package org.hl7.fhir.validation.instance.utils;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.hl7.fhir.r5.context.IWorkerContext;
import org.hl7.fhir.r5.elementmodel.Element;
import org.hl7.fhir.r5.model.ElementDefinition;
import org.hl7.fhir.r5.model.StructureDefinition;
import org.hl7.fhir.r5.model.StructureDefinition.StructureDefinitionKind;
import org.hl7.fhir.utilities.Utilities;

public class NodeStack {

  protected IWorkerContext context;
  private ElementDefinition definition;
  private Element element;
  private ElementDefinition extension;
  private String literalPath; // xpath format
  private List<String> logicalPaths; // dotted format, various entry points
  private NodeStack parent;
  private ElementDefinition type;
  private String workingLang;
  private Map<String, Element> ids;
  private boolean resetPoint = false;
  private boolean contained = false; 

  public NodeStack(IWorkerContext context) {
    this.context = context;
  }

  public NodeStack(IWorkerContext context, String initialPath, Element element, String validationLanguage) {
    this.context = context;
    ids = new HashMap<>();
    this.element = element;
    literalPath = (initialPath == null ? "" : initialPath+".") + element.getPath();
    workingLang = validationLanguage;
    if (!element.getName().equals(element.fhirType())) {
      logicalPaths = new ArrayList<>();
      logicalPaths.add(element.fhirType());
    }
  }

  public NodeStack(IWorkerContext context, Element element, String refPath, String validationLanguage) {
    this.context = context;
    ids = new HashMap<>();
    this.element = element;
    literalPath = refPath + "->" + element.getName();
    workingLang = validationLanguage;
  }

  public String addToLiteralPath(String... path) {
    StringBuilder b = new StringBuilder();
    b.append(getLiteralPath());
    for (String p : path) {
      if (p.startsWith(":")) {
        b.append("[");
        b.append(p.substring(1));
        b.append("]");
      } else {
        b.append(".");
        b.append(p);
      }
    }
    return b.toString();
  }

  private ElementDefinition getDefinition() {
    return definition;
  }

  public Element getElement() {
    return element;
  }

  public String getLiteralPath() {
    return literalPath == null ? "" : literalPath;
  }

  public List<String> getLogicalPaths() {
    return logicalPaths == null ? new ArrayList<String>() : logicalPaths;
  }

  private ElementDefinition getType() {
    return type;
  }

  public NodeStack pushTarget(Element element, int count, ElementDefinition definition, ElementDefinition type) {
    return pushInternal(element, count, definition, type, "->");
  }

  public NodeStack push(Element element, int count, ElementDefinition definition, ElementDefinition type) {
    return pushInternal(element, count, definition, type, ".");
  }

  private NodeStack pushInternal(Element element, int count, ElementDefinition definition, ElementDefinition type, String sep) {
    NodeStack res = new NodeStack(context);
    res.ids = ids;
    res.parent = this;
    res.workingLang = this.workingLang;
    res.element = element;
    res.definition = definition;
    res.contained = contained;
    res.literalPath = getLiteralPath() + sep + element.getName();
    if (count > -1)
      res.literalPath = res.literalPath + "[" + Integer.toString(count) + "]";
    else if (element.getSpecial() == null && element.getProperty().isList())
      res.literalPath = res.literalPath + "[0]";
    else if (element.getProperty().isChoice()) {
      String n = res.literalPath.substring(res.literalPath.lastIndexOf(".") + 1);
      String en = element.getProperty().getName();
      en = en.substring(0, en.length() - 3);
      String t = n.substring(en.length());
      if (isPrimitiveType(Utilities.uncapitalize(t)))
        t = Utilities.uncapitalize(t);
      res.literalPath = res.literalPath.substring(0, res.literalPath.lastIndexOf(".")) + "." + en + ".ofType(" + t + ")";
    }
    res.logicalPaths = new ArrayList<String>();
    if (type != null) {
      // type will be bull if we on a stitching point of a contained resource, or if....
      res.type = type;
      String tn = res.type.getPath();
      String t = tail(definition.getPath());
      if ("Resource".equals(tn)) {
        tn = element.fhirType();
      }
      for (String lp : getLogicalPaths()) {
        res.logicalPaths.add(lp + "." + t);
        if (t.endsWith("[x]"))
          res.logicalPaths.add(lp + "." + t.substring(0, t.length() - 3) + type.getPath());
      }
      res.logicalPaths.add(tn);
    } else if (definition != null) {
      for (String lp : getLogicalPaths()) {
        res.logicalPaths.add(lp + "." + element.getName());
      }
      res.logicalPaths.add(definition.typeSummary());
    } else
      res.logicalPaths.addAll(getLogicalPaths());
    return res;
  }

  private void setType(ElementDefinition type) {
    this.type = type;
  }
  
  public NodeStack resetIds() {
    ids = new HashMap<>();
    resetPoint  = true;
    return this;
  }
  public Map<String, Element> getIds() {
    return ids;
  }
  private String tail(String path) {
    return path.substring(path.lastIndexOf(".") + 1);
  }

  public boolean isPrimitiveType(String code) {
    StructureDefinition sd = context.fetchTypeDefinition(code);
    return sd != null && sd.getKind() == StructureDefinitionKind.PRIMITIVETYPE;
  }

  public String getWorkingLang() {
    return workingLang;
  }

  public void setWorkingLang(String workingLang) {
    this.workingLang = workingLang;
  }

  public NodeStack getParent() {
    return parent;
  }

  public void qualifyPath(String qualifier) {
    literalPath = literalPath + qualifier;
    
  }

  public boolean isResetPoint() {
    return resetPoint;
  }

  @Override
  public String toString() {
    return literalPath;
  }

  public int depth() {
    if (parent == null) {
      return 0;
    } else {
      return parent.depth()+1;
    }
  }

  public boolean isContained() {
    return contained;
  }

  public void setContained(boolean contained) {
    this.contained = contained;
  }


}