import json
import sys

from . import app
from . import bdev
from . import ioat
from . import iscsi
from . import log
from . import lvol
from . import nbd
from . import net
from . import nvmf
from . import pmem
from . import subsystem
from . import vhost
from . import client as rpc_client


def start_subsystem_init(client):
    """Start initialization of subsystems"""
    return client.call('start_subsystem_init')


def get_rpc_methods(client, current=None):
    """Get list of supported RPC methods.
    Args:
        current: Get list of RPC methods only callable in the current state.
    """
    params = {}

    if current:
        params['current'] = current

    return client.call('get_rpc_methods', params)


def _json_dump(config, filename, indent):
    if filename is None:
        if indent is None:
            indent = 2
        elif indent < 0:
            indent = None
        json.dump(config, sys.stdout, indent=indent)
        sys.stdout.write('\n')
    else:
        if indent is None or indent < 0:
            indent = None
        with open(filename, 'w') as file:
            json.dump(config, file, indent=indent)
            file.write('\n')


def _json_load(filename):
    if not filename or filename == '-':
        return json.load(sys.stdin)

    else:
        with open(filename, 'r') as file:
            return json.load(file)


def save_config(client, filename=None, indent=2):
    """Write current (live) configuration of SPDK subsystems and targets.
    Args:
        filename: File where to save JSON configuration to.
            Print to stdout if not provided.
        indent: Indent level. Value less than 0 mean compact mode.
            If filename is not given default then indent level is 2.
            If writing to file of filename is '-' then default is compact mode.
    """
    config = {
        'subsystems': []
    }

    for elem in client.call('get_subsystems'):
        cfg = {
            'subsystem': elem['subsystem'],
            'config': client.call('get_subsystem_config', {"name": elem['subsystem']})
        }
        config['subsystems'].append(cfg)

    _json_dump(config, filename, indent)


def load_config(client, filename=None):
    """Configure SPDK subsystems and tagets using JSON RPC.
    Args:
        filename: JSON Configuration file location.
            If no file path is provided or file is '-' then read configuration from stdin.
    """
    json_config = _json_load(filename)

    # remove subsystems with no config
    subsystems = json_config['subsystems']
    for subsystem in list(subsystems):
        if not subsystem['config']:
            subsystems.remove(subsystem)

    # check if methods in the config file are known
    allowed_methods = client.call('get_rpc_methods')
    for subsystem in list(subsystems):
        config = subsystem['config']
        for elem in list(config):
            if 'method' not in elem or elem['method'] not in allowed_methods:
                raise rpc_client.JSONRPCException("Unknown method was included in the config file")

    while subsystems:
        allowed_methods = client.call('get_rpc_methods', {'current': True})
        allowed_found = False

        for subsystem in list(subsystems):
            config = subsystem['config']
            for elem in list(config):
                if 'method' not in elem or elem['method'] not in allowed_methods:
                    continue

                client.call(elem['method'], elem['params'])
                config.remove(elem)
                allowed_found = True

            if not config:
                subsystems.remove(subsystem)

        if 'start_subsystem_init' in allowed_methods:
            client.call('start_subsystem_init')
            allowed_found = True

        if not allowed_found:
            break

    if subsystems:
        print("Some configs were skipped because the RPC state that can call them passed over.")


def save_subsystem_config(client, filename=None, indent=2, name=None):
    """Write current (live) configuration of SPDK subsystem.
    Args:
        filename: File where to save JSON configuration to.
            Print to stdout if not provided.
        indent: Indent level. Value less than 0 mean compact mode.
            If filename is not given default then indent level is 2.
            If writing to file of filename is '-' then default is compact mode.
    """
    cfg = {
        'subsystem': name,
        'config': client.call('get_subsystem_config', {"name": name})
    }

    _json_dump(cfg, filename, indent)


def load_subsystem_config(client, filename=None):
    """Configure SPDK subsystem using JSON RPC.
    Args:
        filename: JSON Configuration file location.
            If no file path is provided or file is '-' then read configuration from stdin.
    """
    subsystem = _json_load(filename)

    if not subsystem['config']:
        return

    allowed_methods = client.call('get_rpc_methods')
    config = subsystem['config']
    for elem in list(config):
        if 'method' not in elem or elem['method'] not in allowed_methods:
            raise rpc_client.JSONRPCException("Unknown method was included in the config file")

    allowed_methods = client.call('get_rpc_methods', {'current': True})
    for elem in list(config):
        if 'method' not in elem or elem['method'] not in allowed_methods:
            continue

        client.call(elem['method'], elem['params'])
        config.remove(elem)

    if config:
        print("Some configs were skipped because they cannot be called in the current RPC state.")