"""
Functionality needed to run a client request sequence (clients.*.main) in the ImageJ model_server 2.7 script environment
"""

import httplib
import json
import urllib

from ij import IJ
from ij import ImagePlus

HOST = '127.0.0.1'
PORT = 6221
uri = 'http://{}:{}/'.format(HOST, PORT)

def hit_endpoint(method, endpoint, params=None, body=None, drop_none=True):
    """
    Python 2.7 implementation of HTTP client
    :param method: (str) either 'GET' or 'PUT'
    :param endpoint: (str) endpoint of HTTP request
    :param params: (dict) of parameters that are embedded in client request URL
    :param body: (dict) of parameters that JSON-encoded and attached as payload in request
    :param drop_none: (bool) remove (presumably optional) parameters with value equal to None
    :return: (dict) of response status and content, formatted as dict if request is successful
    """
    connection = httplib.HTTPConnection(HOST, PORT)
    if not method in ['GET', 'PUT']:
        raise Exception('Can only handle GET and PUT requests')
    k_pop = []
    if drop_none and params is not None:
        for k, v in params.items():
            if v is None:
                k_pop.append(k)
        for ki in k_pop:
            params.pop(ki)

    if params:
        url = endpoint + '?' + urllib.urlencode(params)
    else:
        url = endpoint
    connection.request(method, url, body=json.dumps(body))
    resp = connection.getresponse()
    resp_str = resp.read()
    try:
        content = json.loads(resp_str)
    except Exception:
        content = {'str': str(resp_str)}
    return {'status': resp.status, 'content': content}


def verify_server(popup=True):
    try:
        resp = hit_endpoint('GET', '/')
    except Exception as e:
        print(e)
        msg = 'Could not find server at: ' + uri
        IJ.log(msg)
        if popup:
            IJ.error(msg)
            raise e
        return False
    if resp['status'] != 200:
        msg = 'Unknown error verifying server at: ' + uri
        if popup:
            IJ.error(msg)
            raise Exception(msg)
        return False
    else:
        IJ.log('Verified server is online at: ' + uri)
        return True

def run_request_sequence(imp, func, params):
    """
    Execute a sequence of client requests in the ImageJ scripting environment
    :param imp: (ij.ImagePlus) input image
    :param func: (func) function that implements client request sequence
    :param params: (dict) parameters specific to client request
    :return: (ij.ImagePlus) output image
    """
    in_path = imp.getProp('Location')
    out_path = func(hit_endpoint, in_path, params)
    return ImagePlus(out_path)