using System.Collections.Generic;
using System.Linq;
using System.Text;
using System;

namespace Swan.Formatters {
  internal class HumanizeJson {
    private readonly StringBuilder _builder = new StringBuilder();
    private readonly Int32 _indent;
    private readonly String _indentStr;
    private readonly Object _obj;

    public HumanizeJson(Object obj, Int32 indent) {
      if(obj == null) {
        return;
      }

      this._indent = indent;
      this._indentStr = new String(' ', indent * 4);
      this._obj = obj;

      this.ParseObject();
    }

    public String GetResult() => this._builder == null ? String.Empty : this._builder.ToString().TrimEnd();

    private void ParseObject() {
      switch(this._obj) {
        case Dictionary<String, Object> dictionary:
          this.AppendDictionary(dictionary);
          break;
        case List<Object> list:
          this.AppendList(list);
          break;
        default:
          this.AppendString();
          break;
      }
    }

    private void AppendDictionary(Dictionary<String, Object> objects) {
      foreach(KeyValuePair<String, Object> kvp in objects) {
        if(kvp.Value == null) {
          continue;
        }

        Boolean writeOutput = false;

        switch(kvp.Value) {
          case Dictionary<String, Object> valueDictionary:
            if(valueDictionary.Count > 0) {
              writeOutput = true;
              _ = this._builder.Append($"{this._indentStr}{kvp.Key,-16}: object").AppendLine();
            }

            break;
          case List<Object> valueList:
            if(valueList.Count > 0) {
              writeOutput = true;
              _ = this._builder.Append($"{this._indentStr}{kvp.Key,-16}: array[{valueList.Count}]").AppendLine();
            }

            break;
          default:
            writeOutput = true;
            _ = this._builder.Append($"{this._indentStr}{kvp.Key,-16}: ");
            break;
        }

        if(writeOutput) {
          _ = this._builder.AppendLine(new HumanizeJson(kvp.Value, this._indent + 1).GetResult());
        }
      }
    }

    private void AppendList(List<Object> objects) {
      Int32 index = 0;
      foreach(Object value in objects) {
        Boolean writeOutput = false;

        switch(value) {
          case Dictionary<String, Object> valueDictionary:
            if(valueDictionary.Count > 0) {
              writeOutput = true;
              _ = this._builder.Append($"{this._indentStr}[{index}]: object").AppendLine();
            }

            break;
          case List<Object> valueList:
            if(valueList.Count > 0) {
              writeOutput = true;
              _ = this._builder.Append($"{this._indentStr}[{index}]: array[{valueList.Count}]").AppendLine();
            }

            break;
          default:
            writeOutput = true;
            _ = this._builder.Append($"{this._indentStr}[{index}]: ");
            break;
        }

        index++;

        if(writeOutput) {
          _ = this._builder.AppendLine(new HumanizeJson(value, this._indent + 1).GetResult());
        }
      }
    }

    private void AppendString() {
      String stringValue = this._obj.ToString();

      if(stringValue.Length + this._indentStr.Length > 96 || stringValue.IndexOf('\r') >= 0 ||
          stringValue.IndexOf('\n') >= 0) {
        _ = this._builder.AppendLine();
        IEnumerable<String> stringLines = stringValue.ToLines().Select(l => l.Trim());

        foreach(String line in stringLines) {
          _ = this._builder.AppendLine($"{this._indentStr}{line}");
        }
      } else {
        _ = this._builder.Append($"{stringValue}");
      }
    }
  }
}