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


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


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


class TestNumbers(unittest.TestCase):
    def test_integer(self):
        toks = tokenize("42")
        self.assertEqual(len(toks), 2)
        self.assertEqual(toks[0], Token('NUMBER', 42))
        self.assertEqual(toks[1], Token('EOF', None))

    def test_float(self):
        toks = tokenize("3.14")
        self.assertEqual(toks[0], Token('NUMBER', 3.14))
        self.assertEqual(toks[1], Token('EOF', None))

    def test_leading_dot(self):
        toks = tokenize(".5")
        self.assertEqual(toks[0], Token('NUMBER', 0.5))

    def test_trailing_dot(self):
        toks = tokenize("10.")
        self.assertEqual(toks[0], Token('NUMBER', 10.0))

    def test_integer_value_type(self):
        toks = tokenize("42")
        self.assertIsInstance(toks[0].value, int)

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


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

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

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

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

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

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


class TestEndToEnd(unittest.TestCase):
    def test_padded_addition(self):
        v = values("  12  +  3 ")
        self.assertEqual(v, [('NUMBER', 12), ('PLUS', '+'), ('NUMBER', 3), ('EOF', None)])

    def test_complex_with_values(self):
        v = values("3.5*(1-2)")
        self.assertEqual(v, [
            ('NUMBER', 3.5),
            ('STAR', '*'),
            ('LPAREN', '('),
            ('NUMBER', 1),
            ('MINUS', '-'),
            ('NUMBER', 2),
            ('RPAREN', ')'),
            ('EOF', None),
        ])

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

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


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