#!/usr/bin/env python
'''
Asterisk and Digium phone config generator for Makers Local 256
'''
import pystache
import json
import hashlib
import argparse
import os
import errno

def render_write(path, config, template, model):
    '''Render the template and write to the specified file'''
    renderer = pystache.Renderer()
    rendered_data = renderer.render_path(template, model)
    out = open('%s/%s' % (path, config), 'w')
    out.write(rendered_data)
    out.close()
    return rendered_data

def mkdir_p(path):
    '''Enable 'mkdir -p'-like functionality'''
    try:
        os.makedirs(path)
    except OSError as exc:
        if exc.errno == errno.EEXIST and os.path.isdir(path):
            pass
        else: raise

def main():
    '''Generate all configs for Asterisk and for phones'''

    # parse the provided options (if any)
    args_parser = argparse.ArgumentParser(
        description='Generate ML256 phone configs')
    args_parser.add_argument('--model', '-m', dest='model',
                             default='phones.json', type=argparse.FileType('r'))
    configs = args_parser.parse_args()

    # load the phone data
    model = json.load(configs.model)

    # set path defaults
    model_defaults = {
        'ast_config_path': '/etc/asterisk/',
        'ast_static_path': '/var/lib/asterisk/static-http/config/',
        'register': '1',
        'http_static_path': 'http://asterisk:8088/static/config/'
    }
    for key, default in model_defaults.iteritems():
        if key not in model:
            model[key] = default

    # ensure that requisite directories exist
    mkdir_p(model['ast_config_path'])
    mkdir_p(model['ast_static_path'])

    # render the sip config
    render_write(model['ast_config_path'], 'phones-sip.conf',
                 'phones-sip.conf.mustache', model)

    # set index for contacts and accumulate shop-wide dialstring
    i = 0
    dial_accum = []
    for phone in model['phones']:
        # set the indexes for writing out contacts
        phone['index'] = i
        i = i + 1
        dial_accum.append('SIP/' + phone['user'])

    model['all_phones_dial'] = '&'.join(dial_accum)

    # render the extensions config
    render_write(model['ast_config_path'], 'extensions.conf',
                 'extensions.conf.mustache', model)

    # render the contacts config
    contacts_data = render_write(model['ast_static_path'], 'contacts.xml',
                                 'contacts.xml.mustache', model)
    model['contacts_md5'] = hashlib.md5(contacts_data.encode()).hexdigest()

    # render the BLF config
    render_write(model['ast_static_path'], 'blf.xml', 'blf.xml.mustache', model)

    # add a default config
    model['phones'].append({
        'user':'anonymous',
        'name':'Unconfigured Phone',
        'number':'anonymous',
        'register':'0',
        'mac':'000000000000'
    })

    # render the phone configs
    for phone in model['phones']:
        # overlay the phone config on a shallow clone of the model
        local_model = model.copy()
        local_model.update(phone)

        # render the individual phone config
        render_write(local_model['ast_static_path'],
                     '%s.cfg' % (local_model['mac']),
                     'phone.cfg.mustache', local_model)

main()