package bjc.dicelang;

import static bjc.dicelang.Errors.ErrorKey.EK_CONS_INVDEFINE;
import static bjc.dicelang.Errors.ErrorKey.EK_CONS_INVPRAG;

import java.io.IOException;
import java.util.LinkedList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import jline.ConsoleReader;
import jline.Terminal;

/**
 * CLI interface to DiceLang
 *
 * @author EVE
 *
 */
public class DiceLangConsole {
	private int commandNumber;

	private final DiceLangEngine eng;

	private ConsoleReader read;

	/**
	 * Create a new console.
	 *
	 * @param args
	 *                The CLI args for the console.
	 */
	public DiceLangConsole(final String[] args) {
		commandNumber = 0;

		eng = new DiceLangEngine();

		if (!CLIArgsParser.parseArgs(args, eng)) {
			System.exit(1);
		}

		Terminal.setupTerminal();
	}

	/**
	 * Run the console.
	 */
	public void run() {
		/*
		 * Set up console.
		 */
		try {
			read = new ConsoleReader();
		} catch (final IOException ioex) {
			System.out.println("ERROR: Console init failed");
			return;
		}

		System.out.println("dice-lang v0.2");

		String comm = null;

		/*
		 * Read initial command.
		 */
		try {
			comm = read.readLine(String.format("(%d) dice-lang> ", commandNumber));
		} catch (final IOException ioex) {
			System.out.println("ERROR: I/O failed");
			return;
		}

		/*
		 * Run commands.
		 */
		while (!comm.equals("quit") && !comm.equals("exit")) {
			if (comm.startsWith("pragma")) {
				/*
				 * Run pragmas.
				 */
				final boolean success = handlePragma(comm.substring(7)); 

				if (success) {
					System.out.println("Pragma completed succesfully");
				} else {
					System.out.println("Pragma execution failed");
				}
			} else {
				/*
				 * Run commands.
				 */
				if(eng.debugMode)
					System.out.printf("\tRaw command: %s\n", comm);

				final boolean success = eng.runCommand(comm);

				if (success) {
					System.out.println("Command completed succesfully");
				} else {
					System.out.println("Command execution failed");
				}

				commandNumber += 1;
			}

			try {
				comm = read.readLine(String.format("(%d) dice-lang> ", commandNumber));
			} catch (final IOException ioex) {
				System.out.println("ERROR: I/O failed");
				return;
			}
		}
	}

	private boolean handlePragma(final String pragma) {
		if(eng.debugMode)
			System.out.println("\tRaw pragma: " + pragma);

		/*
		 * Grab the name from the arguments.
		 */
		String pragmaName = null;
		final int firstIndex = pragma.indexOf(' ');

		/*
		 * Handle argless pragmas.
		 */
		if (firstIndex == -1) {
			pragmaName = pragma;
		} else {
			pragmaName = pragma.substring(0, firstIndex);
		}

		/*
		 * Run pragmas.
		 */
		switch (pragmaName) {
		case "debug":
			System.out.println("\tDebug mode is now " + eng.toggleDebug());
			break;

		case "postfix":
			System.out.println("\tPostfix mode is now " + eng.togglePostfix());
			break;

		case "prefix":
			System.out.println("\tPrefix mode is now " + eng.togglePrefix());
			break;

		case "stepeval":
			System.out.println("\tStepeval mode is now" + eng.toggleStepEval());
			break;

		case "define":
			return defineMode(pragma.substring(7));

		case "help":
			return helpMode(pragma.substring(5));

		default:
			Errors.inst.printError(EK_CONS_INVPRAG, pragma);
			return false;
		}

		return true;
	}

	/*
	 * Run a help mode.
	 */
	private static boolean helpMode(final String pragma) {
		switch (pragma.trim()) {
		case "help":
			System.out.println("\tGet help on pragmas");
			break;

		case "debug":
			System.out.println("\tToggle debug mode. (Output stage results)");
			break;

		case "postfix":
			System.out.println("\tToggle postfix mode. (Don't shunt tokens)");
			break;

		case "prefix":
			System.out.println("\tToggle prefix mode. (Reverse token order instead of shunting)");
			break;

		case "stepeval":
			System.out.println("\tToggle stepeval mode. (Print out evaluation progress)");
			break;

		case "define":
			System.out.println("\tAdd a macro rewrite directive.");
			System.out.println("\tdefine <priority> <type> <recursion> <guard> <circular> <patterns>...");
			break;

		default:
			System.out.println("\tNo help available for pragma " + pragma);
		}

		// Help always works
		return true;
	}

	/*
	 * Matches slash-delimited strings (like /text/ or /text\/text/).
	 */
	private final Pattern slashPattern = Pattern.compile("/((?:\\\\.|[^/\\\\])*)/");

	private boolean defineMode(final String defineText) {
		/*
		 * Grab all of the separator spaces.
		 */
		final int firstIndex = defineText.indexOf(' ');
		final int secondIndex = defineText.indexOf(' ', firstIndex + 1);
		final int thirdIndex = defineText.indexOf(' ', secondIndex + 1);
		final int fourthIndex = defineText.indexOf(' ', thirdIndex + 1);
		final int fifthIndex = defineText.indexOf(' ', fourthIndex + 1);
		final int sixthIndex = defineText.indexOf(' ', fifthIndex + 1);

		/*
		 * Error if we got something we didn't need.
		 */
		if (firstIndex == -1) {
			Errors.inst.printError(EK_CONS_INVDEFINE, "(no priority)");
			return false;
		} else if (secondIndex == -1) {
			Errors.inst.printError(EK_CONS_INVDEFINE, "(no define type)");
			return false;
		} else if (thirdIndex == -1) {
			Errors.inst.printError(EK_CONS_INVDEFINE, "(no recursion type)");
			return false;
		} else if (fourthIndex == -1) {
			Errors.inst.printError(EK_CONS_INVDEFINE, "(no guard type)");
			return false;
		} else if (fifthIndex == -1) {
			Errors.inst.printError(EK_CONS_INVDEFINE, "(no circularity)");
			return false;
		} else if (sixthIndex == -1) {
			Errors.inst.printError(EK_CONS_INVDEFINE, "(no patterns)");
			return false;
		}

		final int priority = Integer.parseInt(defineText.substring(0, firstIndex));

		final String defineType = defineText.substring(firstIndex + 1, secondIndex);

		Define.Type type;
		boolean subMode = false;

		switch (defineType) {
		case "line":
			type = Define.Type.LINE;
			break;

		case "token":
			type = Define.Type.TOKEN;
			break;

		case "subline":
			type = Define.Type.LINE;
			subMode = true;
			break;

		case "subtoken":
			type = Define.Type.TOKEN;
			subMode = true;
			break;

		default:
			Errors.inst.printError(EK_CONS_INVDEFINE, "(unknown type)");
			return false;
		}

		final boolean doRecur = defineText.substring(secondIndex + 1,
		                        thirdIndex).equalsIgnoreCase("true");
		final boolean hasGuard = defineText.substring(thirdIndex + 1,
		                         fourthIndex).equalsIgnoreCase("true");
		final boolean isCircular = defineText.substring(thirdIndex + 1,
		                           fourthIndex).equalsIgnoreCase("true");

		final String pats = defineText.substring(fifthIndex + 1).trim();
		final Matcher patMatcher = slashPattern.matcher(pats);

		String guardPattern = null;

		if (hasGuard) {
			if (!patMatcher.find()) {
				Errors.inst.printError(EK_CONS_INVDEFINE, "(no guard pattern)");
				return false;
			}

			guardPattern = patMatcher.group(1);
		}

		if (!patMatcher.find()) {
			Errors.inst.printError(EK_CONS_INVDEFINE, "(no search pattern)");
			return false;
		}

		final String searchPattern = patMatcher.group(1);
		final List<String> replacePatterns = new LinkedList<>();

		while (patMatcher.find()) {
			replacePatterns.add(patMatcher.group(1));
		}

		final Define dfn = new Define(priority, subMode, doRecur, isCircular, guardPattern,
		                              searchPattern,
		                              replacePatterns);

		if (dfn.inError) return false;

		if (type == Define.Type.LINE) {
			eng.addLineDefine(dfn);
		} else {
			eng.addTokenDefine(dfn);
		}

		return true;
	}

	/**
	 * Main method.
	 *
	 * @param args
	 *                CLI arguments.
	 */
	public static void main(final String[] args) {
		final DiceLangConsole console = new DiceLangConsole(args);

		console.run();
	}
}