package de.ugoe.cs.swe.bnftools.ui.formatter;

import java.util.ArrayList;
import java.util.Iterator;

import org.apache.commons.lang.StringEscapeUtils;
import org.apache.commons.lang.StringUtils;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.xtext.parsetree.LeafNode;

import de.ugoe.cs.swe.bnftools.ebnf.EtsiBnf;
import de.ugoe.cs.swe.bnftools.ebnf.Rule;
import de.ugoe.cs.swe.bnftools.ebnf.RuleReference;
import de.ugoe.cs.swe.bnftools.ebnf.SectionHeading;
import de.ugoe.cs.swe.bnftools.ebnf.StringRule;

public class EbnfHtmlFormatterVisitor extends EbnfFormatterVisitor {

	private ArrayList<MetaTextEntry> metaTexts = new ArrayList<MetaTextEntry>();
	private ArrayList<MetaTextEntry> transformedTexts = new ArrayList<MetaTextEntry>();
	private int lastMetaTextBlock = 0;
	
	public EbnfHtmlFormatterVisitor(EObject rootNode, FormatterConfig config) {
		super(rootNode, config);
		this.config = config;
		buf = new StringBuffer();
	}

	protected void weaveComments() {
		bufferPositionOriginalText = 0;
		bufferPositionFormattedTextNoWhitespaces = 0;
		bufferPositionFormattedText = 0;
		
		StringBuffer result = new StringBuffer();
		formattedTextNoWhitespaces = buf.toString().replaceAll("[ \t\n\r]", "");
		formattedText = buf.toString();

		MetaTextEntry currentMetaText = null;
		if (metaTexts.iterator().hasNext())
			currentMetaText = metaTexts.iterator().next();

		MetaTextEntry currentTransformedText = null;
		if (transformedTexts.iterator().hasNext())
			currentTransformedText = transformedTexts.iterator().next();
		
		while (bufferPositionFormattedTextNoWhitespaces <= formattedTextNoWhitespaces.length()) {
			skipWhitespacesOriginalText();
			skipWhitespacesFormattedText(result);
			
			if (!(bufferPositionOriginalText < originalText.length()))
				break;
			
			char formattedPositionNoWhitespaces;
			if (bufferPositionFormattedTextNoWhitespaces == formattedTextNoWhitespaces.length()) {
				formattedPositionNoWhitespaces = ' ';
			} else {
				formattedPositionNoWhitespaces = formattedTextNoWhitespaces.charAt(bufferPositionFormattedTextNoWhitespaces);
			}
			char originalPosition = originalText.charAt(bufferPositionOriginalText);
			
			if (formattedPositionNoWhitespaces != originalPosition) {
//				if ((currentMetaText != null) && (bufferPositionFormattedTextNoWhitespaces == currentMetaText.getOffset())) {
//					result.append(currentMetaText.getText());
//					metaTexts.remove(currentMetaText);
//					if (metaTexts.iterator().hasNext())
//						currentMetaText = metaTexts.iterator().next();
//					else
//						currentMetaText = null;
//				}

				if (formattedPositionNoWhitespaces == ';') { // formatted text always outputs the optional semicolon, skip it if necessary
					bufferPositionFormattedTextNoWhitespaces++;
					bufferPositionFormattedText++;
				} else if (isCommentNext(originalText, bufferPositionOriginalText)) {
					LeafNode currentComment = allComments.get(allCommentsPosition); 
					if (currentComment.getTotalOffset() == bufferPositionOriginalText) {
						if (isMultiLineComment(currentComment.getText())) {
							int newLinesCount = scanBackNewlinesCount(originalText, bufferPositionOriginalText-1);
							if (newLinesCount > 0) {
								if (scanBackNewlinesCount(result.toString(), result.toString().length()-1) == 0) {
									result.append("\n\n");
								}
								
								result.append(currentComment.getText());
								result.append("\n");
							} else {
								String lastWhiteSpaces = scanBackWhitespaces(result.toString(), result.toString().length()-1);
								result.delete(result.toString().length() - lastWhiteSpaces.length(), result.toString().length());
								result.append(" " + stripEndingNewline(currentComment.getText()));
								result.append(lastWhiteSpaces);
							}
						} else if (isSingleLineComment(currentComment.getText())) {
							int newLinesCount = scanBackNewlinesCount(originalText, bufferPositionOriginalText-1);
							String lastWhiteSpaces = scanBackWhitespaces(result.toString(), result.toString().length()-1);
							result.delete(result.toString().length() - lastWhiteSpaces.length(), result.toString().length());
							if (newLinesCount > 0) {
								result.append("\n\n" + stripEndingNewline(currentComment.getText()));
							} else {
								result.append(" " + stripEndingNewline(currentComment.getText()));
							}
							result.append(lastWhiteSpaces);
						}
						bufferPositionOriginalText+=currentComment.getLength();
						allCommentsPosition++;
					}
				} else { // disaster handling: return original unformatted text!
					System.err.println("Disaster Recovery: returning original text!!");
					buf = new StringBuffer();
					buf.append(originalText);
					return;
				}
			} else {
				if (lastMetaTextBlock == 0 && (currentMetaText != null) && (bufferPositionFormattedTextNoWhitespaces == currentMetaText.getOffset())) {
					result.append(currentMetaText.getText());
					metaTexts.remove(currentMetaText);
					if (metaTexts.iterator().hasNext())
						currentMetaText = metaTexts.iterator().next();
					else
						currentMetaText = null;
					lastMetaTextBlock = 1;
				}

				if (currentTransformedText != null && currentTransformedText.getOffset() == bufferPositionFormattedTextNoWhitespaces) {
					result.append(currentTransformedText.getTransformedText());
					bufferPositionOriginalText += currentTransformedText.getText().length();
					bufferPositionFormattedText += currentTransformedText.getText().length();
					bufferPositionFormattedTextNoWhitespaces += currentTransformedText.getText().replaceAll("[ \t\r\n]", "").length();
					transformedTexts.remove(currentTransformedText);
					currentTransformedText = null;
					
					if (transformedTexts.iterator().hasNext())
						currentTransformedText = transformedTexts.iterator().next();
				} else {
					String text = formattedText.substring(bufferPositionFormattedText, bufferPositionFormattedText+1);
					result.append(text);
					bufferPositionOriginalText++;
					bufferPositionFormattedText++;
					bufferPositionFormattedTextNoWhitespaces++;
				}

				if (lastMetaTextBlock == 1 && (currentMetaText != null) && (bufferPositionFormattedTextNoWhitespaces == currentMetaText.getOffset())) {
					result.append(currentMetaText.getText());
					metaTexts.remove(currentMetaText);
					if (metaTexts.iterator().hasNext())
						currentMetaText = metaTexts.iterator().next();
					else
						currentMetaText = null;
					lastMetaTextBlock = 0;
				}
			}
		}
		buf = result;
	}
	
	protected void metaText(String str) {
		MetaTextEntry metaTextEntry = new MetaTextEntry(str, buf.toString().replaceAll("[ \t\n\r]", "").length());
		metaTexts.add(metaTextEntry);
	}

	protected void textTransformed(String original, String transformed) {
		MetaTextEntry metaText = new MetaTextEntry(original, transformed, buf.toString().replaceAll("[ \t\n\r]", "").length());
		transformedTexts.add(metaText);
		buf.append(original);
		newLineOffsetCounter += original.length();
	}

	// -----------------------------------------------------------------------------
	
	protected void visitAfter(EtsiBnf node) {
		weaveComments();
	}

	protected void visitBefore(SectionHeading node) {
		if (!lastWasSectionHeading && !buf.substring(buf.length()-2).equals("\n\n"))
			newLine();
		
		lastWasSectionHeading=true;
		
		metaText("<h1>");
		text(node.getSectionHeader().replaceAll("[\n\r]", ""));
		metaText("</h1>");
	}

	protected void visitAfter(SectionHeading node) {
	}
	
	protected void visitBefore(RuleReference node) {
		wrap();
		
		metaText("<a href=\"#" + node.getRuleref().getName() + "\">");
		text(node.getRuleref().getName());
		metaText("</a>");
	}

	protected void visitAfter(RuleReference node) {
	}

	protected void visitBefore(Rule node) {
		if (lastWasSectionHeading)
			newLine();
		
		lastWasSectionHeading=false;

		newLineOffsetCounter = 0;

		if (node.getRulenumber() > 0)
			text(node.getRulenumber() + ". ");
		
		metaText("<a name=\"#" + node.getName() + "\">");
		text(node.getName());
		metaText("</a>");
		text(" ::= ");
		
		rightHandSideRuleOffset = newLineOffsetCounter;
		ruleSpacingStack.push(newLineOffsetCounter);
	}
	
	protected void visitAfter(Rule node) {
		metaText("<br/>");
		text(";");
		newLine();
		ruleSpacingStack.pop();
	}
	
	protected void visitBefore(StringRule node) {
		wrap();
		if (node.getLiteral() != null) {
//			text("\"" + node.getLiteral() + "\"");
			textTransformed("\"" + node.getLiteral() + "\"", StringEscapeUtils.escapeHtml("\"" + node.getLiteral() + "\""));
//			textTransformed("\"" + node.getLiteral() + "\"", "gnabar");
		} else if (node.getColon() != null) {
//			text("\"\"\"");
			textTransformed("\"\"\"", StringEscapeUtils.escapeHtml("\"\"\""));
//			textTransformed("\"\"\"", "gnabar");
		}
	}

	protected void visitAfter(StringRule node) {
	}
}