import unittest
from calc.lexer import tokenize, Token, LexError


def kinds(src):
    return [t.kind for t in tokenize(src)]


def tok(src):
    return [(t.kind, t.value) for t in tokenize(src)]


class TestNumbers(unittest.TestCase):
    def test_integer(self):
        result = tokenize("42")
        self.assertEqual(result[0], Token('NUMBER', 42))
        self.assertEqual(result[1], Token('EOF', None))
        self.assertIsInstance(result[0].value, int)

    def test_float(self):
        result = tokenize("3.14")
        self.assertEqual(result[0].kind, 'NUMBER')
        self.assertAlmostEqual(result[0].value, 3.14)
        self.assertIsInstance(result[0].value, float)

    def test_leading_dot(self):
        result = tokenize(".5")
        self.assertEqual(result[0].kind, 'NUMBER')
        self.assertAlmostEqual(result[0].value, 0.5)

    def test_trailing_dot(self):
        result = tokenize("10.")
        self.assertEqual(result[0].kind, 'NUMBER')
        self.assertAlmostEqual(result[0].value, 10.0)
        self.assertIsInstance(result[0].value, float)


class TestOperatorsAndParens(unittest.TestCase):
    def test_plus(self):
        self.assertIn(Token('PLUS', '+'), tokenize("+"))

    def test_minus(self):
        self.assertIn(Token('MINUS', '-'), tokenize("-"))

    def test_star(self):
        self.assertIn(Token('STAR', '*'), tokenize("*"))

    def test_slash(self):
        self.assertIn(Token('SLASH', '/'), tokenize("/"))

    def test_lparen(self):
        self.assertIn(Token('LPAREN', '('), tokenize("("))

    def test_rparen(self):
        self.assertIn(Token('RPAREN', ')'), tokenize(")"))

    def test_sequence(self):
        self.assertEqual(kinds("1+2*3"),
                         ['NUMBER', 'PLUS', 'NUMBER', 'STAR', 'NUMBER', 'EOF'])


class TestWhitespaceAndErrors(unittest.TestCase):
    def test_whitespace_skipped(self):
        self.assertEqual(kinds("  12  +  3 "),
                         ['NUMBER', 'PLUS', 'NUMBER', 'EOF'])

    def test_tab_skipped(self):
        self.assertEqual(kinds("1\t+\t2"), ['NUMBER', 'PLUS', 'NUMBER', 'EOF'])

    def test_complex_expr(self):
        self.assertEqual(kinds("3.5*(1-2)"),
                         ['NUMBER', 'STAR', 'LPAREN', 'NUMBER', 'MINUS', 'NUMBER', 'RPAREN', 'EOF'])

    def test_lex_error_at_sign(self):
        with self.assertRaises(LexError) as ctx:
            tokenize("1 @ 2")
        self.assertIn('@', str(ctx.exception))

    def test_lex_error_dollar(self):
        with self.assertRaises(LexError):
            tokenize("$")

    def test_lex_error_letter(self):
        with self.assertRaises(LexError):
            tokenize("abc")

    def test_lex_error_position(self):
        with self.assertRaises(LexError) as ctx:
            tokenize("1 @ 2")
        self.assertIn('2', str(ctx.exception))


if __name__ == '__main__':
    unittest.main()