"""
managing loading and interacting with pytest plugins. 
"""
import py
from py.__.test.plugin import api

def check_old_use(mod, modname):
    clsname = modname[len('pytest_'):].capitalize() + "Plugin" 
    assert not hasattr(mod, clsname), (mod, clsname)

class PluginManager(object):
    def __init__(self, comregistry=None):
        if comregistry is None: 
            comregistry = py._com.Registry()
        self.comregistry = comregistry 
        self.MultiCall = self.comregistry.MultiCall
        self.impname2plugin = {}

        self.hook = py._com.Hooks(
            hookspecs=api.PluginHooks, 
            registry=self.comregistry) 

    def _getpluginname(self, plugin, name):
        if name is None:
            if hasattr(plugin, '__name__'):
                name = plugin.__name__.split(".")[-1]
            else:
                name = id(plugin) 
        return name 

    def register(self, plugin, name=None):
        assert not self.isregistered(plugin)
        name = self._getpluginname(plugin, name)
        assert name not in self.impname2plugin
        self.impname2plugin[name] = plugin
        self.hook.pytest_plugin_registered(plugin=plugin)
        self.comregistry.register(plugin)
        return True

    def unregister(self, plugin):
        self.hook.pytest_plugin_unregistered(plugin=plugin)
        self.comregistry.unregister(plugin)
        for name, value in self.impname2plugin.items():
            if value == plugin:
                del self.impname2plugin[name]

    def isregistered(self, plugin, name=None):
        return self._getpluginname(plugin, name) in self.impname2plugin

    def getplugins(self):
        return list(self.comregistry)

    # API for bootstrapping 
    #
    def getplugin(self, importname):
        impname = canonical_importname(importname)
        return self.impname2plugin[impname]

    def _envlist(self, varname):
        val = py.std.os.environ.get(varname, None)
        if val is not None:
            return val.split(',')
        return ()
    
    def consider_env(self):
        for spec in self._envlist("PYTEST_PLUGINS"):
            self.import_plugin(spec)

    def consider_preparse(self, args):
        for opt1,opt2 in zip(args, args[1:]):
            if opt1 == "-p": 
                self.import_plugin(opt2)

    def consider_conftest(self, conftestmodule):
        cls = getattr(conftestmodule, 'ConftestPlugin', None)
        if cls is not None:
            raise ValueError("%r: 'ConftestPlugins' only existed till 1.0.0b1, "
                "were removed in 1.0.0b2" % (cls,))
        if self.register(conftestmodule, name=conftestmodule.__file__):
            self.consider_module(conftestmodule)

    def consider_module(self, mod):
        attr = getattr(mod, "pytest_plugins", ())
        if attr:
            if not isinstance(attr, (list, tuple)):
                attr = (attr,)
            for spec in attr:
                self.import_plugin(spec) 

    def import_plugin(self, spec):
        assert isinstance(spec, str)
        modname = canonical_importname(spec)
        if modname in self.impname2plugin:
            return
        mod = importplugin(modname)
        check_old_use(mod, modname) 
        self.register(mod)
        self.consider_module(mod)
    # 
    #
    # API for interacting with registered and instantiated plugin objects 
    #
    # 
    def getfirst(self, attrname):
        for x in self.comregistry.listattr(attrname):
            return x

    def listattr(self, attrname, plugins=None, extra=()):
        return self.comregistry.listattr(attrname, plugins=plugins, extra=extra)

    def notify_exception(self, excinfo=None):
        if excinfo is None:
            excinfo = py.code.ExceptionInfo()
        excrepr = excinfo.getrepr(funcargs=True, showlocals=True)
        return self.hook.pytest_internalerror(excrepr=excrepr)

    def do_addoption(self, parser):
        methods = self.comregistry.listattr("pytest_addoption", reverse=True)
        mc = py._com.MultiCall(methods, parser=parser)
        mc.execute()

    def pytest_plugin_registered(self, plugin):
        if hasattr(self, '_config'):
            self.call_plugin(plugin, "pytest_addoption", parser=self._config._parser)
            self.call_plugin(plugin, "pytest_configure", config=self._config)

    def call_plugin(self, plugin, methname, **kwargs):
        return self.MultiCall(self.listattr(methname, plugins=[plugin]), 
                **kwargs).execute(firstresult=True)

    def do_configure(self, config):
        assert not hasattr(self, '_config')
        config.pluginmanager.register(self)
        self._config = config
        config.hook.pytest_configure(config=self._config)

    def do_unconfigure(self, config):
        config = self._config 
        del self._config 
        config.hook.pytest_unconfigure(config=config)
        config.pluginmanager.unregister(self)

    def do_itemrun(self, item, pdb=None):
        res = self.hook.pytest_itemrun(item=item, pdb=pdb) 
        if res is None:
            raise ValueError("could not run %r" %(item,))

# 
#  XXX old code to automatically load classes
#
def canonical_importname(name):
    name = name.lower()
    modprefix = "pytest_"
    if not name.startswith(modprefix):
        name = modprefix + name 
    return name 

def importplugin(importspec):
    try:
        return __import__(importspec) 
    except ImportError, e:
        if str(e).find(importspec) == -1:
            raise
        try:
            return __import__("py.__.test.plugin.%s" %(importspec), None, None, '__doc__')
        except ImportError, e:
            if str(e).find(importspec) == -1:
                raise
            #print "syspath:", py.std.sys.path
            #print "curdir:", py.std.os.getcwd()
            return __import__(importspec)  # show the original exception