namespace Carbon.Json
{
  using System;
  using System.Collections.Generic;
  using System.Globalization;
  using System.Linq;

  public partial class JsonObject
  {
    public void SafeAdd(string name, Func<JsonNode> valueFn)
    {
      if (valueFn != null)
      {
        var value = valueFn();
        if (null != value)
        {
          items.Add(name, value);
        }
      }
    }

    public void SafeAdd(string name, JsonNode value)
    {
      if (null != value)
      {
        items.Add(name, value);
      }
    }

    public T NullableProperty<T>(string propertyName) where T : JsonNode
    {
      if (this.TryGetValue(propertyName, out JsonNode value))
      {
        if (value.IsNull)
        {
          return null;
        }
        if (value is T tval)
        {
          return tval;
        }
        /* it's present, but not the correct type...  */
        throw new Exception($"Property {propertyName} in object expected type {typeof(T).Name} but value of type {value.Type.ToString()} was found.");
      }
      return null;
    }

    public JsonObject Property(string propertyName)
    {
      return PropertyT<JsonObject>(propertyName);
    }

    public T PropertyT<T>(string propertyName) where T : JsonNode
    {
      if (this.TryGetValue(propertyName, out JsonNode value))
      {
        if (value.IsNull)
        {
          return null; // we're going to assume that the consumer knows what to do if null is explicity returned?
        }

        if (value is T tval)
        {
          return tval;
        }
        /* it's present, but not the correct type...  */
        throw new Exception($"Property {propertyName} in object expected type {typeof(T).Name} but value of type {value.Type.ToString()} was found.");
      }
      return null;
    }

    public int NumberProperty(string propertyName, ref int output) => output = this.PropertyT<JsonNumber>(propertyName)?.ToInt() ?? output;
    public float NumberProperty(string propertyName, ref float output) => output = this.PropertyT<JsonNumber>(propertyName)?.ToFloat() ?? output;
    public byte NumberProperty(string propertyName, ref byte output) => output = this.PropertyT<JsonNumber>(propertyName)?.ToByte() ?? output;
    public long NumberProperty(string propertyName, ref long output) => output = this.PropertyT<JsonNumber>(propertyName)?.ToLong() ?? output;
    public double NumberProperty(string propertyName, ref double output) => output = this.PropertyT<JsonNumber>(propertyName)?.ToDouble() ?? output;
    public decimal NumberProperty(string propertyName, ref decimal output) => output = this.PropertyT<JsonNumber>(propertyName)?.ToDecimal() ?? output;
    public short NumberProperty(string propertyName, ref short output) => output = this.PropertyT<JsonNumber>(propertyName)?.ToShort() ?? output;
    public DateTime NumberProperty(string propertyName, ref DateTime output) => output = this.PropertyT<JsonNumber>(propertyName)?.ToDateTime() ?? output;

    public int? NumberProperty(string propertyName, ref int? output) => output = this.NullableProperty<JsonNumber>(propertyName)?.ToInt() ?? null;
    public float? NumberProperty(string propertyName, ref float? output) => output = this.NullableProperty<JsonNumber>(propertyName)?.ToFloat() ?? null;
    public byte? NumberProperty(string propertyName, ref byte? output) => output = this.NullableProperty<JsonNumber>(propertyName)?.ToByte() ?? null;
    public long? NumberProperty(string propertyName, ref long? output) => output = this.NullableProperty<JsonNumber>(propertyName)?.ToLong() ?? null;
    public double? NumberProperty(string propertyName, ref double? output) => output = this.NullableProperty<JsonNumber>(propertyName)?.ToDouble() ?? null;
    public decimal? NumberProperty(string propertyName, ref decimal? output) => output = this.NullableProperty<JsonNumber>(propertyName)?.ToDecimal() ?? null;
    public short? NumberProperty(string propertyName, ref short? output) => output = this.NullableProperty<JsonNumber>(propertyName)?.ToShort() ?? null;

    public DateTime? NumberProperty(string propertyName, ref DateTime? output) => output = this.NullableProperty<JsonNumber>(propertyName)?.ToDateTime() ?? null;


    public string StringProperty(string propertyName) => this.PropertyT<JsonString>(propertyName)?.ToString();
    public string StringProperty(string propertyName, ref string output) => output = this.PropertyT<JsonString>(propertyName)?.ToString() ?? output;
    public char StringProperty(string propertyName, ref char output) => output = this.PropertyT<JsonString>(propertyName)?.ToChar() ?? output;
    public char? StringProperty(string propertyName, ref char? output) => output = this.PropertyT<JsonString>(propertyName)?.ToChar() ?? null;

    public DateTime StringProperty(string propertyName, ref DateTime output) => DateTime.TryParse(this.PropertyT<JsonString>(propertyName)?.ToString(), out output) ? output : output;
    public DateTime? StringProperty(string propertyName, ref DateTime? output) => output = DateTime.TryParse(this.PropertyT<JsonString>(propertyName)?.ToString(), out var o) ? o : output;


    public bool BooleanProperty(string propertyName, ref bool output) => output = this.PropertyT<JsonBoolean>(propertyName)?.ToBoolean() ?? output;
    public bool? BooleanProperty(string propertyName, ref bool? output) => output = this.PropertyT<JsonBoolean>(propertyName)?.ToBoolean() ?? null;

    public T[] ArrayProperty<T>(string propertyName, ref T[] output, Func<JsonNode, T> deserializer)
    {
      var array = this.PropertyT<JsonArray>(propertyName);
      if (array != null)
      {
        output = new T[array.Count];
        for (var i = 0; i < output.Length; i++)
        {
          output[i] = deserializer(array[i]);
        }
      }
      return output;
    }

    public Dictionary<string, T> DictionaryProperty<T>(string propertyName, ref Dictionary<string, T> output, Func<JsonNode, T> deserializer)
    {
      var dictionary = this.PropertyT<JsonObject>(propertyName);
      if (output == null)
      {
        output = new Dictionary<string, T>();
      }
      else
      {
        output.Clear();
      }
      if (dictionary != null)
      {
        foreach (var key in dictionary.Keys)
        {
          output[key] = deserializer(dictionary[key]);
        }
      }
      return output;
    }

    public static JsonObject Create<T>(IDictionary<string, T> source, Func<T, JsonNode> selector)
    {
      if (source == null || selector == null)
      {
        return null;
      }
      var result = new JsonObject();

      foreach (var key in source.Keys)
      {
        result.SafeAdd(key, selector(source[key]));
      }
      return result;
    }
  }

  public partial class JsonString
  {
    public static string DateFormat = "yyyy-MM-dd";
    public static string DateTimeFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss.FFFFFFFZ";
    public static string DateTimeRfc1123Format = "R";

    public static JsonString Create(string value) => value == null ? null : new JsonString(value);
    public static JsonString Create(char? value) => value is char c ? new JsonString(c.ToString()) : null;

    public static JsonString CreateDate(DateTime? value) => value is DateTime date ? new JsonString(date.ToString(DateFormat, CultureInfo.CurrentCulture)) : null;
    public static JsonString CreateDateTime(DateTime? value) => value is DateTime date ? new JsonString(date.ToString(DateTimeFormat, CultureInfo.CurrentCulture)) : null;
    public static JsonString CreateDateTimeRfc1123(DateTime? value) => value is DateTime date ? new JsonString(date.ToString(DateTimeRfc1123Format, CultureInfo.CurrentCulture)) : null;

    public char ToChar() => this.Value?.ToString()?.FirstOrDefault() ?? default(char);
    public static implicit operator char(JsonString value) => value?.ToString()?.FirstOrDefault() ?? default(char);
    public static implicit operator char? (JsonString value) => value?.ToString()?.FirstOrDefault();

    public static implicit operator DateTime(JsonString value) => DateTime.TryParse(value, out var output) ? output : default(DateTime);
    public static implicit operator DateTime? (JsonString value) => DateTime.TryParse(value, out var output) ? output : default(DateTime?);

  }
  public partial class JsonBoolean
  {
    public static JsonBoolean Create(bool? value) => value is bool b ? new JsonBoolean(b) : null;

  }
  public partial class JsonNumber
  {
    public static readonly DateTime EpochDate = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
    private static long ToUnixTime(DateTime dateTime)
    {
      return (long)dateTime.Subtract(EpochDate).TotalSeconds;
    }
    private static DateTime FromUnixTime(long totalSeconds)
    {
      return EpochDate.AddSeconds(totalSeconds);
    }

    public static JsonNumber Create(int? value) => value is int n ? new JsonNumber(n) : null;
    public static JsonNumber Create(long? value) => value is long n ? new JsonNumber(n) : null;
    public static JsonNumber Create(float? value) => value is float n ? new JsonNumber(n) : null;
    public static JsonNumber Create(double? value) => value is double n ? new JsonNumber(n) : null;
    public static JsonNumber Create(decimal? value) => value is decimal n ? new JsonNumber(n) : null;
    public static JsonNumber Create(DateTime? value) => value is DateTime date ? new JsonNumber(ToUnixTime(date)) : null;

    public static implicit operator DateTime(JsonNumber number) => FromUnixTime(number);
    public DateTime ToDateTime() => this;

    public JsonNumber(decimal value)
    {
      this.value = value.ToString();
    }
  }

  public partial class XNodeArray
  {
    public static XNodeArray Create<T>(T[] source, Func<T, JsonNode> selector)
    {
      if (source == null || selector == null)
      {
        return null;
      }
      var result = new XNodeArray();
      foreach (var item in source.Select(selector))
      {
        result.SafeAdd(item);
      }
      return result;
    }
    public void SafeAdd(JsonNode item)
    {
      if (item != null)
      {
        items.Add(item);
      }
    }
    public void SafeAdd(Func<JsonNode> itemFn)
    {
      if (itemFn != null)
      {
        var item = itemFn();
        if (item != null)
        {
          items.Add(item);
        }
      }
    }
  }


}