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


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


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

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

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

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


class TestOperatorsAndParens(unittest.TestCase):
    def test_each_operator(self):
        self.assertEqual(kinds("+"), ['PLUS', 'EOF'])
        self.assertEqual(kinds("-"), ['MINUS', 'EOF'])
        self.assertEqual(kinds("*"), ['STAR', 'EOF'])
        self.assertEqual(kinds("/"), ['SLASH', 'EOF'])
        self.assertEqual(kinds("("), ['LPAREN', 'EOF'])
        self.assertEqual(kinds(")"), ['RPAREN', 'EOF'])

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


class TestWhitespace(unittest.TestCase):
    def test_spaces(self):
        tokens = tokenize("  12  +  3 ")
        self.assertEqual([t.kind for t in tokens], ['NUMBER', 'PLUS', 'NUMBER', 'EOF'])
        self.assertEqual(tokens[0].value, 12)
        self.assertEqual(tokens[2].value, 3)

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


class TestErrors(unittest.TestCase):
    def test_at_sign_raises_lex_error(self):
        with self.assertRaises(LexError) as ctx:
            tokenize("1 @ 2")
        msg = str(ctx.exception)
        self.assertIn('@', msg)
        self.assertIn('2', msg)  # position 2

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

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


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


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