"""HuggingFace Jobs executor — skeleton for v0.

Per ADR-005, HF Jobs is one of two v0 target executors. This file is a
STUB. The full integration uses `huggingface_hub.run_job` (added in
huggingface_hub >= 0.27, ~2026 era) which spins up a containerized job
backed by HF's compute pool.

Pricing reference (2026-05-26): A100 ≈ $4.18/hr, H100 ≈ $9.50/hr. Cold
start ≈ 60s. NO inter-job networking — must use object-store rendezvous.

Status: SKELETON. Real implementation pending v0 polish wave.
"""
from __future__ import annotations

from typing import Any, Callable, Mapping

from composer_replication.diloco.serverless.executor import (
    ReplicaHandle,
    ServerlessExecutor,
)


class HFJobsExecutor(ServerlessExecutor):
    """Run replicas as HuggingFace Jobs in parallel.

    Reference implementation pattern:

        from huggingface_hub import run_job
        jobs = []
        for rank in range(N):
            job = run_job(
                image="...",  # container with composer_replication installed
                command=[
                    "python", "-m",
                    "composer_replication.diloco.serverless.replica_entrypoint",
                    "--rank", str(rank),
                    "--rendezvous", "hf://datasets/myuser/run42/",
                ],
                env={"REPLICA_RANK": str(rank), "WORLD_SIZE": str(N)},
                gpu="a100",
            )
            jobs.append(job)
        return [ReplicaHandle(rank=i, backend_name="hf_jobs",
                              metadata={"job_id": jobs[i].id})
                for i in range(N)]

    Object-store rendezvous works naturally with the HF Datasets-as-storage
    pattern — `hf://datasets/{user}/{run_id}/` is fsspec-compatible via
    `huggingface_hub`'s fsspec integration.

    Status: SKELETON.
    """
    backend_name = "hf_jobs"
    supports_inter_replica_network = False

    def __init__(self) -> None:
        try:
            from huggingface_hub import HfApi  # noqa: F401
        except ImportError as e:
            raise RuntimeError(
                "HFJobsExecutor requires huggingface_hub. Got: " + repr(e)
            )
        # Real implementation: instantiate HfApi, validate token, etc.
        raise NotImplementedError(
            "HFJobsExecutor is a v0 skeleton; full implementation pending. "
            "Use LocalProcessExecutor for testing."
        )

    def launch_replicas(
        self,
        n_replicas: int,
        entrypoint: str | Callable[..., Any],
        entrypoint_args: Mapping[str, Any],
        *,
        gpu: str | None = "a100",
        timeout: int = 3600,
    ) -> list[ReplicaHandle]:
        raise NotImplementedError

    def poll(self, handle: ReplicaHandle) -> str:
        raise NotImplementedError

    def stream_logs(self, handle: ReplicaHandle, *, n_lines: int = 200) -> str:
        raise NotImplementedError

    def cancel(self, handle: ReplicaHandle) -> None:
        raise NotImplementedError

    def collect(
        self,
        handles: list[ReplicaHandle],
        *,
        timeout: int | None = None,
    ) -> list[dict[str, Any]]:
        raise NotImplementedError


__all__ = ["HFJobsExecutor"]