"""SLURM module."""

import re
import shlex
import subprocess
from dataclasses import dataclass, field
from itertools import groupby
from operator import attrgetter


@dataclass
class SlurmCpu:
    """SLURM CPU resource."""

    allocated: int
    idle: int
    total: int

    def __post_init__(self):
        self.allocated = int(self.allocated)
        self.idle = int(self.idle)
        self.total = int(self.total)


@dataclass
class SlurmGpu:
    """SLURM GPU resource."""

    name: str = field(default='None')
    nb: int = field(default=0)

    def __post_init__(self):
        self.name = str(self.name).capitalize()
        self.nb = int(self.nb)

    def __bool__(self):
        return self.nb > 0


@dataclass
class SlurmNode:
    """SLURM node resource."""

    cluster: str
    partition: str
    hostname: str
    state: str
    cpu: SlurmCpu
    mem: int
    gpu: SlurmGpu

    def __init__(self, cluster, partition, hostname, state, cpus_state, memory_mb, gres):  # noqa: PLR0913
        self.cluster = None if 'N/A' in cluster else cluster.strip()
        self.partition = partition.strip()
        self.hostname = hostname.strip()
        self.state = state.strip().lower()
        self.cpu = SlurmCpu(*re.findall(r'(\d+)/(\d+)/\d+/(\d+)', cpus_state)[0])
        self.mem = int(memory_mb) // 1000  # in GB
        self.gpu = SlurmGpu(*re.findall(r'gpu:(\w+):(\d+)', gres)[0] if 'gpu:' in gres else [])


def sinfo_run(username: str = None) -> str:
    """SLURM SINFO run command."""
    flags = '--federation --noheader --responding'
    fmt = 'Cluster,PartitionName,NodeHost,StateLong,CPUsState,Memory,Gres'
    cmd = f'sinfo {flags} --Format={fmt}'

    if username:
        cmd = f'su - {username} -c "{cmd}"'

    return subprocess.check_output(shlex.split(cmd, posix=False)).decode('utf-8')


def sinfo_reader(result: str) -> list:
    """SLURM SINFO reader."""
    return [SlurmNode(*re.findall('.{20}', node)) for node in result.splitlines()]


def sinfo_filter(resources: list, with_states=('idle', 'mixed')) -> dict:
    """SLURM SINFO filtered resources available with a given state(s).

    Grouped by cluster and partition names.

    """
    resources = {
        cluster: {
            partition: available
            for partition, nodes in groupby(partitions, key=attrgetter('partition'))
            if (available := [node for node in nodes if node.state in with_states])
        }
        for cluster, partitions in groupby(resources, key=attrgetter('cluster'))
    }

    return {key: values for key, values in resources.items() if values}


def sinfo(username: str = None, with_states=('idle', 'mixed')) -> dict:
    """SLURM SINFO resources available for a given user."""
    return sinfo_filter(sinfo_reader(sinfo_run(username=username)), with_states=with_states)