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):
        toks = tokenize("42")
        self.assertEqual(toks, [Token('NUMBER', 42), Token('EOF', None)])

    def test_float(self):
        toks = tokenize("3.14")
        self.assertEqual(toks, [Token('NUMBER', 3.14), Token('EOF', None)])

    def test_float_leading_dot(self):
        toks = tokenize(".5")
        self.assertEqual(toks, [Token('NUMBER', 0.5), Token('EOF', None)])

    def test_float_trailing_dot(self):
        toks = tokenize("10.")
        self.assertEqual(toks, [Token('NUMBER', 10.0), Token('EOF', None)])

    def test_integer_value_is_int(self):
        toks = tokenize("7")
        self.assertIsInstance(toks[0].value, int)

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


class TestOperatorsAndParens(unittest.TestCase):
    def test_single_plus(self):
        self.assertEqual(kinds("+"), ['PLUS', 'EOF'])

    def test_single_minus(self):
        self.assertEqual(kinds("-"), ['MINUS', 'EOF'])

    def test_single_star(self):
        self.assertEqual(kinds("*"), ['STAR', 'EOF'])

    def test_single_slash(self):
        self.assertEqual(kinds("/"), ['SLASH', 'EOF'])

    def test_single_lparen(self):
        self.assertEqual(kinds("("), ['LPAREN', 'EOF'])

    def test_single_rparen(self):
        self.assertEqual(kinds(")"), ['RPAREN', 'EOF'])

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

    def test_expression_3_5_star_paren(self):
        self.assertEqual(kinds("3.5*(1-2)"),
                         ['NUMBER', 'STAR', 'LPAREN', 'NUMBER', 'MINUS', 'NUMBER', 'RPAREN', 'EOF'])


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

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

    def test_spaces_values(self):
        toks = tokenize("  12  +  3 ")
        self.assertEqual(toks[0].value, 12)
        self.assertEqual(toks[1].kind, 'PLUS')
        self.assertEqual(toks[2].value, 3)

    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")

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

    def test_lex_error_message_contains_position(self):
        try:
            tokenize("1 @ 2")
            self.fail("expected LexError")
        except LexError as e:
            # position 2 is the '@'
            self.assertIn('2', str(e))

    def test_empty_string(self):
        self.assertEqual(kinds(""), ['EOF'])

    def test_complex_expression(self):
        toks = tokenize("3.5*(1-2)")
        self.assertEqual(
            [(t.kind, t.value) for t in toks],
            [('NUMBER', 3.5), ('STAR', '*'), ('LPAREN', '('),
             ('NUMBER', 1), ('MINUS', '-'), ('NUMBER', 2),
             ('RPAREN', ')'), ('EOF', None)]
        )


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