"""Tests for BaseEnvironment unified execution model.

Tests _wrap_command(), _extract_cwd_from_output(), _embed_stdin_heredoc(),
init_session() failure handling, and the CWD marker contract.
"""

import subprocess
from unittest.mock import MagicMock

from tools.environments.base import BaseEnvironment


class _TestableEnv(BaseEnvironment):
    """Concrete subclass for testing base class methods."""

    def __init__(self, cwd="/tmp", timeout=10):
        super().__init__(cwd=cwd, timeout=timeout)

    def _run_bash(self, cmd_string, *, login=False, timeout=120, stdin_data=None):
        raise NotImplementedError("Use mock")

    def cleanup(self):
        pass


class TestWrapCommand:
    def test_basic_shape(self):
        env = _TestableEnv()
        env._snapshot_ready = True
        wrapped = env._wrap_command("echo hello", "/tmp")

        assert "source" in wrapped
        assert "cd -- /tmp" in wrapped or "cd -- '/tmp'" in wrapped
        assert "eval 'echo hello'" in wrapped
        assert "__hermes_ec=$?" in wrapped
        assert "export -p >" in wrapped
        assert "pwd -P >" in wrapped
        assert env._cwd_marker in wrapped
        assert "exit $__hermes_ec" in wrapped

    def test_no_snapshot_skips_source(self):
        env = _TestableEnv()
        env._snapshot_ready = False
        wrapped = env._wrap_command("echo hello", "/tmp")

        assert "source" not in wrapped

    def test_single_quote_escaping(self):
        env = _TestableEnv()
        env._snapshot_ready = True
        wrapped = env._wrap_command("echo 'hello world'", "/tmp")

        assert "eval 'echo '\\''hello world'\\'''" in wrapped

    def test_tilde_not_quoted(self):
        env = _TestableEnv()
        env._snapshot_ready = True
        wrapped = env._wrap_command("ls", "~")

        assert "cd -- ~" in wrapped
        assert "cd -- '~'" not in wrapped

    def test_tilde_subpath_with_spaces_uses_home_and_quotes_suffix(self):
        env = _TestableEnv()
        env._snapshot_ready = True
        wrapped = env._wrap_command("ls", "~/my repo")

        assert "cd -- $HOME/'my repo'" in wrapped
        assert "cd -- ~/my repo" not in wrapped

    def test_tilde_slash_maps_to_home(self):
        env = _TestableEnv()
        env._snapshot_ready = True
        wrapped = env._wrap_command("ls", "~/")

        assert "cd -- $HOME" in wrapped
        assert "cd -- ~/" not in wrapped

    def test_hyphen_prefixed_workdir_is_passed_after_double_dash(self):
        env = _TestableEnv()
        env._snapshot_ready = True
        wrapped = env._wrap_command("pwd", "-demo")

        assert "builtin cd -- -demo || exit 126" in wrapped

    def test_cd_failure_exit_126(self):
        env = _TestableEnv()
        env._snapshot_ready = True
        wrapped = env._wrap_command("ls", "/nonexistent")

        assert "exit 126" in wrapped


class TestAtomicSnapshotWrite:
    """Regression for #38249: concurrent terminal calls in one session both
    source AND rewrite the shared env snapshot. A non-atomic ``export -p >
    snap`` truncates-then-writes in place, so a concurrent ``source snap`` can
    read a half-written file and embed ``declare -x``/``export`` fragments into
    PATH, breaking ``ls``/``git``/``tr`` with command-not-found. The write must
    be atomic: ``export -p > snap.tmp.$$`` then ``mv -f snap.tmp.$$ snap`` (mv
    is atomic on POSIX same-fs), so a reader sees the old-or-new complete file,
    never a torn one."""

    def test_wrap_command_uses_atomic_temp_then_mv(self):
        env = _TestableEnv()
        env._snapshot_ready = True
        wrapped = env._wrap_command("echo hi", "/tmp")
        # Writes go to a temp file, not directly over the live snapshot.
        assert "export -p > " in wrapped
        assert ".tmp." in wrapped
        # Then an atomic rename onto the real snapshot path.
        assert "mv -f " in wrapped
        # The env-dump must NOT write the live snapshot in place (the bug).
        snap = env._snapshot_path
        assert f"export -p > {snap} " not in wrapped
        assert f"export -p > '{snap}'" not in wrapped

    def test_temp_path_is_per_process_unique(self):
        """``$$`` (bash PID) makes concurrent processes use distinct temp files
        so their temp writes can't clobber each other before the mv."""
        env = _TestableEnv()
        env._snapshot_ready = True
        wrapped = env._wrap_command("echo hi", "/tmp")
        assert ".tmp.$$" in wrapped or ".tmp.'$$'" in wrapped or "'.tmp.'$$" in wrapped

    def test_temp_path_static_part_is_quoted(self):
        """The static path portion must be shlex-quoted (Windows/Git-Bash
        ``C:/Users/...`` or spaces) while ``$$`` stays outside the quotes so
        it still expands. The bug-prone form is a bare unquoted temp path."""
        env = _TestableEnv()
        env._snapshot_ready = True
        env._snapshot_path = "/tmp/has space/hermes-snap-x.sh"
        wrapped = env._wrap_command("echo hi", "/tmp")
        # The space in the path must be quoted, not left bare in the temp name.
        assert "/tmp/has space/hermes-snap-x.sh.tmp.$$" not in wrapped
        # $$ must remain shell-expandable (not swallowed inside quotes as a literal).
        assert "$$" in wrapped

    def test_init_session_bootstrap_also_atomic(self):
        """The init_session bootstrap (first snapshot write) must be atomic too
        — it's the same shared file a concurrent command could source."""
        env = _TestableEnv()
        captured = {}

        def fake_run_bash(cmd_string, *, login=False, timeout=120, stdin_data=None):
            captured["cmd"] = cmd_string
            raise RuntimeError("stop after capture")  # we only need the script

        env._run_bash = fake_run_bash  # type: ignore[assignment]
        try:
            env.init_session()
        except Exception:
            pass
        boot = captured.get("cmd", "")
        assert ".tmp." in boot and "mv -f " in boot, boot


class TestExtractCwdFromOutput:
    def test_happy_path(self):
        env = _TestableEnv()
        marker = env._cwd_marker
        result = {
            "output": f"hello\n{marker}/home/user{marker}\n",
        }
        env._extract_cwd_from_output(result)

        assert env.cwd == "/home/user"
        assert marker not in result["output"]

    def test_missing_marker(self):
        env = _TestableEnv()
        result = {"output": "hello world\n"}
        env._extract_cwd_from_output(result)

        assert env.cwd == "/tmp"  # unchanged

    def test_marker_in_command_output(self):
        """If the marker appears in command output AND as the real marker,
        rfind grabs the last (real) one."""
        env = _TestableEnv()
        marker = env._cwd_marker
        result = {
            "output": f"user typed {marker} in their output\nreal output\n{marker}/correct/path{marker}\n",
        }
        env._extract_cwd_from_output(result)

        assert env.cwd == "/correct/path"

    def test_output_cleaned(self):
        env = _TestableEnv()
        marker = env._cwd_marker
        result = {
            "output": f"hello\n{marker}/tmp{marker}\n",
        }
        env._extract_cwd_from_output(result)

        assert "hello" in result["output"]
        assert marker not in result["output"]


class TestEmbedStdinHeredoc:
    def test_heredoc_format(self):
        result = BaseEnvironment._embed_stdin_heredoc("cat", "hello world")

        assert result.startswith("cat << '")
        assert "hello world" in result
        assert "HERMES_STDIN_" in result

    def test_unique_delimiter_each_call(self):
        r1 = BaseEnvironment._embed_stdin_heredoc("cat", "data")
        r2 = BaseEnvironment._embed_stdin_heredoc("cat", "data")

        # Extract delimiters
        d1 = r1.split("'")[1]
        d2 = r2.split("'")[1]
        assert d1 != d2  # UUID-based, should be unique


class TestInitSessionFailure:
    def test_snapshot_ready_false_on_failure(self):
        env = _TestableEnv()

        def failing_run_bash(*args, **kwargs):
            raise RuntimeError("bash not found")

        env._run_bash = failing_run_bash
        env.init_session()

        assert env._snapshot_ready is False

    def test_login_flag_when_snapshot_not_ready(self):
        """When _snapshot_ready=False, execute() should pass login=True to _run_bash."""
        env = _TestableEnv()
        env._snapshot_ready = False

        calls = []
        def mock_run_bash(cmd, *, login=False, timeout=120, stdin_data=None):
            calls.append({"login": login})
            # Return a mock process handle
            mock = MagicMock()
            mock.poll.return_value = 0
            mock.returncode = 0
            mock.stdout = iter([])
            return mock

        env._run_bash = mock_run_bash
        env.execute("echo test")

        assert len(calls) == 1
        assert calls[0]["login"] is True


class TestCwdMarker:
    def test_marker_contains_session_id(self):
        env = _TestableEnv()
        assert env._session_id in env._cwd_marker

    def test_unique_per_instance(self):
        env1 = _TestableEnv()
        env2 = _TestableEnv()
        assert env1._cwd_marker != env2._cwd_marker


class TestAtomicSnapshotConcurrencyBehavioral:
    """Behavioral regression for #38249 — actually EXECUTES the generated
    snapshot write concurrently and asserts the file never tears.

    The string-inspection tests prove the right script is emitted; this proves
    the emitted script's guarantee holds: N concurrent writers + readers, and
    the snapshot is ALWAYS a complete, parseable env dump — never truncated
    mid-line with a `declare -x` / `export` fragment that would corrupt PATH.
    """

    def _run(self, script, env=None):
        return subprocess.run(["/bin/bash", "-c", script], capture_output=True,
                              text=True, env=env)

    def test_concurrent_writes_never_tear_the_snapshot(self, tmp_path):
        import shutil
        if not shutil.which("bash"):
            import pytest; pytest.skip("bash required")
        snap = str(tmp_path / "hermes-snap-x.sh")
        _q = __import__("shlex").quote
        _snap_tmp = _q(snap + ".tmp.") + "$$"
        # One writer iteration = the exact atomic sequence _wrap_command emits.
        writer = (
            "for i in $(seq 1 40); do "
            f"export BIG_$i=$(head -c 400 /dev/zero | tr '\\0' x); "
            f"{{ export -p > {_snap_tmp} && mv -f {_snap_tmp} {_q(snap)}; }} "
            f"2>/dev/null || rm -f {_snap_tmp} 2>/dev/null || true; "
            "done"
        )
        # Reader: repeatedly source the snapshot and check PATH never absorbs
        # an `export `/`declare -x` fragment (the corruption signature).
        reader = (
            f"export PATH=/usr/bin:/bin; "
            "for i in $(seq 1 80); do "
            f"( source {_q(snap)} >/dev/null 2>&1 || true; "
            "case \"$PATH\" in *'declare -x'*|*'export '*) echo CORRUPT; ;; esac ); "
            "done"
        )
        # seed a valid snapshot first
        self._run(f"export -p > {_q(snap)}")
        # launch 6 concurrent writers + 6 readers
        procs = [self._run(f"{writer} & {writer} & {reader} & {reader} & wait")
                 for _ in range(3)]
        corrupt = any("CORRUPT" in p.stdout for p in procs)
        assert not corrupt, "snapshot tore — PATH absorbed a declare-x/export fragment"
        # final snapshot must still be a complete, sourceable env dump
        final = self._run(f"source {_q(snap)} >/dev/null 2>&1 && echo OK || echo BROKEN")
        assert "OK" in final.stdout, f"final snapshot not sourceable: {final.stdout} {final.stderr}"

    def test_failed_export_does_not_destroy_good_snapshot(self, tmp_path):
        """If `export -p` fails, the `&&`-chained mv must NOT clobber the
        existing good snapshot (the failure-path fix)."""
        import shutil
        if not shutil.which("bash"):
            import pytest; pytest.skip("bash required")
        snap = str(tmp_path / "snap.sh")
        _q = __import__("shlex").quote
        self._run(f"echo 'export GOOD=1' > {_q(snap)}")  # seed good snapshot
        _snap_tmp = _q(snap + ".tmp.") + "$$"
        # Simulate a failed dump: redirect export into an unwritable temp dir so
        # the export side fails; mv must then NOT run (&&) and not clobber snap.
        bad_tmp = _q("/nonexistent-dir/snap.tmp.") + "$$"
        script = (
            f"{{ export -p > {bad_tmp} && mv -f {bad_tmp} {_q(snap)}; }} "
            f"2>/dev/null || rm -f {bad_tmp} 2>/dev/null || true"
        )
        self._run(script)
        out = self._run(f"cat {_q(snap)}")
        assert "export GOOD=1" in out.stdout, "good snapshot was destroyed by a failed export"