"""Re-run the six regressions the GPT-6 module review found surviving.

Each mutation is applied to a copy of the tree, the suite is run, and the
mutation must FAIL the suite. A survivor means the tests still cannot tell.
"""
import io, os, shutil, subprocess, sys, tempfile

ROOT = os.path.dirname(os.path.abspath(__file__))
CACHE = os.path.join(ROOT, ".gocache")

MUTATIONS = [
    ("11: non-2xx returns nothing instead of all-UNKNOWN", "s2.go",
     "\tif status < 200 || status > 299 {\n\t\treturn allUnknown(len(asked))\n\t}",
     "\tif status < 200 || status > 299 {\n\t\treturn nil\n\t}"),

    ("12a: the revision is ignored when matching answers to questions", "s2.go",
     "\t\tpair := ItemRevision{ItemID: *r.ItemID, Revision: *r.Revision}",
     "\t\tpair := ItemRevision{ItemID: *r.ItemID}"),

    ("12b: STALE is dropped from the closed vocabulary", "s2.go",
     "\tcase VISIBLE, NOT_VISIBLE, STALE, UNKNOWN:",
     "\tcase VISIBLE, NOT_VISIBLE, UNKNOWN:"),

    ("13: the batch cap is doubled", "subject.go",
     "const MaxS2Pairs = 256",
     "const MaxS2Pairs = 512"),

    ("14: a 403 loses its ErrContractBreach sentinel", "s3.go",
     '\t\treturn nil, fmt.Errorf("%w: S3 answered 403 where the contract requires 404", ErrContractBreach)',
     '\t\treturn nil, fmt.Errorf("S3 answered 403")'),

    ("10: redirects are followed", "transport.go",
     '\t\t\treturn fmt.Errorf("suite: refusing to follow a redirect to %q", req.URL.Host)',
     "\t\t\treturn nil"),

    ("1: the Host header override is not checked", "transport.go",
     "\tif req.Host != \"\" {",
     "\tif false {"),

    ("2: duplicate JSON keys are not rejected in S2", "s2.go",
     "\tif err := rejectAmbiguousJSON(body); err != nil {\n\t\treturn allUnknown(len(asked))\n\t}",
     "\tif false {\n\t\treturn allUnknown(len(asked))\n\t}"),

    ("9: hostname labels are not validated", "transport.go",
     "\t\tif err := validLabel(label); err != nil {",
     "\t\tif false {\n\t\t\t_ = label\n\t\tif err := error(nil); err != nil {"),
]

survivors = []
for name, path, before, after in MUTATIONS:
    work = tempfile.mkdtemp(prefix="mut-")
    tree = os.path.join(work, "m")
    # Only the module's own files: the worktree root also holds unreadable
    # dotfiles that a whole-tree copy trips over.
    os.makedirs(tree)
    for entry in os.listdir(ROOT):
        if entry.endswith(".go") or entry == "go.mod":
            shutil.copy2(os.path.join(ROOT, entry), os.path.join(tree, entry))
    shutil.copytree(os.path.join(ROOT, "fixtures"), os.path.join(tree, "fixtures"))
    shutil.copytree(os.path.join(ROOT, "conformance"), os.path.join(tree, "conformance"))

    target = os.path.join(tree, path)
    src = io.open(target, encoding="utf-8").read()
    if before not in src:
        print("SKIP  %s — anchor not found in %s" % (name, path))
        shutil.rmtree(work)
        continue
    io.open(target, "w", encoding="utf-8").write(src.replace(before, after, 1))

    env = dict(os.environ, GOCACHE=CACHE)
    r = subprocess.run(["go", "test", "./..."], cwd=tree, capture_output=True, text=True, env=env)
    shutil.rmtree(work)

    if r.returncode == 0:
        print("SURVIVED  %s" % name)
        survivors.append(name)
    else:
        print("caught    %s" % name)

print()
if survivors:
    print("%d mutation(s) survived:" % len(survivors))
    for s in survivors:
        print("  -", s)
    sys.exit(1)
print("all %d mutations caught" % len(MUTATIONS))