package scanner;

import static org.junit.Assert.*;

import java.io.InputStream;

import org.junit.Test;

import constructs.Token;
import constructs.Token.Type;
import constructs.TokenFactory;
import error.ErrorManager;
import testutils.TestUtilities;

public class LispScannerTypeTester {

    @Test
    public void givenEmptyFile_ReturnsCorrectTypes() {
        String input = "";
        Token.Type[] expectedTypes = {};

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test(expected = TokenFactory.BadCharacterException.class)
    public void givenBadCharacter_ThrowsException() {
        String input = "[";
        Token.Type[] expectedTypes = {};

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test
    public void givenBadCharacter_ExceptionContainsCorrectSeverity() {
        String input = "abc\ndef[";
        Token.Type[] expectedTypes = { Type.IDENTIFIER, Type.IDENTIFIER };

        try {
            assertTokenTypesMatch(input, expectedTypes);
        } catch (TokenFactory.BadCharacterException e) {
            assertTrue(e.getSeverity() < ErrorManager.CRITICAL_LEVEL);
        }
    }

    @Test
    public void givenNil_ReturnsCorrectTypes() {
        String input = "()";
        Token.Type[] expectedTypes = { Type.LEFT_PAREN, Type.RIGHT_PAREN };

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test
    public void givenListOfNumbers_ReturnsCorrectTypes() {
        String input = "(1 2)";
        Token.Type[] expectedTypes = { Type.LEFT_PAREN, Type.NUMBER, Type.NUMBER, Type.RIGHT_PAREN };

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test
    public void givenString_ReturnsCorrectTypes() {
        String input = "\"string\"";
        Token.Type[] expectedTypes = { Type.STRING };

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test
    public void givenStringWithEscapedDoubleQuote_ReturnsCorrectTypes() {
        String input = "\"string \n hi \\\" bye\"";
        Token.Type[] expectedTypes = { Type.STRING };

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test
    public void givenStringWithEscapedDoubleQuoteAndComment_ReturnsCorrectTypes() {
        String input = "\"string \n hi \\\" ; bye\"";
        Token.Type[] expectedTypes = { Type.STRING };

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test(expected = LispScanner.UnterminatedStringException.class)
    public void givenUnterminatedString_ThrowsException() {
        String input = "\"oh no!";
        Token.Type[] expectedTypes = { Type.STRING };

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test()
    public void givenUnterminatedString_ExceptionHasCorrectSeverity() {
        String input = "\"oh no!";
        Token.Type[] expectedTypes = { Type.STRING };

        try {
            assertTokenTypesMatch(input, expectedTypes);
        } catch (LispScanner.UnterminatedStringException e) {
            assertTrue(e.getSeverity() < ErrorManager.CRITICAL_LEVEL);
        }
    }

    @Test()
    public void givenUnterminatedString_ExceptionContainsMessage() {
        String input = "\"oh no!";
        Token.Type[] expectedTypes = { Type.STRING };

        try {
            assertTokenTypesMatch(input, expectedTypes);
        } catch (LispScanner.UnterminatedStringException e) {
            String message = e.getMessage();
            assertNotNull(message);
            assertTrue(message.length() > 0);
        }
    }

    @Test
    public void givenIdentifier_ReturnsCorrectTypes() {
        String input = "abcdefgHIJKLMNOP1234";
        Token.Type[] expectedTypes = { Type.IDENTIFIER };

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test
    public void givenSingleDigitNumber_ReturnsCorrectTypes() {
        String input = "1";
        Token.Type[] expectedTypes = { Type.NUMBER };

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test
    public void givenMultipleDigitNumber_ReturnsCorrectTypes() {
        String input = "1234567890";
        Token.Type[] expectedTypes = { Type.NUMBER };

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test
    public void givenQuote_ReturnsCorrectTypes() {
        String input = "'";
        Token.Type[] expectedTypes = { Type.QUOTE_MARK };

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test
    public void givenManyTypesWithNoWhitespace_ReturnsCorrectTypes() {
        String input = "xxx\"hi\"999()'aaa";
        Token.Type[] expectedTypes = { Type.IDENTIFIER, Type.STRING, Type.NUMBER, Type.LEFT_PAREN, Type.RIGHT_PAREN,
                                       Type.QUOTE_MARK, Type.IDENTIFIER };

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test
    public void givenFunctionCall_ReturnsCorrectTypes() {
        String input = "(defun myFunction (x)\n  (print x))";
        Token.Type[] expectedTypes = { Type.LEFT_PAREN, Type.IDENTIFIER, Type.IDENTIFIER, Type.LEFT_PAREN,
                                       Type.IDENTIFIER, Type.RIGHT_PAREN, Type.LEFT_PAREN, Type.IDENTIFIER,
                                       Type.IDENTIFIER, Type.RIGHT_PAREN, Type.RIGHT_PAREN };

        assertTokenTypesMatch(input, expectedTypes);
    }

    private void assertTokenTypesMatch(String input, Token.Type[] expectedTypeList) {
        InputStream stringInputStream = TestUtilities.createInputStreamFromString(input);
        LispScanner lispScanner = new LispScanner(stringInputStream, "stringInputStream");

        for (Token.Type expectedType : expectedTypeList)
            assertEquals(expectedType, lispScanner.getNextToken().getType());

        assertEquals(Token.Type.EOF, lispScanner.getNextToken().getType());
    }

}