from jinja2 import Environment, FileSystemLoader
import pprint
import os

from yaml import safe_load
try:
    from yaml import CLoader as Loader
except ImportError:
    from yaml import Loader

def main(template_filepath,yaml_filepath,output_filepath):
    
    with open(yaml_filepath, 'r') as file:
        devices = safe_load(file)
    
    template_path = os.path.dirname(os.path.abspath(template_filepath))
    template_filename = os.path.basename(template_filepath)
    
    env = Environment(loader=FileSystemLoader(template_path))
    template = env.get_template(template_filename)
    
    #Path("./output").mkdir(parents=True, exist_ok=True)

    ### Specify output file - current write to script working directory
    #filename = "./output/bdr_output.config"

    ### open output file mode="w" for create/truncate
    #output = open(filename, mode="w", encoding="utf-8")        
    output = open(output_filepath, mode="w", encoding="utf-8")        

    
    for host, keys in devices.items():
        device = "{"
        for key, value in keys.items():
            device += "'{}':'{}', ".format(key,value)
        device += "'Hostname':'{}' }}".format(host)
        #pprint.pprint(device)

        device_dict = eval(device)
        #pprint.pprint(device_dict)
        content = template.render( device_dict )
                
        print('{}\n'.format(content))
        output.write('{}\n'.format(content))
    
    return 0

if __name__ == "__main__":

    import argparse
    
    parser = argparse.ArgumentParser(description='Arguments for '
                                                 'Config_builder.py')
    parser.add_argument('-template',
                        help='Template config with JINJA markup',
                        required=True
                        )

    parser.add_argument('-yaml',
                        help='YAML file with devices and config variables',
                        required=True
                        )

    parser.add_argument('-output',
                        help='Output File',
                        required=True
                        )

    custom_args = parser.parse_known_args()[0]
    
    template = custom_args.template
    yaml = custom_args.yaml
    output = custom_args.output
        
    main(template,yaml,output)