cob", from: determinationId),
            uam: await parseForecastValues(ofType: "uam", from: determinationId)
        )

        return await backgroundContext.perform {
            do {
                let orefDetermination = try self.backgroundContext.existingObject(with: determinationId) as? OrefDetermination

                // Log the type of the fetched object
                print("Fetched object type: \(type(of: orefDetermination))")
                print("Fetched object description: \(orefDetermination)")

                // Check if the fetched object is of the expected type
                if let orefDetermination = orefDetermination {
                    print("Successfully cast to OrefDetermination")
                    let forecastSet = orefDetermination.forecasts
                    print("Fetched forecast set: \(forecastSet)")

                    result = Determination(
                        id: orefDetermination.id ?? UUID(),
                        reason: orefDetermination.reason ?? "",
                        units: orefDetermination.smbToDeliver as Decimal?,
                        insulinReq: self.decimal(from: orefDetermination.insulinReq),
                        eventualBG: orefDetermination.eventualBG as? Int,
                        sensitivityRatio: self.decimal(from: orefDetermination.sensitivityRatio),
                        rate: self.decimal(from: orefDetermination.rate),
                        duration: self.decimal(from: orefDetermination.duration),
                        iob: self.decimal(from: orefDetermination.iob),
                        cob: orefDetermination.cob != 0 ? Decimal(orefDetermination.cob) : nil,
                        predictions: predictions,
                        deliverAt: orefDetermination.deliverAt,
                        carbsReq: orefDetermination.carbsRequired != 0 ? Decimal(orefDetermination.carbsRequired) : nil,
                        temp: TempType(rawValue: orefDetermination.temp ?? "absolute"),
                        bg: self.decimal(from: orefDetermination.glucose),
                        reservoir: self.decimal(from: orefDetermination.reservoir),
                        isf: self.decimal(from: orefDetermination.insulinSensitivity),
                        timestamp: orefDetermination.timestamp,
                        tdd: self.decimal(from: orefDetermination.totalDailyDose),
                        insulin: nil,
                        current_target: self.decimal(from: orefDetermination.currentTarget),
                        insulinForManualBolus: self.decimal(from: orefDetermination.insulinForManualBolus),
                        manualBolusErrorString: self.decimal(from: orefDetermination.manualBolusErrorString),
                        minDelta: self.decimal(from: orefDetermination.minDelta),
                        expectedDelta: self.decimal(from: orefDetermination.expectedDelta),
                        minGuardBG: nil,
                        minPredBG: nil,
                        threshold: self.decimal(from: orefDetermination.threshold),
                        carbRatio: self.decimal(from: orefDetermination.carbRatio),
                        received: orefDetermination.enacted // this is actually part of NS...
                    )
                } else {
                    print("Fetched object is not of type OrefDetermination")
                }
            } catch {
                print("Failed to fetch managed object: \(error)")
            }

            return result
        }
    }
}