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):
        tokens = tokenize("42")
        self.assertEqual(len(tokens), 2)
        self.assertEqual(tokens[0], Token('NUMBER', 42))
        self.assertEqual(tokens[1], Token('EOF', None))
        self.assertIsInstance(tokens[0].value, int)

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

    def test_float_leading_dot(self):
        tokens = tokenize(".5")
        self.assertEqual(tokens[0], Token('NUMBER', 0.5))
        self.assertIsInstance(tokens[0].value, float)

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

    def test_zero(self):
        tokens = tokenize("0")
        self.assertEqual(tokens[0], Token('NUMBER', 0))


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

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

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

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

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

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

    def test_expression(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']
        )
        t = tokenize("  12  +  3 ")
        self.assertEqual(t[0].value, 12)
        self.assertEqual(t[1].kind, 'PLUS')
        self.assertEqual(t[2].value, 3)

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

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

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

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

    def test_lexerror_message_has_char_and_pos(self):
        try:
            tokenize("1 @ 2")
            self.fail("Expected LexError")
        except LexError as e:
            msg = str(e)
            self.assertIn('@', msg)
            self.assertIn('2', msg)  # position 2

    def test_eof_always_last(self):
        tokens = tokenize("1+2")
        self.assertEqual(tokens[-1].kind, 'EOF')

    def test_empty_string(self):
        tokens = tokenize("")
        self.assertEqual(tokens, [Token('EOF', None)])


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