"""
FTP benchmark.

Usage:
    ftpbench --help
    ftpbench -h <host> -u <user> -p <password> [options] login
    ftpbench -h <host> -u <user> -p <password> [options] upload <workdir> [-s <size>]
    ftpbench -h <host> -u <user> -p <password> [options] download <workdir> [-s <size>] [--files <count>]

Connection options:
    -h <host>, --host=<host>              FTP host [default: 127.0.0.1:21]
                                          You can list multiple servers, separated by commas,
                                          e.g.: -h 10.0.0.1,10.0.0.2,10.0.0.3.
                                          Auto-detection of dns round-robin records is supported.
    -u <user>, --user=<user>              FTP user
    -p <password>, --password=<password>  FTP password

Timing options:
    -t <sec>, --timeout=<sec>             Timeout for operation [default: 10]
    --maxrun=<minutes>                    Duration of benchmarking in minutes [default: 5]
    --fixevery=<sec>                      Recording period for stat values [default: 5]

Benchmark options:
    -c <count>, --concurrent=<count>      Concurrent operations [default: 10]
    --csv=<file>                          Save result to csv file
    <workdir>                             Base ftp dir to store test files
    -s <size>, --size=<size>              Size of test files in MB [default: 10]
    --files <count>                       Number of files generated for download test [default: 10]
"""
# ------------------------------------------------------------------------------


__author__ = "Konstantin Enchant <sirkonst@gmail.com>"

try:
    import docopt
except ImportError:  # for standalone
    from . import docopt

from gevent.monkey import patch_all
patch_all()
import gevent
from gevent import Timeout
from gevent.pool import Pool

from contextlib import contextmanager
from ftplib import FTP as _FTP, error_temp, error_perm
from itertools import cycle
import uuid
import os
from socket import error as sock_error

try:
    import dns.resolver as resolver
except ImportError:
    resolver = None

try:
    from timecard import *
except ImportError:  # for standalone
    from .timecard import *
# ------------------------------------------------------------------------------


class Data(object):
    chunk = "x" * 65536

    def __init__(self, size):
        self.size = size
        self.read = 0

    def __iter__(self):
        return self

    def __next__(self):
        tosend = self.size - self.read
        if tosend == 0:
            raise StopIteration

        if tosend > 65536:
            self.read += 65536
            return self.chunk
        else:
            self.read += tosend
            return self.chunk[:tosend]

def parse_hostport(s, default_port=None):
    if s[-1] == ']':
        # ipv6 literal (with no port)
        return (s, default_port)

    out = s.rsplit(":", 1)
    if len(out) == 1:
        # No port
        port = default_port
    else:
        try:
            port = int(out[1])
        except ValueError:
            raise ValueError("Invalid host:port '%s'" % s)

    return (out[0], port)

class FTP(object):

    def __init__(self, host, user, password, timeout, stats):
        self.hosts = host.split(",")
        self.user = user
        self.password = password
        self.timeout = timeout
        self.stats = stats
        if len(self.hosts) > 1:
            self.stats.server = MultiMetric("server")
            for h in self.hosts:
                self.stats.server[h] = Int(h)
        self.upload_files = []

        if len(self.hosts) > 1:
            def _roundrobin():
                for h in cycle(self.hosts):
                    yield h
            self._host_roundrobin = _roundrobin()

    @property
    def port(self):
        n = len(self.hosts)
        if n == 1:
            host, port = parse_hostport(self.hosts[0], default_port=21)
            return port
        else:
            h = next(self._host_roundrobin)
            host, port = parse_hostport(h, default_port=21)
            return port
            
    @property
    def host(self):
        n = len(self.hosts)
        if n == 1:
            host, port = parse_hostport(self.hosts[0], default_port=21)
            return host
        else:
            h = next(self._host_roundrobin)
            self.stats.server[h] += 1
            host, port = parse_hostport(h, default_port=21)
            return host

    @contextmanager
    def connect(self):
        with Timeout(self.timeout):
            ftp = _FTP()
            ftp.set_debuglevel(2)
            ftp.connect(self.host, self.port)
            ftp.login(self.user, self.password)

        try:
            yield ftp
        finally:
            ftp.close()

    def upload(self, path, data):
        with self.connect() as ftp:
            self.upload_files.append(path)

            with Timeout(self.timeout):
                ftp.voidcmd("TYPE I")  # binary mode
                channel = ftp.transfercmd("STOR " + path)

            for chunk in data:
                with Timeout(self.timeout):
                    channel.sendall(bytes(chunk, "utf-8"))
                    self.stats.traffic += len(chunk)

            with Timeout(self.timeout):
                channel.close()
                ftp.voidresp()

    def donwload(self, path):
        with self.connect() as ftp:
            with Timeout(self.timeout):
                ftp.voidcmd("TYPE I")  # binary mode
                channel = ftp.transfercmd("RETR " + path)

            while True:
                with Timeout(self.timeout):
                    chunk = channel.recv(65536)
                    if not chunk:
                        break
                    self.stats.traffic += len(chunk)

            with Timeout(self.timeout):
                channel.close()
                ftp.voidresp()

    def clean(self):
        with self.connect() as ftp:
            for path in self.upload_files:
                ftp.delete(path)


def run_bench_login(opts):
    stats = Timecard(opts["csvfilename"])
    stats.time = AutoDateTime(show_date=False)
    stats.requests = TotalAndSec("request")
    stats.success = TotalAndSec("success")
    stats.latency = Timeit("latency", limits=[1, 2, 5])
    stats.fail = MultiMetric("fails-total")
    stats.fail.timeout = Int("timeout")
    stats.fail.rejected = Int("rejected")

    ftp = FTP(
        opts["host"], opts["user"], opts["password"],
        opts["timeout"], stats=stats)

    print(("\n\rStart login benchmark: concurrent={} timeout={}s\n\r".format(
        opts["concurrent"], opts["timeout"]
    )))

    stats.write_headers()

    def _print_stats():
        i = 0
        while True:
            i += 1
            if i == opts["fixevery"]:
                stats.write_line(fix=True)
                i = 0
            else:
                stats.write_line(fix=False)
            gevent.sleep(1)

    def _check():
        stats.requests += 1
        try:
            with stats.latency():
                with ftp.connect():
                    pass
        except Timeout:
            stats.fail.timeout += 1
        except (error_temp, error_perm, sock_error):
            stats.fail.rejected += 1
        else:
            stats.success += 1

    gr_stats = gevent.spawn(_print_stats)
    gr_pool = Pool(size=opts["concurrent"])
    try:
        with Timeout(opts["maxrun"] * 60 or None):
            while True:
                gr_pool.wait_available()
                gr_pool.spawn(_check)
    except (KeyboardInterrupt, Timeout):
        pass
    finally:
        print("\n")
        gr_stats.kill()
        gr_pool.kill()


def run_bench_upload(opts):
    stats = Timecard(opts["csvfilename"])
    stats.time = AutoDateTime(show_date=False)
    stats.request = MultiMetric("request")
    stats.request.total = Int("total")
    stats.request.complete = Int("complete")
    stats.request.timeout = Int("timeout")
    stats.request.rejected = Int("rejected")
    stats.traffic = Traffic("traffic")
    stats.uploadtime = Timeit("upload-time")

    ftp = FTP(
        opts["host"], opts["user"], opts["password"],
        opts["timeout"], stats=stats
    )

    print((
        "\n\rStart upload benchmark: concurrent={} timeout={}s size={}MB\n\r"
        "".format(opts["concurrent"], opts["timeout"], opts["size"])
    ))

    stats.write_headers()

    def _print_stats():
        i = 0
        while True:
            i += 1
            if i == opts["fixevery"]:
                stats.write_line(fix=True)
                i = 0
            else:
                stats.write_line(fix=False)
            gevent.sleep(1)

    def _check():
        stats.request.total += 1
        try:
            path = os.path.join(
                opts["workdir"], "bench_write-%s" % uuid.uuid1().hex)
            data = Data(opts["size"] * 1024 * 1024)
            with stats.uploadtime():
                ftp.upload(path, data)
        except Timeout:
            stats.request.timeout += 1
        except (error_temp, error_perm, sock_error):
            stats.request.rejected += 1
        else:
            stats.request.complete += 1

    gr_stats = gevent.spawn(_print_stats)
    gr_pool = Pool(size=opts["concurrent"])
    try:
        with Timeout(opts["maxrun"] * 60 or None):
            while True:
                gr_pool.wait_available()
                gr_pool.spawn(_check)
    except (KeyboardInterrupt, Timeout):
        pass
    finally:
        print("\n")
        gr_stats.kill()
        gr_pool.kill()
        print("Cleanning...")
        ftp.timeout = 60
        ftp.clean()


def run_bench_download(opts):
    stats = Timecard(opts["csvfilename"])
    stats.time = AutoDateTime(show_date=False)
    stats.request = MultiMetric("request")
    stats.request.total = Int("total")
    stats.request.complete = Int("complete")
    stats.request.timeout = Int("timeout")
    stats.request.rejected = Int("rejected")
    stats.traffic = Traffic("traffic")
    stats.downloadtime = Timeit("download-time")

    ftp = FTP(
        opts["host"], opts["user"], opts["password"],
        opts["timeout"], stats=stats
    )

    print("Preparing for testing...")
    ftp.timeout = 60
    for _ in range(opts["countfiles"]):
        path = os.path.join(
            opts["workdir"], "bench_read-%s" % uuid.uuid1().hex)
        data = Data(opts["size"] * 1024 * 1024)
        ftp.upload(path, data)
    ftp.timeout = opts["timeout"]
    filesiter = cycle(ftp.upload_files)

    print((
        "\n\rStart download benchmark: concurrent={} timeout={}s size={}MB"
        " filecount={}\n\r"
        "".format(
            opts["concurrent"], opts["timeout"], opts["size"],
            opts["countfiles"])
    ))

    stats.write_headers()

    def _print_stats():
        i = 0
        while True:
            i += 1
            if i == opts["fixevery"]:
                stats.write_line(fix=True)
                i = 0
            else:
                stats.write_line(fix=False)
            gevent.sleep(1)

    def _check():
        stats.request.total += 1
        try:
            with stats.downloadtime():
                ftp.donwload(next(filesiter))
        except Timeout:
            stats.request.timeout += 1
        except (error_temp, error_perm, sock_error):
            stats.request.rejected += 1
        else:
            stats.request.complete += 1

    gr_stats = gevent.spawn(_print_stats)
    gr_pool = Pool(size=opts["concurrent"])
    try:
        with Timeout(opts["maxrun"] * 60 or None):
            while True:
                gr_pool.wait_available()
                gr_pool.spawn(_check)
    except (KeyboardInterrupt, Timeout):
        pass
    finally:
        print("\n")
        gr_stats.kill()
        gr_pool.kill()
        print("Cleanning...")
        ftp.timeout = 60
        ftp.clean()


def main():
    try:
        arguments = docopt.docopt(__doc__)
        opts = dict()

        opts["host"] = arguments["--host"]
        if resolver and "," not in opts["host"]:
            try:
                hosts = []
                for x in resolver.query(opts["host"], "A"):
                    hosts.append(x.to_text())
                opts["host"] = ",".join(hosts)
            except resolver.NXDOMAIN:
                pass

        opts["user"] = arguments["--user"]
        opts["password"] = arguments["--password"]
        opts["concurrent"] = int(arguments["--concurrent"])
        opts["timeout"] = int(arguments["--timeout"])
        opts["maxrun"] = int(arguments["--maxrun"])
        opts["size"] = int(arguments["--size"])
        opts["workdir"] = arguments["<workdir>"]
        opts["csvfilename"] = arguments["--csv"]
        opts["fixevery"] = int(arguments["--fixevery"])
        opts["countfiles"] = int(arguments["--files"])
    except docopt.DocoptExit as e:
        print(e)
    else:
        if arguments["login"]:
            run_bench_login(opts)
        elif arguments["upload"]:
            run_bench_upload(opts)
        elif arguments["download"]:
            run_bench_download(opts)


if __name__ == "__main__":
    main()