import Foundation
import Logging
import Models
import MQTTNIO
import NIO

/// Sets up the application environment and connections required.
///
/// - Parameters:
///   - eventLoopGroup: The event loop group for the application.
///   - logger: An optional logger for debugging.
///   - autoConnect: A flag whether to auto-connect to the MQTT broker or not.
// public func bootstrap(
//   eventLoopGroup: EventLoopGroup,
//   logger: Logger? = nil,
//   autoConnect: Bool = true
// ) -> EventLoopFuture<DewPointEnvironment> {
//   logger?.debug("Bootstrapping Dew Point Controller...")
//
//   return loadEnvVars(eventLoopGroup: eventLoopGroup, logger: logger)
//     .and(loadTopics(eventLoopGroup: eventLoopGroup, logger: logger))
//     .makeDewPointEnvironment(eventLoopGroup: eventLoopGroup, logger: logger)
//     .connectToMQTTBroker(autoConnect: autoConnect, logger: logger)
// }
//
// /// Loads the ``EnvVars`` either using the defualts, from a file in the root directory under `.dewPoint-env` or in the shell / application environment.
// ///
// /// - Parameters:
// ///   - eventLoopGroup: The event loop group for the application.
// ///   - logger: An optional logger for debugging.
// private func loadEnvVars(
//   eventLoopGroup: EventLoopGroup,
//   logger: Logger?
// ) -> EventLoopFuture<EnvVars> {
//   logger?.debug("Loading env vars...")
//
//   // TODO: Need to have the env file path passed in / dynamic.
//   let envFilePath = URL(fileURLWithPath: #file)
//     .deletingLastPathComponent()
//     .deletingLastPathComponent()
//     .deletingLastPathComponent()
//     .appendingPathComponent(".dewPoint-env")
//
//   let decoder = JSONDecoder()
//   let encoder = JSONEncoder()
//
//   let defaultEnvVars = EnvVars()
//
//   let defaultEnvDict = (try? encoder.encode(defaultEnvVars))
//     .flatMap { try? decoder.decode([String: String].self, from: $0) }
//     ?? [:]
//
//   // Read from file `.dewPoint-env` file if it exists.
//   let localEnvVarsDict = (try? Data(contentsOf: envFilePath))
//     .flatMap { try? decoder.decode([String: String].self, from: $0) }
//     ?? [:]
//
//   // Merge with variables in the shell environment.
//   let envVarsDict = defaultEnvDict
//     .merging(localEnvVarsDict, uniquingKeysWith: { $1 })
//     .merging(ProcessInfo.processInfo.environment, uniquingKeysWith: { $1 })
//
//   // Produces the final env vars from the merged items or uses defaults if something
//   // went wrong.
//   let envVars = (try? JSONSerialization.data(withJSONObject: envVarsDict))
//     .flatMap { try? decoder.decode(EnvVars.self, from: $0) }
//     ?? defaultEnvVars
//
//   logger?.debug("Done loading env vars...")
//   return eventLoopGroup.next().makeSucceededFuture(envVars)
// }
//
// // MARK: TODO perhaps make loading from file an option passed in when app is launched.
//
// /// Load the topics from file in application root directory at `.topics`, if available or fall back to the defualt.
// ///
// ///  - Parameters:
// ///   - eventLoopGroup: The event loop group for the application.
// ///   - logger: An optional logger for debugging.
// private func loadTopics(eventLoopGroup: EventLoopGroup, logger: Logger?) -> EventLoopFuture<Topics> {
//   logger?.debug("Loading topics from file...")
//
//   let topicsFilePath = URL(fileURLWithPath: #file)
//     .deletingLastPathComponent()
//     .deletingLastPathComponent()
//     .deletingLastPathComponent()
//     .appendingPathComponent(".topics")
//
//   let decoder = JSONDecoder()
//
//   // Attempt to load the topics from file in root directory.
//   let localTopics = (try? Data(contentsOf: topicsFilePath))
//     .flatMap { try? decoder.decode(Topics.self, from: $0) }
//
//   logger?.debug(
//     localTopics == nil
//       ? "Failed to load topics from file, falling back to defaults."
//       : "Done loading topics from file."
//   )
//
//   // If we were able to load from file use that, else fallback to the defaults.
//   return eventLoopGroup.next().makeSucceededFuture(localTopics ?? .init())
// }
//
// private extension EventLoopFuture where Value == (EnvVars, Topics) {
//
//   /// Creates the ``DewPointEnvironment`` for the application after the ``EnvVars`` have been loaded.
//   ///
//   ///  - Parameters:
//   ///   - eventLoopGroup: The event loop group for the application.
//   ///   - logger: An optional logger for the application.
//   func makeDewPointEnvironment(
//     eventLoopGroup: EventLoopGroup,
//     logger: Logger?
//   ) -> EventLoopFuture<DewPointEnvironment> {
//     map { envVars, topics in
//       let mqttClient = MQTTClient(envVars: envVars, eventLoopGroup: eventLoopGroup, logger: logger)
//       return DewPointEnvironment(
//         envVars: envVars,
//         mqttClient: mqttClient,
//         topics: topics
//       )
//     }
//   }
// }
//
// private extension EventLoopFuture where Value == DewPointEnvironment {
//
//   /// Connects to the MQTT broker after the ``DewPointEnvironment`` has been setup.
//   ///
//   /// - Parameters:
//   ///   - logger: An optional logger for debugging.
//   func connectToMQTTBroker(autoConnect: Bool, logger: Logger?) -> EventLoopFuture<DewPointEnvironment> {
//     guard autoConnect else { return self }
//     return flatMap { environment in
//       logger?.debug("Connecting to MQTT Broker...")
//       return environment.mqttClient.connect()
//         .map { _ in
//           logger?.debug("Successfully connected to MQTT Broker...")
//           return environment
//         }
//     }
//   }
// }
//
// private extension MQTTNIO.MQTTClient {
//
//   convenience init(envVars: EnvVars, eventLoopGroup: EventLoopGroup, logger: Logger?) {
//     self.init(
//       host: envVars.host,
//       port: envVars.port != nil ? Int(envVars.port!) : nil,
//       identifier: envVars.identifier,
//       eventLoopGroupProvider: .shared(eventLoopGroup),
//       logger: logger,
//       configuration: .init(
//         version: .v5_0,
//         userName: envVars.userName,
//         password: envVars.password
//       )
//     )
//   }
// }