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


def kinds(src):
    return [t.kind for t in tokenize(src)]


def pairs(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")])

    def test_float(self):
        result = tokenize("3.14")
        self.assertEqual(result[0], Token("NUMBER", 3.14))
        self.assertEqual(result[1], Token("EOF"))

    def test_float_leading_dot(self):
        result = tokenize(".5")
        self.assertEqual(result[0], Token("NUMBER", 0.5))
        self.assertEqual(result[1], Token("EOF"))

    def test_float_trailing_dot(self):
        result = tokenize("10.")
        self.assertEqual(result[0], Token("NUMBER", 10.0))
        self.assertEqual(result[1], Token("EOF"))

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

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


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

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

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

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

    def test_lparen(self):
        self.assertIn("LPAREN", kinds("("))

    def test_rparen(self):
        self.assertIn("RPAREN", kinds(")"))

    def test_expression_1_plus_2_times_3(self):
        self.assertEqual(
            kinds("1+2*3"),
            ["NUMBER", "PLUS", "NUMBER", "STAR", "NUMBER", "EOF"],
        )

    def test_all_operators(self):
        self.assertEqual(
            kinds("+-*/()"),
            ["PLUS", "MINUS", "STAR", "SLASH", "LPAREN", "RPAREN", "EOF"],
        )


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

    def test_tabs_skipped(self):
        self.assertEqual(kinds("1\t+\t2"), ["NUMBER", "PLUS", "NUMBER", "EOF"])

    def test_complex_expression(self):
        self.assertEqual(
            pairs("3.5*(1-2)"),
            [
                ("NUMBER", 3.5),
                ("STAR", None),
                ("LPAREN", None),
                ("NUMBER", 1),
                ("MINUS", None),
                ("NUMBER", 2),
                ("RPAREN", None),
                ("EOF", None),
            ],
        )

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

    def test_invalid_dollar_raises_lex_error(self):
        with self.assertRaises(LexError):
            tokenize("$5")

    def test_invalid_letter_raises_lex_error(self):
        with self.assertRaises(LexError):
            tokenize("x")

    def test_lex_error_message_contains_char(self):
        try:
            tokenize("1 @ 2")
        except LexError as e:
            self.assertIn("@", str(e))

    def test_lex_error_message_contains_position(self):
        try:
            tokenize("1 @ 2")
        except LexError as e:
            self.assertIn("2", str(e))


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