package org.json.junit;

/*
Copyright (c) 2020 JSON.org

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

The Software shall be used for Good, not Evil.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

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

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.JSONTokener;
import org.junit.Test;

/**
 * Test specific to the {@link org.json.JSONTokener} class.
 * @author John Aylward
 *
 */
public class JSONTokenerTest {

    /**
     * verify that back() fails as expected.
     * @throws IOException thrown if something unexpected happens.
     */
    @Test
    public void verifyBackFailureZeroIndex() throws IOException {
        Reader reader = new StringReader("some test string"); 
        try {
            final JSONTokener tokener = new JSONTokener(reader);
            try {
                // this should fail since the index is 0;
                tokener.back();
                fail("Expected an exception");
            } catch (JSONException e) {
                assertEquals("Stepping back two steps is not supported", e.getMessage());
            } catch (Exception e) {
                fail("Unknown Exception type " + e.getClass().getCanonicalName()+" with message "+e.getMessage());
            }
            
        } finally {
            reader.close();
        }
    }
    /**
     * verify that back() fails as expected.
     * @throws IOException thrown if something unexpected happens.
     */
    @Test
    public void verifyBackFailureDoubleBack() throws IOException {
        Reader reader = new StringReader("some test string");
        try {
            final JSONTokener tokener = new JSONTokener(reader);
            tokener.next();
            tokener.back();
            try {
                // this should fail since the index is 0;
                tokener.back();
                fail("Expected an exception");
            } catch (JSONException e) {
                assertEquals("Stepping back two steps is not supported", e.getMessage());
            } catch (Exception e) {
                fail("Unknown Exception type " + e.getClass().getCanonicalName()+" with message "+e.getMessage());
            }
       } finally {
           reader.close();
       }
    }
    
    @Test
    public void testValid() {
        checkValid("0",Number.class);
        checkValid(" 0  ",Number.class);
        checkValid("23",Number.class);
        checkValid("23.5",Number.class);
        checkValid(" 23.5  ",Number.class);
        checkValid("null",null);
        checkValid(" null  ",null);
        checkValid("true",Boolean.class);
        checkValid(" true\n",Boolean.class);
        checkValid("false",Boolean.class);
        checkValid("\nfalse  ",Boolean.class);
        checkValid("{}",JSONObject.class);
        checkValid(" {}  ",JSONObject.class);
        checkValid("{\"a\":1}",JSONObject.class);
        checkValid(" {\"a\":1}  ",JSONObject.class);
        checkValid("[]",JSONArray.class);
        checkValid(" []  ",JSONArray.class);
        checkValid("[1,2]",JSONArray.class);
        checkValid("\n\n[1,2]\n\n",JSONArray.class);
        checkValid("1 2", String.class);
    }
    
    @Test
    public void testErrors() {
        // Check that stream can detect that a value is found after
        // the first one
        checkError(" { \"a\":1 }  4 ");
        checkError("null \"a\"");
        checkError("{} true");
    }
    
    private Object checkValid(String testStr, Class<?> aClass)  {
        Object result = nextValue(testStr);

        // Check class of object returned
        if( null == aClass ) {
            if(JSONObject.NULL.equals(result)) {
                // OK
            } else {
                throw new JSONException("Unexpected class: "+result.getClass().getSimpleName());
            }
        } else {
            if( null == result ) {
                throw new JSONException("Unexpected null result");
            } else if(!aClass.isAssignableFrom(result.getClass()) ) {
                throw new JSONException("Unexpected class: "+result.getClass().getSimpleName());
            }
        }
        
        return result;
    }

    private void checkError(String testStr) {
        try {
            nextValue(testStr);
            
            fail("Error should be triggered: (\""+testStr+"\")");
        } catch (JSONException e) {
            // OK
        }
    }
    
    /**
     * Verifies that JSONTokener can read a stream that contains a value. After
     * the reading is done, check that the stream is left in the correct state
     * by reading the characters after. All valid cases should reach end of stream.
     * @param testStr
     * @return
     * @throws Exception
     */
    private Object nextValue(String testStr) throws JSONException {
        StringReader sr = new StringReader(testStr);
        try {
            JSONTokener tokener = new JSONTokener(sr);
    
            Object result = tokener.nextValue();
    
            if( result == null ) {
                throw new JSONException("Unable to find value token in JSON stream: ("+tokener+"): "+testStr);
            }
            
            char c = tokener.nextClean();
            if( 0 != c ) {
                throw new JSONException("Unexpected character found at end of JSON stream: "+c+ " ("+tokener+"): "+testStr);
            }
    
            return result;
        } finally {
            sr.close();
        }

    }
    
    /**
     * Tests the failure of the skipTo method with a buffered reader. Preferably
     * we'd like this not to fail but at this time we don't have a good recovery.
     * 
     * @throws IOException thrown if something unexpected happens.
     */
    @Test
    public void testSkipToFailureWithBufferedReader() throws IOException {
        final byte[] superLongBuffer = new byte[1000001];
        // fill our buffer
        for(int i=0;i<superLongBuffer.length;i++) {
            superLongBuffer[i] = 'A';
        }
        
        Reader reader = new BufferedReader(new InputStreamReader(
                new ByteArrayInputStream(superLongBuffer)));
        try {
            final JSONTokener tokener = new JSONTokener(reader);
            try {
                // this should fail since the internal markAhead buffer is only 1,000,000
                // but 'B' doesn't exist in our buffer that is 1,000,001 in size
                tokener.skipTo('B');
                fail("Expected exception");
            } catch (JSONException e) {
                assertEquals("Mark invalid", e.getMessage());
            } catch (Exception e) {
                fail("Unknown Exception type " + e.getClass().getCanonicalName()+" with message "+e.getMessage());
            }
        } finally {
            reader.close();
        }
    }

    /**
     * Tests the success of the skipTo method with a String reader.
     * 
     * @throws IOException thrown if something unexpected happens.
     */
    @Test
    public void testSkipToSuccessWithStringReader() throws IOException {
        final StringBuilder superLongBuffer = new StringBuilder(1000001);
        // fill our buffer
        for(int i=0;i<superLongBuffer.length();i++) {
            superLongBuffer.append('A');
        }
        Reader reader = new StringReader(superLongBuffer.toString());
        try {
            final JSONTokener tokener = new JSONTokener(reader);
            try {
                // this should not fail since the internal markAhead is ignored for StringReaders
                tokener.skipTo('B');
            } catch (Exception e) {
                fail("Unknown Exception type " + e.getClass().getCanonicalName()+" with message "+e.getMessage());
            }
        } finally {
            reader.close();
        }
    }

    /**
     * Verify that next and back are working properly and tracking the correct positions
     * with different new line combinations.
     */
    @Test
    public void testNextBackComboWithNewLines() {
        final String testString = "this is\nA test\r\nWith some different\rNew Lines";
        //                         ^       ^         ^                    ^
        // index positions         0       8        16                   36
        final JSONTokener tokener = new JSONTokener(testString);
        assertEquals(" at 0 [character 1 line 1]", tokener.toString());
        assertEquals('t',tokener.next());
        assertEquals(" at 1 [character 2 line 1]", tokener.toString());
        tokener.skipTo('\n');
        assertEquals("skipTo() improperly modifying indexes"," at 7 [character 8 line 1]", tokener.toString());
        assertEquals('\n',tokener.next());
        assertEquals(" at 8 [character 0 line 2]", tokener.toString());
        assertEquals('A',tokener.next());
        assertEquals(" at 9 [character 1 line 2]", tokener.toString());
        tokener.back();
        assertEquals(" at 8 [character 0 line 2]", tokener.toString());
        tokener.skipTo('\r');
        assertEquals("skipTo() improperly modifying indexes"," at 14 [character 6 line 2]", tokener.toString());
        // verify \r\n combo doesn't increment the line twice
        assertEquals('\r', tokener.next());
        assertEquals(" at 15 [character 0 line 3]", tokener.toString());
        assertEquals('\n', tokener.next());
        assertEquals(" at 16 [character 0 line 3]", tokener.toString());
        // verify stepping back after reading the \n of an \r\n combo doesn't  increment the line incorrectly
        tokener.back();
        assertEquals(" at 15 [character 6 line 2]", tokener.toString());
        assertEquals('\n', tokener.next());
        assertEquals(" at 16 [character 0 line 3]", tokener.toString());
        assertEquals('W', tokener.next());
        assertEquals(" at 17 [character 1 line 3]", tokener.toString());
        assertEquals('i', tokener.next());
        assertEquals(" at 18 [character 2 line 3]", tokener.toString());
        tokener.skipTo('\r');
        assertEquals("skipTo() improperly modifying indexes"," at 35 [character 19 line 3]", tokener.toString());
        assertEquals('\r', tokener.next());
        assertEquals(" at 36 [character 0 line 4]", tokener.toString());
        tokener.back();
        assertEquals(" at 35 [character 19 line 3]", tokener.toString());
        assertEquals('\r', tokener.next());
        assertEquals(" at 36 [character 0 line 4]", tokener.toString());
        assertEquals('N', tokener.next());
        assertEquals(" at 37 [character 1 line 4]", tokener.toString());
        
        // verify we get the same data just walking though, no calls to back
        final JSONTokener t2 = new JSONTokener(testString);
        for(int i=0; i<7; i++) {
            assertTrue(t2.toString().startsWith(" at " + i + " "));
            assertEquals(testString.charAt(i), t2.next());
        }
        assertEquals(" at 7 [character 8 line 1]", t2.toString());
        assertEquals(testString.charAt(7), t2.next());
        assertEquals(" at 8 [character 0 line 2]", t2.toString());
        for(int i=8; i<14; i++) {
            assertTrue(t2.toString().startsWith(" at " + i + " "));
            assertEquals(testString.charAt(i), t2.next());
        }
        assertEquals(" at 14 [character 6 line 2]", t2.toString());
        assertEquals('\r', t2.next());
        assertEquals(" at 15 [character 0 line 3]", t2.toString());
        assertEquals('\n', t2.next());
        assertEquals(" at 16 [character 0 line 3]", t2.toString());
        assertEquals('W', t2.next());
        assertEquals(" at 17 [character 1 line 3]", t2.toString());
        for(int i=17; i<37; i++) {
            assertTrue(t2.toString().startsWith(" at " + i + " "));
            assertEquals(testString.charAt(i), t2.next());
        }
        assertEquals(" at 37 [character 1 line 4]", t2.toString());
        for(int i=37; i<testString.length(); i++) {
            assertTrue(t2.toString().startsWith(" at " + i + " "));
            assertEquals(testString.charAt(i), t2.next());
        }
        assertEquals(" at "+ testString.length() +" [character 9 line 4]", t2.toString());
        // end of the input
        assertEquals(0, t2.next());
        assertFalse(t2.more());
   }
}