"""Backend users service."""
from __future__ import annotations

import hashlib
from collections import defaultdict
from typing import Any
from sqlmodel import Session, delete, or_, select
from models import (PartnerGroup, PartnerGroupMember, PartnerLink, PartnerLinkRequest, PlayPreference,
    PromptDismissal, RolePreference, ScenarioPreference, User, UserPreference)
from backend.constants import BLOCKED_RATINGS, POSITIVE_RATINGS, SUPPRESSED_RATINGS



def create_user(self) -> User:
    public_id = self._make_memorable_id()
    private_token = self._make_memorable_pass()
    with Session(self.engine) as session:
        while session.get(User, public_id):
            public_id = self._make_memorable_id()
        user = User(id=public_id, private_token=private_token)
        session.add(user)
        session.add(UserPreference(user_id=public_id, show_images=False))
        session.commit()
        session.refresh(user)
        return user

def _load_play_preferences(self, session: Session, user_id: str) -> dict[str, dict[str, Any]]:
    prefs = session.exec(select(PlayPreference).where(PlayPreference.user_id == user_id)).all()
    return {
        pref.kink_id: {
            "interest_state": pref.interest_state,
            "directions": self._deserialize_directions(pref.directions_csv),
        }
        for pref in prefs
    }

def _load_role_preferences(self, session: Session, user_id: str) -> list[str]:
    prefs = session.exec(select(RolePreference).where(RolePreference.user_id == user_id)).all()
    return sorted(pref.kink_id for pref in prefs)

def get_user(self, user_id: str) -> dict | None:
    with Session(self.engine) as session:
        user = session.get(User, user_id)
        if not user:
            return None
        play_map = self._load_play_preferences(session, user.id)
        scenario_map = self._load_scenario_preferences(session, user.id)
        role_ids = self._load_role_preferences(session, user.id)
        links = session.exec(
            select(PartnerLink).where(
                or_(PartnerLink.left_user_id == user.id, PartnerLink.right_user_id == user.id)
            )
        ).all()
        incoming_req = session.exec(
            select(PartnerLinkRequest).where(PartnerLinkRequest.to_user_id == user.id)
        ).all()
        outgoing_req = session.exec(
            select(PartnerLinkRequest).where(PartnerLinkRequest.from_user_id == user.id)
        ).all()
        pref = session.get(UserPreference, user.id)
        partners = [
            link.right_user_id if link.left_user_id == user.id else link.left_user_id
            for link in links
        ]
        return {
            "id": user.id,
            "private_token": user.private_token,
            "plays": play_map,
            "scenario_preferences": scenario_map,
            "roles": role_ids,
            "partners": sorted(partners),
            "incoming_partner_requests": sorted(r.from_user_id for r in incoming_req),
            "outgoing_partner_requests": sorted(r.to_user_id for r in outgoing_req),
            "partner_groups": self.list_partner_groups(user.id),
            "preferences": {
                "show_images": bool(pref.show_images) if pref else False,
            },
        }

def authenticate_user(self, user_id: str, private_token: str) -> dict | None:
    user = self.get_user(user_id)
    if not user:
        return None
    if user["private_token"] != private_token:
        return None
    return user

def all_users(self) -> dict[str, dict]:
    with Session(self.engine) as session:
        users = session.exec(select(User).order_by(User.id)).all()
    return {user.id: self.get_user(user.id) for user in users}

def delete_user(self, user_id: str) -> None:
    with Session(self.engine) as session:
        user = session.get(User, user_id)
        if not user:
            return
        session.exec(delete(PlayPreference).where(PlayPreference.user_id == user_id))
        session.exec(delete(ScenarioPreference).where(ScenarioPreference.user_id == user_id))
        session.exec(delete(RolePreference).where(RolePreference.user_id == user_id))
        session.exec(delete(UserPreference).where(UserPreference.user_id == user_id))
        session.exec(delete(PromptDismissal).where(PromptDismissal.user_id == user_id))
        session.exec(
            delete(PartnerLinkRequest).where(
                or_(PartnerLinkRequest.from_user_id == user_id, PartnerLinkRequest.to_user_id == user_id)
            )
        )
        session.exec(delete(PartnerLink).where(or_(PartnerLink.left_user_id == user_id, PartnerLink.right_user_id == user_id)))
        session.exec(delete(PartnerGroupMember).where(PartnerGroupMember.member_user_id == user_id))
        groups = session.exec(select(PartnerGroup).where(PartnerGroup.owner_user_id == user_id)).all()
        for group in groups:
            session.exec(delete(PartnerGroupMember).where(PartnerGroupMember.group_id == group.id))
            session.delete(group)
        session.delete(user)
        session.commit()

def export_user_data(self, user_id: str) -> dict[str, Any]:
    user = self.get_user(user_id)
    if not user:
        return {}
    board = self.play_board(user_id)
    groups = self.list_partner_groups(user_id)
    with Session(self.engine) as session:
        roles = session.exec(select(RolePreference).where(RolePreference.user_id == user_id)).all()
    return {
        "user_id": user_id,
        "plays": user.get("plays", {}),
        "scenario_preferences": user.get("scenario_preferences", {}),
        "roles": [r.kink_id for r in roles],
        "partners": user.get("partners", []),
        "partner_groups": groups,
        "board": board,
        "preferences": user.get("preferences", {}),
    }

def partner_activity_hash(self, user_id: str) -> str:
    with Session(self.engine) as session:
        partner_ids = self._linked_partner_ids(session, user_id)
        if not partner_ids:
            return ""
        parts = []
        for pid in sorted(partner_ids):
            plays = session.exec(
                select(PlayPreference).where(PlayPreference.user_id == pid).order_by(PlayPreference.kink_id)
            ).all()
            scenarios = session.exec(
                select(ScenarioPreference).where(ScenarioPreference.user_id == pid).order_by(ScenarioPreference.parent_kink_id, ScenarioPreference.scenario_kink_id)
            ).all()
            play_states = ",".join(
                f"{p.kink_id}={p.interest_state}:{p.directions_csv or ''}"
                for p in plays
            )
            scenario_states = ",".join(
                f"{p.parent_kink_id}>{p.scenario_kink_id}={p.interest_state}:{p.directions_csv or ''}"
                for p in scenarios
            )
            states = f"{play_states}|scenarios:{scenario_states}"
            parts.append(f"{pid}:{len(plays)}:{len(scenarios)}:{hashlib.md5(states.encode(), usedforsecurity=False).hexdigest()[:8]}")
    return hashlib.md5(":".join(parts).encode(), usedforsecurity=False).hexdigest()[:12]

def save_preferences(self, user_id: str, show_images: bool | None = None) -> dict | None:
    with Session(self.engine) as session:
        if not session.get(User, user_id):
            return None
        pref = session.get(UserPreference, user_id)
        if not pref:
            pref = UserPreference(user_id=user_id, show_images=False)
            session.add(pref)
        if show_images is not None:
            pref.show_images = show_images
        session.commit()
    return self.get_user(user_id)

def remove_play_preference(self, user_id: str, kink_id: str) -> None:
    changed = False
    with Session(self.engine) as session:
        pref = session.get(PlayPreference, (user_id, kink_id))
        if pref:
            session.delete(pref)
            session.commit()
            changed = True
    if changed:
        self.invalidate_recommendation_cache()

def save_play_preference(
    self,
    user_id: str,
    kink_id: str,
    interest_state: str,
    directions: list[str] | None = None,
) -> None:
    with Session(self.engine) as session:
        pref = session.get(PlayPreference, (user_id, kink_id))
        kink = self._catalog()["detail_by_id"].get(kink_id)
        normalized_directions = self._normalize_directions(directions)
        if not normalized_directions and kink:
            normalized_directions = self._default_directions_for_kink(kink, interest_state)
        serialized = self._serialize_directions(normalized_directions)
        if pref:
            pref.interest_state = interest_state
            pref.directions_csv = serialized
        else:
            session.add(
                PlayPreference(
                    user_id=user_id,
                    kink_id=kink_id,
                    interest_state=interest_state,
                    directions_csv=serialized,
                )
            )
        session.commit()
    self.invalidate_recommendation_cache()

def save_role_preference(self, user_id: str, kink_id: str, selected: bool) -> None:
    with Session(self.engine) as session:
        pref = session.get(RolePreference, (user_id, kink_id))
        if selected:
            if not pref:
                session.add(RolePreference(user_id=user_id, kink_id=kink_id))
        elif pref:
            session.delete(pref)
        session.commit()

def role_cards(self, user_id: str) -> list[dict[str, Any]]:
    user = self.get_user(user_id)
    if not user:
        return []
    detail_by_id = self._catalog()["detail_by_id"]
    items = [detail_by_id[kink_id] for kink_id in user.get("roles", []) if kink_id in detail_by_id]
    items.sort(key=lambda item: (-item["popularity"], item["name"].lower()))
    return items

def link_users(self, left_id: str, right_id: str) -> bool:
    if left_id == right_id:
        return False
    ordered = tuple(sorted((left_id, right_id)))
    with Session(self.engine) as session:
        if not session.get(User, left_id) or not session.get(User, right_id):
            return False
        if not session.get(PartnerLink, ordered):
            session.add(PartnerLink(left_user_id=ordered[0], right_user_id=ordered[1]))
            session.commit()
    self.ensure_pair_partner_groups(left_id, right_id)
    return True


def _clear_partner_requests_between(session: Session, a: str, b: str) -> None:
    session.exec(delete(PartnerLinkRequest).where(PartnerLinkRequest.from_user_id == a, PartnerLinkRequest.to_user_id == b))
    session.exec(delete(PartnerLinkRequest).where(PartnerLinkRequest.from_user_id == b, PartnerLinkRequest.to_user_id == a))


def request_partner_link(self, from_id: str, to_id: str) -> tuple[bool, str]:
    """Create a pending link request, or link immediately if the other person already asked you."""
    if from_id == to_id:
        return False, "Cannot link to yourself"
    with Session(self.engine) as session:
        if not session.get(User, from_id) or not session.get(User, to_id):
            return False, "Unknown user"
        ordered = tuple(sorted((from_id, to_id)))
        if session.get(PartnerLink, ordered):
            return False, "Already linked"
        reverse = session.get(PartnerLinkRequest, (to_id, from_id))
        if reverse:
            _clear_partner_requests_between(session, from_id, to_id)
            session.commit()
            if not self.link_users(from_id, to_id):
                return False, "Could not complete link"
            return True, "linked"
        if session.get(PartnerLinkRequest, (from_id, to_id)):
            return True, "pending"
        session.add(
            PartnerLinkRequest(from_user_id=from_id, to_user_id=to_id, created_at=self._now_iso())
        )
        session.commit()
    return True, "sent"


def accept_partner_request(self, accepter_id: str, from_user_id: str) -> bool:
    """Accept an incoming request from ``from_user_id``."""
    if accepter_id == from_user_id:
        return False
    with Session(self.engine) as session:
        req = session.get(PartnerLinkRequest, (from_user_id, accepter_id))
        if not req:
            return False
        session.delete(req)
        session.commit()
    return self.link_users(from_user_id, accepter_id)


def decline_partner_request(self, decliner_id: str, from_user_id: str) -> bool:
    """Decline an incoming request from ``from_user_id``."""
    with Session(self.engine) as session:
        req = session.get(PartnerLinkRequest, (from_user_id, decliner_id))
        if not req:
            return False
        session.delete(req)
        session.commit()
    return True


def cancel_partner_request(self, from_id: str, to_id: str) -> bool:
    """Withdraw an outgoing request."""
    with Session(self.engine) as session:
        req = session.get(PartnerLinkRequest, (from_id, to_id))
        if not req:
            return False
        session.delete(req)
        session.commit()
    return True

def dismiss_prompt(self, user_id: str, kink_id: str) -> None:
    with Session(self.engine) as session:
        existing = session.get(PromptDismissal, (user_id, kink_id))
        if not existing:
            session.add(PromptDismissal(user_id=user_id, kink_id=kink_id))
            session.commit()

def play_board(self, user_id: str) -> dict[str, list[dict[str, Any]]]:
    user = self.get_user(user_id)
    if not user:
        return {"to_me": [], "by_me": [], "together": [], "hidden": [], "no_go": []}
    detail_by_id = self._catalog()["detail_by_id"]
    board = {"to_me": [], "by_me": [], "together": [], "hidden": [], "no_go": []}
    for kink_id, state in user["plays"].items():
        kink = detail_by_id.get(kink_id)
        if not kink:
            continue
        item = {
            "id": kink["id"],
            "name": kink["name"],
            "summary": kink["summary"],
            "popularity": kink["popularity"],
            "interest_state": state["interest_state"],
            "directions": state["directions"],
        }
        if state["interest_state"] in BLOCKED_RATINGS:
            board["no_go"].append(item)
            continue
        if state["interest_state"] in SUPPRESSED_RATINGS:
            board["hidden"].append(item)
            continue
        placed = False
        for direction in state["directions"]:
            if direction in board:
                board[direction].append(item)
                placed = True
        if not placed:
            board["together"].append(item)
    for key in board:
        board[key].sort(key=lambda item: (-item["popularity"], item["name"].lower()))
    return board