/*
 * Enter_with_Prefix.bsh - a Beanshell macro for jEdit
 * that starts a new line continuing any recognized
 * sequence that started the previous.  For example,
 * if the previous line beings with "1." the next will
 * be prefixed with "2.".  It supports alpha lists (a., b., etc...),
 * bullet lists (+, =, *, etc..), comments, Javadocs, 
 * Java import statements, e-mail replies (>, |, :),
 * and is easy to extend with new sequence types.  Suggested
 * shortcut for this macro is S+ENTER (SHIFT+ENTER).
 *
 * Copyright (C) 2004 Ollie Rutherfurd <oliver@rutherfurd.net>
 *
 * $Id$
 */
import java.util.regex.Pattern;
import java.util.regex.Matcher;

DEBUG = false;

Prefix(Matcher m){
	/** leading whitespace */
	this.leading = m.group(1);
	/** body of prefix */
	this.body = m.group(2);
	/** trailing whitespace */
	this.trailing = m.group(3);
	return this;
}

/**
 * Increments to next:
 *  - "a. " -> "b. "
 *  - "a) " -> "b) "
 *  - "a] " -> "b] "
 */
AlphaList(){
	name = "Alpha List";
	pattern = Pattern.compile("^(\\s*(?:[|#*/>]+\\s+)?)([A-z][.)])(\\s+)");
	String getNextPrefix(prefix){
		char next = prefix.body.charAt(0) + 1;
		return prefix.leading + next + prefix.body.charAt(1) + prefix.trailing;
	}
	return this;
}

/**
 * Continues any of:
 * - "= "
 * - "* "
 * - "+ "
 */
BulletList(){
	name = "Bullet List";
	pattern = Pattern.compile("^(\\s*)([=*+])(\\s+)");
	String getNextPrefix(prefix){
		return prefix.leading + prefix.body + prefix.trailing;
	}
	return this;
}

/**
 * Continues one or more of:
 * - "*"
 * - ";"
 * - "#"
 * - "/"
 * - "-"
 */
Comment(){
	name = "Comment";
	pattern = Pattern.compile("^(\\s*)([*;#/-]+)(\\s*)");
	String getNextPrefix(prefix){
		return prefix.leading + prefix.body + prefix.trailing;
	}
	return this;
}

/**
 * Continues without leading "/":
 * - "/**" -> " * "
 * - "/*"  -> " *"
 */
JavaDoc(){
	name = "JavaDoc";
	pattern = Pattern.compile("^(\\s*)(/[*]{1,2})(\\s*)");
	String getNextPrefix(prefix){
		return prefix.leading + (prefix.body.length() == 3 ? " * " : " *") + prefix.trailing;
	}
	return this;
}

/**
 * Continues an import statement without the class name.
 * "import com.foo.Blah;" -> "import com.foo."
 */
JavaImport(){
	name = "Java Import";
	pattern = Pattern.compile("^(\\b)(import\\s+)((?:[a-z]+[.])+)");
	String getNextPrefix(prefix){
		return prefix.leading + prefix.body + prefix.trailing;
	}
	return this;
}

/**
 * Continues any sequence of:
 * - "|"
 * - ":"
 * - ">"
 */
Generic(){
	name = "Generic";
	pattern = Pattern.compile("^(\\s*)([|:>]+)(\\s*)");
	String getNextPrefix(prefix){
		return prefix.leading + prefix.body + prefix.trailing;
	}
	return this;
}

/**
 * Increments to next:
 * - "1. " -> "2. "
 * - "1) " -> "2) "
 * - "1] " -> "2] "
 */
NumberedList(){
	name = "Numbered List";
	pattern = Pattern.compile("^(\\s*(?:[|#*/>]+\\s+)?)([0-9]+[.)])(\\s+)");
	String getNextPrefix(prefix){
		int next = Integer.parseInt(prefix.body.substring(0,prefix.body.length()-1)) + 1;
		return prefix.leading + next + prefix.body.substring(prefix.body.length()-1) + prefix.trailing;
	}
	return this;
}

/**
 * Continues:
 * - '+ "'
 * - "+ '"
 */
MultiLineString(){
	name = "Multi-line String";
	pattern = Pattern.compile("^(\\s+)([+]\\s*[\"'])(\\s*)");
	String getNextPrefix(prefix){
		return prefix.leading + prefix.body + prefix.trailing;
	}
	return this;
}

/**
 * Continues sequence of non-alpha characters or spaces.
 */
NonAlpha(){
	name = "(Non-Alpha)";
	pattern = Pattern.compile("^(\\s*)([^A-z ]+)(\\s*)");
	String getNextPrefix(prefix){
		return prefix.leading + prefix.body + prefix.trailing;
	}
	return this;
}


/**
 * Returns object containing:
 * - leading (usually whitespace)
 * - body (of prefix)
 * - trailing (usually whitespace)
 * or null if no match.
 */
getPrefix(String line, scheme){
	Matcher m = scheme.pattern.matcher(line);
	if(DEBUG)
		Macros.message(view, "checking: '" + line + "'\n"
					   + "scheme: " + scheme.name + "\n"
					   + "pattern: " + scheme.pattern.pattern() + "\n"
					   + "matches: " + m.lookingAt());
	if(m.lookingAt() == false)
		return null;
	p = Prefix(m);
	// hack to prevent NonAlpha from 
	// screwing up standard indentation
	if("".equals(p.body.trim())){
		if(DEBUG)
			Macros.message(view, "Skipping because 'body' is all whitespace");
		return null;
	}
	return p;
}


insertNewlineWithPrefix(View view){
	// as there's overlap between which 
	// regex's match, the ordering
	// here is significant.
	Object[] schemes = {NumberedList(),
						AlphaList(),
						MultiLineString(),
						BulletList(),
						JavaImport(),
						JavaDoc(),
						Comment(),
						Generic(),
						NonAlpha(),
					   };
	JEditTextArea textArea = view.getTextArea();
	String line = textArea.getLineText(textArea.getCaretLine());
	for(int i=0; i < schemes.length; i++){
		p = getPrefix(line,schemes[i]);
		if(p != null){
			String prefix = schemes[i].getNextPrefix(p);
			view.getStatus().setMessageAndClear("Continued " + schemes[i].name);
			textArea.setSelectedText("");
			int caret = textArea.getCaretPosition();
			textArea.getBuffer().insert(caret,"\n" + prefix);
			textArea.setCaretPosition(caret + prefix.length() + 1);
			return;
		}
	}
	view.getStatus().setMessageAndClear("No match found");
	// didn't find a match, use fallback behavior
	textArea.insertEnterAndIndent();
}

insertNewlineWithPrefix(view);

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