import logging, warnings
from twisted.python.filepath import FilePath
from os import path, getenv
from rdflib import Graph
from rdflib import URIRef
from namespaces import MUS, L9
log = logging.getLogger('showconfig')

_config = None # graph
def getGraph():
    warnings.warn("code that's using showconfig.getGraph should be "
                  "converted to use the sync graph", stacklevel=2)
    global _config
    if _config is None:
        graph = Graph()
        # note that logging is probably not configured the first time
        # we're in here
        warnings.warn("reading n3 files around %r" % root())
        for f in FilePath(root()).globChildren("*.n3") + FilePath(root()).globChildren("build/*.n3"):
            graph.parse(location=f.path, format='n3')
        _config = graph
    return _config

def root():
    r = getenv("LIGHT9_SHOW")
    if r is None:
        raise OSError(
            "LIGHT9_SHOW env variable has not been set to the show root")
    return r

_showUri = None
def showUri():
    """Return the show URI associated with $LIGHT9_SHOW."""
    global _showUri
    if _showUri is None:
        _showUri = URIRef(file(path.join(root(), 'URI')).read().strip())
    return _showUri

def songOnDisk(song):
    """given a song URI, where's the on-disk file that mpd would read?"""
    graph = getGraph()
    root = graph.value(showUri(), L9['musicRoot'])
    if not root:
        raise ValueError("%s has no :musicRoot" % showUri())

    name = graph.value(song, L9['songFilename'])
    if not name:
        raise ValueError("Song %r has no :songFilename" % song)

    return path.abspath(path.join(root, name))

def songFilenameFromURI(uri):
    """
    'http://light9.bigasterisk.com/show/dance2007/song8' -> 'song8'

    everything that uses this should be deprecated for real URIs
    everywhere"""
    assert isinstance(uri, URIRef)
    return uri.split('/')[-1]

def getSongsFromShow(graph, show):
    playList = graph.value(show, L9['playList'])
    if not playList:
        raise ValueError("%r has no l9:playList" % show)
    # The patch in https://github.com/RDFLib/rdflib/issues/305 fixed a
    # serious bug here.
    songs = list(graph.items(playList))

    return songs

def curvesDir():
    return path.join(root(),"curves")

def subFile(subname):
    return path.join(root(),"subs",subname)

def subsDir():
    return path.join(root(),'subs')