package de.superx.util;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import java.io.BufferedReader;
import java.io.FilterReader;
import java.io.IOException;
import java.io.LineNumberReader;
import java.io.StringReader;
import java.nio.CharBuffer;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.lang3.text.StrTokenizer;
import org.junit.Assert;
import org.junit.Test;

public class TrailingDelimiterRemovingReaderTest {

    private static final String[] lines = new String[] { "1^2^3", "3^4^5", "6^7^8" };

    private static final String GOOD_CSV_TRAILING = String.join("^\n", lines[0], lines[1]) + "^";

    private static final String GOOD_CSV = String.join("\n", lines[0], lines[1]);

    private static final String BAD_CSV_TRAILING = lines[0] + "^\n^" + lines[1] + "^";

    private static final String BAD_CSV = lines[0] + "\n" + lines[1] + "^";
    
    @Test
    public void testStringTokenizerWithLeadingBackslash() throws IOException {
       StrTokenizer csvTokenizer = TrailingDelimiterRemovingReader.csvTokenizer;
       String input = "\\^one\\^two^three^^five";
       csvTokenizer.reset(input);
       List<String> result = new ArrayList<String>();
       while (csvTokenizer.hasNext()) {
           result.add(csvTokenizer.next());
       }
       assertEquals("\\^one\\^two", result.get(0));
       assertEquals("three", result.get(1));
       assertEquals("", result.get(2));
       assertEquals("five", result.get(3));
    }

    @Test
    public void testGoodCsvTrailing() throws IOException {
        CharBuffer target = CharBuffer.allocate(100);
        int total;
        try (TrailingDelimiterRemovingReader tsrr = new TrailingDelimiterRemovingReader(new BufferedReader(new StringReader(GOOD_CSV_TRAILING)), "^", 3, true, null)) {
            total = readAllFrom(tsrr, target);
        }
        assertEquals("Count read", 12, total);
    }

    @Test
    public void testGoodCsv() throws IOException {
        CharBuffer target = CharBuffer.allocate(100);
        int total;
        TrailingDelimiterRemovingReader tsrr = new TrailingDelimiterRemovingReader(new BufferedReader(new StringReader(GOOD_CSV)), "^", 3, false, null);
        total = readAllFrom(tsrr, target);
        assertEquals("Count read", 12, total);
    }

    @Test
    public void testBadCsvTrailing() throws IOException {
        CharBuffer target = CharBuffer.allocate(100);
        TrailingDelimiterRemovingReader tsrr = new TrailingDelimiterRemovingReader(new BufferedReader(new StringReader(BAD_CSV_TRAILING)), "^", 3, true, null);
        RuntimeException exception = Assert.assertThrows(RuntimeException.class, () -> {
            readAllFrom(tsrr, target);
        });
        assertTrue(exception.getMessage().contains("line 2"));
        assertTrue(exception.getMessage().contains("Expected 3"));
        assertTrue(exception.getMessage().contains("found 4"));
    }

    @Test
    public void testBadCsv() throws IOException {
        CharBuffer target = CharBuffer.allocate(100);
        TrailingDelimiterRemovingReader tsrr = new TrailingDelimiterRemovingReader(new BufferedReader(new StringReader(BAD_CSV)), "^", 3, false, null);
        RuntimeException exception = Assert.assertThrows(RuntimeException.class, () -> {
            readAllFrom(tsrr, target);
        });
        assertTrue(exception.getMessage().contains("line 2"));
        assertTrue(exception.getMessage().contains("Expected 3"));
        assertTrue(exception.getMessage().contains("found 4"));
    }

    @Test
    public void testEscapedDelimiterCsv() throws IOException {
        String line = "^^^^^^^^^^^^^^Studienvergangenheit F1\\\\^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^525^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^11^^^^^^^\n";
        CharBuffer target = CharBuffer.allocate(line.length());
        LineNumberReader lnr = new LineNumberReader(new StringReader(line));
        TrailingDelimiterRemovingReader tsrr = new TrailingDelimiterRemovingReader(new BufferedReader(lnr), "^", 105, true, null);
        int total = readAllFrom(tsrr, target);
        assertEquals("Count read", line.length() - lnr.getLineNumber(), total);
    }

    @Test
    public void testEscapedBackslashCsv() throws IOException {
        String line = "^^^^^^^^^^^^^^Studienverg\\^angenheit F1^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^525^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^11^^^^^^^\n";
        CharBuffer target = CharBuffer.allocate(line.length());
        LineNumberReader lnr = new LineNumberReader(new StringReader(line));
        TrailingDelimiterRemovingReader tsrr = new TrailingDelimiterRemovingReader(new BufferedReader(lnr), "^", 105, true, null);
        int total = readAllFrom(tsrr, target);
        assertEquals("Count read", line.length() - lnr.getLineNumber(), total);
    }

    private int readAllFrom(FilterReader fr, CharBuffer target) throws IOException {
        int total = 0;
        int countRead = 0;
        while ((countRead = fr.read(target)) != -1) {
            total += countRead;
        }
        fr.close();
        return total;
    }
}