package rclang.impl;

import java.util.ArrayList;
import java.util.HashMap;

import rclang.g4.RCLangParser.AdditionExpContext;
import rclang.g4.RCLangParser.AssignmentExpContext;
import rclang.g4.RCLangParser.AtomExpContext;
import rclang.g4.RCLangParser.MathExpContext;
import rclang.g4.RCLangParser.MoveExpContext;
import rclang.g4.RCLangParser.MultiplyExpContext;
import rclang.g4.RCLangParser.OffExpContext;
import rclang.g4.RCLangParser.PrintExpContext;
import rclang.g4.RCLangParser.StopExpContext;
import rclang.g4.RCLangParser.TurnExpContext;
import rclang.g4.RCLangBaseVisitor;

public class RCLangBaseVisitorImpl extends RCLangBaseVisitor<String> {
	private ArrayList<String> mVariables = new ArrayList<String>();
	private ArrayList<String> mImports = new ArrayList<String>();
	private ArrayList<String> mExternalData = new ArrayList<String>();
	private HashMap<Integer, String> mFragments = new HashMap<Integer, String>();
	private Integer mLineCount = 0;

	/**
	 * @return the output
	 */
	public ArrayList<String> getImports() {
		return mImports;
	}

	/**
	 * @return the output
	 */
	public ArrayList<String> getExternalData() {
		return mExternalData;
	}

	/**
	 * @return the output
	 */
	public HashMap<Integer, String> getFragments() {
		return mFragments;
	}

	@Override
	public String visitAssignmentExp(AssignmentExpContext ctx) {
		String varID = ctx.VARIABLE().getText();

		if (!mVariables.contains(varID)) {
			mVariables.add(varID);
		}

		mLineCount++;
		mFragments.put(mLineCount, ctx.getText());
		return "Integer " + ctx.getText() + ";\n";
	}

	@Override
	public String visitMoveExp(MoveExpContext ctx) {
		String[] imports = {
			"java.util.ArrayList",
			"lejos.hardware.motor.BasicMotor"
		};
		String[] data = {
			"public ArrayList<lejos.hardware.motor.RegulatedMotor> MOVE_MOTORS = new ArrayList<lejos.hardware.motor.BasicMotor>();"
		};

		for (String im : imports) {
			if (!mImports.contains(im)) {
				mImports.add(im);
			}
		}

		for (String dat : data) {
			if (!mExternalData.contains(dat)) {
				mExternalData.add(dat);
			}
		}

		mLineCount++;
		mFragments.put(mLineCount, ctx.getText());

		Integer speed = Integer.valueOf(this.visitMathExp(ctx.mathExp()));
		String stmt = ""
				+ "for (lejos.hardware.motor.RegulatedMotor m : MOVE_MOTORS) {\n"
				+ "    m.setSpeed(" + Math.abs(speed) + ");\n"
				+ "    " + (speed > 0 ? "m.forward()" : "m.backward()") + ";\n"
				+ "    m.stop();\n"
				+ ");\n";

		mLineCount += 4;
		return stmt;
	}

	@Override
	public String visitTurnExp(TurnExpContext ctx) {
		String[] imports = {
			"java.util.ArrayList",
			"lejos.hardware.motor.BasicMotor"
		};
		String[] data = {
			"public ArrayList<lejos.hardware.motor.BasicMotor> TURN_MOTORS = new ArrayList<lejos.hardware.motor.BasicMotor>();"
		};

		for (String im : imports) {
			if (!mImports.contains(im)) {
				mImports.add(im);
			}
		}

		for (String dat : data) {
			if (!mExternalData.contains(dat)) {
				mExternalData.add(dat);
			}
		}

		mLineCount++;
		mFragments.put(mLineCount, ctx.getText());

		String stmt = ""
				+ "for (lejos.hardware.motor.BasicMotor m : TURN_MOTORS) {\n"
				+ "    m.rotate(" + this.visitMathExp(ctx.mathExp()) + ");\n"
				+ ");\n";

		mLineCount += 2;
		return stmt;
	}

	@Override
	public String visitPrintExp(PrintExpContext ctx) {
		String[] imports = {
			"lejos.hardware.lcd.LCD"
		};

		for (String im : imports) {
			if (!mImports.contains(im)) {
				mImports.add(im);
			}
		}

		mLineCount++;
		mFragments.put(mLineCount, ctx.getText());
		return "LCD.drawString(" + ctx.getText() + ", 0, 4);\n";
	}

	@Override
	public String visitStopExp(StopExpContext ctx) {
		// TODO: How to stop all currently connected motors?
		return super.visitStopExp(ctx);
	}

	@Override
	public String visitOffExp(OffExpContext ctx) {
		// TODO: How to turn off the EV3 control unit?
		return super.visitOffExp(ctx);
	}

	@Override
	public String visitAdditionExp(AdditionExpContext ctx) {
		Integer left = Integer.valueOf(this.visitMultiplyExp(ctx.left));
		Integer right = Integer.valueOf(this.visitMultiplyExp(ctx.right));
		char op = ctx.op.getText().charAt(0);

		switch (op) {
		case '+':
			return String.valueOf(left + right);
		case '-':
			return String.valueOf(left - right);
		default:
			throw new IllegalArgumentException("Unknown operator " + op);
		}
	}

	@Override
	public String visitMultiplyExp(MultiplyExpContext ctx) {
		Integer start = Integer.valueOf(this.visitAtomExp(ctx.start));
		Integer right = Integer.valueOf(this.visitAtomExp(ctx.right));
		char op = ctx.op.getText().charAt(0);

		switch (op) {
		case '*':
			return String.valueOf(left * right);
		case '/':
			return String.valueOf(left / right);
		default:
			throw new IllegalArgumentException("Unknown operator " + op);
		}
	}

	@Override
	public String visitAtomExp(AtomExpContext ctx) {
		String text = ctx.getText();

		if (text.charAt(0) == '(') {
			// strip parenthesis and continue
			return this.visitAdditionExp(ctx.additionExp());
		}

		//return this.visitNumber(ctx.number());
		return ctx.Number().getText();
	}

	/*
	@Override
	public String visitNumber(NumberContext ctx) {
		mFragments.put(mLineCount, ctx.getText());
		return ctx.getText();
	}
	*/

}