import asyncio
import os
import logging
import re

logger = logging.getLogger(__name__)

# Allow overriding the zpool binary path via env (for bind-mounted host tools)
ZPOOL_BIN = os.environ.get("ZPOOL_BIN", "zpool")


async def get_zfs_pool_map() -> dict[str, dict]:
    """Return a dict mapping device names to ZFS pool and vdev info.

    e.g. {"sda": {"pool": "tank", "vdev": "raidz2-0"},
          "sdb": {"pool": "fast", "vdev": "mirror-0"}}
    """
    pool_map = {}
    try:
        # When running in a container with pid:host, use nsenter to run
        # zpool in the host mount namespace so it finds its own libs.
        use_nsenter = os.environ.get("ZFS_USE_NSENTER", "").lower() in ("1", "true")
        if use_nsenter:
            cmd = ["nsenter", "-t", "1", "-m", "--", "zpool", "status", "-P"]
        else:
            cmd = [ZPOOL_BIN, "status", "-P"]

        proc = await asyncio.create_subprocess_exec(
            *cmd,
            stdout=asyncio.subprocess.PIPE,
            stderr=asyncio.subprocess.PIPE,
        )
        stdout, _ = await proc.communicate()
        if proc.returncode != 0:
            return pool_map

        current_pool = None
        current_vdev = None
        in_config = False

        for line in stdout.decode().splitlines():
            stripped = line.strip()

            if stripped.startswith("pool:"):
                current_pool = stripped.split(":", 1)[1].strip()
                current_vdev = None
                in_config = False
                continue

            if stripped.startswith("NAME") and "STATE" in stripped:
                in_config = True
                continue

            if stripped.startswith("errors:") or stripped == "":
                if stripped.startswith("errors:"):
                    in_config = False
                continue

            if not in_config or not current_pool:
                continue

            # Count leading tab depth to distinguish pool/vdev/device lines.
            # Pool name = 1 tab, vdev = 2 tabs, device = 3+ tabs
            tab_count = len(line) - len(line.lstrip('\t'))

            if tab_count == 2 and "/dev/" not in stripped:
                # This is a vdev line (mirror-0, raidz2-0, etc.)
                current_vdev = stripped.split()[0]
            elif "/dev/" in stripped:
                parts = stripped.split()
                dev_path = parts[0]
                try:
                    real = os.path.realpath(dev_path)
                    dev_name = os.path.basename(real)
                    # Strip partition numbers (sda1 -> sda)
                    dev_name = re.sub(r'\d+$', '', dev_name)
                    pool_map[dev_name] = {
                        "pool": current_pool,
                        "vdev": current_vdev or current_pool,
                    }
                except Exception:
                    pass
    except FileNotFoundError:
        logger.debug("zpool not available")
    return pool_map