"""Parallel workflow execution via SLURM
"""

import os
import sys

from .base import (GraphPluginBase, logger)

from ...interfaces.base import CommandLine


def node_completed_status(checknode):
    """
    A function to determine if a node has previously completed it's work
    :param checknode: The node to check the run status
    :return: boolean value True indicates that the node does not need to be run.
    """
    """ TODO: place this in the base.py file and refactor """
    node_state_does_not_require_overwrite = (checknode.overwrite is False or
                                             (checknode.overwrite is None and not
                                              checknode._interface.always_run)
                                             )
    hash_exists = False
    try:
        hash_exists, _, _, _ = checknode.hash_exists()
    except Exception:
        hash_exists = False
    return (hash_exists and node_state_does_not_require_overwrite)


class SLURMGraphPlugin(GraphPluginBase):
    """Execute using SLURM

    The plugin_args input to run can be used to control the SGE execution.
    Currently supported options are:

    - template : template to use for batch job submission
    - qsub_args : arguments to be prepended to the job execution script in the
                  qsub call

    """
    _template = "#!/bin/bash"

    def __init__(self, **kwargs):
        if 'plugin_args' in kwargs and kwargs['plugin_args']:
            if 'retry_timeout' in kwargs['plugin_args']:
                self._retry_timeout = kwargs['plugin_args']['retry_timeout']
            if 'max_tries' in kwargs['plugin_args']:
                self._max_tries = kwargs['plugin_args']['max_tries']
            if 'template' in kwargs['plugin_args']:
                self._template = kwargs['plugin_args']['template']
                if os.path.isfile(self._template):
                    self._template = open(self._template).read()
            if 'sbatch_args' in kwargs['plugin_args']:
                self._sbatch_args = kwargs['plugin_args']['sbatch_args']
            if 'dont_resubmit_completed_jobs' in kwargs['plugin_args']:
                self._dont_resubmit_completed_jobs = kwargs['plugin_args']['dont_resubmit_completed_jobs']
            else:
                self._dont_resubmit_completed_jobs = False
        super(SLURMGraphPlugin, self).__init__(**kwargs)

    def _submit_graph(self, pyfiles, dependencies, nodes):
        def make_job_name(jobnumber, nodeslist):
            """
            - jobnumber: The index number of the job to create
            - nodeslist: The name of the node being processed
            - return: A string representing this job to be displayed by SLURM
            """
            job_name = 'j{0}_{1}'.format(jobnumber, nodeslist[jobnumber]._id)
            # Condition job_name to be a valid bash identifier (i.e. - is invalid)
            job_name = job_name.replace('-', '_').replace('.', '_').replace(':', '_')
            return job_name
        batch_dir, _ = os.path.split(pyfiles[0])
        submitjobsfile = os.path.join(batch_dir, 'submit_jobs.sh')

        cache_doneness_per_node = dict()
        if self._dont_resubmit_completed_jobs:  # A future parameter for controlling this behavior could be added here
            for idx, pyscript in enumerate(pyfiles):
                node = nodes[idx]
                node_status_done = node_completed_status(node)

                # if the node itself claims done, then check to ensure all
                # dependancies are also done
                if node_status_done and idx in dependencies:
                    for child_idx in dependencies[idx]:
                        if child_idx in cache_doneness_per_node:
                            child_status_done = cache_doneness_per_node[child_idx]
                        else:
                            child_status_done = node_completed_status(nodes[child_idx])
                        node_status_done = node_status_done and child_status_done

                cache_doneness_per_node[idx] = node_status_done

        with open(submitjobsfile, 'wt') as fp:
            fp.writelines('#!/usr/bin/env bash\n')
            fp.writelines('# Condense format attempted\n')
            for idx, pyscript in enumerate(pyfiles):
                node = nodes[idx]
                if cache_doneness_per_node.get(idx, False):
                    continue
                else:
                    template, sbatch_args = self._get_args(
                        node, ["template", "sbatch_args"])

                    batch_dir, name = os.path.split(pyscript)
                    name = '.'.join(name.split('.')[:-1])
                    batchscript = '\n'.join((template,
                                             '%s %s' % (sys.executable, pyscript)))
                    batchscriptfile = os.path.join(batch_dir,
                                                   'batchscript_%s.sh' % name)

                    batchscriptoutfile = batchscriptfile + '.o'
                    batchscripterrfile = batchscriptfile + '.e'

                    with open(batchscriptfile, 'wt') as batchfp:
                        batchfp.writelines(batchscript)
                        batchfp.close()
                    deps = ''
                    if idx in dependencies:
                        values = ''
                        for jobid in dependencies[idx]:
                            # Avoid dependancies of done jobs
                            if not self._dont_resubmit_completed_jobs or cache_doneness_per_node[jobid] == False:
                                values += "${{{0}}}:".format(make_job_name(jobid, nodes))
                        if values != '':  # i.e. if some jobs were added to dependency list
                            values = values.rstrip(':')
                            deps = '--dependency=afterok:%s' % values
                    jobname = make_job_name(idx, nodes)
                    # Do not use default output locations if they are set in self._sbatch_args
                    stderrFile = ''
                    if self._sbatch_args.count('-e ') == 0:
                        stderrFile = '-e {errFile}'.format(
                            errFile=batchscripterrfile)
                    stdoutFile = ''
                    if self._sbatch_args.count('-o ') == 0:
                        stdoutFile = '-o {outFile}'.format(
                            outFile=batchscriptoutfile)
                    full_line = '{jobNm}=$(sbatch {outFileOption} {errFileOption} {extraSBatchArgs} {dependantIndex} -J {jobNm} {batchscript} | awk \'/^Submitted/ {{print $4}}\')\n'.format(
                        jobNm=jobname,
                        outFileOption=stdoutFile,
                        errFileOption=stderrFile,
                        extraSBatchArgs=sbatch_args,
                        dependantIndex=deps,
                        batchscript=batchscriptfile)
                    fp.writelines(full_line)
        cmd = CommandLine('bash', environ=dict(os.environ),
                          terminal_output='allatonce')
        cmd.inputs.args = '%s' % submitjobsfile
        cmd.run()
        logger.info('submitted all jobs to queue')
