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


class TestNumbers(unittest.TestCase):
    def test_integer(self):
        result = tokenize("42")
        self.assertEqual(result, [Token('NUMBER', 42), Token('EOF', None)])
        self.assertIsInstance(result[0].value, int)

    def test_float_standard(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_eof_is_last(self):
        result = tokenize("42")
        self.assertEqual(result[-1].kind, 'EOF')


class TestOperatorsAndParens(unittest.TestCase):
    def _kinds(self, src):
        return [t.kind for t in tokenize(src)]

    def test_plus(self):
        self.assertEqual(self._kinds("+"), ['PLUS', 'EOF'])

    def test_minus(self):
        self.assertEqual(self._kinds("-"), ['MINUS', 'EOF'])

    def test_star(self):
        self.assertEqual(self._kinds("*"), ['STAR', 'EOF'])

    def test_slash(self):
        self.assertEqual(self._kinds("/"), ['SLASH', 'EOF'])

    def test_lparen(self):
        self.assertEqual(self._kinds("("), ['LPAREN', 'EOF'])

    def test_rparen(self):
        self.assertEqual(self._kinds(")"), ['RPAREN', 'EOF'])

    def test_expression_1_plus_2_star_3(self):
        self.assertEqual(
            self._kinds("1+2*3"),
            ['NUMBER', 'PLUS', 'NUMBER', 'STAR', 'NUMBER', 'EOF'],
        )


class TestWhitespaceAndErrors(unittest.TestCase):
    def _kinds(self, src):
        return [t.kind for t in tokenize(src)]

    def test_whitespace_around_tokens(self):
        result = tokenize("  12  +  3 ")
        self.assertEqual(
            [t.kind for t in result],
            ['NUMBER', 'PLUS', 'NUMBER', 'EOF'],
        )
        nums = [t.value for t in result if t.kind == 'NUMBER']
        self.assertEqual(nums, [12, 3])

    def test_complex_expression(self):
        result = tokenize("3.5*(1-2)")
        self.assertEqual(
            [t.kind for t in result],
            ['NUMBER', 'STAR', 'LPAREN', 'NUMBER', 'MINUS', 'NUMBER', 'RPAREN', 'EOF'],
        )
        self.assertAlmostEqual(result[0].value, 3.5)
        self.assertEqual(result[3].value, 1)
        self.assertEqual(result[5].value, 2)

    def test_lex_error_at_sign(self):
        with self.assertRaises(LexError):
            tokenize("1 @ 2")

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

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

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

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

    def test_tab_whitespace(self):
        result = tokenize("1\t+\t2")
        self.assertEqual(
            [t.kind for t in result],
            ['NUMBER', 'PLUS', 'NUMBER', 'EOF'],
        )


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