package de.hs_mannheim.informatik.spreadsheet;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Part of a simplified spreadsheet system for the PR1 programming lab at Hochschule Mannheim.
 *
 * @author  Oliver Hummel & Victor Waitz
 */
public class Axel {
	static Scanner keyboard = new Scanner(System.in);
	static Spreadsheet spr = new Spreadsheet(11, 11);
	static String saveFilePath = "Axel\\resources\\zahlen.csv";

	public static void main(String[] args) throws FileNotFoundException {
		System.out.println("Welcome to Axel (Totally not Excel)");
		System.out.println();

		spr.loadSpecialTable();
		System.out.println(spr);

		// spr.saveCsv("/tmp/test.csv");

		while (true) {
			String userCommandPositionInput = userCommandPositionInput();
			if (userCommandPositionInput.charAt(0) == '*') {
				executeCommand(userCommandPositionInput);
				System.out.println(spr);
				continue;
			}
			String userPositionInput = userCommandPositionInput;

			String userValueFormulaInput = userValueFormulaInput(userPositionInput);

			spr.put(userPositionInput, userValueFormulaInput);

			System.out.println(spr);
		}

	}


	//? User input for a program command or a position
	public static String userCommandPositionInput() {
		System.out.println();
		System.out.println("Input a command for the program or a position");
		System.out.printf("List of program commands: *clear, *load, *save, *exit or *help %nFormat for position: A1 or B14%n");
		System.out.print("Input: ");
		String userCommandPositionInput = keyboard.nextLine();

		return userCommandPositionComputation(userCommandPositionInput);
	}

	public static String userCommandPositionComputation(String userCommandPositionInput) {

		if (userCommandPositionInput.isEmpty()) {
			System.out.println("Input is empty!");
			return userCommandPositionInput();
		}

		//? Program command
		if (userCommandPositionInput.charAt(0) == '*') {
			if (!(userCommandErrorCheck(userCommandPositionInput))) {
				System.out.println("Invalid command!");
				return userCommandPositionInput();
			}
			return userCommandPositionInput;
		}

		//? Position
		if (!(userPositionErrorCheck(userCommandPositionInput, spr))) {
			System.out.println("Invalid position!");
			return userCommandPositionInput();
		}

		if (!(userPositionBoundsErrorCheck(userCommandPositionInput, spr))) {
			System.out.println("Position out of bounds!");
			return userCommandPositionInput();
		}

		return userCommandPositionInput;
	}

	public static boolean userCommandErrorCheck(String CommandToCheck) {
		//? true if valid
		//? valid inputs are: *clear, *exit, *save, *load, *help (and all upper case variants)

		CommandToCheck = CommandToCheck.toLowerCase();
		if (CommandToCheck.equals("*clear") || CommandToCheck.equals("*exit") || CommandToCheck.equals("*save") || CommandToCheck.equals("*load") || CommandToCheck.equals("*help")) {
			return true;
		}
		return false;
	}

	public static boolean userPositionErrorCheck(String positionToCheck, Spreadsheet spr) {
		//? true if valid
		//? valid inputs are: A1, B14, C79, E99, F1, G99, J1, M98, ... (and all lower case variants)

		positionToCheck = positionToCheck.toUpperCase();

		//? Check if input is the right length
		if (positionToCheck.length() < 2 || positionToCheck.length() > 3) {
			return false;
		}

		//? Check if input is in the right format
		if (!(Character.isLetter(positionToCheck.charAt(0)) && Character.isDigit(positionToCheck.charAt(1)))) {
			return false;
		}

		if (positionToCheck.length() == 3) {
			if (!(Character.isDigit(positionToCheck.charAt(2)))) {
				return false;
			}
		}

		return true;
	}

	public static boolean userPositionBoundsErrorCheck(String positionToCheck, Spreadsheet spr) {
		//? true if valid

		positionToCheck = positionToCheck.toUpperCase();

		if ((spr.getRow(positionToCheck) >= spr.getRowsLCount()) || (spr.getCol(positionToCheck) >= spr.getColsCount())) {
			return false;
		}

		return true;
	}


	//? User input for a value or a formula
	public static String userValueFormulaInput(String currentPos) {
		System.out.println();
		System.out.printf("Input a value of a formula for the selected position: %s.%n", currentPos);
		System.out.printf("Format for a value: 7 or 1337 %nFormat for a formula: =7*6 or =SUMME(A1:A3)%n");
		System.out.print("Input: ");
		String userCommandInput = keyboard.nextLine();

		return userValueFormulaComputation(userCommandInput, currentPos);
	}

	public static String userValueFormulaComputation(String userValueFormulaInput, String currentPos) {
		if (userValueFormulaInput.isEmpty()) {
			System.out.println("Input is empty!");
			return userValueFormulaInput(currentPos);
		}

		//? Formula
		if (userValueFormulaInput.charAt(0) == '=') {
			if (!(userFormulaErrorCheck(userValueFormulaInput))) {
				System.out.println("Invalid formula!");
				return userValueFormulaInput(currentPos);
			}
			return userValueFormulaInput;
		}

		//? Value
		if (!(userValueErrorCheck(userValueFormulaInput))) {
			System.out.println("Invalid value!");
			return userValueFormulaInput(currentPos);
		}

		return userValueFormulaInput;
	}

	public static boolean userFormulaErrorCheck(String formulaToCheck) {
		//? true if valid
		//? valid inputs are: =7*6, =SUM(A1:A3), =A1, =A1+A2, =A1-A2, ... (and all lower case variants)

		//? remove '=' at the beginning and make everything upper case
		formulaToCheck = formulaToCheck.toUpperCase().substring(1);

		if (formulaToCheck.startsWith("SUMME(") || formulaToCheck.startsWith("PRODUKT(") || formulaToCheck.startsWith("MITTELWERT(") || formulaToCheck.startsWith("STABW(") || formulaToCheck.startsWith("MIN(") || formulaToCheck.startsWith("MAX(")) {
			return userFormulaFunctionErrorCheck(formulaToCheck);
		}

		return userFormulaExpressionErrorCheck(formulaToCheck);
	}

	public static boolean userFormulaFunctionErrorCheck(String functionToCheck) {
		String[] functionCorners = spr.isolateFunctionCorners(functionToCheck);

		if (functionCorners.length != 2) {
			return false;
		}

		for (String functionCorner : functionCorners) {
			if (!(spr.isValueCellName(functionCorner).equals("cellName"))) {
				return false;
			}

			if (!userPositionBoundsErrorCheck(functionCorner, spr)) {
				System.out.print("Out of bounds - ");
				return false;
			}
		}
		if (functionToCheck.startsWith("MITTELWERT(") || functionToCheck.startsWith("STABW(")) {
			String[] functionBlock = spr.wholeFunctionBlock(functionToCheck);
			boolean allEmpty = true;

			for (String cell : functionBlock) {
				if (!cell.isEmpty()) {
					allEmpty = false;
				}
			}
			if (allEmpty) {
				System.out.print("Division by zero - ");
				return false;
			}
		}
		if (functionToCheck.startsWith("STABW(")) {
			String[] functionBlock = spr.wholeFunctionBlock(functionToCheck);
			String[] notEmptyValues = spr.extractNotEmptyCells(functionBlock);

			if (notEmptyValues.length < 2) {
				System.out.print("Division by zero - ");
				return false;
			}
		}
		return true;
	}

	public static boolean userFormulaExpressionErrorCheck(String expressionToCheck) {
		//TODO ME: Maybe not worth the time
		return true;
	}

	public static boolean userValueErrorCheck(String valueToCheck) {
		//? true if valid
		//? valid inputs are: 7, 1337, 0, , -213,...

		//? For floating point numbers
		// String digitCheckRegex = "-?\\d+(\\.\\d+)?";
		//? For integers
		String digitCheckRegex = "-?\\d+";
		if (!(valueToCheck.matches(digitCheckRegex))) {
			return false;
		}
		return true;
	}


	public static void executeCommand(String command) throws FileNotFoundException {
		switch (command) {
			case "*clear":
				progClear();
				break;

			case "*load":
				progLoad();
				break;

			case "*save":
				progSave();
				break;

			case "*exit":
				progExit();
				break;
		}
	}

	private static void progClear(){
		System.out.println("Are you sure you want to clear the table? (yes/no)");
		System.out.print("Input: ");
		String userClearInput = keyboard.nextLine().toLowerCase();

		if (userClearInput.equals("yes") || userClearInput.equals("y")){
			spr.clearTable();
			System.out.println("Table cleared!");
		}
	}

	private static void progLoad() throws FileNotFoundException {
		spr.readCsv(saveFilePath, ",", "Amogus");
		System.out.println("File loaded!");
	}

	private static void progSave() throws FileNotFoundException {
		String savePath = saveFilePath;
		spr.saveCsv(savePath);
		System.out.println("File saved");
	}

	private static void progExit() throws FileNotFoundException {
		System.out.println("Do you want to save befor you exit? (yes/no)");
		System.out.print("Input: ");
		String userExitInput = keyboard.nextLine().toLowerCase();

		if (userExitInput.equals("yes") || userExitInput.equals("y")) {
			progSave();
		}
		System.out.println("Goodbye!");
	}

}