import base64
import json
import os
from cryptography.fernet import Fernet
from pathlib import Path

from django.conf import settings
from django.contrib.auth.models import User
from django.db import models

from troggle.core.models.troggle import DataIssue, Expedition, Person, PersonExpedition

"""This imports the registered troggle users, who are nearly-all, but not quite, Persons.
exceptions are "expo" and "expoadmin" which are created by the databaseReset.py import program.

This imports unencrypted email addresses but never exports them.

Passwords are only ever stored as hashes using the standard Django functions.
"""

todo = """  
- [copy these from paper notes]
"""

USERS_FILE = "users_e.json"
ENCRYPTED_DIR = "encrypted"
def load_users():
    """These are the previously registered users of the troggle system.
    """
    PARSER_USERS = "_users"
    DataIssue.objects.filter(parser=PARSER_USERS).delete()

    key = settings.LONGTERM_SECRET_KEY # Django generated
    k = base64.urlsafe_b64encode(key.encode("utf8")[:32]) # make Fernet compatible 
    f = Fernet(k)
    
    jsonfile = settings.EXPOWEB / ENCRYPTED_DIR / USERS_FILE
    jsonurl = "/" + str(Path(ENCRYPTED_DIR) / USERS_FILE)
    if not (jsonfile.is_file()):
        message = f"   ! Users json file does not exist: '{jsonfile}'"
        DataIssue.objects.create(parser=PARSER_USERS, message=message)
        print(message)
        return None
         
    with open(jsonfile, 'r', encoding='utf-8') as json_f:
        message = ""
        try:
            registered_users_dict = json.load(json_f)
        except FileNotFoundError:
            message = f"File {jsonfile} not found!"
        except json.JSONDecodeError:
            message = f"Invalid JSON format! - JSONDecodeError for  {jsonfile}"
        except Exception as e:
            message = f"! Troggle USERs.  Failed to load {jsonfile} JSON file. Exception <{e}>"
        if message:
            print(message)
            DataIssue.objects.update_or_create(parser=PARSER_USERS, message=message, url=jsonurl)
            return None
    users_list = registered_users_dict["registered_users"]
    
    print(f" - {len(users_list)} users read from JSON")
    for userdata in users_list:   
        if userdata["username"]:
            if userdata["username"] in [ "expo", "expoadmin" ]:
                continue
            if "encrypted" not in userdata:
                userdata["encrypted"] = True
            try:
                u = userdata["username"]
                email = userdata["email"]
                if userdata["encrypted"]: 
                    email = f.decrypt(email).decode()
                print(f" - user: '{u} <{email}>' ")
                if existing_user := User.objects.filter(username=userdata["username"]): # WALRUS
                    # print(f" - deleting existing user '{existing_user[0]}' before importing")
                    existing_user[0].delete()
                user = User.objects.create_user(userdata["username"], email, "secret")
                user.set_password = "secret" # special attribute stores hash not password
                user.is_staff = False
                user.is_superuser = False
                user.save()
            except Exception as e:
                print(f"Exception <{e}>\n{len(User.objects.all())} users now in db:\n{User.objects.all()}")
                formatted_json = json.dumps(userdata, indent=4)
                print(formatted_json)
                raise
                return None
        else:
            print(f" - user: BAD username for {userdata} ")

    ru = []
    for u in User.objects.all():
        if u.username == "expo":
            continue
        if u.username == "expoadmin":
            continue
        e_email = f.encrypt(u.email.encode("utf8")).decode()
        ru.append({"username":u.username, "email": e_email, "password": u.password, "encrypted": True})
        # print(u.username, e_email)
        original = f.decrypt(e_email).decode()
        print(u.username, original)
        
    jsondict = { "registered_users": ru }
    encryptedfile = settings.EXPOWEB / ENCRYPTED_DIR / "encrypt.json"
    if settings.DEVSERVER:
        with open(encryptedfile, 'w', encoding='utf-8') as json_f:
            json.dump(jsondict, json_f, indent=1)
    return True