"""
Gunicorn config extension and hooks. This config file adds some extra settings and memory management.
Gunicorn configuration should be managed by .ini files entries of RhodeCode or VCSServer
"""

import gc
import os
import sys
import math
import time
import threading
import traceback
import random
from gunicorn.glogging import Logger


def get_workers():
    import multiprocessing
    return multiprocessing.cpu_count() * 2 + 1

# GLOBAL
errorlog = '-'
accesslog = '-'


# SERVER MECHANICS
# None == system temp dir
# worker_tmp_dir is recommended to be set to some tmpfs
worker_tmp_dir = None
tmp_upload_dir = None

# Custom log format
access_log_format = (
    '%(t)s %(p)s INFO  [GNCRN] %(h)-15s rqt:%(L)s %(s)s %(b)-6s "%(m)s:%(U)s %(q)s" usr:%(u)s "%(f)s" "%(a)s"')

# self adjust workers based on CPU count
# workers = get_workers()


def _get_process_rss(pid=None):
    try:
        import psutil
        if pid:
            proc = psutil.Process(pid)
        else:
            proc = psutil.Process()
        return proc.memory_info().rss
    except Exception:
        return None


def _get_config(ini_path):

    try:
        import configparser
    except ImportError:
        import ConfigParser as configparser
    try:
        config = configparser.RawConfigParser()
        config.read(ini_path)
        return config
    except Exception:
        return None


def _time_with_offset(memory_usage_check_interval):
    return time.time() - random.randint(0, memory_usage_check_interval/2.0)


def pre_fork(server, worker):
    pass


def post_fork(server, worker):

    # memory spec defaults
    _memory_max_usage = 0
    _memory_usage_check_interval = 60
    _memory_usage_recovery_threshold = 0.8

    ini_path = os.path.abspath(server.cfg.paste)
    conf = _get_config(ini_path)

    section = 'server:main'
    if conf and conf.has_section(section):

        if conf.has_option(section, 'memory_max_usage'):
            _memory_max_usage = conf.getint(section, 'memory_max_usage')

        if conf.has_option(section, 'memory_usage_check_interval'):
            _memory_usage_check_interval = conf.getint(section, 'memory_usage_check_interval')

        if conf.has_option(section, 'memory_usage_recovery_threshold'):
            _memory_usage_recovery_threshold = conf.getfloat(section, 'memory_usage_recovery_threshold')

    worker._memory_max_usage = _memory_max_usage
    worker._memory_usage_check_interval = _memory_usage_check_interval
    worker._memory_usage_recovery_threshold = _memory_usage_recovery_threshold

    # register memory last check time, with some random offset so we don't recycle all
    # at once
    worker._last_memory_check_time = _time_with_offset(_memory_usage_check_interval)

    if _memory_max_usage:
        server.log.info("[%-10s] WORKER spawned with max memory set at %s", worker.pid,
                        _format_data_size(_memory_max_usage))
    else:
        server.log.info("[%-10s] WORKER spawned", worker.pid)


def pre_exec(server):
    server.log.info("Forked child, re-executing.")


def on_starting(server):
    server_lbl = '{} {}'.format(server.proc_name, server.address)
    server.log.info("Server %s is starting.", server_lbl)


def when_ready(server):
    server.log.info("Server %s is ready. Spawning workers", server)


def on_reload(server):
    pass


def _format_data_size(size, unit="B", precision=1, binary=True):
    """Format a number using SI units (kilo, mega, etc.).

    ``size``: The number as a float or int.

    ``unit``: The unit name in plural form. Examples: "bytes", "B".

    ``precision``: How many digits to the right of the decimal point. Default
    is 1.  0 suppresses the decimal point.

    ``binary``: If false, use base-10 decimal prefixes (kilo = K = 1000).
    If true, use base-2 binary prefixes (kibi = Ki = 1024).

    ``full_name``: If false (default), use the prefix abbreviation ("k" or
    "Ki").  If true, use the full prefix ("kilo" or "kibi"). If false,
    use abbreviation ("k" or "Ki").

    """

    if not binary:
        base = 1000
        multiples = ('', 'k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y')
    else:
        base = 1024
        multiples = ('', 'Ki', 'Mi', 'Gi', 'Ti', 'Pi', 'Ei', 'Zi', 'Yi')

    sign = ""
    if size > 0:
        m = int(math.log(size, base))
    elif size < 0:
        sign = "-"
        size = -size
        m = int(math.log(size, base))
    else:
        m = 0
    if m > 8:
        m = 8

    if m == 0:
        precision = '%.0f'
    else:
        precision = '%%.%df' % precision

    size = precision % (size / math.pow(base, m))

    return '%s%s %s%s' % (sign, size.strip(), multiples[m], unit)


def _check_memory_usage(worker):
    memory_max_usage = worker._memory_max_usage
    if not memory_max_usage:
        return

    memory_usage_check_interval = worker._memory_usage_check_interval
    memory_usage_recovery_threshold = memory_max_usage * worker._memory_usage_recovery_threshold

    elapsed = time.time() - worker._last_memory_check_time
    if elapsed > memory_usage_check_interval:
        mem_usage = _get_process_rss()
        if mem_usage and mem_usage > memory_max_usage:
            worker.log.info(
                "memory usage %s > %s, forcing gc",
                _format_data_size(mem_usage), _format_data_size(memory_max_usage))
            # Try to clean it up by forcing a full collection.
            gc.collect()
            mem_usage = _get_process_rss()
            if mem_usage > memory_usage_recovery_threshold:
                # Didn't clean up enough, we'll have to terminate.
                worker.log.warning(
                    "memory usage %s > %s after gc, quitting",
                    _format_data_size(mem_usage), _format_data_size(memory_max_usage))
                # This will cause worker to auto-restart itself
                worker.alive = False
        worker._last_memory_check_time = time.time()


def worker_int(worker):
    worker.log.info("[%-10s] worker received INT or QUIT signal", worker.pid)

    # get traceback info, on worker crash
    id2name = dict([(th.ident, th.name) for th in threading.enumerate()])
    code = []
    for thread_id, stack in sys._current_frames().items():
        code.append(
            "\n# Thread: %s(%d)" % (id2name.get(thread_id, ""), thread_id))
        for fname, lineno, name, line in traceback.extract_stack(stack):
            code.append('File: "%s", line %d, in %s' % (fname, lineno, name))
            if line:
                code.append("  %s" % (line.strip()))
    worker.log.debug("\n".join(code))


def worker_abort(worker):
    worker.log.info("[%-10s] worker received SIGABRT signal", worker.pid)


def worker_exit(server, worker):
    worker.log.info("[%-10s] worker exit", worker.pid)


def child_exit(server, worker):
    worker.log.info("[%-10s] worker child exit", worker.pid)


def pre_request(worker, req):
    worker.start_time = time.time()
    worker.log.debug(
        "GNCRN PRE  WORKER [cnt:%s]: %s %s", worker.nr, req.method, req.path)


def post_request(worker, req, environ, resp):
    total_time = time.time() - worker.start_time
    # Gunicorn sometimes has problems with reading the status_code
    status_code = getattr(resp, 'status_code', '')
    worker.log.debug(
        "GNCRN POST WORKER [cnt:%s]: %s %s resp: %s, Load Time: %.4fs",
        worker.nr, req.method, req.path, status_code, total_time)
    _check_memory_usage(worker)


class RhodeCodeLogger(Logger):
    """
    Custom Logger that allows some customization that gunicorn doesn't allow
    """

    datefmt = r"%Y-%m-%d %H:%M:%S"

    def __init__(self, cfg):
        Logger.__init__(self, cfg)

    def now(self):
        """ return date in RhodeCode Log format """
        now = time.time()
        msecs = int((now - long(now)) * 1000)
        return time.strftime(self.datefmt, time.localtime(now)) + '.{0:03d}'.format(msecs)


logger_class = RhodeCodeLogger