@_exported import CoreModels
import Dependencies
import DependenciesMacros
import Foundation

public extension DependencyValues {
  var locationClient: LocationClient {
    get { self[LocationClient.self] }
    set { self[LocationClient.self] = newValue }
  }
}

@DependencyClient
public struct LocationClient: Sendable {

  /// Estimate the climate zone by the heating design temperature and
  /// the state code (ex. "OH").
  public var estimatedClimateZone:
    @Sendable (_ heatingTemperature: Double, _ stateCode: String) async throws -> ClimateZone

  /// Estimate the design temperatures based on location's coordinates.
  public var estimatedDesignTemperatures: @Sendable (Coordinates) async throws -> DesignTemperatures

  /// Get location details from a zip code.
  public var search: @Sendable (_ zipCode: Int) async throws -> [Location]

  public func estimateDesignTemperaturesAndClimateZone(
    coordinates: Coordinates,
    stateCode: String
  ) async throws -> (DesignTemperatures, ClimateZone) {
    let designTemperatures = try await estimatedDesignTemperatures(coordinates)
    let climateZone = try await estimatedClimateZone(
      heatingTemperature: designTemperatures.heating,
      stateCode: stateCode
    )
    return (designTemperatures, climateZone)
  }

}

struct DecodingError: Error {}

extension LocationClient: TestDependencyKey {
  public static let testValue: LocationClient = Self()
}

// Intermediate response returned from 'https://app.zipcodebase.com'
private struct IntermediateResponse: Codable, Equatable, Sendable {

  let city: String
  let latitude: String
  let longitude: String
  let zipCode: String
  let state: String
  let stateCode: String
  let county: String

  func toLocation() throws -> Location {
    guard let longitude = Double(longitude), let latitude = Double(latitude) else {
      throw DecodingError()
    }
    return .init(
      city: city,
      state: state,
      stateCode: stateCode,
      zipCode: zipCode,
      county: county,
      coordinates: .init(latitude: latitude, longitude: longitude)
    )
  }

  private enum CodingKeys: String, CodingKey {
    case city
    case latitude
    case longitude
    case zipCode = "postal_code"
    case state
    case stateCode = "state_code"
    case county = "province"
  }
}

// TODO: Need to add climate zone 7 (-17).
private func estimatedHeatingTemperature(_ coordinates: Coordinates) -> Double {
  let latitude = coordinates.latitude
  let longitude = coordinates.longitude

  // Gulf coast region
  if latitude < 31, longitude > -95 && longitude < -89 {
    return 35
  }

  // Florida
  if latitude < 31, longitude > -87.5 && longitude < -80 {
    return 40
  }

  let absLat = abs(latitude)
  if absLat < 30 { return 35 }
  if absLat < 33 { return 30 }
  if absLat < 36 { return 25 }
  if absLat < 40 { return 15 }
  if absLat < 45 { return 5 }
  return 0
}

// TODO: Need to add climate zone 7 (89).
private func estimatedCoolingTemperature(_ coordinates: Coordinates) -> Double {
  let latitude = coordinates.latitude
  let longitude = coordinates.longitude

  // Gulf coast and Florida
  if latitude < 31, longitude > -95 && longitude < -80 {
    return 95
  }

  let absLat = abs(latitude)
  if absLat < 30 { return 95 }
  if absLat < 33 { return 92 }
  if absLat < 36 { return 90 }
  if absLat < 40 { return 90 }
  if absLat < 45 { return 88 }
  return 85
}

// TODO: Need to add climate zone 7.
private func determineClimateZone(heatingTemperature: Double, stateCode: String) -> ClimateZone {
  let hotHumidStates = ["FL", "LA", "TX", "MS", "AL", "GA", "SC"]
  if hotHumidStates.contains(stateCode.uppercased()) {
    return .two
  }

  if heatingTemperature >= 45 { return .one }
  if heatingTemperature >= 35 { return .two }
  if heatingTemperature >= 25 { return .three }
  if heatingTemperature >= 15 { return .four }
  if heatingTemperature >= 5 { return .five }
  return .six
}

#if DEBUG

  extension IntermediateResponse {
    static let mock = Self(
      city: "Monroe",
      latitude: "39.4413000",
      longitude: "-84.3652000",
      zipCode: "45050",
      state: "Ohio",
      stateCode: "OH",
      county: "Butler"
    )
  }
#endif