"""Modal cloud execution environment using the native Modal SDK directly.

Uses ``Sandbox.create()`` + ``Sandbox.exec()`` instead of the older runtime
wrapper, while preserving Hermes' persistent snapshot behavior across sessions.
"""

import asyncio
import json
import logging
import shlex
import threading
import uuid
from pathlib import Path
from typing import Any, Dict, Optional

from hermes_constants import get_hermes_home
from tools.environments.base import BaseEnvironment
from tools.interrupt import is_interrupted

logger = logging.getLogger(__name__)

_SNAPSHOT_STORE = get_hermes_home() / "modal_snapshots.json"
_DIRECT_SNAPSHOT_NAMESPACE = "direct"


def _load_snapshots() -> Dict[str, str]:
    """Load snapshot ID mapping from disk."""
    if _SNAPSHOT_STORE.exists():
        try:
            return json.loads(_SNAPSHOT_STORE.read_text())
        except Exception:
            pass
    return {}


def _save_snapshots(data: Dict[str, str]) -> None:
    """Persist snapshot ID mapping to disk."""
    _SNAPSHOT_STORE.parent.mkdir(parents=True, exist_ok=True)
    _SNAPSHOT_STORE.write_text(json.dumps(data, indent=2))


def _direct_snapshot_key(task_id: str) -> str:
    return f"{_DIRECT_SNAPSHOT_NAMESPACE}:{task_id}"


def _get_snapshot_restore_candidate(task_id: str) -> tuple[str | None, bool]:
    """Return a snapshot id and whether it came from the legacy key format."""
    snapshots = _load_snapshots()

    namespaced_key = _direct_snapshot_key(task_id)
    snapshot_id = snapshots.get(namespaced_key)
    if isinstance(snapshot_id, str) and snapshot_id:
        return snapshot_id, False

    legacy_snapshot_id = snapshots.get(task_id)
    if isinstance(legacy_snapshot_id, str) and legacy_snapshot_id:
        return legacy_snapshot_id, True

    return None, False


def _store_direct_snapshot(task_id: str, snapshot_id: str) -> None:
    """Persist the direct Modal snapshot id under the direct namespace."""
    snapshots = _load_snapshots()
    snapshots[_direct_snapshot_key(task_id)] = snapshot_id
    snapshots.pop(task_id, None)
    _save_snapshots(snapshots)


def _delete_direct_snapshot(task_id: str, snapshot_id: str | None = None) -> None:
    """Remove direct Modal snapshot entries for a task, including legacy keys."""
    snapshots = _load_snapshots()
    updated = False

    for key in (_direct_snapshot_key(task_id), task_id):
        value = snapshots.get(key)
        if value is None:
            continue
        if snapshot_id is None or value == snapshot_id:
            snapshots.pop(key, None)
            updated = True

    if updated:
        _save_snapshots(snapshots)


def _resolve_modal_image(image_spec: Any) -> Any:
    """Convert registry references or snapshot ids into Modal image objects."""
    import modal as _modal

    if not isinstance(image_spec, str):
        return image_spec

    if image_spec.startswith("im-"):
        return _modal.Image.from_id(image_spec)

    return _modal.Image.from_registry(
        image_spec,
        setup_dockerfile_commands=[
            "RUN rm -rf /usr/local/lib/python*/site-packages/pip* 2>/dev/null; "
            "python -m ensurepip --upgrade --default-pip 2>/dev/null || true",
        ],
    )


class _AsyncWorker:
    """Background thread with its own event loop for async-safe Modal calls."""

    def __init__(self):
        self._loop: Optional[asyncio.AbstractEventLoop] = None
        self._thread: Optional[threading.Thread] = None
        self._started = threading.Event()

    def start(self):
        self._thread = threading.Thread(target=self._run_loop, daemon=True)
        self._thread.start()
        self._started.wait(timeout=30)

    def _run_loop(self):
        self._loop = asyncio.new_event_loop()
        asyncio.set_event_loop(self._loop)
        self._started.set()
        self._loop.run_forever()

    def run_coroutine(self, coro, timeout=600):
        if self._loop is None or self._loop.is_closed():
            raise RuntimeError("AsyncWorker loop is not running")
        future = asyncio.run_coroutine_threadsafe(coro, self._loop)
        return future.result(timeout=timeout)

    def stop(self):
        if self._loop and self._loop.is_running():
            self._loop.call_soon_threadsafe(self._loop.stop)
        if self._thread:
            self._thread.join(timeout=10)


class ModalEnvironment(BaseEnvironment):
    """Modal cloud execution via native Modal sandboxes."""

    def __init__(
        self,
        image: str,
        cwd: str = "/root",
        timeout: int = 60,
        modal_sandbox_kwargs: Optional[Dict[str, Any]] = None,
        persistent_filesystem: bool = True,
        task_id: str = "default",
    ):
        super().__init__(cwd=cwd, timeout=timeout)

        self._persistent = persistent_filesystem
        self._task_id = task_id
        self._base_image = image
        self._sandbox = None
        self._app = None
        self._worker = _AsyncWorker()
        self._synced_creds: Dict[str, tuple] = {}

        sandbox_kwargs = dict(modal_sandbox_kwargs or {})

        restored_snapshot_id = None
        restored_from_legacy_key = False
        if self._persistent:
            restored_snapshot_id, restored_from_legacy_key = _get_snapshot_restore_candidate(
                self._task_id
            )
            if restored_snapshot_id:
                logger.info("Modal: restoring from snapshot %s", restored_snapshot_id[:20])

        import modal as _modal

        cred_mounts = []
        try:
            from tools.credential_files import get_credential_file_mounts

            for mount_entry in get_credential_file_mounts():
                cred_mounts.append(
                    _modal.Mount.from_local_file(
                        mount_entry["host_path"],
                        remote_path=mount_entry["container_path"],
                    )
                )
                logger.info(
                    "Modal: mounting credential %s -> %s",
                    mount_entry["host_path"],
                    mount_entry["container_path"],
                )
        except Exception as e:
            logger.debug("Modal: could not load credential file mounts: %s", e)

        self._worker.start()

        async def _create_sandbox(image_spec: Any):
            app = await _modal.App.lookup.aio("hermes-agent", create_if_missing=True)
            create_kwargs = dict(sandbox_kwargs)
            if cred_mounts:
                existing_mounts = list(create_kwargs.pop("mounts", []))
                existing_mounts.extend(cred_mounts)
                create_kwargs["mounts"] = existing_mounts
            sandbox = await _modal.Sandbox.create.aio(
                "sleep",
                "infinity",
                image=image_spec,
                app=app,
                timeout=int(create_kwargs.pop("timeout", 3600)),
                **create_kwargs,
            )
            return app, sandbox

        try:
            target_image_spec = restored_snapshot_id or image
            try:
                # _resolve_modal_image keeps the Modal bootstrap fix together:
                # it applies ensurepip via setup_dockerfile_commands before
                # Modal builds or restores the image.
                effective_image = _resolve_modal_image(target_image_spec)
                self._app, self._sandbox = self._worker.run_coroutine(
                    _create_sandbox(effective_image),
                    timeout=300,
                )
            except Exception as exc:
                if not restored_snapshot_id:
                    raise

                logger.warning(
                    "Modal: failed to restore snapshot %s, retrying with base image: %s",
                    restored_snapshot_id[:20],
                    exc,
                )
                _delete_direct_snapshot(self._task_id, restored_snapshot_id)
                base_image = _resolve_modal_image(image)
                self._app, self._sandbox = self._worker.run_coroutine(
                    _create_sandbox(base_image),
                    timeout=300,
                )
            else:
                if restored_snapshot_id and restored_from_legacy_key:
                    _store_direct_snapshot(self._task_id, restored_snapshot_id)
                    logger.info(
                        "Modal: migrated legacy snapshot entry for task %s",
                        self._task_id,
                    )
        except Exception:
            self._worker.stop()
            raise

        logger.info("Modal: sandbox created (task=%s)", self._task_id)

    def _sync_credential_files(self) -> None:
        """Push credential files into the running sandbox."""
        try:
            from tools.credential_files import get_credential_file_mounts

            mounts = get_credential_file_mounts()
            if not mounts:
                return

            for entry in mounts:
                host_path = entry["host_path"]
                container_path = entry["container_path"]
                hp = Path(host_path)
                try:
                    stat = hp.stat()
                    file_key = (stat.st_mtime, stat.st_size)
                except OSError:
                    continue

                if self._synced_creds.get(container_path) == file_key:
                    continue

                try:
                    content = hp.read_text(encoding="utf-8")
                except Exception:
                    continue

                import base64

                b64 = base64.b64encode(content.encode("utf-8")).decode("ascii")
                container_dir = str(Path(container_path).parent)
                cmd = (
                    f"mkdir -p {shlex.quote(container_dir)} && "
                    f"echo {shlex.quote(b64)} | base64 -d > {shlex.quote(container_path)}"
                )

                async def _write():
                    proc = await self._sandbox.exec.aio("bash", "-c", cmd)
                    await proc.wait.aio()

                self._worker.run_coroutine(_write(), timeout=15)
                self._synced_creds[container_path] = file_key
                logger.debug(
                    "Modal: synced credential %s -> %s",
                    host_path,
                    container_path,
                )
        except Exception as e:
            logger.debug("Modal: credential file sync failed: %s", e)

    def execute(
        self,
        command: str,
        cwd: str = "",
        *,
        timeout: int | None = None,
        stdin_data: str | None = None,
    ) -> dict:
        self._sync_credential_files()

        if stdin_data is not None:
            marker = f"HERMES_EOF_{uuid.uuid4().hex[:8]}"
            while marker in stdin_data:
                marker = f"HERMES_EOF_{uuid.uuid4().hex[:8]}"
            command = f"{command} << '{marker}'\n{stdin_data}\n{marker}"

        exec_command, sudo_stdin = self._prepare_command(command)

        # Modal sandboxes execute commands via exec() and cannot pipe
        # subprocess stdin directly. When a sudo password is present,
        # use a shell-level pipe from printf.
        if sudo_stdin is not None:
            exec_command = (
                f"printf '%s\\n' {shlex.quote(sudo_stdin.rstrip())} | {exec_command}"
            )

        effective_cwd = cwd or self.cwd
        effective_timeout = timeout or self.timeout
        full_command = f"cd {shlex.quote(effective_cwd)} && {exec_command}"

        result_holder = {"value": None, "error": None}

        def _run():
            try:
                async def _do_execute():
                    process = await self._sandbox.exec.aio(
                        "bash",
                        "-c",
                        full_command,
                        timeout=effective_timeout,
                    )
                    stdout = await process.stdout.read.aio()
                    stderr = await process.stderr.read.aio()
                    exit_code = await process.wait.aio()
                    if isinstance(stdout, bytes):
                        stdout = stdout.decode("utf-8", errors="replace")
                    if isinstance(stderr, bytes):
                        stderr = stderr.decode("utf-8", errors="replace")
                    output = stdout
                    if stderr:
                        output = f"{stdout}\n{stderr}" if stdout else stderr
                    return output, exit_code

                output, exit_code = self._worker.run_coroutine(
                    _do_execute(),
                    timeout=effective_timeout + 30,
                )
                result_holder["value"] = {
                    "output": output,
                    "returncode": exit_code,
                }
            except Exception as e:
                result_holder["error"] = e

        t = threading.Thread(target=_run, daemon=True)
        t.start()
        while t.is_alive():
            t.join(timeout=0.2)
            if is_interrupted():
                try:
                    self._worker.run_coroutine(
                        self._sandbox.terminate.aio(),
                        timeout=15,
                    )
                except Exception:
                    pass
                return {
                    "output": "[Command interrupted - Modal sandbox terminated]",
                    "returncode": 130,
                }

        if result_holder["error"]:
            return {
                "output": f"Modal execution error: {result_holder['error']}",
                "returncode": 1,
            }
        return result_holder["value"]

    def cleanup(self):
        """Snapshot the filesystem (if persistent) then stop the sandbox."""
        if self._sandbox is None:
            return

        if self._persistent:
            try:
                async def _snapshot():
                    img = await self._sandbox.snapshot_filesystem.aio()
                    return img.object_id

                try:
                    snapshot_id = self._worker.run_coroutine(_snapshot(), timeout=60)
                except Exception:
                    snapshot_id = None

                if snapshot_id:
                    _store_direct_snapshot(self._task_id, snapshot_id)
                    logger.info(
                        "Modal: saved filesystem snapshot %s for task %s",
                        snapshot_id[:20],
                        self._task_id,
                    )
            except Exception as e:
                logger.warning("Modal: filesystem snapshot failed: %s", e)

        try:
            self._worker.run_coroutine(
                self._sandbox.terminate.aio(),
                timeout=15,
            )
        except Exception:
            pass
        finally:
            self._worker.stop()
            self._sandbox = None
            self._app = None