using System.Globalization;

using MeWeb.Core.Checks;

namespace MeWeb.App.Services;

public static class Texts
{
  public static string Summary(Finding finding) => finding?.Summary is null ? "" : Localizer.Instance.Format(finding.Summary, finding.Args.Select(Argument).ToArray());

  public static string Value(Fact fact)
  {
    if (fact.Text is not null) return Isolate(fact.Text);
    if (fact.Key is null) return fact.Date is null ? "" : Date(fact.Date);
    var args = fact.Amount is null ? fact.Args.Select(Argument).ToArray() : new object[] { Money(fact.Amount.Value, fact.Currency) };
    return Localizer.Instance.Format(fact.Key, args);
  }

  public static string Source(Fact fact)
  {
    var parts = new List<string>();
    if (fact.Basis is not null) parts.Add(Localizer.Instance[fact.Basis]);
    if (fact.Date is not null && fact.Key is not null) parts.Add(Date(fact.Date));
    return string.Join(", ", parts);
  }

  public static string Money(decimal amount, string currency)
  {
    var format = (NumberFormatInfo)Localizer.Instance.Culture.NumberFormat.Clone();
    format.CurrencySymbol = currency switch
    {
      "EUR" => "€",
      "USD" => "$",
      "GBP" => "£",
      _ => currency ?? "",
    };
    return amount.ToString("C2", format);
  }

  public static string Date(string text)
  {
    var culture = Localizer.Instance.Culture;
    if (DateTime.TryParseExact(text, "yyyy-MM-dd", CultureInfo.InvariantCulture, DateTimeStyles.None, out var day)) return day.ToString("d", culture);
    if (DateTime.TryParseExact(text, "yyyy-MM", CultureInfo.InvariantCulture, DateTimeStyles.None, out var month)) return month.ToString("Y", culture);
    return text;
  }

  public static string Isolate(string text) => string.IsNullOrEmpty(text) ? text : $"\u2068{text}\u2069";

  static object Argument(string text) =>
      DateTime.TryParseExact(text, "yyyy-MM-dd", CultureInfo.InvariantCulture, DateTimeStyles.None, out var day) ? day.ToString("d", Localizer.Instance.Culture) : text;
}