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].kind, 'EOF')
        self.assertIsInstance(result[0].value, int)

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

    def test_float_leading_dot(self):
        result = tokenize(".5")
        self.assertAlmostEqual(result[0].value, 0.5)

    def test_float_trailing_dot(self):
        result = tokenize("10.")
        self.assertAlmostEqual(result[0].value, 10.0)
        self.assertIsInstance(result[0].value, float)


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

    def test_minus_slash(self):
        ks = kinds("4-2/1")
        self.assertIn('MINUS', ks)
        self.assertIn('SLASH', ks)

    def test_parens(self):
        ks = kinds("(1)")
        self.assertIn('LPAREN', ks)
        self.assertIn('RPAREN', ks)

    def test_complex_expr(self):
        result = tok("3.5*(1-2)")
        expected_kinds = ['NUMBER', 'STAR', 'LPAREN', 'NUMBER', 'MINUS', 'NUMBER', 'RPAREN', 'EOF']
        self.assertEqual([k for k, v in result], expected_kinds)
        self.assertAlmostEqual(result[0][1], 3.5)


class TestWhitespaceAndErrors(unittest.TestCase):
    def test_whitespace_skipped(self):
        result = tok("  12  +  3 ")
        self.assertEqual([k for k, v in result], ['NUMBER', 'PLUS', 'NUMBER', 'EOF'])
        self.assertEqual(result[0][1], 12)
        self.assertEqual(result[2][1], 3)

    def test_tab_whitespace(self):
        result = kinds("\t1\t+\t2\t")
        self.assertEqual(result, ['NUMBER', 'PLUS', 'NUMBER', 'EOF'])

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

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

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

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


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