from flask import Flask
from flask import request
from lxml import etree
import json
import time
import Parser


app = Flask(__name__)


def process_xml(request: request, type: str) -> str:
    """Function to process 

    :param request: Received request
    :type request: request
    :param type: Type of needed processing: xsd, xslt or xpath
    :type type: str
    :raises ValueError: is raised when type is different than those provided above
    :return: response JSON converted to string
    :rtype: str
    """
    start = time.time_ns()

    response = dict()
    try:
        request_data = json.loads(request.get_data(as_text=True))
        data = request_data['data']
        process = request_data['process']
        if (type == "xsd"):
            response['result'] = Parser.xsd(data, process)
        elif (type == "xslt"):
            response['result'] = Parser.xslt(data, process)
        elif (type == "xpath"):
            response['result'] = Parser.xpath(data, process)
        else:
            raise ValueError("Valid operation types are: xsd, xslt, xpath")

        response['status'] = "OK"
    except KeyError as e:
        response['result'] = "Missing key: " + str(e)
        response['status'] = "ERR"
    except Exception as e:
        response['result'] = str(e)
        response['status'] = "ERR"
    finally:
        exec_time = (time.time_ns() - start) / 10**6
        response['time'] = f"{exec_time:.03f}"
        response['processor'] = "libxml2 over lxml"
        return json.dumps(response)


@app.route("/xpath", methods=["POST"])
def xpath():
    return process_xml(request, "xpath")

@app.route("/xsd", methods=["POST"])
def xsd():
    return process_xml(request, "xsd")

@app.route("/xslt", methods=["POST"])
def xslt():
    return process_xml(request, "xslt")

if __name__ == "__main__":
    app.run()