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, [Token('NUMBER', 42), Token('EOF', None)])

    def test_float(self):
        result = tokenize("3.14")
        self.assertEqual(len(result), 2)
        self.assertEqual(result[0].kind, 'NUMBER')
        self.assertAlmostEqual(result[0].value, 3.14)
        self.assertEqual(result[1].kind, 'EOF')

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

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

    def test_number_value_is_int_for_integer(self):
        result = tokenize("42")
        self.assertIsInstance(result[0].value, int)

    def test_number_value_is_float_for_float(self):
        result = tokenize("3.14")
        self.assertIsInstance(result[0].value, float)


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

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

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

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

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

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

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

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


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

    def test_whitespace_values(self):
        tokens = tokenize("  12  +  3 ")
        self.assertEqual(tokens[0].value, 12)
        self.assertEqual(tokens[2].value, 3)

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

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

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

    def test_invalid_letter_raises(self):
        with self.assertRaises(LexError):
            tokenize("a")

    def test_lexerror_message_contains_char(self):
        try:
            tokenize("1 @ 2")
            self.fail("Expected LexError")
        except LexError as e:
            self.assertIn('@', str(e))

    def test_lexerror_message_contains_position(self):
        try:
            tokenize("1 @ 2")
            self.fail("Expected LexError")
        except LexError as e:
            self.assertIn('2', str(e))

    def test_complex_with_parens_values(self):
        tokens = tokenize("3.5*(1-2)")
        self.assertAlmostEqual(tokens[0].value, 3.5)
        self.assertEqual(tokens[3].value, 1)
        self.assertEqual(tokens[5].value, 2)


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