import py
import pytest


def parse_numprocesses(s):
    if s == 'auto':
        import multiprocessing
        return multiprocessing.cpu_count()
    else:
        return int(s)


def pytest_addoption(parser):
    group = parser.getgroup("xdist", "distributed and subprocess testing")
    group._addoption('-n', dest="numprocesses", metavar="numprocesses",
           action="store",
           type=parse_numprocesses,
           help="shortcut for '--dist=load --tx=NUM*popen', "
                "you can use 'auto' here for auto detection CPUs number on "
                "host system")
    group._addoption('--max-slave-restart', action="store", default=None,
                     help="maximum number of slaves that can be restarted "
                          "when crashed (set to zero to disable this feature)")
    group._addoption('--dist', metavar="distmode",
           action="store", choices=['load', 'each', 'no'],
           type="choice", dest="dist", default="no",
           help=("set mode for distributing tests to exec environments.\n\n"
                 "each: send each test to each available environment.\n\n"
                 "load: send each test to available environment.\n\n"
                 "(default) no: run tests inprocess, don't distribute."))
    group._addoption('--tx', dest="tx", action="append", default=[],
           metavar="xspec",
           help=("add a test execution environment. some examples: "
                 "--tx popen//python=python2.5 --tx socket=192.168.1.102:8888 "
                 "--tx ssh=user@codespeak.net//chdir=testcache"))
    group._addoption('-d',
           action="store_true", dest="distload", default=False,
           help="load-balance tests.  shortcut for '--dist=load'")
    group.addoption('--rsyncdir', action="append", default=[], metavar="DIR",
           help="add directory for rsyncing to remote tx nodes.")
    group.addoption('--rsyncignore', action="append", default=[], metavar="GLOB",
           help="add expression for ignores when rsyncing to remote tx nodes.")

    parser.addini('rsyncdirs', 'list of (relative) paths to be rsynced for'
         ' remote distributed testing.', type="pathlist")
    parser.addini('rsyncignore', 'list of (relative) glob-style paths to be ignored '
         'for rsyncing.', type="pathlist")
    parser.addini("looponfailroots", type="pathlist",
        help="directories to check for changes", default=[py.path.local()])

# -------------------------------------------------------------------------
# distributed testing hooks
# -------------------------------------------------------------------------
def pytest_addhooks(pluginmanager):
    from xdist import newhooks
    # avoid warnings with pytest-2.8
    method = getattr(pluginmanager, "add_hookspecs", None)
    if method is None:
        method = pluginmanager.addhooks
    method(newhooks)

# -------------------------------------------------------------------------
# distributed testing initialization
# -------------------------------------------------------------------------


@pytest.mark.trylast
def pytest_configure(config):
    if config.getoption("dist") != "no":
        from xdist.dsession import DSession
        session = DSession(config)
        config.pluginmanager.register(session, "dsession")
        tr = config.pluginmanager.getplugin("terminalreporter")
        tr.showfspath = False

@pytest.mark.tryfirst
def pytest_cmdline_main(config):
    if config.option.numprocesses:
        config.option.dist = "load"
        config.option.tx = ['popen'] * config.option.numprocesses
    if config.option.distload:
        config.option.dist = "load"
    val = config.getvalue
    if not val("collectonly"):
        usepdb = config.option.usepdb  # a core option
        if val("looponfail"):
            if usepdb:
                raise pytest.UsageError("--pdb incompatible with --looponfail.")
        elif val("dist") != "no":
            if usepdb:
                raise pytest.UsageError("--pdb incompatible with distributing tests.")
