"""Per-scan sandbox session lifecycle."""

from __future__ import annotations

import logging
import os
import sys
from pathlib import Path
from typing import TYPE_CHECKING, Any

from agents.sandbox.entries import BaseEntry, LocalDir
from agents.sandbox.manifest import Environment, Manifest

from strix.config import load_settings
from strix.runtime.backends import backend_supports_bind_mounts, get_backend
from strix.runtime.caido_bootstrap import bootstrap_caido


if TYPE_CHECKING:
    from strix.runtime.status import StatusSink


logger = logging.getLogger(__name__)


# In-container Caido sidecar port (matches the image's caido-cli bind).
_CONTAINER_CAIDO_PORT = 48080


_SESSION_CACHE: dict[str, dict[str, Any]] = {}

# Manifest root inside the container; entry keys hang off this path.
_WORKSPACE_ROOT = "/workspace"

_PROTECTED_METADATA_NAMES = (".git", ".agents", ".codex")


def _host_identity_env() -> dict[str, str]:
    # Read the platform through a local so it is not narrowed to whichever OS is
    # type-checking: comparing sys.platform directly makes one of these branches
    # statically dead, and which one flips between Linux and macOS.
    platform_name: str = sys.platform
    if platform_name != "linux":
        return {}
    # Bind-mount ownership only needs mapping on Linux, where the container uid
    # must match the host's.
    return {"STRIX_HOST_UID": str(os.getuid()), "STRIX_HOST_GID": str(os.getgid())}


def build_bind_mounts(local_sources: list[dict[str, Any]]) -> list[dict[str, Any]]:
    bind_mounts: list[dict[str, Any]] = []
    for src in local_sources:
        ws_subdir = src.get("workspace_subdir") or ""
        host_path = src.get("source_path") or ""
        if not ws_subdir or not host_path:
            continue
        resolved = Path(host_path).expanduser().resolve()
        target = f"{_WORKSPACE_ROOT}/{ws_subdir}"
        bind_mounts.append({"source": str(resolved), "target": target, "read_only": False})
        if src.get("protect_metadata"):
            bind_mounts.extend(_metadata_mounts(resolved, target))
    return bind_mounts


def build_manifest_entries(local_sources: list[dict[str, Any]]) -> dict[str | Path, BaseEntry]:
    entries: dict[str | Path, BaseEntry] = {}
    for src in local_sources:
        ws_subdir = src.get("workspace_subdir") or ""
        host_path = src.get("source_path") or ""
        if not ws_subdir or not host_path:
            continue
        entries[ws_subdir] = LocalDir(src=Path(host_path).expanduser().resolve())
    return entries


def _metadata_mounts(tree: Path, target: str) -> list[dict[str, Any]]:
    mounts: list[dict[str, Any]] = []
    for name in _PROTECTED_METADATA_NAMES:
        metadata = tree / name
        if not metadata.is_dir() and not metadata.is_file():
            continue
        if not metadata.resolve().is_relative_to(tree):
            continue
        mounts.append({"source": str(metadata), "target": f"{target}/{name}", "read_only": True})
        gitdir = _gitdir_from_pointer(metadata) if metadata.is_file() else None
        if gitdir is not None and gitdir.exists() and gitdir.is_relative_to(tree):
            relative = gitdir.relative_to(tree).as_posix()
            mounts.append(
                {"source": str(gitdir), "target": f"{target}/{relative}", "read_only": True}
            )
    return mounts


def _gitdir_from_pointer(git_file: Path) -> Path | None:
    try:
        content = git_file.read_text(encoding="utf-8", errors="replace")
    except OSError:
        return None
    for line in content.splitlines():
        prefix, _, value = line.partition(":")
        if prefix.strip() == "gitdir" and value.strip():
            candidate = Path(value.strip()).expanduser()
            if not candidate.is_absolute():
                candidate = git_file.parent / candidate
            return candidate.resolve()
    return None


async def create_or_reuse(
    scan_id: str,
    *,
    image: str,
    local_sources: list[dict[str, Any]],
    status_sink: StatusSink | None = None,
) -> dict[str, Any]:
    """Return the existing session bundle for ``scan_id`` or create a new one.

    Each ``local_sources`` entry exposes its host ``source_path`` at
    ``/workspace/<workspace_subdir>`` inside the container.
    """

    def report(phase: str) -> None:
        if status_sink is not None:
            status_sink(phase)

    cached = _SESSION_CACHE.get(scan_id)
    if cached is not None:
        logger.info("Reusing existing sandbox session for scan %s", scan_id)
        return cached

    backend_name = load_settings().runtime.backend
    backend = get_backend(backend_name)

    if backend_supports_bind_mounts(backend_name):
        bind_mounts = build_bind_mounts(local_sources)
        entries: dict[str | Path, BaseEntry] = {}
    else:
        bind_mounts = []
        entries = build_manifest_entries(local_sources)

    # Caido runs as an in-container sidecar; HTTP(S) traffic from any
    # process started via ``session.exec`` (the SDK's Shell tool, etc.)
    # picks up these env vars automatically. ``NO_PROXY`` keeps the
    # agent-browser CDP daemon's localhost traffic from looping back
    # through Caido.
    container_caido_url = f"http://127.0.0.1:{_CONTAINER_CAIDO_PORT}"
    manifest = Manifest(
        entries=entries,
        environment=Environment(
            value={
                "PYTHONUNBUFFERED": "1",
                "HOST_GATEWAY": "host.docker.internal",
                **_host_identity_env(),
                "http_proxy": container_caido_url,
                "https_proxy": container_caido_url,
                "ALL_PROXY": container_caido_url,
                "NO_PROXY": "localhost,127.0.0.1",
            },
        ),
    )

    logger.info(
        "Creating sandbox session for scan %s (backend=%s, image=%s)",
        scan_id,
        backend_name,
        image,
    )
    report("Starting sandbox container")
    client, session = await backend(
        image=image,
        manifest=manifest,
        exposed_ports=(_CONTAINER_CAIDO_PORT,),
        bind_mounts=bind_mounts,
    )

    report("Setting up the proxy")
    caido_endpoint = await session.resolve_exposed_port(_CONTAINER_CAIDO_PORT)
    scheme = "https" if caido_endpoint.tls else "http"
    host_caido_url = f"{scheme}://{caido_endpoint.host}:{caido_endpoint.port}"
    logger.debug("Caido host endpoint resolved: %s", host_caido_url)

    caido_client = await bootstrap_caido(
        session,
        host_url=host_caido_url,
        container_url=container_caido_url,
    )

    bundle = {
        "client": client,
        "session": session,
        "caido_client": caido_client,
    }
    _SESSION_CACHE[scan_id] = bundle
    logger.info("Sandbox session for scan %s ready and cached", scan_id)
    return bundle


async def cleanup(scan_id: str) -> None:
    """Tear down ``scan_id``'s container and drop its cache entry.

    Best-effort: any error during ``client.delete`` is logged and
    swallowed. We never want a cleanup failure to prevent the next
    scan from starting; the worst case is a stranded container that
    Docker's normal reaping will catch on next ``docker prune``.
    """
    bundle = _SESSION_CACHE.pop(scan_id, None)
    if bundle is None:
        logger.debug("cleanup(%s): no cached session", scan_id)
        return

    caido_client = bundle.get("caido_client")
    if caido_client is not None:
        try:
            await caido_client.aclose()
        except Exception:  # noqa: BLE001
            logger.debug("cleanup(%s): caido_client.aclose() raised", scan_id, exc_info=True)

    client = bundle["client"]
    try:
        await client.delete(bundle["session"])
        logger.info("Cleaned up sandbox session for scan %s", scan_id)
    except Exception:
        logger.exception(
            "cleanup(%s): client.delete raised; container may need manual reaping",
            scan_id,
        )

    docker_client = getattr(client, "docker_client", None)
    if docker_client is not None:
        try:
            docker_client.close()
        except Exception:  # noqa: BLE001
            logger.debug("cleanup(%s): docker_client.close() raised", scan_id, exc_info=True)
