package scanner;

import static org.junit.Assert.assertEquals;

import java.io.IOException;
import java.io.InputStream;

import org.junit.Test;

import scanner.Token.Type;
import testutils.TestUtilities;

public class LispScannerTypeTester {

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

        assertTokenTypesMatch(input, expectedTypes);
    }

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

        assertTokenTypesMatch(input, expectedTypes);
    }

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

        assertTokenTypesMatch(input, expectedTypes);
    }

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

        assertTokenTypesMatch(input, expectedTypes);
    }

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

        assertTokenTypesMatch(input, expectedTypes);
    }

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

        assertTokenTypesMatch(input, expectedTypes);
    }

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

        assertTokenTypesMatch(input, expectedTypes);
    }

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

        assertTokenTypesMatch(input, expectedTypes);
    }

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

        assertTokenTypesMatch(input, expectedTypes);
    }

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

        assertTokenTypesMatch(input, expectedTypes);
    }

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

        assertTokenTypesMatch(input, expectedTypes);
    }

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

        assertTokenTypesMatch(input, expectedTypes);
    }

    @Test
    public void givenFunctionCall_returnsCorrectTokenTypes() throws IOException {
        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) throws IOException {
        InputStream stringInputStream = TestUtilities.createInputStreamFromString(input);
        LispScanner lispScanner = new LispScanner(stringInputStream, "stringInputStream");

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

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

}