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):
        toks = tokenize("42")
        self.assertEqual(len(toks), 2)
        self.assertEqual(toks[0], Token('NUMBER', 42))
        self.assertIsInstance(toks[0].value, int)
        self.assertEqual(toks[1].kind, 'EOF')

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

    def test_leading_dot(self):
        toks = tokenize(".5")
        self.assertAlmostEqual(toks[0].value, 0.5)
        self.assertIsInstance(toks[0].value, float)

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

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


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

    def test_all_ops(self):
        k = kinds("1-2/3")
        self.assertEqual(k, ['NUMBER', 'MINUS', 'NUMBER', 'SLASH', 'NUMBER', 'EOF'])

    def test_parens(self):
        k = kinds("(1)")
        self.assertEqual(k, ['LPAREN', 'NUMBER', 'RPAREN', 'EOF'])

    def test_complex(self):
        result = values("3.5*(1-2)")
        self.assertEqual(result, [
            ('NUMBER', 3.5),
            ('STAR', '*'),
            ('LPAREN', '('),
            ('NUMBER', 1),
            ('MINUS', '-'),
            ('NUMBER', 2),
            ('RPAREN', ')'),
            ('EOF', ''),
        ])


class TestWhitespaceAndErrors(unittest.TestCase):
    def test_spaces_skipped(self):
        k = kinds("  12  +  3 ")
        self.assertEqual(k, ['NUMBER', 'PLUS', 'NUMBER', 'EOF'])
        toks = tokenize("  12  +  3 ")
        self.assertEqual(toks[0].value, 12)
        self.assertEqual(toks[2].value, 3)

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

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

    def test_invalid_dollar(self):
        with self.assertRaises(LexError) as ctx:
            tokenize("$")
        self.assertIn('$', str(ctx.exception))

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

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


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