#!/usr/bin/env python

import errno, sys, os

where = os.path.realpath(sys.argv[0])
base = os.path.dirname(os.path.dirname(where))

whoami = '''\
I am a "bin/tahoe" executable who is only for the convenience of running
Tahoe from its source distribution -- I work only when invoked as the "tahoe"
script that lives in the "bin/" subdirectory of a Tahoe source code
distribution, and only if you have already run "make".
'''

# look for Tahoe.home .
homemarker = os.path.join(base, "Tahoe.home")
if not os.path.exists(homemarker):
    print whoami
    print '''\
I just tried to run and found that I am not living in such a directory, so I
am stopping now. To run Tahoe after it has been is installed, please execute
my brother, also named "tahoe", who gets installed into the appropriate place
for executables when you run "make install" (perhaps as /usr/bin/tahoe).
'''
    sys.exit(1)

# we've found our home. Put the tahoe support/lib etc. in our PYTHONPATH.
if sys.platform == "win32":
    supportdir = os.path.join(base, "support", "Lib", "site-packages")
else:
    supportdir = os.path.join(base, "support",
                              "lib",
                              "python%d.%d" % sys.version_info[:2],
                              "site-packages")

# update PYTHONPATH so that child processes (like twistd) will use this too
pp = os.environ.get("PYTHONPATH")
if pp:
    pp = os.pathsep.join([supportdir] + pp.split(os.pathsep))
else:
    pp = supportdir
os.environ["PYTHONPATH"] = pp

executable = os.path.join(base, "support", "bin", "tahoe")

try:
    os.execve(executable, [executable] + sys.argv[1:], os.environ)
except (OSError, IOError), le:
    if le.args[0] == errno.ENOENT:
        print whoami
        print '''\
I just tried to run and could not find my brother, named
"../support/bin/tahoe". To run Tahoe when it is installed, please execute my
brother, also named "tahoe", who gets installed into the appropriate place
for executables when you run "make install" (perhaps as /usr/bin/tahoe).
'''
        raise
except Exception, le:
    print whoami
    print '''\
I just tried to invoke my brother, named "../support/bin/tahoe" and got an
exception.
'''
    raise