import pytest
import sys
import os
sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
from slic.utils.eval import *

# Valid expressions
@pytest.mark.parametrize("expr, expected", [
    ("1 + 2", 3),
    ("4 - 2", 2),
    ("3 * 5", 15),
    ("10 / 2", 5.0),
    ("10 % 3", 1),
    ("-5", -5),
    ("+7", 7),
    ("1 + 2 * 3", 7),
    ("(1 + 2) * 3", 9),
    ("-(-3)", 3),
    ("-2 + 4 * 2", 6),
    ("(4 + 5) * (6 - 1)", 45),
    ("(((3)))", 3),
    ("-(-(-2))", -2),
    ("3 + +4", 7),
    ("3 + -4", -1),
    ("True + 1", 2),
    ("'string'", 'string'),
    ("1e1000 * 1e1000", float("inf")), 
    ("'a' + 'b'", "ab")     # string concatenation supported !!!
])
def test_arithmetic_eval_valid(expr, expected):
    assert arithmetic_eval(expr) == expected

# Expressions with unsupported operations or node types
@pytest.mark.parametrize("expr, expected_message", [

    # test ArithmeticEvalError of get_operator
    ("2 ** 3",        "Unsupported BinOp Pow"),
    ("3 << 1",        "Unsupported BinOp LShift"),

    # test ArithmeticEvalError of arithmetic_eval
    ("1 < 2",         "Unsupported node type Compare"),
    ("abs(3)",        "Unsupported node type Call"),
    ("a + 2",         "Unsupported node type Name"),
    ("string",        "Unsupported node type Name"),
    ("[1, 2] + [3]",  "Unsupported node type List"),
    ("{1: 2}",        "Unsupported node type Dict"),
])
def test_arithmetic_eval_raises_with_message(expr, expected_message):
    with pytest.raises(ArithmeticEvalError, match=expected_message):
        arithmetic_eval(expr)

# Expressions that are syntactically valid but cause Python runtime errors
@pytest.mark.parametrize("expr, exception", [
    ("1 / 0", ZeroDivisionError),
    ("10 % 0", ZeroDivisionError), 
])
def test_arithmetic_eval_runtime_errors(expr, exception):
    with pytest.raises(exception):
        arithmetic_eval(expr)

# forgiving_eval: returns original expression string on error
@pytest.mark.parametrize("expr, expected", [
    ("1 + 2", 3),
    ("bad + 2", "bad + 2"),
    ("1 / 0", "1 / 0"),
    ("2 ** 10", "2 ** 10"),
])
def test_forgiving_eval(expr, expected):
    assert forgiving_eval(expr) == expected

# defaulting_eval: returns provided default value on error
@pytest.mark.parametrize("expr, default, expected", [
    ("3 * 4", 0, 12),
    ("invalid + 1", 99, 99),
    ("1 / 0", -1, -1),
    ("2 ** 10", 42, 42),
])
def test_defaulting_eval(expr, default, expected):
    assert defaulting_eval(expr, default=default) == expected