using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using HEAL.Attic;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Optimization;
using Newtonsoft.Json.Linq;

namespace HeuristicLab.JsonInterface {
  /// <summary>
  /// Static class to instantiate an IAlgorithm object with a json interface template and config.
  /// </summary>
  public static class JsonTemplateInstantiator {
    private struct InstData {
      public JToken Template { get; set; }
      public JArray Config { get; set; }
      public IDictionary<string, JsonItem> Objects { get; set; }
    }

    /// <summary>
    /// Instantiate an IAlgorithm object with a template and config.
    /// </summary>
    /// <param name="templateFile">Template file (json), generated with JCGenerator.</param>
    /// <param name="configFile">Config file (json) for the template.</param>
    /// <returns>confugrated IOptimizer object</returns>
    public static IOptimizer Instantiate(string templateFile, string configFile = "") {
      InstData instData = new InstData() {
        Objects = new Dictionary<string, JsonItem>()
      };

      // parse template and config files
      instData.Template = JToken.Parse(File.ReadAllText(templateFile));
      if(!string.IsNullOrEmpty(configFile))
        instData.Config = JArray.Parse(File.ReadAllText(configFile));

      // extract metadata information
      string optimizerName = instData.Template[Constants.Metadata][Constants.Optimizer].ToString();
      string hLFileLocation = instData.Template[Constants.Metadata][Constants.HLFileLocation].ToString();

      // deserialize hl file
      ProtoBufSerializer serializer = new ProtoBufSerializer();
      IOptimizer optimizer = (IOptimizer)serializer.Deserialize(hLFileLocation);

      // collect all parameterizedItems from template
      CollectParameterizedItems(instData);
      
      // if config != null -> merge Template and Config 
      if (instData.Config != null)
        MergeTemplateWithConfig(instData);

      // get algorthm data and object
      JsonItem optimizerData = instData.Objects[optimizerName];

      // inject configuration
      JsonItemConverter.Inject(optimizer, optimizerData);

      return optimizer;
    }

    #region Helper
    private static void CollectParameterizedItems(InstData instData) {
      foreach (JObject item in instData.Template[Constants.Parameters]) {
        string[] pathParts = item.Property("Path").Value.ToString().Split('.');
        
        // rebuilds object tree
        JsonItem parent = null;
        StringBuilder partialPath = new StringBuilder();
        for(int i = 0; i < pathParts.Length-1; ++i) {
          partialPath.Append(pathParts[i]);
          JsonItem tmp = null;
          if (instData.Objects.TryGetValue(partialPath.ToString(), out JsonItem value)) {
            tmp = value;
          } else {
            tmp = new JsonItem() { Name = pathParts[i] };
            if (parent != null) parent.AddChilds(tmp);
            instData.Objects.Add(partialPath.ToString(), tmp);
          }
          partialPath.Append(".");
          parent = tmp;
        }

        JsonItem data = JsonItem.BuildJsonItem(item);
        parent.AddChilds(data);
        instData.Objects.Add(data.Path, data);
      }
    }
    
    private static void MergeTemplateWithConfig(InstData instData) {
      foreach (JObject obj in instData.Config) {
        // build item from config object
        JsonItem item = JsonItem.BuildJsonItem(obj);
        // override default value
        if (instData.Objects.TryGetValue(item.Path, out JsonItem param)) {
          param.Value = item.Value;
          // override ActualName (for LookupParameters)
          if (param.ActualName != null)
            param.ActualName = item.ActualName;
        } else throw new InvalidDataException($"No parameter with path='{item.Path}' defined!");
      }
    }

    private static JsonItem GetData(string key, InstData instData)
    {
      if (instData.Objects.TryGetValue(key, out JsonItem value))
        return value;
      else
        throw new InvalidDataException($"Type of item '{key}' is not defined!");
    }
    #endregion
  }
}