Parse csv data in python

parser.py

#!/usr/local/bin/python
import json
import sys
import time

material_specular_metalness = 0
material_albedo_diffuse = 0
material_specular_metalness_off = 0

def process_line(line):
    fields = line.split(',', 1 )
    model_id = fields[0]
    materials = fields[1].replace('\"\"','\"')
    materials_cleaned = materials[1:-2]
    materials_json = json.loads(materials_cleaned)

    del materials_json['updatedAt'] # remove this field from the dict

    material_albedo = False
    material_diffuse = False

    material_metalness = False
    material_specular = False

    global material_specular_metalness
    global material_albedo_diffuse
    global material_specular_metalness_off

    for material_id, mat in materials_json.iteritems():

        channels = mat['channels']
        diffuse_pbr = channels['DiffusePBR']
        albedo_pbr = channels['AlbedoPBR']

        metalness_pbr = channels['MetalnessPBR']
        specular_pbr = channels['SpecularPBR']

        if diffuse_pbr['enable']:
            material_diffuse = True
        if albedo_pbr['enable']:
            material_albedo = True

        if metalness_pbr['enable']:
            material_metalness = True
        if specular_pbr['enable']:
            material_specular = True

        if metalness_pbr is False and specular_pbr is False:
            material_specular_metalness_off += 1
            return model_id

        if material_albedo and material_diffuse:
            material_albedo_diffuse += 1
            return model_id

        if material_metalness and material_specular:
            material_specular_metalness += 1
            return model_id

    return None

def parse(filename):

    first_line = True

    global material_specular_metalness
    global material_albedo_diffuse
    global material_specular_metalness_off

    with open(filename,"r") as file:
        for line in file:
            if first_line:
                first_line = False
                continue
            modelid = process_line(line)
            if modelid is not None:
                print modelid
    print 'case specular/metalness {}, albedo/diffuse {}, specular/metalness off {}'.format(material_specular_metalness,material_albedo_diffuse,material_specular_metalness_off)

if __name__ == "__main__":
    if len(sys.argv) > 1:
        parse(sys.argv[1])
    else:
        print 'usage: {} data.cvs'.format(sys.argv[0])