//
//  StorageService.swift
//  AutoCatCore
//
//  Created by Selim Mustafaev on 22.06.2024.
//  Copyright © 2024 Selim Mustafaev. All rights reserved.
//

import Foundation
import RealmSwift

public actor StorageService: StorageServiceProtocol {
    
    let settingsService: SettingsServiceProtocol
    
    var realm: Realm!
    
    public init(settingsService: SettingsServiceProtocol, isTest: Bool = false) async throws {
        
        self.settingsService = settingsService
        realm = try await setup(isTest: isTest)
    }
    
    // Swift 6.0 and 6.1 crashes if this code is placed directly into init
    private func setup(isTest: Bool) async throws -> Realm {
        
        var realmConfig: Realm.Configuration

        if isTest {
            realmConfig = .defaultConfiguration
            realmConfig.inMemoryIdentifier = UUID().uuidString
        } else {
            realmConfig = Realm.Configuration(
                schemaVersion: 42,
                migrationBlock: { migration, oldSchemaVersion in }
            )
        }

        return try await Realm.open(configuration: realmConfig)
    }
    
    public var dbFileURL: URL? {
        get async {
            realm.configuration.fileURL
        }
    }
    
    public var config: Realm.Configuration {
        realm.configuration
    }
    
    public func deleteAll() async throws {
        
        try await realm.asyncWrite {
            realm.deleteAll()
        }
    }
    
    @discardableResult
    public func updateVehicle(dto: VehicleDto, policy: DbUpdatePolicy) async throws -> Bool {
        
        let shouldUpdate = switch policy {
        case .always:
            true
        case .ifExists:
            realm.object(ofType: Vehicle.self, forPrimaryKey: dto.getNumber()) != nil
        }
        
        guard shouldUpdate else {
            return false
        }
        
        try await realm.asyncWrite {
            realm.add(Vehicle(dto: dto), update: .all)
        }
        
        return true
    }
    
    public func loadVehicle(number: String) async throws -> VehicleDto {
        
        if let vehicle = realm.object(ofType: Vehicle.self, forPrimaryKey: number) {
            return vehicle.dto
        } else {
            throw StorageError.vehicleNotFound
        }
    }
    
    public func loadVehicles() async -> [VehicleDto] {
        
        realm.objects(Vehicle.self)
            .sorted(byKeyPath: "updatedDate", ascending: false)
            .map(\.shallowDto)
    }
    
    public func deleteVehicle(number: String) async throws {
        guard let vehicle = realm.object(ofType: Vehicle.self, forPrimaryKey: number) else {
            throw StorageError.vehicleNotFound
        }
        
        try await realm.asyncWrite {
            realm.delete(vehicle)
        }
    }
}