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


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


def kind_value(src):
    return [(t.kind, t.value) for t in tokenize(src)]


class TestNumbers(unittest.TestCase):
    def test_integer(self):
        tokens = tokenize("42")
        self.assertEqual(tokens[0], Token('NUMBER', 42))
        self.assertEqual(tokens[1], Token('EOF', None))

    def test_float(self):
        tokens = tokenize("3.14")
        self.assertIsInstance(tokens[0].value, float)
        self.assertAlmostEqual(tokens[0].value, 3.14)

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

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

    def test_lex_error_at(self):
        with self.assertRaises(LexError) as ctx:
            tokenize("1 @ 2")
        self.assertIn('@', str(ctx.exception))

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

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

    def test_lex_error_position(self):
        with self.assertRaises(LexError) as ctx:
            tokenize("1 @ 2")
        self.assertIn('2', str(ctx.exception))


class TestSpecificExamples(unittest.TestCase):
    """Exact examples from the DoD."""

    def test_dod_42(self):
        toks = tokenize("42")
        self.assertEqual(toks[0].kind, 'NUMBER')
        self.assertEqual(toks[0].value, 42)
        self.assertEqual(toks[1].kind, 'EOF')

    def test_dod_spaced(self):
        self.assertEqual(kinds("  12  +  3 "), ['NUMBER', 'PLUS', 'NUMBER', 'EOF'])

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

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


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