"""macresource - Locate and open the resources needed for a script."""

from Carbon import Res
import os
import sys
import MacOS
import macostools

class ArgumentError(TypeError): pass
class ResourceFileNotFoundError(ImportError): pass

def need(restype, resid, filename=None, modname=None):
    """Open a resource file, if needed. restype and resid
    are required parameters, and identify the resource for which to test. If it
    is available we are done. If it is not available we look for a file filename
    (default: modname with .rsrc appended) either in the same folder as
    where modname was loaded from, or otherwise across sys.path.
    
    Returns the refno of the resource file opened (or None)"""

    if modname is None and filename is None:
        raise ArgumentError, "Either filename or modname argument (or both) must be given"
    
    if type(resid) is type(1):
        try:
            h = Res.GetResource(restype, resid)
        except Res.Error:
            pass
        else:
            return None
    else:
        try:
            h = Res.GetNamedResource(restype, resid)
        except Res.Error:
            pass
        else:
            return None
            
    # Construct a filename if we don't have one
    if not filename:
        if '.' in modname:
            filename = modname.split('.')[-1] + '.rsrc'
        else:
            filename = modname + '.rsrc'
    
    # Now create a list of folders to search
    searchdirs = []
    if modname == '__main__':
        # If we're main we look in the current directory
        searchdirs = [os.curdir]
    if sys.modules.has_key(modname):
        mod = sys.modules[modname]
        if hasattr(mod, '__file__'):
            searchdirs = [os.path.dirname(mod.__file__)]
    searchdirs.extend(sys.path)
    
    # And look for the file
    for dir in searchdirs:
        pathname = os.path.join(dir, filename)
        if os.path.exists(pathname):
            break
    else:
        raise ResourceFileNotFoundError, filename
    
    refno = open_pathname(pathname)
    
    # And check that the resource exists now
    if type(resid) is type(1):
        h = Res.GetResource(restype, resid)
    else:
        h = Res.GetNamedResource(restype, resid)
    return refno
    
def open_pathname(pathname, verbose=0):
    """Open a resource file given by pathname, possibly decoding an
    AppleSingle file"""
    try:
        refno = Res.FSpOpenResFile(pathname, 1)
    except Res.Error, arg:
        if arg[0] in (-37, -39):
            # No resource fork. We may be on OSX, and this may be either
            # a data-fork based resource file or a AppleSingle file
            # from the CVS repository.
            try:
                refno = Res.FSOpenResourceFile(pathname, u'', 1)
            except Res.Error, arg:
                if arg[0] != -199:
                    # -199 is "bad resource map"
                    raise
            else:
                return refno
            # Finally try decoding an AppleSingle file
            pathname = _decode(pathname, verbose=verbose)
            refno = Res.FSOpenResourceFile(pathname, u'', 1)
        else:
            raise
    return refno
    
def resource_pathname(pathname, verbose=0):
    """Return the pathname for a resource file (either DF or RF based).
    If the pathname given already refers to such a file simply return it,
    otherwise first decode it."""
    try:
        refno = Res.FSpOpenResFile(pathname, 1)
        Res.CloseResFile(refno)
    except Res.Error, arg:
        if arg[0] in (-37, -39):
            # No resource fork. We may be on OSX, and this may be either
            # a data-fork based resource file or a AppleSingle file
            # from the CVS repository.
            try:
                refno = Res.FSOpenResourceFile(pathname, u'', 1)
            except Res.Error, arg:
                if arg[0] != -199:
                    # -199 is "bad resource map"
                    raise
            else:
                return refno
            # Finally try decoding an AppleSingle file
            pathname = _decode(pathname, verbose=verbose)
        else:
            raise
    return pathname
    
def open_error_resource():
    """Open the resource file containing the error code to error message
    mapping."""
    need('Estr', 1, filename="errors.rsrc", modname=__name__)
    
def _decode(pathname, verbose=0):
    # Decode an AppleSingle resource file, return the new pathname.
    newpathname = pathname + '.df.rsrc'
    if os.path.exists(newpathname) and \
        os.stat(newpathname).st_mtime >= os.stat(pathname).st_mtime:
        return newpathname
    if hasattr(os, 'access') and not \
        os.access(os.path.dirname(pathname), os.W_OK|os.X_OK):
        # The destination directory isn't writeable. Create the file in
        # a temporary directory
        import tempfile
        fd, newpathname = tempfile.mkstemp(".rsrc")
    if verbose:
        print 'Decoding', pathname, 'to', newpathname
    import applesingle
    applesingle.decode(pathname, newpathname, resonly=1)
    return newpathname
