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


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


def toks(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].kind, 'NUMBER')
        self.assertEqual(result[0].value, 42)
        self.assertIsInstance(result[0].value, int)
        self.assertEqual(result[1].kind, 'EOF')

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

    def test_float_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)

    def test_zero(self):
        result = tokenize("0")
        self.assertEqual(result[0].value, 0)


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

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

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

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

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

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

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


class TestWhitespaceAndErrors(unittest.TestCase):
    def test_spaces_skipped(self):
        result = toks("  12  +  3 ")
        self.assertEqual(result, [('NUMBER', 12), ('PLUS', '+'), ('NUMBER', 3), ('EOF', None)])

    def test_complex_expression(self):
        result = toks("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("$5")

    def test_letter_raises(self):
        with self.assertRaises(LexError):
            tokenize("1 + x")

    def test_error_contains_position(self):
        with self.assertRaises(LexError) as ctx:
            tokenize("1 @ 2")
        msg = str(ctx.exception)
        self.assertIn('2', msg)  # position 2


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