import os
import sys
import json


def fix_session_file(input_file, output_file):

    # Most issues are due to inconsistencies in terms of which subsets are
    # defined where. So this function simply removes all subsets from the
    # session file.

    with open(input_file) as f:
        session = json.load(f)

    # Find all subsets and subset groups in session file

    subsets = []
    for key, value in session.items():
        if value['_type'] in ['glue.core.subset.Subset',
                              'glue.core.subset_group.GroupedSubset',
                              'glue.core.subset_group.SubsetGroup']:
            subsets.append(key)
            if 'state' in value:
                subsets.append(value['state'])

    for subset in subsets:
        session.pop(subset)

    # Now remove all traces of subsets

    layer_states = []

    for key, value in session.items():

        # Remove subsets from data
        if value['_type'] == 'glue.core.data.Data':
            value['subsets'] = []

        # Remove subset groups from data collection
        if value['_type'] == 'glue.core.data_collection.DataCollection':
            value['groups'] = []
            value['subset_group_count'] = 0

        # Find all layer states that mention subsets
        if 'values' in value and 'layer' in value['values']:
            if value['values']['layer'] in subsets:
                layer_states.append(key)

    for layer_state in layer_states:
        session.pop(layer_state)

    for key, value in session.items():

        # Find all callback lists that include these layer states
        if 'values' in value:
            for layer_state in layer_states:
                if layer_state in value['values']:
                    value['values'].remove(layer_state)

        if 'layers' in value:
            for layer in value['layers'][:]:
                if layer['state'] in layer_states:
                    value['layers'].remove(layer)

    with open(output_file, 'w') as f:
        json.dump(session, f, indent=2)


if len(sys.argv) != 3:
    print("Usage: python remove_subsets_from_glu.py input_file.glu output_file.glu")
    sys.exit(1)

if os.path.exists(sys.argv[2]):
    print("ERROR: file {0} already exists".format(sys.argv[2]))
    sys.exit(1)

fix_session_file(*sys.argv[1:])