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].kind, 'NUMBER')
        self.assertEqual(toks[0].value, 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].kind, 'NUMBER')
        self.assertAlmostEqual(toks[0].value, 3.14)
        self.assertIsInstance(toks[0].value, float)

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

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


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

    def test_minus(self):
        self.assertIn('MINUS', kinds("1-2"))

    def test_slash(self):
        self.assertIn('SLASH', kinds("4/2"))

    def test_parens(self):
        k = kinds("(1)")
        self.assertEqual(k[0], 'LPAREN')
        self.assertEqual(k[-2], 'RPAREN')

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


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

    def test_tab_whitespace(self):
        k = kinds("1\t+\t2")
        self.assertEqual(k, ['NUMBER', 'PLUS', 'NUMBER', '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("$100")

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

    def test_lex_error_position_in_message(self):
        try:
            tokenize("1 @ 2")
            self.fail("LexError not raised")
        except LexError as e:
            msg = str(e)
            self.assertIn('@', msg)
            self.assertIn('2', msg)  # position 2


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