import os
import re
from typing import Any

from services.runner import run_cmd


def _top_dirs_cmd(path: str, limit: int) -> list[str]:
    _ = limit
    return ["du", "-x", "-h", "-d", "1", path]


_SIZE_RE = re.compile(r"^\s*([0-9]+(?:\.[0-9]+)?)([KMGTP]?)(i?B?)?$", re.IGNORECASE)


def _size_to_bytes(value: str) -> float:
    m = _SIZE_RE.match(value.strip())
    if not m:
        return -1.0
    num = float(m.group(1))
    unit = (m.group(2) or "").upper()
    mul = {
        "": 1,
        "K": 1024,
        "M": 1024**2,
        "G": 1024**3,
        "T": 1024**4,
        "P": 1024**5,
    }.get(unit, 1)
    return num * mul


def _format_top_dirs(raw: str, limit: int) -> str:
    rows: list[tuple[float, str]] = []
    for line in raw.splitlines():
        line = line.strip()
        if not line:
            continue
        parts = line.split(maxsplit=1)
        if len(parts) != 2:
            continue
        size, name = parts
        rows.append((_size_to_bytes(size), f"{size}\t{name}"))
    rows.sort(key=lambda x: x[0])
    return "\n".join(line for _sz, line in rows[-max(1, limit):])


async def build_disk_report(cfg: dict[str, Any], mount: str, usage: int) -> str:
    limit = int(cfg.get("disk_report", {}).get("top_dirs", 8))

    lines = ["🧱 Disk report", f"💽 {mount}: {usage}%"]

    rc, out = await run_cmd(_top_dirs_cmd(mount, limit), timeout=30)
    if rc == 0 and out.strip():
        top_out = _format_top_dirs(out, limit)
        lines.append("")
        lines.append("Top directories:")
        lines.append(top_out)

    docker_dir = cfg.get("disk_report", {}).get("docker_dir", "/var/lib/docker")
    if docker_dir and os.path.exists(docker_dir):
        rc2, out2 = await run_cmd(_top_dirs_cmd(docker_dir, limit), timeout=30)
        if rc2 == 0 and out2.strip():
            top_out2 = _format_top_dirs(out2, limit)
            lines.append("")
            lines.append(f"Docker dir: {docker_dir}")
            lines.append(top_out2)

    logs_dir = cfg.get("disk_report", {}).get("logs_dir", "/var/log")
    if logs_dir and os.path.exists(logs_dir):
        rc3, out3 = await run_cmd(_top_dirs_cmd(logs_dir, limit), timeout=30)
        if rc3 == 0 and out3.strip():
            top_out3 = _format_top_dirs(out3, limit)
            lines.append("")
            lines.append(f"Logs dir: {logs_dir}")
            lines.append(top_out3)

    return "\n".join(lines)