import random
import string

import pytest

from src.contracts.parser import parse_output, parse_statement_lines

GOOD_OUTPUT = """
<analysis>
<label>VULNERABLE</label>
<cwe>CWE-120</cwe>
<statements>12-14, 27</statements>
<trace>
  <step>line 12: buf = getenv("PATH")   [source: env input]</step>
  <step>line 27: memcpy(dst, buf, n)    [sink: unchecked copy]</step>
</trace>
<explanation>The buffer is filled from an unchecked environment variable and then
copied without a bounds check, allowing overflow.</explanation>
</analysis>
"""


def test_well_formed_parses_ok():
    out = parse_output(GOOD_OUTPUT)
    assert out.format_ok is True
    assert out.label == "VULNERABLE"
    assert out.cwe == "CWE-120"
    assert out.statement_lines == {12, 13, 14, 27}
    assert len(out.trace) == 2
    assert out.trace[0].line == 12
    assert "source" in out.trace[0].tag
    assert out.trace[1].line == 27
    assert out.explanation


def test_safe_label_with_none_cwe():
    text = """<analysis><label>SAFE</label><cwe>NONE</cwe><statements></statements>
    <trace></trace><explanation>No vulnerability found in this function.</explanation></analysis>"""
    out = parse_output(text)
    assert out.format_ok is True
    assert out.label == "SAFE"
    assert out.cwe == "NONE"
    assert out.statement_lines == set()


@pytest.mark.parametrize(
    "bad",
    [
        "",
        "not even xml",
        "<analysis></analysis>",
        "<analysis><label>MAYBE</label></analysis>",
        "<analysis><label>VULNERABLE</label><cwe>not-a-cwe</cwe></analysis>",
        "<analysis><label>VULNERABLE</label><cwe>CWE-120</cwe></analysis>",  # no explanation
        "<label>VULNERABLE</label>",  # no wrapping analysis tag
        "<analysis><label></label><cwe>NONE</cwe><explanation>x</explanation></analysis>",
        "<analysis>" * 50,
        None,
        12345,
    ],
)
def test_malformed_never_crashes(bad):
    out = parse_output(bad)
    assert out.format_ok is False


def test_bad_statement_range_does_not_crash_but_is_logged():
    text = (
        "<analysis><label>VULNERABLE</label><cwe>CWE-120</cwe>"
        "<statements>99999999999999999999999999-1</statements>"
        "<explanation>x</explanation></analysis>"
    )
    out = parse_output(text)
    assert out.format_ok is True  # structurally valid; the bad range is just logged
    assert out.statement_lines == set()
    assert out.parse_errors


def test_fuzz_never_crashes():
    rng = random.Random(42)
    alphabet = string.printable
    tags = ["<analysis>", "</analysis>", "<label>", "</label>", "<cwe>", "</cwe>",
            "<statements>", "</statements>", "<trace>", "</trace>", "<step>",
            "</step>", "<explanation>", "</explanation>", "VULNERABLE", "SAFE",
            "CWE-120", "NONE", "line 12: foo()"]
    for _ in range(150):
        n_pieces = rng.randint(0, 15)
        pieces = []
        for _ in range(n_pieces):
            if rng.random() < 0.5:
                pieces.append(rng.choice(tags))
            else:
                pieces.append("".join(rng.choice(alphabet) for _ in range(rng.randint(0, 20))))
        garbage = "".join(pieces)
        out = parse_output(garbage)  # must not raise
        assert isinstance(out.format_ok, bool)


def test_parse_statement_lines_ranges():
    lines, errors = parse_statement_lines("12-14, 27")
    assert lines == {12, 13, 14, 27}
    assert errors == []


def test_parse_statement_lines_rejects_inverted_range():
    lines, errors = parse_statement_lines("20-10")
    assert lines == set()
    assert errors