from datetime import timedelta

from django.contrib.auth.decorators import login_required
from django.http import HttpResponse
from django.shortcuts import redirect, render
from django.utils import timezone

from apps.epic.models import GateSlot, Room, RoomInvite, debit_token, select_token
from apps.lyric.models import Token


RESERVE_TIMEOUT = timedelta(seconds=60)


def _expire_reserved_slots(room):
    cutoff = timezone.now() - RESERVE_TIMEOUT
    room.gate_slots.filter(
        status=GateSlot.RESERVED,
        reserved_at__lt=cutoff,
    ).update(status=GateSlot.EMPTY, gamer=None, reserved_at=None)


def _gate_context(room, user):
    _expire_reserved_slots(room)
    slots = room.gate_slots.order_by("slot_number")
    pending_slot = slots.filter(status=GateSlot.RESERVED).first()
    user_reserved_slot = None
    user_filled_slot = None
    carte_token = None
    carte_slots_claimed = 0
    carte_nvm_slot_number = None
    if user.is_authenticated:
        user_reserved_slot = slots.filter(gamer=user, status=GateSlot.RESERVED).first()
        user_filled_slot = slots.filter(gamer=user, status=GateSlot.FILLED).first()
        carte_token = user.tokens.filter(
            token_type=Token.CARTE, current_room=room
        ).first()
        if carte_token:
            carte_slots_claimed = carte_token.slots_claimed
            # NVM shown on the highest-numbered slot this user filled via CARTE
            nvm_slot = slots.filter(
                debited_token_type=Token.CARTE, gamer=user, status=GateSlot.FILLED
            ).order_by("-slot_number").first()
            if nvm_slot:
                carte_nvm_slot_number = nvm_slot.slot_number
    carte_active = carte_token is not None
    eligible = (
        user.is_authenticated
        and pending_slot is None
        and user_reserved_slot is None
        and user_filled_slot is None
        and not carte_active
    )
    token_depleted = eligible and select_token(user) is None
    can_drop = eligible and not token_depleted
    is_last_slot = (
        user_reserved_slot is not None
        and slots.filter(status=GateSlot.EMPTY).count() == 0
    )
    user_can_reject = user_reserved_slot is not None or user_filled_slot is not None or carte_active
    return {
        "slots": slots,
        "pending_slot": pending_slot,
        "user_reserved_slot": user_reserved_slot,
        "user_filled_slot": user_filled_slot,
        "can_drop": can_drop,
        "token_depleted": token_depleted,
        "is_last_slot": is_last_slot,
        "user_can_reject": user_can_reject,
        "carte_active": carte_active,
        "carte_slots_claimed": carte_slots_claimed,
        "carte_nvm_slot_number": carte_nvm_slot_number,
    }


@login_required
def create_room(request):
    if request.method == "POST":
        name = request.POST.get("name", "").strip()
        if name:
            room = Room.objects.create(name=name, owner=request.user)
            return redirect("epic:gatekeeper", room_id=room.id)
    return redirect("/gameboard/")


def gatekeeper(request, room_id):
    room = Room.objects.get(id=room_id)
    ctx = _gate_context(room, request.user)
    ctx["room"] = room
    return render(request, "apps/gameboard/room.html", ctx)


@login_required
def drop_token(request, room_id):
    if request.method == "POST":
        room = Room.objects.get(id=room_id)
        token_id = request.POST.get("token_id")
        if token_id:
            token = request.user.tokens.filter(id=token_id).first()
        else:
            token = select_token(request.user)
        if token is None:
            return HttpResponse(status=402)
        if token.token_type == Token.CARTE:
            # CARTE enters the machine without reserving a slot — all slots
            # become individually claimable via .drop-token-btn
            token.current_room = room
            token.save()
            request.session["kit_token_id"] = str(token.id)
            return redirect("epic:gatekeeper", room_id=room_id)
        if room.gate_slots.filter(status=GateSlot.RESERVED).exists():
            return redirect("epic:gatekeeper", room_id=room_id)
        if room.gate_slots.filter(gamer=request.user, status=GateSlot.FILLED).exists():
            return redirect("epic:gatekeeper", room_id=room_id)
        slot = room.gate_slots.filter(
            status=GateSlot.EMPTY
        ).order_by("slot_number").first()
        if slot:
            slot.gamer = request.user
            slot.status = GateSlot.RESERVED
            slot.reserved_at = timezone.now()
            slot.save()
            request.session["kit_token_id"] = str(token.id)
    return redirect("epic:gatekeeper", room_id=room_id)


@login_required
def confirm_token(request, room_id):
    if request.method == "POST":
        room = Room.objects.get(id=room_id)
        slot_number = request.POST.get("slot_number")
        if slot_number:
            # CARTE per-slot fill: directly fill the requested slot
            carte = request.user.tokens.filter(
                token_type=Token.CARTE, current_room=room
            ).first()
            if carte:
                slot = room.gate_slots.filter(
                    slot_number=slot_number, status=GateSlot.EMPTY
                ).first()
                if slot:
                    debit_token(request.user, slot, carte)
                    # slots_claimed is the high-water mark — advance if beyond current
                    if int(slot_number) > carte.slots_claimed:
                        carte.slots_claimed = int(slot_number)
                        carte.save()
        else:
            slot = room.gate_slots.filter(
                gamer=request.user, status=GateSlot.RESERVED
            ).first()
            if slot:
                token_id = request.session.pop("kit_token_id", None)
                token = None
                if token_id:
                    token = request.user.tokens.filter(id=token_id).first()
                if not token:
                    token = select_token(request.user)
                if token:
                    debit_token(request.user, slot, token)
    return redirect("epic:gatekeeper", room_id=room_id)


@login_required
def return_token(request, room_id):
    if request.method == "POST":
        room = Room.objects.get(id=room_id)
        # CARTE full return: reset token + all CARTE-debited slots
        carte = request.user.tokens.filter(
            token_type=Token.CARTE, current_room=room
        ).first()
        if carte:
            room.gate_slots.filter(
                debited_token_type=Token.CARTE, gamer=request.user
            ).update(
                gamer=None, status=GateSlot.EMPTY, filled_at=None,
                debited_token_type=None, debited_token_expires_at=None,
            )
            carte.current_room = None
            carte.slots_claimed = 0
            carte.save()
            request.session.pop("kit_token_id", None)
            return redirect("epic:gatekeeper", room_id=room_id)
        slot = room.gate_slots.filter(
            gamer=request.user,
            status__in=[GateSlot.RESERVED, GateSlot.FILLED],
        ).first()
        if slot:
            if slot.status == GateSlot.FILLED:
                if slot.debited_token_type == Token.COIN:
                    coin = request.user.tokens.filter(
                        token_type=Token.COIN, current_room=room
                    ).first()
                    if coin:
                        coin.current_room = None
                        coin.next_ready_at = None
                        coin.save()
                elif slot.debited_token_type in (Token.FREE, Token.TITHE):
                    Token.objects.create(
                        user=request.user,
                        token_type=slot.debited_token_type,
                        expires_at=slot.debited_token_expires_at,
                    )
            request.session.pop("kit_token_id", None)
            slot.gamer = None
            slot.status = GateSlot.EMPTY
            slot.reserved_at = None
            slot.filled_at = None
            slot.debited_token_type = None
            slot.debited_token_expires_at = None
            slot.save()
    return redirect("epic:gatekeeper", room_id=room_id)


@login_required
def release_slot(request, room_id):
    """Un-fill a single CARTE-claimed slot without returning the CARTE itself."""
    if request.method == "POST":
        room = Room.objects.get(id=room_id)
        slot_number = request.POST.get("slot_number")
        if slot_number:
            slot = room.gate_slots.filter(
                slot_number=slot_number,
                debited_token_type=Token.CARTE,
                gamer=request.user,
                status=GateSlot.FILLED,
            ).first()
            if slot:
                slot.gamer = None
                slot.status = GateSlot.EMPTY
                slot.filled_at = None
                slot.debited_token_type = None
                slot.debited_token_expires_at = None
                slot.save()
    return redirect("epic:gatekeeper", room_id=room_id)


@login_required
def invite_gamer(request, room_id):
    if request.method == "POST":
        room = Room.objects.get(id=room_id)
        email = request.POST.get("invitee_email", "").strip()
        if email:
            RoomInvite.objects.get_or_create(
                room=room,
                inviter=request.user,
                invitee_email=email,
                defaults={"status": RoomInvite.PENDING}
            )
    return redirect("epic:gatekeeper", room_id=room_id)


@login_required
def delete_room(request, room_id):
    if request.method == "POST":
        room = Room.objects.get(id=room_id)
        if request.user == room.owner:
            room.delete()
    return redirect("/gameboard/")


@login_required
def abandon_room(request, room_id):
    if request.method == "POST":
        room = Room.objects.get(id=room_id)
        room.gate_slots.filter(gamer=request.user).update(
            gamer=None, status="EMPTY", filled_at=None
        )
        room.invites.filter(
            invitee_email=request.user.email,
            status=RoomInvite.PENDING
        ).delete()
    return redirect("/gameboard/")


def gate_status(request, room_id):
    room = Room.objects.get(id=room_id)
    ctx = _gate_context(room, request.user)
    ctx["room"] = room
    return render(request, "apps/gameboard/_partials/_gatekeeper.html", ctx)