import os
import sys

M4SS_VALID_MACHINES = [
    'intel-corei7-64',
]

def __set_defaults_m4ss_embedded_linux_yocto():
    global M4SS_VALID_MACHINES
    global M4SS_VALID_DISTROS

    local_conf_exists = os.path.isfile(os.path.join(build_dir, 'conf', 'local.conf'))

    def required_var_error(varname, valid_vals):
        sys.stderr.write("ERROR: You must set '%s' before setting up the environment.\n" % (varname,))
        sys.stderr.write("    Set '%s' variable with one of the possible values.\n"
                         "    Possible values are: %s\n\n" % (varname, valid_vals))
        sys.exit(1)

    def maybe_set_default(varname, valid_vals):
        try:
            val = os.environ[varname]
        except KeyError:
            val = None

        if val:
            if val in valid_vals:
                set_default(varname, val)
                return val
            else:
                required_var_error(varname, valid_vals)
        elif not local_conf_exists:
            required_var_error(varname, valid_vals)

    maybe_set_default('MACHINE', M4SS_VALID_MACHINES)
    set_default('DISTRO', 'm4ss')

def __after_init_m4ss_embedded_linux_yocto():
    PLATFORM_ROOT_DIR = os.environ['PLATFORM_ROOT_DIR']

    append_layers([os.path.join(PLATFORM_ROOT_DIR, 'sources', p) for p in [
        'meta-openembedded/meta-oe',
        'meta-openembedded/meta-filesystems',
        'meta-openembedded/meta-networking',
        'meta-openembedded/meta-python',
        'meta-intel',
        'meta-virtualization',
        'meta-mender/meta-mender-core',
    ]])

run_set_defaults(__set_defaults_m4ss_embedded_linux_yocto)
run_after_init(__after_init_m4ss_embedded_linux_yocto)