"""Run trusted unit tests with no inherited credentials or external I/O.

This is an accident guard for this suite, not an OS sandbox for hostile Python.
Direct pytest bypasses it. Use make test (already installed dependencies only).
"""
from __future__ import annotations

import hashlib
import json
import os
from pathlib import Path
import runpy
import socket
import subprocess
import sys
import tempfile

ROOT = Path(__file__).resolve().parents[1]
SELF = Path(__file__).resolve()
SHELL_FIXTURES = {
    "printf 'the-secret-value'", "printf 'sekret'", "printf 'new'",
    "printf '%s' '{\"wrap_info\":{\"token\":\"hvs.WRAP\"}}'",
    "printf 'not-json'",
}
JOURNAL_CODE_SHA256 = '69aa18f302fd698104cb2253b4af0c3a077e72a0a427183e3dce1444c4926df9'


class IsolationDenied(PermissionError, subprocess.SubprocessError):
    """A unit test attempted an unreviewed external operation."""


def clean_environment(home: Path, temporary: Path) -> dict[str, str]:
    # Construct, never copy/inventory the caller's environment.
    return {'HOME': str(home), 'TMPDIR': str(temporary), 'PATH': '/usr/bin:/bin',
            'LANG': 'C.UTF-8', 'PYTHONDONTWRITEBYTECODE': '1',
            'PYTEST_DISABLE_PLUGIN_AUTOLOAD': '1'}


def inside(path: Path, roots: tuple[Path, ...]) -> bool:
    return any(path == root or root in path.parents for root in roots)


class Guard:
    def __init__(self, temporary: Path, read_roots: list[Path], child: bool = False, git_metadata: bool = False):
        self.temporary = temporary.resolve()
        self.read_roots = tuple(p.resolve() for p in read_roots)
        self.child = child
        self.git_metadata = git_metadata
        self.loopback_test = False
        self.endpoints: set[tuple[str, int]] = set()
        self.launch = None
        self.original_popen = subprocess.Popen

    def fixture_path(self, value: str) -> Path:
        path = Path(value).resolve()
        if not inside(path, (self.temporary,)):
            raise IsolationDenied('unit isolation: non-fixture path')
        return path

    def audit(self, event, args):
        if event == 'open' and not isinstance(args[0], int):
            path = Path(os.fsdecode(args[0])).resolve()
            mode, flags = args[1:3]
            write = ((isinstance(mode, str) and any(c in mode for c in 'wax+'))
                     or (isinstance(flags, int) and flags & (os.O_WRONLY | os.O_RDWR | os.O_CREAT | os.O_TRUNC | os.O_APPEND)))
            roots = (self.temporary,) if write else self.read_roots
            if path != Path('/dev/null') and not inside(path, roots):
                raise IsolationDenied('unit isolation: file outside reviewed roots')
        if event == 'subprocess.Popen':
            if self.launch is None or tuple(args[1]) != self.launch:
                raise IsolationDenied('unit isolation: unexpected process')
        if event in {'os.system', 'os.exec', 'os.posix_spawn', 'os.fork', 'os.forkpty'}:
            raise IsolationDenied('unit isolation: native execution disabled')
        if event.startswith('socket.'):
            if not self.loopback_test or self.child:
                raise IsolationDenied('unit isolation: sockets disabled')
            if event == 'socket.__new__':
                if args[1] != socket.AF_INET or args[2] & 15 != socket.SOCK_STREAM:
                    raise IsolationDenied('unit isolation: socket family/type denied')
            elif event == 'socket.bind':
                if args[1] != ('127.0.0.1', 0):
                    raise IsolationDenied('unit isolation: only ephemeral fixture bind')
            elif event == 'socket.connect':
                if args[1] not in self.endpoints:
                    raise IsolationDenied('unit isolation: only this fixture endpoint')
            elif event not in {'socket.gethostname'}:
                raise IsolationDenied('unit isolation: DNS/socket operation denied')

    def python_payload(self, argv):
        """Closed subprocess inventory; every allowed Python child installs guard."""
        from warden import case_inputs
        if (len(argv) == 5 and argv[:3] == [sys.executable, '-I', '-c']
                and argv[3] == case_inputs._VALIDATE):
            directory = self.fixture_path(argv[4])
            if not directory.name.startswith('warden-case-validator-'):
                raise IsolationDenied('unit isolation: validator fixture directory differs')
            # Reverify copied modules immediately before launch, independently of caller.
            for relative, digest in case_inputs.SOURCE_PINS.items():
                if hashlib.sha256((directory / relative).read_bytes()).hexdigest() != digest:
                    raise IsolationDenied('unit isolation: validator source pin differs')
            return {'code': argv[3], 'args': [str(directory)]}
        if len(argv) == 3 and argv[:2] == [sys.executable, '-c'] and argv[2] == 'print("SYNTHETIC-SECRET")':
            return {'code': argv[2], 'args': []}
        if (len(argv) == 6 and argv[:3] == [sys.executable, '-B', '-c']
                and hashlib.sha256(argv[3].encode()).hexdigest() == JOURNAL_CODE_SHA256):
            self.fixture_path(argv[4])
            if len(argv[5]) > 192:
                raise IsolationDenied('unit isolation: journal source bound')
            return {'code': argv[3], 'args': argv[4:]}
        if len(argv) >= 2 and argv[0] in (sys.executable, 'python3'):
            script = Path(argv[1]).resolve()
            args = argv[2:]
            if script == ROOT / 'tests/unit_isolation_probe.py' and len(args) == 1 and args[0] in {'state', 'socket', 'provider', 'home', 'nested'}:
                return {'script': str(script), 'args': args}
            if script == ROOT / 'scripts/check_layer_conformance.py' and not args:
                return {'script': str(script), 'args': args}
            if script == ROOT / 'scripts/emit_high_risk_paths.py' and args == ['--check']:
                return {'script': str(script), 'args': args, 'git_metadata': True}
            if script == ROOT / 'scripts/check_principals_drift.py' and len(args) == 4 and args[::2] == ['--inventory', '--infra']:
                for value in args[1::2]:
                    self.fixture_path(value)
                return {'script': str(script), 'args': args}
            if script == ROOT / 'scripts/build_flex_auth_registry.py':
                if (len(args) in (3, 5) and Path(args[0]).resolve() == ROOT / 'examples/inventory.seed.yaml'
                        and args[-2] == '-o' and (len(args) == 3 or args[1] == '--zone-resolutions')):
                    self.fixture_path(args[-1])
                    if len(args) == 5:
                        self.fixture_path(args[2])
                    return {'script': str(script), 'args': args}
        raise IsolationDenied('unit isolation: command not in reviewed subprocess inventory')

    def popen(self, argv, *pos, **kw):
        if pos or kw.get('executable') or kw.get('preexec_fn') or kw.get('pass_fds') or kw.get('close_fds') is False:
            raise IsolationDenied('unit isolation: unexpected process options')
        if kw.pop('shell', False):
            if self.child or not isinstance(argv, str) or argv not in SHELL_FIXTURES:
                raise IsolationDenied('unit isolation: unreviewed shell command')
            return self.spawn(['/bin/bash', '--noprofile', '--norc', '-c', argv], kw)
        if not isinstance(argv, (list, tuple)):
            raise IsolationDenied('unit isolation: argv list required')
        argv = [os.fspath(x) for x in argv]
        # Never run a real provider: the only shell fixture is an exact-byte double.
        from warden.doubles import _DOUBLES
        metadata_commands = (['git', 'log', '-1', '--format=%H %cI', '--', str(ROOT / 'registry/routing/catalog.yaml')],
                             ['git', 'status', '--porcelain', '--', str(ROOT / 'registry/routing/catalog.yaml')])
        if self.child and not (self.git_metadata and argv in metadata_commands):
            raise IsolationDenied('unit isolation: nested process disabled')
        candidate = Path(argv[0])
        if not candidate.is_absolute():
            import shutil
            resolved = shutil.which(argv[0], path=kw.get('env', os.environ).get('PATH', ''))
            candidate = Path(resolved) if resolved else candidate
        if self.child and self.git_metadata:
            if Path(kw.get('cwd', '.')).resolve() != ROOT:
                raise IsolationDenied('unit isolation: metadata cwd differs')
            command = ['/usr/bin/git', '-c', 'core.fsmonitor=false', '-c', 'core.hooksPath=/dev/null', '--no-pager', *argv[1:]]
        elif candidate.is_absolute() and inside(candidate.resolve(), (self.temporary,)) and candidate.name in _DOUBLES:
            if candidate.read_text() != _DOUBLES[candidate.name].script:
                raise IsolationDenied('unit isolation: double bytes differ')
            tail = argv[1:]
            if (candidate.name == 'bao' and tail not in (
                    ['kv', 'get', '-field=NPM_AUTH_TOKEN', 'platform/x/y'],
                    ['kv', 'get', '-field=API_KEY', 'platform/x/y/z'],
                    ['login', '-method=oidc'], ['write', 'secret/x'])) or (candidate.name == 'key-cape' and tail != ['login']):
                raise IsolationDenied('unit isolation: double arguments differ')
            command = ['/bin/bash', '--noprofile', '--norc', str(candidate), *tail]
        else:
            payload = self.python_payload(argv)
            payload.update(temporary=str(self.temporary), read_roots=[str(x) for x in self.read_roots])
            command = [sys.executable, '-I', str(SELF), '--child', json.dumps(payload)]
        return self.spawn(command, kw)

    def spawn(self, command, kw):
        cwd = Path(kw.get('cwd') or ROOT).resolve()
        if not inside(cwd, (ROOT, self.temporary)):
            raise IsolationDenied('unit isolation: non-fixture working directory')
        kw['cwd'] = str(cwd)
        # env supplied by tests is never propagated: even synthetic token mutations
        # remain in the parent. All approved children have only this fresh environment.
        kw['env'] = clean_environment(self.temporary / 'home', self.temporary)
        kw['env'].update(GIT_CONFIG_NOSYSTEM='1', GIT_CONFIG_GLOBAL='/dev/null', GIT_OPTIONAL_LOCKS='0')
        self.launch = tuple(command)
        try:
            return self.original_popen(command, **kw)
        finally:
            self.launch = None

    def install(self):
        sys.addaudithook(self.audit)
        subprocess.Popen = self.popen
        guard = self
        original_socket = socket.socket
        class FixtureSocket(original_socket):
            def bind(self, address):
                super().bind(address)
                guard.endpoints.add(self.getsockname())
        socket.socket = FixtureSocket
        def numeric_addresses(host, port, family=0, type=0, proto=0, flags=0):
            if not guard.loopback_test or (host, port) not in guard.endpoints:
                raise IsolationDenied('unit isolation: DNS/external endpoint denied')
            return [(socket.AF_INET, socket.SOCK_STREAM, 6, '', (host, port))]
        socket.getaddrinfo = numeric_addresses
        def local_name(host=''):
            if not guard.loopback_test or host != '127.0.0.1':
                raise IsolationDenied('unit isolation: hostname lookup denied')
            return 'localhost'
        socket.getfqdn = local_name

    def pytest_configure(self, config):
        config._unit_guard = self

    # Exact single synthetic HTTP test only; no other test gets a loopback lease.
    def pytest_runtest_setup(self, item):
        self.loopback_test = item.nodeid == 'tests/test_desk.py::test_approve_flow_http_dry'
        self.endpoints.clear()

    def pytest_runtest_teardown(self, item):
        self.loopback_test = False
        self.endpoints.clear()


def worker(temporary: Path, arguments: list[str], netkingdom: Path | None, phase: Path | None):
    sys.dont_write_bytecode = True
    tempfile.tempdir = str(temporary)
    paths = [ROOT / 'src']
    if phase:
        paths.append(phase / 'src')
    # Explicit trusted source roots only, never ambient PYTHONPATH/plugins.
    sys.path[:0] = [str(p) for p in paths]
    roots = [ROOT, *paths, Path(sys.prefix), Path(sys.base_prefix), temporary]
    if phase:
        roots.append(phase / 'tests/fixtures/ops-warden-coordination-profile.json')
    if netkingdom:
        roots.append(netkingdom)
        os.environ['WARDEN_TEST_NETKINGDOM_ROOT'] = str(netkingdom)
    guard = Guard(temporary, roots)
    guard.install()
    # Pytest itself and collection run only after installation.
    import pytest
    raise SystemExit(pytest.main(['-p', 'no:cacheprovider', '--basetemp', str(temporary / 'pytest'), *arguments], plugins=[guard]))


def main():
    if sys.argv[1:2] == ['--child']:
        payload = json.loads(sys.argv[2])
        temporary = Path(payload['temporary'])
        sys.dont_write_bytecode = True
        tempfile.tempdir = str(temporary)
        sys.path.insert(0, str(ROOT / 'src'))
        guard = Guard(temporary, [Path(p) for p in payload['read_roots']], child=True,
                      git_metadata=payload.get('git_metadata', False))
        guard.install()
        sys.argv = [payload.get('script', '-c'), *payload['args']]
        if 'script' in payload:
            runpy.run_path(payload['script'], run_name='__main__')
        else:
            exec(compile(payload['code'], '<reviewed-unit-child>', 'exec'), {'__name__': '__main__'})
        return
    if sys.argv[1:2] == ['--worker']:
        temporary = Path(sys.argv[2])
        netkingdom = Path(sys.argv[3]) if sys.argv[3] else None
        phase = Path(sys.argv[4]) if sys.argv[4] else None
        worker(temporary, sys.argv[5:], netkingdom, phase)
        return
    import argparse
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--netkingdom-root', type=Path, default=ROOT.parent / 'net-kingdom')
    parser.add_argument('--phase-memory-root', type=Path, default=ROOT.parent / 'phase-memory')
    options, arguments = parser.parse_known_args()
    netkingdom = options.netkingdom_root.resolve() if options.netkingdom_root.is_dir() else None
    phase = options.phase_memory_root.resolve() if (options.phase_memory_root / 'src').is_dir() else None
    with tempfile.TemporaryDirectory(prefix='warden-unit-') as directory:
        temporary = Path(directory)
        home = temporary / 'home'
        home.mkdir()
        result = subprocess.run([sys.executable, '-I', str(SELF), '--worker', str(temporary),
                                 str(netkingdom) if netkingdom else '', str(phase) if phase else '', *arguments],
                                cwd=ROOT, env=clean_environment(home, temporary))
        raise SystemExit(result.returncode)


if __name__ == '__main__':
    main()