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


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


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


class TestNumbers(unittest.TestCase):
    def test_integer(self):
        tokens = tokenize("42")
        self.assertEqual(tokens[0], Token('NUMBER', 42))
        self.assertEqual(tokens[0].value, 42)
        self.assertIsInstance(tokens[0].value, int)
        self.assertEqual(tokens[1].kind, 'EOF')

    def test_float(self):
        t = tokenize("3.14")
        self.assertEqual(t[0].kind, 'NUMBER')
        self.assertAlmostEqual(t[0].value, 3.14)
        self.assertIsInstance(t[0].value, float)

    def test_leading_dot(self):
        t = tokenize(".5")
        self.assertEqual(t[0].kind, 'NUMBER')
        self.assertAlmostEqual(t[0].value, 0.5)

    def test_trailing_dot(self):
        t = tokenize("10.")
        self.assertEqual(t[0].kind, 'NUMBER')
        self.assertAlmostEqual(t[0].value, 10.0)
        self.assertIsInstance(t[0].value, float)


class TestOperatorsAndParens(unittest.TestCase):
    def test_1plus2star3(self):
        self.assertEqual(kinds("1+2*3"),
                         ['NUMBER', 'PLUS', 'NUMBER', 'STAR', 'NUMBER', 'EOF'])

    def test_all_operators(self):
        self.assertEqual(kinds("+-*/()"),
                         ['PLUS', 'MINUS', 'STAR', 'SLASH', 'LPAREN', 'RPAREN', 'EOF'])


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

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

    def test_complex_expression(self):
        result = values("3.5*(1-2)")
        self.assertEqual(result, [
            ('NUMBER', 3.5),
            ('STAR', '*'),
            ('LPAREN', '('),
            ('NUMBER', 1),
            ('MINUS', '-'),
            ('NUMBER', 2),
            ('RPAREN', ')'),
            ('EOF', None),
        ])

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

    def test_invalid_dollar_raises(self):
        with self.assertRaises(LexError):
            tokenize("$10")

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

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


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