# Copyright 2021 Max Planck Institute for Software Systems, and
# National University of Singapore
#
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# without limitation the rights to use, copy, modify, merge, publish,
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# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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import argparse
import sys
import os
import importlib
import importlib.util
import json
import pickle
import fnmatch
import simbricks.exectools as exectools
import simbricks.experiments as exp
import simbricks.runtime as runtime

def mkdir_if_not_exists(path):
    if not os.path.exists(path):
        os.mkdir(path)


parser = argparse.ArgumentParser()
parser.add_argument('experiments', metavar='EXP', type=str, nargs='+',
        help='An experiment file to run')
parser.add_argument('--filter', metavar='PATTERN', type=str, nargs='+',
        help='Pattern to match experiment names against')
parser.add_argument('--pickled', action='store_const', const=True,
        default=False,
        help='Read exp files as pickled runs instead of exp.py files')
parser.add_argument('--runs', metavar='N', type=int, default=1,
        help='Number of repetition for each experiment')
parser.add_argument('--firstrun', metavar='N', type=int, default=1,
        help='ID for first run')
parser.add_argument('--force', action='store_const', const=True, default=False,
        help='Run experiments even if output already exists')
parser.add_argument('--verbose', action='store_const', const=True,
        default=False,
        help='Verbose output')
parser.add_argument('--pcap', action='store_const', const=True, default=False,
        help='Dump pcap file (if supported by simulator)')

g_env = parser.add_argument_group('Environment')
g_env.add_argument('--repo', metavar='DIR', type=str,
        default='..', help='Repo directory')
g_env.add_argument('--workdir', metavar='DIR', type=str,
        default='./out/', help='Work directory base')
g_env.add_argument('--outdir', metavar='DIR',  type=str,
        default='./out/', help='Output directory base')
g_env.add_argument('--cpdir', metavar='DIR',  type=str,
        default='./out/', help='Checkpoint directory base')
g_env.add_argument('--hosts', metavar='JSON_FILE', type=str,
        default=None, help='List of hosts to use (json)')

g_par = parser.add_argument_group('Parallel Runtime')
g_par.add_argument('--parallel', dest='runtime', action='store_const',
        const='parallel', default='sequential',
        help='Use parallel instead of sequential runtime')
g_par.add_argument('--cores', metavar='N', type=int,
        default=len(os.sched_getaffinity(0)),
        help='Number of cores to use for parallel runs')
g_par.add_argument('--mem', metavar='N', type=int, default=None,
        help='Memory limit for parallel runs (in MB)')

g_slurm = parser.add_argument_group('Slurm Runtime')
g_slurm.add_argument('--slurm', dest='runtime', action='store_const',
        const='slurm', default='sequential',
        help='Use slurm instead of sequential runtime')
g_slurm.add_argument('--slurmdir', metavar='DIR',  type=str,
        default='./slurm/', help='Slurm communication directory')

g_dist = parser.add_argument_group('Distributed Runtime')
g_par.add_argument('--dist', dest='runtime', action='store_const',
        const='dist', default='sequential',
        help='Use sequential distributed runtime instead of local')

args = parser.parse_args()


def load_executors(path):
    """ Load hosts list from json file and return list of executors. """
    with open(path, 'r') as f:
        hosts = json.load(f)

        exs = []
        for h in hosts:
            if h['type'] == 'local':
                ex = exectools.LocalExecutor()
            elif h['type'] == 'remote':
                ex = exectools.RemoteExecutor(h['host'], h['workdir'])
            else:
                raise RuntimeError('invalid host type "' + h['type'] + '"')
            ex.ip = h['ip']
            exs.append(ex)
    return exs

if args.hosts is None:
    executors = [exectools.LocalExecutor()]
else:
    executors = load_executors(args.hosts)

def warn_multi_exec():
    if len(executors) > 1:
        print('Warning: multiple hosts specified, only using first one for now',
                file=sys.stderr)

# initialize runtime
if args.runtime == 'parallel':
    warn_multi_exec()
    rt = runtime.LocalParallelRuntime(cores=args.cores, mem=args.mem,
            verbose=args.verbose, exec=executors[0])
elif args.runtime == 'slurm':
    rt = runtime.SlurmRuntime(args.slurmdir, args, verbose=args.verbose)
elif args.runtime == 'dist':
    rt = runtime.DistributedSimpleRuntime(executors, verbose=args.verbose)
else:
    warn_multi_exec()
    rt = runtime.LocalSimpleRuntime(verbose=args.verbose, exec=executors[0])

def add_exp(e, run, prereq, create_cp, restore_cp, no_simbricks):
    outpath = '%s/%s-%d.json' % (args.outdir, e.name, run)
    if os.path.exists(outpath) and not args.force:
        print('skip %s run %d' % (e.name, run))
        return None

    workdir = '%s/%s/%d' % (args.workdir, e.name, run)
    cpdir = '%s/%s/%d' % (args.cpdir, e.name, 0)

    env = exp.ExpEnv(args.repo, workdir, cpdir)
    env.create_cp = create_cp
    env.restore_cp = restore_cp
    env.no_simbricks=no_simbricks
    env.pcap_file = ''
    if args.pcap:
        env.pcap_file = workdir+'/pcap'

    run = runtime.Run(e, run, env, outpath, prereq)
    rt.add_run(run)
    return run

# load experiments
if not args.pickled:
    # default: load python modules with experiments
    experiments = []
    for path in args.experiments:
        modname, _ = os.path.splitext(os.path.basename(path))

        spec = importlib.util.spec_from_file_location(modname, path)
        mod = importlib.util.module_from_spec(spec)
        spec.loader.exec_module(mod)
        experiments += mod.experiments

    for e in experiments:
        # apply filter if any specified
        if (args.filter) and (len(args.filter) > 0):
            match = False
            for f in args.filter:
                if fnmatch.fnmatch(e.name, f):
                    match = True
                    break
            if not match:
                continue

        # if this is an experiment with a checkpoint we might have to create it
        if e.no_simbricks:
                no_simbricks = True
        else:
                no_simbricks = False
        if e.checkpoint:
            prereq = add_exp(e, 0, None, True, False, no_simbricks)
        else:
            prereq = None

        for run in range(args.firstrun, args.firstrun + args.runs):
            add_exp(e, run, prereq, False, e.checkpoint, no_simbricks)
else:
    # otherwise load pickled run object
    for path in args.experiments:
        with open(path, 'rb') as f:
            rt.add_run(pickle.load(f))

rt.start()