from __future__ import generators

import py
from conftesthandle import Conftest

optparse = py.compat.optparse

# XXX move to Config class
basetemp = None
def ensuretemp(string, dir=1): 
    """ return temporary directory path with
        the given string as the trailing part. 
    """ 
    global basetemp
    if basetemp is None: 
        basetemp = py.path.local.make_numbered_dir(prefix='pytest-')
    return basetemp.ensure(string, dir=dir) 
  
class CmdOptions(object):
    """ pure container instance for holding cmdline options 
        as attributes. 
    """
    def __repr__(self):
        return "<CmdOptions %r>" %(self.__dict__,)

class Config(object): 
    """ central hub for dealing with configuration/initialization data. """ 
    Option = optparse.Option

    def __init__(self): 
        self.option = CmdOptions()
        self._parser = optparse.OptionParser(
            usage="usage: %prog [options] [query] [filenames of tests]")
        self.conftest = Conftest()
        self._initialized = False
        self._overwrite_dict = {}

    def parse(self, args): 
        """ parse cmdline arguments into this config object. 
            Note that this can only be called once per testing process. 
        """ 
        assert not self._initialized, (
                "can only parse cmdline args once per Config object")
        self._initialized = True
        self.conftest.setinitial(args) 
        self.conftest.rget('adddefaultoptions')()
        args = [str(x) for x in args]
        cmdlineoption, args = self._parser.parse_args(args) 
        self.option.__dict__.update(vars(cmdlineoption))
        fixoptions(self.option)  # XXX fixing should be moved to sessions
        if not args:
            args.append(py.std.os.getcwd())
        self.topdir = gettopdir(args)
        self.args = args 

    def initdirect(self, topdir, repr, coltrails=None):
        assert not self._initialized
        self._initialized = True
        self.topdir = py.path.local(topdir)
        self.merge_repr(repr)
        self._coltrails = coltrails 

    def getcolitems(self):
        """ return initial collectors. """
        trails = getattr(self, '_coltrails', None)
        return [self._getcollector(path) for path in (trails or self.args)]

    def _getcollector(self, path):
        if isinstance(path, tuple):
            relpath, names = path
            fspath = self.topdir.join(relpath)
            col = self._getcollector(fspath)
        else:
            path = py.path.local(path)
            assert path.check(), "%s: path does not exist" %(path,)
            col = self._getrootcollector(path)
            names = path.relto(col.fspath).split(path.sep)
        return col.getitembynames(names)

    def _getrootcollector(self, path):
        pkgpath = path.pypkgpath()
        if pkgpath is None:
            pkgpath = path.check(file=1) and path.dirpath() or path
        col = self.conftest.rget("Directory", pkgpath)(pkgpath)
        col.config = self
        return col 
             
    def addoptions(self, groupname, *specs): 
        """ add a named group of options to the current testing session. 
            This function gets invoked during testing session initialization. 
        """ 
        optgroup = optparse.OptionGroup(self._parser, groupname) 
        optgroup.add_options(specs) 
        self._parser.add_option_group(optgroup)
        for opt in specs: 
            if hasattr(opt, 'default') and opt.dest:
                setattr(self.option, opt.dest, opt.default) 
        return self.option

    def getvalue(self, name, path=None): 
        """ return 'name' value looked up from the first conftest file 
            found up the path (including the path itself). 
            if path is None, lookup the value in the initial
            conftest modules found during command line parsing. 
        """
        try:
            return self._overwrite_dict[name]
        except KeyError:
            return self.conftest.rget(name, path) 

    def initsession(self):
        """ return an initialized session object. """
        cls = self._getsessionclass()
        session = cls(self)
        #session.fixoptions()
        return session

    def _getsessionclass(self): 
        """ return Session class determined from cmdline options
            and looked up in initial config modules. 
        """
        if self.option.session is not None:
            return self.conftest.rget(self.option.session)
        else:
            name = self._getsessionname()
            importpath = globals()[name]
            mod = __import__(importpath, None, None, '__doc__')
            return getattr(mod, name)

    def _getsessionname(self):
        """ return default session name as determined from options. """
        name = 'TerminalSession'
        if self.option.dist:
            name = 'RSession'
        elif self.option.tkinter:
            name = 'TkinterSession'
        else:
            optnames = 'startserver runbrowser apigen restreport boxing'.split()
            for opt in optnames:
                if getattr(self.option, opt, False):
                    name = 'LSession'
                    break
            else:
                if self.getvalue('dist_boxing'):
                    name = 'LSession'
                if self.option.looponfailing:
                    name = 'RemoteTerminalSession'
                elif self.option.executable:
                    name = 'RemoteTerminalSession'
        return name

    def is_boxed(self):
        # XXX probably not a good idea to have this special function ...
        return self.option.boxing or self.getvalue("dist_boxing")

    def _reparse(self, args):
        """ this is used from tests that want to re-invoke parse(). """
        global config_per_process
        oldconfig = py.test.config
        try:
            config_per_process = py.test.config = Config()
            config_per_process.parse(args) 
            return config_per_process
        finally: 
            config_per_process = py.test.config = oldconfig 

    def _overwrite(self, name, value):
        """ this is used from tests to overwrite values irrespectives of conftests.
        """
        self._overwrite_dict[name] = value

    def make_repr(self, conftestnames, optnames=None): 
        """ return a marshallable representation 
            of conftest and cmdline options. 
            if optnames is None, all options
            on self.option will be transferred. 
        """ 
        conftestdict = {}
        for name in conftestnames: 
            value = self.getvalue(name)
            checkmarshal(name, value)
            conftestdict[name] = value 
        cmdlineopts = {}
        if optnames is None:
            optnames = dir(self.option)
        for name in optnames: 
            if not name.startswith("_"):
                value = getattr(self.option, name)
                checkmarshal(name, value)
                cmdlineopts[name] = value
        l = []
        for path in self.args:
            path = py.path.local(path)
            l.append(path.relto(self.topdir)) 
        return l, conftestdict, cmdlineopts

    def merge_repr(self, repr): 
        """ merge in the conftest and cmdline option values
            found in the given representation (produced
            by make_repr above).  

            The repr-contained conftest values are
            stored on the default conftest module (last
            priority) and the cmdline options on self.option. 
        """
        class override:
            def __init__(self, d):
                self.__dict__.update(d)
        args, conftestdict, cmdlineopts = repr
        self.args = [self.topdir.join(x) for x in args]
        self.conftest.setinitial(self.args)
        self.conftest._path2confmods[None].append(override(conftestdict))
        for name, val in cmdlineopts.items(): 
            setattr(self.option, name, val) 

    def get_collector_trail(self, collector):
        """ provide a trail relative to the topdir, 
            which can be used to reconstruct the
            collector (possibly on a different host
            starting from a different topdir). 
        """ 
        chain = collector.listchain()
        relpath = chain[0].fspath.relto(self.topdir)
        if not relpath:
            if chain[0].fspath == self.topdir:
                relpath = "."
            else:
                raise ValueError("%r not relative to %s" 
                         %(chain[0], self.topdir))
        return relpath, tuple([x.name for x in chain[1:]])

# this is the one per-process instance of py.test configuration 
config_per_process = Config()

# default import paths for sessions 

TkinterSession = 'py.__.test.tkinter.reportsession'
TerminalSession = 'py.__.test.terminal.terminal'
TerminalSession = 'py.__.test.terminal.terminal'
RemoteTerminalSession = 'py.__.test.terminal.remote'
RSession = 'py.__.test.rsession.rsession'
LSession = 'py.__.test.rsession.rsession'

#
# helpers
#

def checkmarshal(name, value):
    try:
        py.std.marshal.dumps(value)
    except ValueError:
        raise ValueError("%s=%r is not marshallable" %(name, value))

def fixoptions(option):
    """ sanity checks and making option values canonical. """

    # implied options
    if option.usepdb:
        if not option.nocapture:
            #print "--pdb implies --nocapture"
            option.nocapture = True

    if option.runbrowser and not option.startserver:
        #print "--runbrowser implies --startserver"
        option.startserver = True

    # conflicting options 
    if option.looponfailing and option.usepdb:
        raise ValueError, "--looponfailing together with --pdb not supported."
    if option.looponfailing and option.dist:
        raise ValueError, "--looponfailing together with --dist not supported."
    if option.executable and option.usepdb:
        raise ValueError, "--exec together with --pdb not supported."


def gettopdir(args): 
    """ return the top directory for the given paths.
        if the common base dir resides in a python package 
        parent directory of the root package is returned. 
    """
    args = [py.path.local(arg) for arg in args]
    p = reduce(py.path.local.common, args)
    assert p, "cannot determine common basedir of %s" %(args,)
    pkgdir = p.pypkgpath()
    if pkgdir is None:
        return p
    else:
        return pkgdir.dirpath()