#! /usr/bin/env python

import os
import sys
import httplib
import urllib
from urlparse import urlparse
from getpass import getpass

try:
    import json
except ImportError:
    import simplejson as json

DEFAULT_CONFIG = {
    'api_server': 'https://api-dev.bugzilla.mozilla.org/latest',
    'server': 'https://bugzilla.mozilla.org'
}

def json_request(method, url, query_args=None, body=None):
    if query_args is None:
        query_args = {}

    headers = {'Accept': 'application/json',
               'Content-Type': 'application/json'}

    urlparts = urlparse(url)
    if urlparts.scheme == 'https':
        connclass = httplib.HTTPSConnection
    elif urlparts.scheme == 'http':
        connclass = httplib.HTTPConnection
    else:
        raise ValueError('unknown scheme "%s"' % urlparts.scheme)
    conn = connclass(urlparts.netloc)
    path = urlparts.path
    if query_args:
        path += '?%s' % urllib.urlencode(query_args)
    if body is not None:
        body = json.dumps(body)
    conn.request(method, path, body, headers)
    response = conn.getresponse()
    status, reason = response.status, response.reason
    mimetype = response.msg.gettype()
    data = response.read()
    conn.close()

    if mimetype == 'application/json':
        data = json.loads(data)

    return {'status': response.status,
            'reason': response.reason,
            'content_type': mimetype,
            'body': data}

def make_caching_json_request(cache, json_request=json_request):
    from hashlib import sha1 as hashfunc

    def caching_json_request(method, url, query_args=None, body=None):
        key = hashfunc(repr((method, url, query_args, body))).hexdigest()
        if not key in cache:
            cache[key] = json_request(method=method,
                                      url=url,
                                      query_args=query_args,
                                      body=body)
        return cache[key]

    return caching_json_request

class JsonBlobCache(object):
    def __init__(self, cachedir):
        self.cachedir = cachedir

    def __pathforkey(self, key):
        if not isinstance(key, basestring):
            raise ValueError('key must be a string')
        return os.path.join(self.cachedir, '%s.json' % key)

    def __getitem__(self, key):
        if not key in self:
            raise KeyError(key)
        return json.loads(open(self.__pathforkey(key)).read())

    def __setitem__(self, key, value):
        open(self.__pathforkey(key), 'w').write(json.dumps(value))

    def __contains__(self, key):
        return os.path.exists(self.__pathforkey(key))

def getpass_or_die(prompt, getpass=getpass):
    try:
        password = getpass(prompt)
    except KeyboardInterrupt:
        password = None

    if not password:
        print "Aborted."
        sys.exit(1)

    return password

def load_config(filename=None, getpass=getpass_or_die):
    config = {}
    config.update(DEFAULT_CONFIG)

    if not filename:
        filename = os.path.join('~', '.bugzilla-config.json')
        filename = os.path.expanduser(filename)
        if not os.path.exists(filename):
            return config

    config.update(json.loads(open(filename).read()))

    if getpass and 'username' in config and 'password' not in config:
        config['password'] = getpass('Enter password for %s: ' %
                                     config['username'])
    return config

class BugzillaApi(object):
    def __init__(self, config=None, jsonreq=None):
        if config is None:
            config = load_config()

        if jsonreq is None:
            if 'cache_dir' in config:
                cache = JsonBlobCache(os.path.expanduser(config['cache_dir']))
                jsonreq = make_caching_json_request(cache)
            else:
                jsonreq = json_request

        self.config = config
        self.__jsonreq = jsonreq

    def request(self, method, path, query_args=None, body=None):
        if query_args is None:
            query_args = {}

        if 'username' in self.config and 'password' in self.config:
            for name in ['username', 'password']:
                query_args[name] = self.config[name]

        url = '%s%s' % (self.config['api_server'], path)

        response = self.__jsonreq(method=method,
                                  url=url,
                                  query_args=query_args,
                                  body=body)

        if response['content_type'] == 'application/json':
            json_response = response['body']
            if 'error' in json_response and json_response['error']:
                raise BugzillaApiError(response)
            return json_response
        raise BugzillaApiError(response)

class BugzillaApiError(Exception):
    pass

if __name__ == '__main__':
    bzapi = BugzillaApi()
    print bzapi.request('GET', '/attachment/436897',
                        query_args={'attachmentdata': 1})