package tl1.A4;

import java.util.Map;
import java.util.Set;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Iterator;
import java.util.Stack;

public class InvertedListImpl implements InvertedList {

	private HashMap List; // Wörter mapped auf LinkedLists

	public Map getMap() {
		return List;
	}

	public void addDocument(String filename, Map termsPlusFreqs) {
		Set terms = termsPlusFreqs.keySet(); // Set aus Map erstellen
		for (Iterator it = terms.iterator(); it.hasNext();) { // Jeden
																// schlüssel
																// Überprüfen
			String subject = (String) it.next(); // Name rausholen
			int freq = (Integer) termsPlusFreqs.get(subject);
			boolean tester = false;
			// Liste erstellen falls nicht vorhanden!
			if (List == null) {
				List = new HashMap<String, LinkedList>();
			}
			if (!List.isEmpty())
				tester = true;
			if (List.containsKey(subject) && tester) { // bereits in List
														// enthalten
				LinkedList<InvertedListEntry> temp = (LinkedList<InvertedListEntry>) List.get(subject);
				List.remove(subject); // Löschen
				temp.add(new InvertedListEntry(filename, freq));
				List.put(subject, temp);
			} else {
				LinkedList<InvertedListEntry> temp = new LinkedList<InvertedListEntry>();
				temp.add(new InvertedListEntry(filename, freq));
				List.put(subject, temp);
			}

		}
	}

	public int getFrequency(String filename, String term) {
		LinkedList<InvertedListEntry> temp = (LinkedList<InvertedListEntry>) List.get(term);
		if (temp != null) {
			for (Iterator it = temp.listIterator(); it.hasNext();) {
				InvertedListEntry IE = (InvertedListEntry) it.next();
				if (IE.getFilename().equals(filename)) {
					return IE.getFrequency();
				}
			}
		}
		return 0;
	}

	public int getNumberOfDocuments(String term) {
		LinkedList<InvertedListEntry> IL = (LinkedList<InvertedListEntry>) List.get(term);
		return IL.size();		
	}

	public Set<String> getOccurences(String term, int minOccurence) {
		LinkedList<InvertedListEntry> IL = (LinkedList<InvertedListEntry>) List.get(term);
		Set<String> toReturn = new HashSet<String>();
		for(Iterator it = IL.listIterator(); it.hasNext();){
			InvertedListEntry temp = (InvertedListEntry)it.next();
			if(temp.getFrequency()>= minOccurence){
				toReturn.add(temp.getFilename());
			}
		}
		return toReturn;
	}

	public void removeDocument(String filename) {
		Set keys = List.keySet();
		Stack<InvertedListEntry> teststack = new Stack<InvertedListEntry>();
		for (Iterator it = keys.iterator(); it.hasNext();) {
			String name = (String) it.next();
			LinkedList<InvertedListEntry> IL = (LinkedList<InvertedListEntry>) List.get(name);
			for (Iterator it2 = IL.listIterator(); it2.hasNext();) {
				InvertedListEntry temp = (InvertedListEntry)it2.next();
				if (temp.getFilename().equals(filename)){			//sobald gefunden
					teststack.push(temp);
				}
			}
			while(!teststack.empty()){
				IL.remove(teststack.pop());
			}
		}
	}

}