#!/usr/bin/env python


__license__ = 'GPL v3'
__copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'

import itertools
import json
import os
import shlex
import subprocess
import sys
from collections import namedtuple
from contextlib import closing
from functools import partial
from multiprocessing.pool import ThreadPool as Pool
from threading import Thread

from polyglot.builtins import as_bytes

Job = namedtuple('Job', 'cmd human_text cwd')

cpu_count = min(16, max(1, os.cpu_count()))


def run_worker(job, decorate=True):
    cmd, human_text = job.cmd, job.human_text
    human_text = human_text or shlex.join(cmd)
    cwd = job.cwd
    if cmd[0].lower().endswith('cl.exe'):
        cwd = os.environ.get('COMPILER_CWD')
    try:
        p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=cwd)
    except Exception as err:
        return False, human_text, str(err)
    stdout, stderr = p.communicate()
    if stdout:
        stdout = stdout.decode('utf-8')
    if stderr:
        stderr = stderr.decode('utf-8')
    if decorate:
        stdout = human_text + '\n' + (stdout or '')
    ok = p.returncode == 0
    return ok, stdout, (stderr or '')


def create_job(cmd, human_text=None, cwd=None):
    return Job(cmd, human_text, cwd)


def parallel_build(jobs, log, verbose=True):
    p = Pool(cpu_count)
    with closing(p):
        for ok, stdout, stderr in p.imap(run_worker, jobs):
            if verbose or not ok:
                log(stdout)
                if stderr:
                    log(stderr)
            if not ok:
                return False
        return True


def parallel_build_silent(jobs):
    p = Pool(cpu_count)
    results = []
    failed = False
    with closing(p):
        for (ok, stdout, stderr), job in zip(p.imap(partial(run_worker, decorate=False), jobs), jobs):
            results.append((ok, job.cmd, job.human_text, stdout, stderr))
            if not ok:
                failed = True
    return failed, results


def parallel_check_output(jobs, log):
    p = Pool(cpu_count)
    with closing(p):
        for ok, stdout, stderr in p.imap(
                partial(run_worker, decorate=False), ((j, '') for j in jobs)):
            if not ok:
                log(stdout)
                if stderr:
                    log(stderr)
                raise SystemExit(1)
            yield stdout


def get_tasks(it):
    it = tuple(it)
    size, extra = divmod(len(it), cpu_count)
    if extra:
        size += 1
    it = iter(it)
    while 1:
        x = tuple(itertools.islice(it, size))
        if not x:
            return
        yield x


def batched_parallel_jobs(cmd, jobs, cwd=None):
    workers = []

    def get_output(p):
        p.output = p.communicate(as_bytes(json.dumps(p.jobs_batch)))

    for batch in get_tasks(jobs):
        p = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=cwd)
        p.jobs_batch = batch
        p.output_thread = t = Thread(target=get_output, args=(p,))
        t.daemon = True
        t.start()
        workers.append(p)

    failed = False
    ans = []
    for p in workers:
        p.output_thread.join()
        if p.wait() != 0:
            sys.stderr.buffer.write(p.output[1])
            sys.stderr.buffer.flush()
            failed = True
        else:
            ans.extend(json.loads(p.output[0]))
    if failed:
        raise SystemExit('Worker process failed')
    return ans


def threaded_func_jobs(func, jobs_args):

    def f(args):
        return func(*args)

    p = Pool(cpu_count)
    with closing(p):
        return p.map(f, jobs_args)
