#  TODO:
#  - error codes and status codes list and description
#
#
#

import os
import sys
import json

#from enum import Enum

from amqp_server import AMQPServer
from job import Job
from job_cache import JobCache

class StoreAMQPServer(AMQPServer):

    def __init__(self, host, queue):
        self.type = "store"
        self.storeAck = False
        self.jobCache = JobCache('redis', 6379, 1)
        self.job = None
        self.username = None
        self.path = None
        super(StoreAMQPServer, self).__init__(host, queue)

    def execute_callback(self, requestBody):
        # 'requestType' and 'userName' attributes are mandatory
        if "requestType" not in requestBody or "userName" not in requestBody:
            response = { "errorCode": 1, "errorMsg": "Malformed request, missing parameters." }
        elif requestBody["requestType"] == "CSTORE" or requestBody["requestType"] == "HSTORE":
            self.job = Job()
            self.job.setInfo(requestBody)
            self.job.setPhase("PENDING")
            user = requestBody["userName"]
            folderPath = "/home/" + user + "/store"
            userInfo = self.userInfo(user)
            # Check if the user exists on the transfer node
            if not userInfo:
                response = { "responseType": "ERROR",
                             "errorCode": 2,
                             "errorMsg": "The user does not exist on the transfer node." }
            else:
                uid = os.stat(folderPath).st_uid
                gid = os.stat(folderPath).st_gid
                # Check if uid and gid match and avoid privilege escalation
                if uid == userInfo[1] and gid == userInfo[2] and uid != 0 and gid != 0:
                    # If write permissions are set and the 'store' folder is not empty,
                    # it means that data is ready to be copied, otherwise, nothing can
                    # be done until the write permissions are restored or new data is
                    # copied on the transfer node by the user.
                    if os.access(folderPath, os.W_OK) and os.listdir(folderPath):
                        response = { "responseType": "STORE_ACK" }
                        self.storeAck = True
                    else:
                        response = { "responseType": "ERROR",
                                     "errorCode": 3,
                                     "errorMsg": "Service busy." }                                                
                else:
                    response = { "responseType": "ERROR",
                                 "errorCode": 4,
                                 "errorMsg": "Permission denied." }
        elif requestBody["requestType"] == "STORE_CON":
            if self.storeAck:
                self.storeAck = False
                user = requestBody["userName"]
                self.prepare(user)
                self.jobCache.set(self.job)
                redisResponse = self.jobCache.get(self.job.jobId)
                if "error" in redisResponse:
                    response = { "responseType": "ERROR",
                                 "errorCode": 5,
                                 "errorMsg": "Job creation failed." }
                else:
                    response = { "responseType": "STORE_RUN", 
                                 "jobId": self.job.jobId }
            else:
                response = { "responseType": "ERROR",
                             "errorCode": 6,
                             "errorMsg": "Store request not acknowledged." }
        else:
            response = { "responseType": "ERROR",
                         "errorCode": 7,
                         "errorMsg": "Unkown request type." }

        return response

    # to be removed from store_preprocessor.py
    # or simply add a chmod -x here, to be faster?
    def prepare(self, username):
        self.username = username
        self.path = "/home/" + username + "/store"
        for folder, subfolders, files in os.walk(self.path):
            os.chown(folder, 0, 0)
            os.chmod(folder, 0o555)
            for s in subfolders:
                os.chown(os.path.join(folder, s), 0, 0)
                os.chmod(os.path.join(folder, s), 0o555)
            for f in files:
                os.chown(os.path.join(folder, f), 0, 0)
                os.chmod(os.path.join(folder, f), 0o555)

    def userInfo(self, username):
        fp = open("/etc/passwd", 'r')
        for line in fp:
            info = line.split(':')
            user = info[0]
            uid = int(info[2])
            gid = int(info[3])
            if user == username:
                return [ user, uid, gid ]
        return False

    def run(self):
        print(f"Starting AMQP server of type {self.type}...")
        super(StoreAMQPServer, self).run()