#   Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
launch for multi process training
"""
import sys
import subprocess
import os
import copy
import argparse

from utils.args import ArgumentGroup, print_arguments

# yapf: disable
parser = argparse.ArgumentParser(__doc__)
multip_g = ArgumentGroup(parser, "multiprocessing",
                         "start paddle training using multi-processing mode.")
multip_g.add_arg("node_ips", str, None,
                 "paddle trainer ips")
multip_g.add_arg("node_id", int, None,
                 "the trainer id of the node for multi-node distributed training.")
multip_g.add_arg("print_config", bool, True,
                 "print the config of multi-processing mode.")
multip_g.add_arg("current_node_ip", str, None,
                 "the ip of current node.")
multip_g.add_arg("split_log_path", str, "log",
                 "log path for each trainer.")
multip_g.add_arg("log_prefix", str, "",
                 "the prefix name of job log.")
multip_g.add_arg("nproc_per_node", int, 8,
                 "the number of process to use on each node.")
multip_g.add_arg("selected_gpus", str, "0,1,2,3,4,5,6,7",
                 "the gpus selected to use.")
multip_g.add_arg("training_script", str, None, "the program/script to be lauched "
                                               "in parallel followed by all the arguments", positional_arg=True)
multip_g.add_arg("training_script_args", str, None,
                 "training script args", positional_arg=True, nargs=argparse.REMAINDER)


# yapf: enable

def start_procs(args):
    """ start_procs """
    default_env = os.environ.copy()

    node_id = args.node_id
    print(args.node_ips)
    node_ips = [x.strip() for x in args.node_ips.split(',')]
    current_ip = args.current_node_ip
    num_nodes = len(node_ips)
    selected_gpus = [x.strip() for x in args.selected_gpus.split(',')]
    selected_gpu_num = len(selected_gpus)
    start_port = int(default_env['PADDLE_PORT'])
    all_trainer_endpoints = ""
    for ip in node_ips:
        cur_port = start_port + 1
        for i in range(args.nproc_per_node):
            cur_port += 1
            if all_trainer_endpoints != "":
                all_trainer_endpoints += ","
            all_trainer_endpoints += "%s:%d" % (ip, cur_port)

    nranks = num_nodes * args.nproc_per_node
    gpus_per_proc = args.nproc_per_node % selected_gpu_num
    if gpus_per_proc == 0:
        gpus_per_proc = selected_gpu_num // args.nproc_per_node
    else:
        gpus_per_proc = selected_gpu_num // args.nproc_per_node + 1

    selected_gpus_per_proc = [selected_gpus[i:i + gpus_per_proc]
                              for i in range(0, len(selected_gpus), gpus_per_proc)]

    if args.print_config:
        print("all_trainer_endpoints: ", all_trainer_endpoints,
              ", node_id: ", node_id,
              ", current_ip: ", current_ip,
              ", num_nodes: ", num_nodes,
              ", node_ips: ", node_ips,
              ", gpus_per_proc: ", gpus_per_proc,
              ", selected_gpus_per_proc: ", selected_gpus_per_proc,
              ", nranks: ", nranks)

    current_env = copy.copy(default_env)
    procs = []
    cmds = []
    log_fns = []
    cur_port = start_port + 1
    for i in range(0, args.nproc_per_node):
        trainer_id = node_id * args.nproc_per_node + i
        cur_port += 1
        current_env.update({
            "FLAGS_selected_gpus": "%s" % ",".join([str(s) for s in selected_gpus_per_proc[i]]),
            "PADDLE_TRAINER_ID": "%d" % trainer_id,
            "PADDLE_CURRENT_ENDPOINT": "%s:%d" % (current_ip, cur_port),
            "PADDLE_TRAINERS_NUM": "%d" % nranks,
            "PADDLE_TRAINER_ENDPOINTS": all_trainer_endpoints,
            "PADDLE_NODES_NUM": "%d" % num_nodes
        })

        cmd = [sys.executable, "-u",
               args.training_script] + args.training_script_args
        cmds.append(cmd)

        if args.split_log_path:
            fn = open("%s/%sjob.log.%d" % (args.split_log_path, args.log_prefix, trainer_id), "a")
            log_fns.append(fn)
            process = subprocess.Popen(cmd, env=current_env, stdout=fn, stderr=fn)
        else:
            process = subprocess.Popen(cmd, env=current_env)
        procs.append(process)

    for i in range(len(procs)):
        proc = procs[i]
        proc.wait()
        if len(log_fns) > 0:
            log_fns[i].close()
        if proc.returncode != 0:
            raise subprocess.CalledProcessError(returncode=procs[i].returncode,
                                                cmd=cmds[i])
        else:
            print("proc %d finsh" % i)
    print("run success")


def main(args):
    """ main_func """
    if args.print_config:
        print_arguments(args)
    start_procs(args)


if __name__ == "__main__":
    lanch_args = parser.parse_args()
    main(lanch_args)