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


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


def vals(tokens):
    return [t.value for t in tokens]


class TestNumbers(unittest.TestCase):
    def test_integer(self):
        toks = tokenize("42")
        self.assertEqual(kinds(toks), ['NUMBER', 'EOF'])
        self.assertEqual(toks[0].value, 42)
        self.assertIsInstance(toks[0].value, int)

    def test_float(self):
        toks = tokenize("3.14")
        self.assertEqual(kinds(toks), ['NUMBER', 'EOF'])
        self.assertAlmostEqual(toks[0].value, 3.14)
        self.assertIsInstance(toks[0].value, float)

    def test_float_leading_dot(self):
        toks = tokenize(".5")
        self.assertEqual(kinds(toks), ['NUMBER', 'EOF'])
        self.assertAlmostEqual(toks[0].value, 0.5)

    def test_float_trailing_dot(self):
        toks = tokenize("10.")
        self.assertEqual(kinds(toks), ['NUMBER', 'EOF'])
        self.assertAlmostEqual(toks[0].value, 10.0)


class TestOperatorsAndParens(unittest.TestCase):
    def test_operators(self):
        toks = tokenize("1+2*3")
        self.assertEqual(kinds(toks), ['NUMBER', 'PLUS', 'NUMBER', 'STAR', 'NUMBER', 'EOF'])

    def test_all_operators(self):
        toks = tokenize("+-*/")
        self.assertEqual(kinds(toks), ['PLUS', 'MINUS', 'STAR', 'SLASH', 'EOF'])

    def test_parens(self):
        toks = tokenize("()")
        self.assertEqual(kinds(toks), ['LPAREN', 'RPAREN', 'EOF'])

    def test_complex_expr(self):
        toks = tokenize("3.5*(1-2)")
        self.assertEqual(kinds(toks), ['NUMBER', 'STAR', 'LPAREN', 'NUMBER', 'MINUS', 'NUMBER', 'RPAREN', 'EOF'])
        self.assertAlmostEqual(toks[0].value, 3.5)
        self.assertEqual(toks[3].value, 1)
        self.assertEqual(toks[5].value, 2)


class TestWhitespaceAndErrors(unittest.TestCase):
    def test_whitespace_skipped(self):
        toks = tokenize("  12  +  3 ")
        self.assertEqual(kinds(toks), ['NUMBER', 'PLUS', 'NUMBER', 'EOF'])
        self.assertEqual(toks[0].value, 12)
        self.assertEqual(toks[2].value, 3)

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

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

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

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

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


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