package org.simantics.xml.sax;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class OntologyCombinator {
	
	String packageLineStart = new String("package");
	String resourceLineStart = "public final Resource ";
	String uriLineStart = "public static final String ";
	
	Set<String> resources = new HashSet<>();
	List<String> ontologyUris = new ArrayList<>();
	List<String> classNames = new ArrayList<>();
	String packageLine = null;
	List<String> sortedResourcses;
	
	protected void process(File[] inputFiles) throws IOException {
		for (File inputFile : inputFiles) {
			BufferedReader reader = new BufferedReader(new FileReader(inputFile));
			try {
				String line;
				String uri = null;
				String filename = inputFile.getName();
				String classname = filename.substring(0,filename.length()-5);
				classNames.add(classname);
				while ((line = reader.readLine()) != null) {
					line = line.trim();
					if (line.startsWith(resourceLineStart)) {
						String res = line.substring(resourceLineStart.length(), line.length()-1);
						resources.add(res);
					} else if (line.startsWith(uriLineStart)) {
						String euri = line.substring(line.indexOf('"')+1, line.length()-2);
						if (uri == null) {
							uri = euri;
						} else {
							int max = Math.min(euri.length(), uri.length());
							for (int i = 0; i < max; i++) {
								if (euri.charAt(i) != uri.charAt(i)) {
									uri = uri.substring(0,i);
									break;
								}
							}
						}
					} else if (line.startsWith(packageLineStart)) {
						packageLine = line;
					}
				}
				if (uri != null && uri.length() > 6) {
					if (uri.endsWith("/")) {
						uri = uri.substring(0, uri.length()-1);
					}
					ontologyUris.add(uri);
				}
				else
					throw new IOException("Could not resolve ontology uri for file " + inputFile.getName());
			} finally {
				reader.close();
			}
		}
		
		sortedResourcses = new ArrayList<>();
		sortedResourcses.addAll(resources);
		Collections.sort(sortedResourcses);
		
	}
	
	public void combine(File[] inputFiles, File outputFile) throws IOException{
		process(inputFiles);
		
		PrintWriter writer = new PrintWriter(new BufferedWriter(new FileWriter(outputFile)));
		String className = outputFile.getName();
		int dp = className.indexOf(".");
		if (dp > 0)
			className = className.substring(0,dp);
		
		try {
			writer.println(packageLine);
			writer.println();
			writer.println("import java.lang.reflect.Field;");
			writer.println("import java.util.Collection;");
			writer.println("import java.util.HashMap;");
			writer.println("import java.util.Map;");
			writer.println("import org.simantics.Simantics;");
			writer.println("import org.simantics.db.ReadGraph;");
			writer.println("import org.simantics.db.Resource;");
			writer.println("import org.simantics.db.exception.DatabaseException;");
			writer.println("import org.simantics.db.request.Read;");
			writer.println("import org.simantics.layer0.Layer0;");
			writer.println();
			writer.println();
			writer.println("public class " + className + " {");
			writer.println("  private static boolean init = false;");
			writer.println("  private static Map<Resource, Object> resourceObjects = new HashMap<>();");
			writer.println("  private static Map<Resource, "+className+"> loaderObjects = new HashMap<>();");
			writer.println();
			writer.println("  private Resource ontologyResource;");
			writer.println("  private Object resourceObject;");
			writer.println();
			writer.println("  static void init(ReadGraph graph) throws DatabaseException{");
			writer.println("     if (init)");
			writer.println("       return;");
			writer.println("     ");
			for (int i = 0; i < inputFiles.length; i++) {
			writer.println("     add(graph.getResource(\"" +ontologyUris.get(i) +"\"), " + classNames.get(i) +".getInstance(graph));");
			}
			writer.println("     ");
			writer.println("     init = true;");
			writer.println("  }");
			writer.println("  ");
			writer.println("  public static void add(Resource resource, Object object) {");
			writer.println("     if (resource == null || object == null)");
			writer.println("        throw new IllegalArgumentException();");
			writer.println("     resourceObjects.put(resource, object);");
			writer.println("     loaderObjects.put(resource, new "+className+"(resource, object));");
			writer.println("  }");
			writer.println("  ");
			writer.println("  public static "+className+" getOntology(final Resource res) throws DatabaseException {");
			writer.println("    return Simantics.getSession().syncRequest(new Read<"+className+">() {");
			writer.println("        @Override");
			writer.println("        public "+className+" perform(ReadGraph graph) throws DatabaseException {");
			writer.println("          return getOntology(graph, res);");
			writer.println("        }");
			writer.println("    });");
			writer.println("  }");
			writer.println("  ");
			writer.println("  public static "+className+" getOntology(ReadGraph graph, Resource res) throws DatabaseException{");
			writer.println("     init(graph);");
			writer.println("     Layer0 L0 = Layer0.getInstance(graph);");
			writer.println("     Collection<Resource> types = graph.getTypes(res);");
			writer.println("     for (Resource type : types) {");
			writer.println("        Resource part = graph.getPossibleObject(type, L0.PartOf);");
			writer.println("        while (part != null) {");
			writer.println("          if (loaderObjects.containsKey(part))");
			writer.println("             return loaderObjects.get(part);");
			writer.println("          part = graph.getPossibleObject(part, L0.PartOf);");
			writer.println("        }");
			writer.println("     }");
			writer.println("     return null;");
			writer.println("  }");
			writer.println("  ");
			writer.println("  private "+className+"(Resource ontologyRes, Object resourceObject) {");
			writer.println("     this.ontologyResource = ontologyRes;");
			writer.println("     this.resourceObject = resourceObject;");
			writer.println("     init();");
			writer.println("  }");
			writer.println("  ");
			writer.println("  private Resource get(String name)  {");
			writer.println("    try {");
			writer.println("      Field field = resourceObject.getClass().getDeclaredField(name);");
			writer.println("      return (Resource)field.get(resourceObject);");
			writer.println("    } catch (Exception e){");
			writer.println("      return null;");
			writer.println("    }");
			writer.println("  }");
			writer.println("  ");
			for (String s : sortedResourcses) {
		    writer.println("  public Resource "+s+";");
			}
			writer.println("  ");
			writer.println("  private void init() {");
			for (String s : sortedResourcses) {
			writer.println("  	"+s+" = get(\""+s+"\");");
			}
			writer.println("  }");
			writer.println("}");
			
			
		}	finally {
			writer.close();
		}
		
	}
}