using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Xml;
using System.Globalization;
using System.Xml.Linq;
using HeuristicLab.Services.Optimization.ControllerService.Azure;
using HeuristicLab.Services.Optimization.ControllerService.Interfaces;
using System.Diagnostics;

namespace HeuristicLab.Services.Optimization.ControllerService {
  public class ScenarioParser {
    private static IList<Model.OptimizationScenario> scenarios;
    private static object lockable = new object();

    private IDataAccessLayer dal = DataAccessLayerProvider.GetLayer();

    public IList<Model.OptimizationScenario> Scenarios {
      get {
        if (scenarios == null) {
          lock (lockable) {
            if (scenarios == null) {
              ParseScenarios();
            }
          }
        }
        return scenarios;
      }
    }
    
    public Model.OptimizationScenario GetByName(string name) {
      foreach (var scen in Scenarios) {
        if (scen.Id == name) {
          return scen;
        }
      }
      return null;
    }

    /*// http://www.sascha-dittmann.de/post/Webseitenpfade-einer-Windows-Azure-Web-Rolle-bestimmen.aspx
    private static IEnumerable<string> WebSiteDirectories {
      get {
        var roleRootDir = Environment.GetEnvironmentVariable("RdRoleRoot");
        if (roleRootDir == null)
          return Enumerable.Empty<string>();
        XNamespace roleModelNs =
          "http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition";
        var roleModelDoc = XDocument.Load(Path.Combine(roleRootDir, "RoleModel.xml"));
        if (roleModelDoc.Root == null)
          return Enumerable.Empty<string>();

        var sites = roleModelDoc.Root.Element(roleModelNs + "Sites");
        if (sites == null)
          return Enumerable.Empty<string>();

        var siteElements = sites.Elements(roleModelNs + "Site");

        return
          from siteElement in siteElements
          where siteElement.Attribute("name") != null
                && siteElement.Attribute("name").Value == "Web"
                && siteElement.Attribute("physicalDirectory") != null
          select Path.Combine(roleRootDir,
                 siteElement.Attribute("physicalDirectory").Value);
      }
    }
     */

    private void ParseScenarios() {
      var scens = new List<Model.OptimizationScenario>();
      /*string path;
      if (WebSiteDirectories.Count() != 0) {
        path = WebSiteDirectories.FirstOrDefault() + @"\Mappings";
      } else {
        path = AppDomain.CurrentDomain.BaseDirectory + @"\Mappings";
      }
        
      foreach (var file in Directory.EnumerateFiles(path, "*.xml")) {
        var scenario = ParseScenarioFromFile(file);
        if (scenario != null)
          scens.Add(scenario);
      }*/

      var scenarioDao = dal.ScenarioDao;
      var blobDao = dal.BlobDao;
      foreach (var entity in scenarioDao.GetAllEntities()) {
        var scenarioXml = blobDao.FindByKey(entity.Scenario).Text;
        var scenario = ParseScenarioFromXml(scenarioXml);
        if (scenario != null)
          scens.Add(scenario);
      }

      scenarios = scens;
    }

    private XmlReaderSettings GetSettings() {
      // Set the validation settings.
      XmlReaderSettings settings = new XmlReaderSettings();
      settings.ValidationType = ValidationType.Schema;
      settings.Schemas.Add("urn:scenario-schema", AppDomain.CurrentDomain.BaseDirectory + @"\Mappings\scenario.xsd");      
      return settings;
    }

    public Model.OptimizationScenario ParseScenarioFromXml(string xml) {
      //using (var reader = XmlReader.Create(new StringReader(xml), GetSettings())) {
        return ParseScenario(new StringReader(xml));
      //}            
    }

   /* private Model.OptimizationScenario ParseScenarioFromFile(string filename) {
      using (var reader = XmlReader.Create(new FileStream(filename, FileMode.Open), GetSettings())) {
        return ParseScenario(reader);
      }      
    } */

    private Model.Problem ParseProblem(XmlReader reader) {
      var problem = new Model.Problem();
      while (reader.Read()) {
        if (reader.NodeType == XmlNodeType.EndElement)
          break;
        if (reader.Name == "parameters")
          problem.Parameters.Items = ParseParameters(reader);
      }
      return problem;
    }

    private void ParseAlgorithms(out IList<Model.Algorithm> algos, XmlReader reader) {
      algos = new List<Model.Algorithm>();
      var depth = reader.Depth;
      do {
        if (reader.Name == "algorithm" && reader.Depth == depth) {
          var innerAlg = new Model.Algorithm();
          algos.Add(innerAlg);
          
          innerAlg.Mapper = reader.GetAttribute("mapper");
          reader.Read();
          for (;;) {
            if (reader.Name == "algorithm" && reader.NodeType == XmlNodeType.EndElement)
              break;

            if (reader.Name == "parameters" && reader.NodeType == XmlNodeType.Element) {
              innerAlg.Parameters.Items = ParseParameters(reader);
              continue;
            }
            else if (reader.Name == "problem" && reader.NodeType == XmlNodeType.Element) {
              innerAlg.Problem = ParseProblem(reader);
              continue;
            }
            else if (reader.Name == "algorithm" && reader.NodeType == XmlNodeType.Element) {
              IList<Model.Algorithm> childAlgos;
              ParseAlgorithms(out childAlgos, reader);
              innerAlg.ChildAlgorithms = childAlgos;
              //TODO: Test with child algorithms
              continue;
            }
            reader.Read();
          }
        }
      } while (reader.Read() && reader.Depth >= depth);
    }

    private Model.OptimizationScenario ParseScenarioElement(XmlReader reader) {
      var scenario = new Model.OptimizationScenario();
      var depth = reader.Depth;
      while (reader.Depth >= depth) {
        if (reader.Name == "scenario" && reader.NodeType == XmlNodeType.EndElement)
          break;

        if (reader.Name == "name") {
          scenario.Id = reader.ReadElementContentAsString();
          continue;
        }
        else if (reader.Name == "algorithm") {
          IList<Model.Algorithm> algos;
          ParseAlgorithms(out algos, reader);
          scenario.Algorithm = algos;
          continue;
        }
        reader.Read();
      }
      return scenario;
    }

    private Model.OptimizationScenario ParseScenario(StringReader str) {
      // Set the validation settings.      
      bool isErrorPresent = false;
      var settings = GetSettings();
      settings.ValidationEventHandler += (sender, args) => {
        Trace.WriteLine(args.Message);
        isErrorPresent = true;
      };
      Model.OptimizationScenario scenario = null;      
      using (var reader = XmlReader.Create(str, settings)) {        
        while (!reader.EOF) {
          if (reader.Name == "scenario" && reader.NodeType == XmlNodeType.Element) {
            scenario = ParseScenarioElement(reader);            
          }
          reader.Read();
        }
      }
      
      if (isErrorPresent)
        return null;
      return scenario;
    }

    struct ValueEntry {
      public double v1;
      public double v2;
    };

    private void ParseDecimalMatrix(Model.DecimalMatrix matrix, XmlReader reader) {      
      IList<ValueEntry> ventries = new List<ValueEntry>();
      while (reader.Read()) {        
        if (reader.Name == "param")
          break;
        if (reader.Name == "value") {
          var val1 = Convert.ToDouble(reader.GetAttribute("v1"), CultureInfo.InvariantCulture.NumberFormat);
          var val2 = Convert.ToDouble(reader.GetAttribute("v2"), CultureInfo.InvariantCulture.NumberFormat);
          ventries.Add(new ValueEntry() { v1 = val1, v2 = val2 });          
        }
      }
      double[][] mat = new double[ventries.Count][];
      int i=0;
      foreach (var entry in ventries) {
        mat[i] = new double[2];
        mat[i][0] = entry.v1;
        mat[i][1] = entry.v2;
        i++;
      }
      matrix.Value = mat;
    }

    private IList<Model.Parameter> ParseParameters(XmlReader reader) {
      IList<Model.Parameter> parameters = new List<Model.Parameter>();
      while (reader.Read()) {
        if (reader.Name == "parameters" && reader.NodeType == XmlNodeType.EndElement)
          break;
        // parse parameter
        if (reader.Name == "param" && reader.NodeType == XmlNodeType.Element) {
          var param = new Model.Parameter();
          var typeAtt = reader.GetAttribute("type");
          param.Type = (Model.ParameterType)Enum.Parse(typeof(Model.ParameterType), typeAtt);
          switch (param.Type) {
            case Model.ParameterType.Boolean:
              param.Value = new Model.BoolValue() { Name = reader.GetAttribute("name"), Value = Convert.ToBoolean(reader.GetAttribute("value")) };
              break;
            case Model.ParameterType.Integer:
            case Model.ParameterType.Percent:
            case Model.ParameterType.Decimal:
              //TODO: Check which comma char is being used; enhance to use any
              param.Value = new Model.DecimalValue() { Name = reader.GetAttribute("name"), Value = Convert.ToDouble(reader.GetAttribute("value"), CultureInfo.InvariantCulture.NumberFormat) };
              break;            
            case Model.ParameterType.DecimalMatrix:
              var decMatrix = new Model.DecimalMatrix() { Name = reader.GetAttribute("name") };
              ParseDecimalMatrix(decMatrix, reader);
              param.Value = decMatrix;
              break;
            case Model.ParameterType.DecimalVector:
              var decVec = new Model.DecimalVector() { Name = reader.GetAttribute("name") };
              ParseDecimalVector(decVec, reader);
              param.Value = decVec;
              break;
            case Model.ParameterType.Type:
              var type = new Model.TypeValue() { Name = reader.GetAttribute("name") };
              ParseType(type, reader);
              param.Value = type;
              break;
            case Model.ParameterType.String:
              param.Value = new Model.StringValue() { Name = reader.GetAttribute("name"), Value = reader.GetAttribute("value") };
              break;
            default:
              Console.WriteLine("Unhandled model type: " + param.Type);
              break;
          }
          parameters.Add(param);
        }
      }
      return parameters;
    }

    private void ParseType(Model.TypeValue type, XmlReader reader) {
      var choices = new List<string>();
      string selected = null;
      while (reader.Read()) {
        if (reader.Name == "param")
          break;
        if (reader.Name == "choice") {
          var choice = reader.GetAttribute("name");
          if (reader.HasAttributes && Convert.ToBoolean(reader.GetAttribute("selected"))) {            
            selected = choice;
          }
          choices.Add(choice);
        }
      }
      type.Options = choices.ToArray();
      type.Value = selected;
    }

    private void ParseDecimalVector(Model.DecimalVector decVec, XmlReader reader) {
      var entries = new List<double>();
      //IList<ValueEntry> ventries = new List<ValueEntry>();
      while (reader.Read()) {
        if (reader.Name == "param")
          break;
        if (reader.Name == "value") {
          var val1 = Convert.ToDouble(reader.GetAttribute("v1"), CultureInfo.InvariantCulture.NumberFormat);
          entries.Add(val1);
        }
      }
      decVec.Value = entries.ToArray();      
    }
  }
}