package bjc.utils.funcutils;

import java.util.ArrayList;
import java.util.Deque;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import bjc.utils.data.BooleanToggle;
import bjc.utils.parserutils.TokenUtils;

import com.ibm.icu.text.BreakIterator;

/**
 * Utility methods for operations on strings.
 *
 * @author ben
 */
public class StringUtils {
	/**
	 * Check if a string consists only of one or more matches of a regular
	 * expression.
	 *
	 * @param input
	 *        The string to check.
	 *
	 * @param rRegex
	 *        The regex to see if the string only contains matches of.
	 *
	 * @return Whether or not the string consists only of multiple matches
	 *         of the provided regex.
	 */
	public static boolean containsOnly(final String input, final String rRegex) {
		if(input == null)
			throw new NullPointerException("Input must not be null");
		else if(rRegex == null) throw new NullPointerException("Regex must not be null");

		/*
		 * This regular expression is fairly simple.
		 *
		 * First, we match the beginning of the string. Then, we start a
		 * non-capturing group whose contents are the passed in regex.
		 * That group is then matched one or more times and the pattern
		 * matches to the end of the string.
		 */
		return input.matches("\\A(?:" + rRegex + ")+\\Z");
	}

	/**
	 * Indent the string being built in a StringBuilder n levels.
	 *
	 * @param builder
	 *        The builder to indent in.
	 *
	 * @param levels
	 *        The number of levels to indent.
	 */
	public static void indentNLevels(final StringBuilder builder, final int levels) {
		for(int i = 0; i < levels; i++) {
			builder.append("\t");
		}
	}

	/**
	 * Print out a deque with a special case for easily showing a deque is
	 * empty.
	 *
	 * @param <ContainedType>
	 *        The type in the deque.
	 *
	 * @param queue
	 *        The deque to print.
	 *
	 * @return A string version of the deque, with allowance for an empty
	 *         deque.
	 */
	public static <ContainedType> String printDeque(final Deque<ContainedType> queue) {
		return queue.isEmpty() ? "(none)" : queue.toString();
	}

	/**
	 * Converts a sequence to an English list.
	 *
	 * @param objects
	 *        The sequence to convert to an English list.
	 *
	 * @param join
	 *        The string to use for separating the last element from the
	 *        rest.
	 *
	 * @param comma
	 *        The string to use as a comma
	 *
	 * @return The sequence as an English list.
	 */
	public static String toEnglishList(final Object[] objects, final String join, final String comma) {
		if(objects == null) throw new NullPointerException("Sequence must not be null");

		final StringBuilder sb = new StringBuilder();

		final String joiner = join;
		final String coma = comma;

		switch(objects.length) {
		case 0:
			/* Empty list. */
			break;
		case 1:
			/* One item. */
			sb.append(objects[0].toString());
			break;
		case 2:
			/* Two items. */
			sb.append(objects[0].toString());
			sb.append(" " + joiner + " ");
			sb.append(objects[1].toString());
			break;
		default:
			/* Three or more items. */
			for(int i = 0; i < objects.length - 1; i++) {
				sb.append(objects[i].toString());
				sb.append(coma + " ");
			}

			/*
			 * Uncomment this to remove serial commas.
			 *
			 * int lc = sb.length() - 1;
			 *
			 * sb.delete(lc - coma.length(), lc);
			 */
			sb.append(joiner + " ");
			sb.append(objects[objects.length - 1].toString());
		}

		return sb.toString();
	}

	/**
	 * Converts a sequence to an English list.
	 *
	 * @param objects
	 *        The sequence to convert to an English list.
	 *
	 * @param join
	 *        The string to use for separating the last element from the
	 *        rest.
	 *
	 * @return The sequence as an English list.
	 */
	public static String toEnglishList(final Object[] objects, final String join) {
		return toEnglishList(objects, join, ",");
	}

	/**
	 * Converts a sequence to an English list.
	 *
	 * @param objects
	 *        The sequence to convert to an English list.
	 *
	 * @param and
	 *        Whether to use 'and' or 'or'.
	 *
	 * @return The sequence as an English list.
	 */
	public static String toEnglishList(final Object[] objects, final boolean and) {
		if(and) {
			return toEnglishList(objects, "and");
		}

		return toEnglishList(objects, "or");
	}

	/**
	 * Count the number of graphemes in a string.
	 *
	 * @param value
	 *        The string to check.
	 *
	 * @return The number of graphemes in the string.
	 */
	public static int graphemeCount(final String value) {
		final BreakIterator it = BreakIterator.getCharacterInstance();
		it.setText(value);

		int count = 0;
		while(it.next() != BreakIterator.DONE) {
			count++;
		}

		return count;
	}

	/**
	 * Count the number of times a pattern matches in a given string.
	 *
	 * @param value
	 *        The string to count occurances in.
	 *
	 * @param pattern
	 *        The pattern to count occurances of.
	 * @return The number of times the pattern matches.
	 */
	public static int countMatches(final String value, final String pattern) {
		Matcher mat = Pattern.compile(pattern).matcher(value);

		int num = 0;
		while(mat.find())
			num += 1;

		return num;
	}

	/**
	 * Get a substring until a specified string.
	 * 
	 * @param strang
	 *        The string to substring.
	 * @param vx
	 *        The place to substring until.
	 * @return The specified substring.
	 */
	public static String substringTo(String strang, String vx) {
		int idx = strang.indexOf(vx);

		if(idx == -1) {
			return strang;
		}

		return strang.substring(0, strang.indexOf(vx));
	}

	/**
	 * Split a line into a series of space-separated arguments, including
	 * string literals.
	 * 
	 * @param com
	 *        The command to split from
	 * @return The split arguments.
	 */
	public static List<String> processArguments(String com) {
		List<String> strings = new ArrayList<>();

		BooleanToggle togg = new BooleanToggle();

		for(String strang : TokenUtils.removeDQuotedStrings(com)) {
			if(togg.get()) {
				strings.add(TokenUtils.descapeString(strang));
			} else {
				for(String strung : strang.split("\\s+")) {
					strings.add(strung);
				}
			}
		}
		return strings;
	}

	public static boolean levelContains(String haystack, String... needles) {
		int nestLevel = 0;
		int i         = 0;

		boolean prevCharWasSlash = false;
		boolean inString = false;

		char stringEnder = ' ';

		while(i < haystack.length()) {
			if(inString == false && nestLevel == 0) {
				for(String needle : needles) {
					if(haystack.regionMatches(i, needle, 0, needle.length())) {
						return true;
					}
				}
			}

			if(inString) {
				if(prevCharWasSlash == true) {
					prevCharWasSlash = false;
				} else if (haystack.charAt(i) == stringEnder) {
					inString = false;
				}
			} else {
				switch(haystack.charAt(i)) {
				case '\'':
					inString = true;
					stringEnder = '\'';
					break;
				case '\"':
					inString = true;
					stringEnder = '\"';
					break;
				case '(':
				case '[':
				case '{':
				case '<':
					nestLevel += 1;
					break;
				case ')':
				case ']':
				case '}':
				case '>':
					nestLevel = Math.max(0, nestLevel - 1);
					break;
				}
			}

			i += 1;
		}

		return false;
	}

	public static List<String> levelSplit(String phrase, String... splits) {
		return levelSplit(phrase, false, splits);
	}

	public static List<String> levelSplit(String phrase, boolean keepDelims, String... splits) {
		String work = phrase;

		List<String> strangs = new ArrayList<>();

		int nestLevel = 0;
		int i         = 0;

		boolean prevCharWasSlash = false;
		boolean inString = false;

		char stringEnder = ' ';

		// Shortcut empty strings
		if(phrase.equals("")) {
			strangs.add("");

			return strangs;
		}

		while(i < work.length()) {
			if(inString == false && nestLevel == 0) {
				for(String split : splits) {
					if(work.regionMatches(i, split, 0, split.length())) {
						strangs.add(work.substring(0, i));

						if(keepDelims) strangs.add(split);

						work = work.substring(i + split.length());
						i = 0;

						continue;
					}
				}
			}

			if(inString) {
				if(prevCharWasSlash == true) {
					prevCharWasSlash = false;
				} else if (work.charAt(i) == stringEnder) {
					inString = false;
				}
			} else {
				/*
				 * @TODO Ben Culkin 9/4/18
				 *
				 * This currently crashes if the string ends
				 * with one of the delimiters in question.
				 */
				switch(work.charAt(i)) {
				case '\'':
					inString = true;
					stringEnder = '\'';
					break;
				case '\"':
					inString = true;
					stringEnder = '\"';
					break;
				case '(':
				case '[':
				case '{':
				case '<':
					nestLevel += 1;
					break;
				case ')':
				case ']':
				case '}':
				case '>':
					nestLevel = Math.max(0, nestLevel - 1);
					break;
				}
			}

			i += 1;
		}

		strangs.add(work);

		return strangs;
	}

	public static List<String> levelSplitRX(String phrase, String patt) {
		return levelSplit(phrase, false, patt);
	}

	// @TODO @FIXME
	//
	// This doesn't seem like its working
	public static List<String> levelSplitRX(String phrase, boolean keepDelims, String patt) {
		Pattern pat = Pattern.compile(patt);

		String work = phrase;
		Matcher mat = pat.matcher(work);

		List<String> strangs = new ArrayList<>();

		int nestLevel = 0;
		int i         = 0;

		boolean prevCharWasSlash = false;
		boolean inString = false;

		char stringEnder = ' ';

		while(i < work.length()) {
			if(inString == false && nestLevel == 0) {
				if(mat.find(i)) {
					strangs.add(work.substring(0, i));
					if(keepDelims) strangs.add(mat.group());
					work = work.substring(mat.end());
					i = 0;

					mat = pat.matcher(work);

					continue;
				}
			}

			if(inString) {
				if(prevCharWasSlash == true) {
					prevCharWasSlash = false;
				} else if (work.charAt(i) == stringEnder) {
					inString = false;
				}
			} else {
				switch(work.charAt(i)) {
				case '\'':
					inString = true;
					stringEnder = '\'';
					break;
				case '\"':
					inString = true;
					stringEnder = '\"';
					break;
				case '(':
				case '[':
				case '{':
				case '<':
					nestLevel += 1;
					break;
				case ')':
				case ']':
				case '}':
				case '>':
					nestLevel = Math.max(0, nestLevel - 1);
					break;
				}
			}

			i += 1;
		}

		strangs.add(work);

		return strangs;
	}
}