import json
import math
import time

from django.core.handlers.wsgi import WSGIRequest
from django.http import HttpResponse
from django.views.decorators.csrf import csrf_exempt

from tmessage.models import tMMessage

from .helper import get_user_object, get_username


def _json_response(data: dict | list, /, *, status: int=200, content_type: str="application/json") -> HttpResponse:
    return HttpResponse(
        json.dumps(data),
        status=status,
        content_type=content_type
    )

RESPONSE_400 = _json_response({ "success": False }, status=400)
RESPONSE_401 = _json_response({ "success": False }, status=401)
RESPONSE_403 = _json_response({ "success": False }, status=403)

@csrf_exempt
def api_messages(request: WSGIRequest) -> HttpResponse:
    username = get_username(request)

    if username is None:
        return RESPONSE_401

    user = get_user_object(username, i_promise_this_user_exists=True)

    if request.method == "POST":
        body = json.loads(request.body)
        reply = body["content"].strip()
        message_id = body["id"]

        if not (isinstance(message_id, int) and isinstance(reply, str)):
            return RESPONSE_400

        try:
            message = tMMessage.objects.get(message_id=message_id)
        except tMMessage.DoesNotExist:
            return RESPONSE_400

        if username != message.u_to.username:
            return RESPONSE_403

        if message.response is not None:
            return RESPONSE_400

        message.response = reply
        message.response_timestamp = math.floor(time.time())
        message.save()

        return _json_response({
            "success": True,
            "content": reply,
            "timestamp":  message.response_timestamp
        })

    elif request.method == "DELETE":
        body = json.loads(request.body)
        message_id = body["id"]

        if not isinstance(message_id, int):
            return RESPONSE_400

        try:
            message = tMMessage.objects.get(message_id=message_id)
        except tMMessage.DoesNotExist:
            return RESPONSE_400

        if username != message.u_to.username:
            return RESPONSE_403

        message.delete()

        return _json_response({
            "success": True
        })

    queryFilter = {}

    if "offset" in request.GET and (request.GET.get("offset") or "").isdigit():
        queryFilter["message_id__lt"] = int(request.GET.get("offset") or "")

    if "unread" in request.GET:
        queryFilter["response"] = None

    if queryFilter:
        msgObjects = user.received.filter(**queryFilter)
    else:
        msgObjects = user.received.all() # type: ignore

    output = []
    messages = msgObjects.order_by("-message_id")[:50].values_list(
        "message_id", "content", "response", "anonymous", "u_from", "sent_timestamp", "response_timestamp"
    )

    for message in messages:
        output.append({
            "id": message[0],
            "content": message[1],
            "response": message[2],
            "from": message[4] if not message[3] and message[4] else None,
            "timestamp": message[5],
            "response_timestamp": message[6]
        })

    return _json_response({
        "success": True,
        "canRespond": True,
        "messages": output,
        "more": msgObjects.count() > 50
    })