"""Tests for calc/lexer.py covering D1-D3."""
import unittest
from calc.lexer import tokenize, Token, LexError


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


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


class TestNumbers(unittest.TestCase):
    def test_integer(self):
        result = tokenize("42")
        self.assertEqual(result, [Token("NUMBER", 42), Token("EOF", None)])
        self.assertIsInstance(result[0].value, int)

    def test_float_standard(self):
        result = tokenize("3.14")
        self.assertEqual(len(result), 2)
        self.assertEqual(result[0].kind, "NUMBER")
        self.assertAlmostEqual(result[0].value, 3.14)
        self.assertIsInstance(result[0].value, float)

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

    def test_float_trailing_dot(self):
        result = tokenize("10.")
        self.assertEqual(result[0].kind, "NUMBER")
        self.assertAlmostEqual(result[0].value, 10.0)
        self.assertIsInstance(result[0].value, float)

    def test_zero(self):
        result = tokenize("0")
        self.assertEqual(result[0], Token("NUMBER", 0))


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_eof_last(self):
        result = tokenize("1+2")
        self.assertEqual(result[-1].kind, "EOF")


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

    def test_tabs_skipped(self):
        self.assertEqual(kinds("1\t+\t2"), ["NUMBER", "PLUS", "NUMBER", "EOF"])

    def test_complex_expression(self):
        result = kv("3.5*(1-2)")
        self.assertEqual(
            result,
            [
                ("NUMBER", 3.5),
                ("STAR", "*"),
                ("LPAREN", "("),
                ("NUMBER", 1),
                ("MINUS", "-"),
                ("NUMBER", 2),
                ("RPAREN", ")"),
                ("EOF", None),
            ],
        )

    def test_at_raises_lex_error(self):
        with self.assertRaises(LexError):
            tokenize("1 @ 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("x")

    def test_lex_error_message_has_char_and_pos(self):
        try:
            tokenize("1 @ 2")
        except LexError as e:
            self.assertIn("@", str(e))

    def test_bare_dot_raises_lex_error(self):
        with self.assertRaises(LexError):
            tokenize(".")


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