import requests
from datetime import timedelta

zero = timedelta(0)

application = 2
container = 3
contentInstance = 4

op_provision = ":8181/restconf/operations/onem2m:onem2m-cse-provisioning"
op_tree = ":8181/restconf/operational/onem2m:onem2m-resource-tree"
op_cleanup = ":8181/restconf/operations/onem2m:onem2m-cleanup-store"

cse_payload = '''
{    "input": {
        "onem2m-primitive": [
           {
                "name": "CSE_ID",
                "value": "%s"
            },
            {
                "name": "CSE_TYPE",
                "value": "IN-CSE"
            }
        ]
    }
}
'''

application_payload = '''
{
  any:
  [
    {"aei":"jb", "api":"jb", "apn":"jb2", "or":"http://hey/you" %s}
  ]
}
'''

_container_payload = '''
{
  any:
  [
    {
      "cr": "jb",
      "mni": 1,
      "mbs": 3,
      "or": "http://hey/you"
      %s
    }
  ]
}
'''

container_payload = '''
{
  any:
  [
    {
      "cr": "jb",
      "or": "http://hey/you"
      %s
    }
  ]
}
'''

contentInstance_payload = '''
{
  "any": [
    {
      "cnf": "1",
      "or": "http://hey/you"
      %s
    }
  ]
}
'''


def which_payload(restype):
    """Return a template payload for the known datatypes."""
    if restype == application:
        return application_payload
    elif restype == container:
        return container_payload
    elif restype == contentInstance:
        return contentInstance_payload
    else:
        return ""


def find_key(response, key):
    try:
        val = response.json()
        return val['any'][0][key]
    except:
        return None


def name(response):
    """Return the resource name in the response."""
    return find_key(response, "rn")


def resid(response):
    """Return the resource id in the response."""
    return find_key(response, "ri")


def parent(response):
    """Return the parent resource id in the response."""
    return find_key(response, "pi")


def content(response):
    """Return the content the response."""
    return find_key(response, "con")


def restype(response):
    """Return the resource type the response."""
    return find_key(response, "rty")


def status(response):
    """Return the protocol status code in the response."""
    try:
        return response.status_code
    except:
        return None


def headers(response):
    """Return the protocol headers in the response."""
    try:
        return response.headers
    except:
        return None


def error(response):
    """Return the error string in the response."""
    try:
        return response.json()['error']
    except:
        return None


def normalize(id):
    if id is not None:
        if id[0] == "/":
            return id[1:]
    return id


def attr2str(attr):
    """Convert a dictionary into a string for a protocol payload."""
    content = ""
    if attr is not None:
        content = ","
        n = len(attr)
        c = 1
        sep = ","
        for i in attr:
            if n == c:
                sep = ""
            n = str(attr[i])
            if i != "con" and n.isdigit():
                content = content + "'%s':%d%s" % (i, int(n), sep)
            else:
                content = content + "'%s':'%s'%s" % (i, n, sep)
            c = c + 1
    return content


class connect:
    def __init__(self, server="localhost", base='InCSE1',
                 auth=('admin', 'admin'), protocol="http"):
        """Connect to a IoTDM server."""
        self.s = requests.Session()
        self.s.auth = auth
        self.s.headers.update({'content-type': 'application/json'})
        self.timeout = (5, 5)
        self.payload = cse_payload % (base)
        self.headers = {
            # Admittedly these are "magic values" but are required
            # and until a proper defaulting initializer is in place
            # are hard-coded.
            'content-type': 'application/json',
            'X-M2M-Origin': '//localhost:10000',
            'X-M2M-RI': '12345',
            'X-M2M-OT': 'NOW'
        }
        self.server = "http://" + server
        if base is not None:
            self.url = self.server + op_provision
            self.r = self.s.post(self.url,
                                 data=self.payload, timeout=self.timeout)

    def create(self, parent, restype, name=None, attr=None):
        """Create resource."""
        if parent is None:
            return None
        payload = which_payload(restype)
        payload = payload % (attr2str(attr))
        if name is None:
            self.headers['X-M2M-NM'] = None
        else:
            self.headers['X-M2M-NM'] = name
        parent = normalize(parent)
        self.url = self.server + ":8282/%s?ty=%s&rcn=1" % (parent, restype)
        self.r = self.s.post(self.url, payload,
                             timeout=self.timeout, headers=self.headers)
        return self.r

    def retrieve(self, id):
        """Retrieve resource."""
        if id is None:
            return None
        id = normalize(id)
        self.url = self.server + ":8282/%s?rcn=5&drt=2" % (id)
        self.headers['X-M2M-NM'] = None
        self.r = self.s.get(self.url, timeout=self.timeout,
                            headers=self.headers)
        return self.r

    def update(self, id, attr=None):
        """Update resource attr"""
        if id is None:
            return None
        id = normalize(id)
        return None

    def delete(self, id):
        """Delete the resource with the provided ID."""
        if id is None:
            return None
        id = normalize(id)
        self.url = self.server + ":8282/%s" % (id)
        self.headers['X-M2M-NM'] = None
        self.r = self.s.delete(self.url, timeout=self.timeout,
                               headers=self.headers)
        return self.r

    def tree(self):
        """Get the resource tree."""
        self.url = self.server + op_tree
        self.r = self.s.get(self.url)
        return self.r

    def kill(self):
        """Kill the tree."""
        self.url = self.server + op_cleanup
        self.r = self.s.post(self.url)
        return self.r