import io
import logging
import os
import shlex
import time
import warnings
from typing import ClassVar, Optional
from urllib.parse import urlparse

from sglang.srt.environ import envs
from sglang.srt.utils import kill_process_tree
from sglang.test.test_utils import (
    DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
    DEFAULT_URL_FOR_TEST,
    CustomTestCase,
    is_in_ci,
    popen_launch_pd_server,
    popen_with_error_check,
    start_subprocess_fail_fast_watcher,
)
from sglang.utils import wait_for_http_ready

logger = logging.getLogger(__name__)


class PDDisaggregationServerBase(CustomTestCase):
    capture_per_side_logs: ClassVar[bool] = False
    extra_prefill_env: ClassVar[dict[str, str]] = {}
    extra_decode_env: ClassVar[dict[str, str]] = {}
    _prefill_stdout_buf: ClassVar[Optional[io.StringIO]] = None
    _prefill_stderr_buf: ClassVar[Optional[io.StringIO]] = None
    _decode_stdout_buf: ClassVar[Optional[io.StringIO]] = None
    _decode_stderr_buf: ClassVar[Optional[io.StringIO]] = None

    @classmethod
    def setUpClass(cls):
        os.environ["MC_TCP_ENABLE_CONNECTION_POOL"] = "true"
        parsed_url = urlparse(DEFAULT_URL_FOR_TEST)
        cls.base_host = parsed_url.hostname
        base_port = str(parsed_url.port)
        cls.lb_port = base_port
        cls.prefill_port = f"{int(base_port) + 100}"
        cls.decode_port = f"{int(base_port) + 200}"
        cls.bootstrap_port = f"{int(base_port) + 500}"
        cls.prefill_url = f"http://{cls.base_host}:{cls.prefill_port}"
        cls.decode_url = f"http://{cls.base_host}:{cls.decode_port}"
        cls.lb_url = f"http://{cls.base_host}:{cls.lb_port}"
        cls.base_url = cls.lb_url
        print(
            f"{cls.base_host=} {cls.lb_port=} {cls.prefill_port=} {cls.decode_port=} {cls.bootstrap_port=}"
        )
        cls.process_lb, cls.process_decode, cls.process_prefill = None, None, None
        if cls.capture_per_side_logs:
            cls._prefill_stdout_buf = io.StringIO()
            cls._prefill_stderr_buf = io.StringIO()
            cls._decode_stdout_buf = io.StringIO()
            cls._decode_stderr_buf = io.StringIO()
        cls._fail_fast_stop = None

        # config transfer backend and rdma devices
        cls._mc_gid_index_set = False
        if is_in_ci():
            cls.transfer_backend = ["--disaggregation-transfer-backend", "mooncake"]
            ib_devices = get_rdma_devices_args()
            cls.rdma_devices = ["--disaggregation-ib-device", ib_devices]
            cls._mc_gid_index_set = _maybe_set_roce_gid_index(ib_devices)
        else:
            cls.transfer_backend = [
                "--disaggregation-transfer-backend",
                envs.SGLANG_TEST_PD_DISAGG_BACKEND.get(),
            ]
            cls.rdma_devices = [
                "--disaggregation-ib-device",
                envs.SGLANG_TEST_PD_DISAGG_DEVICES.get(),
            ]
            if cls.rdma_devices[1] is None:
                cls.rdma_devices = []
                msg = "No RDMA devices specified for disaggregation test, using default settings."
                warnings.warn(msg)

    # Subclasses can set these to customize server args
    extra_prefill_args = []
    extra_decode_args = []

    @classmethod
    def start_prefill(cls):
        prefill_args = [
            "--trust-remote-code",
            "--disaggregation-mode",
            "prefill",
            "--disaggregation-bootstrap-port",
            cls.bootstrap_port,
            "--tp",
            "1",
        ] + list(cls.extra_prefill_args)
        prefill_args += cls.transfer_backend + cls.rdma_devices
        cls.process_prefill = popen_launch_pd_server(
            cls.model,
            cls.prefill_url,
            timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
            other_args=prefill_args,
            env=dict(cls.extra_prefill_env),
            return_stdout_stderr=(
                (cls._prefill_stdout_buf, cls._prefill_stderr_buf)
                if cls.capture_per_side_logs
                else None
            ),
        )

    @classmethod
    def start_decode(cls):
        decode_args = [
            "--trust-remote-code",
            "--disaggregation-mode",
            "decode",
            "--disaggregation-bootstrap-port",
            cls.bootstrap_port,
            "--tp",
            "1",
            "--base-gpu-id",
            "1",
        ] + list(cls.extra_decode_args)
        decode_args += cls.transfer_backend + cls.rdma_devices
        cls.process_decode = popen_launch_pd_server(
            cls.model,
            cls.decode_url,
            timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH,
            other_args=decode_args,
            env=dict(cls.extra_decode_env),
            return_stdout_stderr=(
                (cls._decode_stdout_buf, cls._decode_stderr_buf)
                if cls.capture_per_side_logs
                else None
            ),
        )

    @classmethod
    def launch_all(cls):
        """Start prefill, decode, wait for health, and launch LB."""
        cls.start_prefill()
        cls.start_decode()
        cls.wait_server_ready(cls.prefill_url + "/health", process=cls.process_prefill)
        cls.wait_server_ready(cls.decode_url + "/health", process=cls.process_decode)
        cls.launch_lb()
        cls._fail_fast_stop = start_subprocess_fail_fast_watcher(
            [
                ("prefill", cls.process_prefill),
                ("decode", cls.process_decode),
                ("lb", cls.process_lb),
            ]
        )

    @classmethod
    def launch_lb(cls):
        lb_command = [
            "python3",
            "-m",
            "sglang_router.launch_router",
            "--pd-disaggregation",
            "--mini-lb",  # FIXME: remove this
            "--prefill",
            cls.prefill_url,
            "--decode",
            cls.decode_url,
            "--host",
            cls.base_host,
            "--port",
            cls.lb_port,
        ]
        print("Starting load balancer:", shlex.join(lb_command))
        cls.process_lb = popen_with_error_check(lb_command)
        cls.wait_server_ready(cls.lb_url + "/health", process=cls.process_lb)

    @classmethod
    def wait_server_ready(
        cls, url, timeout=DEFAULT_TIMEOUT_FOR_SERVER_LAUNCH, process=None
    ):
        wait_for_http_ready(url=url, timeout=timeout, process=process)
        print(f"Server {url} is ready")

    @classmethod
    def tearDownClass(cls):
        # Stop the watcher BEFORE killing processes: kill_process_tree
        # below makes them exit with a negative signal rc, which would
        # otherwise trip the watcher and os._exit out of pytest mid-teardown.
        if cls._fail_fast_stop is not None:
            cls._fail_fast_stop.set()
        os.environ.pop("MC_TCP_ENABLE_CONNECTION_POOL")
        if getattr(cls, "_mc_gid_index_set", False):
            os.environ.pop("MC_GID_INDEX", None)
        for process in [cls.process_lb, cls.process_decode, cls.process_prefill]:
            if process:
                try:
                    kill_process_tree(process.pid, wait_timeout=60)
                except Exception as e:
                    print(f"Error killing process {process.pid}: {e}")

        if cls.capture_per_side_logs:
            for buf in (
                cls._prefill_stdout_buf,
                cls._prefill_stderr_buf,
                cls._decode_stdout_buf,
                cls._decode_stderr_buf,
            ):
                if buf is not None:
                    buf.close()
            cls._prefill_stdout_buf = None
            cls._prefill_stderr_buf = None
            cls._decode_stdout_buf = None
            cls._decode_stderr_buf = None

        # wait for 5 seconds
        time.sleep(5)


def _get_available_ib_devices():
    """Auto-detect available high-speed RDMA devices from sysfs.

    Filters for devices that are:
    1. Not Ethernet NICs (excludes devices with 'eth' in the name like mlx5_eth0)
    2. Active (port state)
    3. High-speed (rate >= 100 Gbps to exclude regular Ethernet NICs)
    """
    ib_sysfs_path = "/sys/class/infiniband"
    if not os.path.isdir(ib_sysfs_path):
        logger.warning("IB sysfs path %s does not exist", ib_sysfs_path)
        return None

    all_devices = sorted(os.listdir(ib_sysfs_path))
    logger.warning("All IB devices in sysfs: %s", all_devices)

    devices = []
    for dev in all_devices:
        # Check port 1 state and rate (most devices have single port)
        port_path = os.path.join(ib_sysfs_path, dev, "ports", "1")
        if not os.path.isdir(port_path):
            logger.warning("Device %s: SKIPPED (no port 1)", dev)
            continue

        # Read state and rate for logging
        state = "unknown"
        rate = -1
        state_file = os.path.join(port_path, "state")
        rate_file = os.path.join(port_path, "rate")

        try:
            with open(state_file) as f:
                state = f.read().strip()
        except (OSError, IOError):
            pass

        try:
            with open(rate_file) as f:
                rate_str = f.read().strip()
                rate = int(rate_str.split()[0])
        except (OSError, IOError, ValueError, IndexError):
            pass

        # Log device properties for debugging
        logger.warning(
            "Device %s: state=%s, rate=%d Gbps, has_eth_in_name=%s",
            dev,
            state,
            rate,
            "eth" in dev.lower(),
        )

        # Skip devices with "eth" in the name - these are typically Ethernet NICs
        # that don't work properly with RDMA (e.g., mlx5_eth0)
        if "eth" in dev.lower():
            logger.warning("Device %s: SKIPPED (contains 'eth' in name)", dev)
            continue

        # Check if port is active
        # State format is like "4: ACTIVE" or just "ACTIVE"
        if "ACTIVE" not in state.upper():
            logger.warning("Device %s: SKIPPED (state=%s)", dev, state)
            continue

        # Check rate (filter out low-speed NICs like 10/25 Gbps Ethernet)
        if rate >= 0 and rate < 100:  # Skip devices slower than 100 Gbps
            logger.warning("Device %s: SKIPPED (rate=%d Gbps)", dev, rate)
            continue

        devices.append(dev)
        logger.warning("Device %s: INCLUDED", dev)

    logger.warning("Filtered IB devices: %s (count=%d)", devices, len(devices))
    return devices if devices else None


def get_rdma_devices_args():
    def _parse_list_env(var_name: str):
        val = os.getenv(var_name)
        if not val:
            return None
        items = [x.strip() for x in val.split(",") if x.strip()]
        return items or None

    def _pick_default_pair(rdma_all_devices):
        return [rdma_all_devices[0], rdma_all_devices[len(rdma_all_devices) // 2]]

    # Priority: env var > auto-detect > hardcoded fallback
    rdma_all_devices = (
        _parse_list_env("SGLANG_CI_RDMA_ALL_DEVICES")
        or _get_available_ib_devices()
        or [f"mlx5_roce{i}" for i in range(8)]
    )
    logger.warning("Resolved rdma_all_devices=%s", rdma_all_devices)

    n_rdma = len(rdma_all_devices)

    # 1. Get visible GPU indices
    cuda_visible_devices = os.getenv("CUDA_VISIBLE_DEVICES")
    if not cuda_visible_devices:
        warnings.warn("CUDA_VISIBLE_DEVICES is not set. Using default RDMA devices.")
        return ",".join(_pick_default_pair(rdma_all_devices))

    try:
        # Convert to list of integers (handling possible spaces and empty strings)
        gpu_indices = [
            int(idx.strip()) for idx in cuda_visible_devices.split(",") if idx.strip()
        ]
        if not gpu_indices or len(gpu_indices) > 4:
            return ",".join(_pick_default_pair(rdma_all_devices))
    except ValueError:
        warnings.warn(f"Invalid CUDA_VISIBLE_DEVICES format: {cuda_visible_devices}")
        return ",".join(_pick_default_pair(rdma_all_devices))

    # 2. Calculate base RDMA index group (each group of 4 GPUs uses consecutive devices)
    base_rdma_group = (min(gpu_indices) // 4) * 4
    for gpu_idx in gpu_indices:
        if not (base_rdma_group <= gpu_idx < base_rdma_group + 4):
            warnings.warn(
                f"GPU index {gpu_idx} is outside expected group "
                f"{base_rdma_group}-{base_rdma_group+3}"
            )

    # 3. Generate RDMA device names
    # Detect total GPUs on the node (not just visible ones)
    try:
        import torch

        total_gpus = torch.cuda.device_count()
    except Exception:
        total_gpus = 8  # Fallback to common 8-GPU setup

    # Handle edge cases
    if total_gpus == 0:
        total_gpus = 8
    if n_rdma > total_gpus:
        logger.warning(
            "More RDMA devices (%d) than GPUs (%d), using first and middle device",
            n_rdma,
            total_gpus,
        )
        return ",".join(_pick_default_pair(rdma_all_devices))

    # Calculate how many GPUs share each RDMA device
    gpus_per_rdma = max(1, total_gpus // n_rdma)
    logger.warning(
        "GPU-to-RDMA mapping: total_gpus=%d, n_rdma=%d, gpus_per_rdma=%d",
        total_gpus,
        n_rdma,
        gpus_per_rdma,
    )

    rdma_devices = []
    base_gpu = min(gpu_indices)
    for gpu_idx in gpu_indices:
        nic_index = min((gpu_idx - base_gpu) // gpus_per_rdma, n_rdma - 1)
        rdma_devices.append(rdma_all_devices[nic_index])

    if not rdma_devices:
        return ",".join(_pick_default_pair(rdma_all_devices))

    # Deduplicate while preserving order
    return ",".join(dict.fromkeys(rdma_devices))


_IB_SYSFS = "/sys/class/infiniband"


def _roce_v2_gid_index(device: str):
    """Return a RoCEv2 GID index for a device, preferring a global (routable)
    GID over a link-local (fe80::) one, or None if the device has no RoCEv2 GID.
    """
    port = os.path.join(_IB_SYSFS, device, "ports", "1")
    types_dir = os.path.join(port, "gid_attrs", "types")
    try:
        indices = sorted(int(x) for x in os.listdir(types_dir) if x.isdigit())
    except OSError:
        return None
    fallback = None
    for i in indices:
        try:
            with open(os.path.join(types_dir, str(i))) as f:
                if f.read().strip() != "RoCE v2":
                    continue
        except OSError:
            continue
        if fallback is None:
            fallback = i
        try:
            with open(os.path.join(port, "gids", str(i))) as f:
                gid = f.read().strip()
        except OSError:
            gid = ""
        # Prefer a global GID; link-local (fe80::) entries don't route between
        # NICs on some fabrics.
        if gid and not gid.lower().startswith("fe80"):
            return i
    return fallback


def _detect_roce_gid_index(devices):
    """Return a single RoCEv2 GID index shared by all `devices`, or None.

    None when any device is InfiniBand (mooncake selects the GID automatically
    there), when a device has no RoCEv2 GID, or when devices disagree on the
    index — MC_GID_INDEX is a single global value, so a divergent set can't be
    satisfied and is left to mooncake's own selection.
    """
    picked = None
    for device in [d.strip() for d in devices if d.strip()]:
        try:
            with open(os.path.join(_IB_SYSFS, device, "ports", "1", "link_layer")) as f:
                if f.read().strip() != "Ethernet":
                    return None
        except OSError:
            return None
        idx = _roce_v2_gid_index(device)
        if idx is None:
            return None
        if picked is None:
            picked = idx
        elif picked != idx:
            return None
    return picked


def _maybe_set_roce_gid_index(ib_devices) -> bool:
    """Export MC_GID_INDEX for a RoCE fabric; return True if this call set it.

    On RoCE-only hosts mooncake's automatic GID selection can come up empty
    ("GID is NULL, please check your GID index by specifying MC_GID_INDEX"),
    leaving the KV-transfer RDMA endpoint with no GID so every prefill->decode
    transfer fails and PD accuracy collapses to 0. InfiniBand hosts don't need
    this (auto GID works), and a user-provided MC_GID_INDEX is left untouched.
    """
    if not ib_devices or os.environ.get("MC_GID_INDEX"):
        return False
    gid_index = _detect_roce_gid_index(ib_devices.split(","))
    if gid_index is None:
        return False
    os.environ["MC_GID_INDEX"] = str(gid_index)
    logger.warning("RoCE fabric detected; set MC_GID_INDEX=%d for mooncake", gid_index)
    return True