WeatherService.cs

using Ardalis.Result.Sample.Core.DTOs;
using Ardalis.Result.Sample.Core.Model;
using Microsoft.Extensions.Localization;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Ardalis.Result.Sample.Core.Services
{
    public class WeatherService
    {
        public WeatherService(IStringLocalizer<WeatherService> stringLocalizer)
        {
            _stringLocalizer = stringLocalizer;
        }
        private static readonly string[] Summaries = new[]
        {
            "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
        };

        private IStringLocalizer<WeatherService> _stringLocalizer;

        public Task<Result<IEnumerable<WeatherForecast>>> GetForecastAsync(ForecastRequestDto model)
        {
            return Task.FromResult(GetForecast(model));
        }

        public Result<IEnumerable<WeatherForecast>> GetForecast(ForecastRequestDto model)
        {
            switch (model.PostalCode)
            {
                case "NotFound":
                    return Result.NotFound();
                case "Conflict":
                    return Result.Conflict();
            }

            // validate model
            if (model.PostalCode.Length > 10)
            {
                return Result.Invalid(new List<ValidationError> {
                    new ValidationError
                    {
                        Identifier = nameof(model.PostalCode),
                        ErrorMessage = _stringLocalizer["PostalCode cannot exceed 10 characters."].Value }
                });
            }

            if (string.IsNullOrWhiteSpace(model.PostalCode))
            {
                return Result.Invalid(new List<ValidationError> {
                    new ValidationError
                    {
                        Identifier = nameof(model.PostalCode),
                        ErrorMessage = "PostalCode is required" }
                    });
            }

            // test value
            if (model.PostalCode == "55555")
            {
                return Result.Success(Enumerable.Range(1, 1)
                    .Select(index =>
                    new WeatherForecast
                    {
                        Date = DateTime.Now,
                        TemperatureC = 0,
                        Summary = Summaries[0]
                    }));
            }

            var rng = new Random();
            return Result.Success<IEnumerable<WeatherForecast>>(Enumerable.Range(1, 5)
                .Select(index => new WeatherForecast
                {
                    Date = DateTime.Now.AddDays(index),
                    TemperatureC = rng.Next(-20, 55),
                    Summary = Summaries[rng.Next(Summaries.Length)]
                })
            .ToArray());
        }

        public Result<WeatherForecast> GetSingleForecast(ForecastRequestDto model)
        {
            switch (model.PostalCode)
            {
                case "NotFound":
                    return Result.NotFound();
                case "Conflict":
                    return Result.Conflict();
            }

            // validate model
            if (model.PostalCode.Length > 10)
            {
                return Result.Invalid(new List<ValidationError> {
                    new ValidationError
                    {
                        Identifier = nameof(model.PostalCode),
                        ErrorMessage = _stringLocalizer["PostalCode cannot exceed 10 characters."].Value }
                });
            }

            // test value
            if (model.PostalCode == "55555")
            {
                return Result.Success(
                    new WeatherForecast
                    {
                        Date = DateTime.Now,
                        TemperatureC = 0,
                        Summary = Summaries[0]
                    });
            }

            var rng = new Random();
            return Result.Success(new WeatherForecast
            {
                Date = DateTime.Now.AddDays(rng.Next(1, 5)),
                TemperatureC = rng.Next(-20, 55),
                Summary = Summaries[rng.Next(Summaries.Length)]
            });
        }
    }
}