"""User settings + per-sender image allowlist (SPEC §9.1 Settings, §9.4)."""

from __future__ import annotations

from typing import Annotated

from fastapi import APIRouter, Depends
from pydantic import BaseModel
from sqlalchemy import func, select
from sqlalchemy.ext.asyncio import AsyncSession

from app.db import get_session
from app.identity.deps import CurrentUser, require_csrf
from app.models import Message, User

router = APIRouter(prefix="/settings", tags=["settings"])

DbSession = Annotated[AsyncSession, Depends(get_session)]

_ALLOWED_ORDER = {"asc", "desc"}


class SettingsOut(BaseModel):
    thread_order: str = "asc"
    tz: str = "UTC"
    allowed_image_senders: list[str] = []


class SettingsPatch(BaseModel):
    thread_order: str | None = None
    tz: str | None = None


class QuotaOut(BaseModel):
    used_bytes: int
    quota_bytes: int


def allowed_image_senders(user: User) -> set[str]:
    value = user.settings.get("allowed_image_senders", [])
    if isinstance(value, list):
        return {str(e).lower() for e in value}
    return set()


def add_allowed_image_sender(user: User, email: str) -> None:
    current = sorted(allowed_image_senders(user))
    if email.lower() not in current:
        current.append(email.lower())
    # Reassign the whole dict so SQLAlchemy detects the JSONB change.
    user.settings = {**user.settings, "allowed_image_senders": current}


def _settings_out(user: User) -> SettingsOut:
    s = user.settings
    return SettingsOut(
        thread_order=str(s.get("thread_order", "asc")),
        tz=str(s.get("tz", "UTC")),
        allowed_image_senders=sorted(allowed_image_senders(user)),
    )


@router.get("", response_model=SettingsOut)
async def get_settings_endpoint(user: CurrentUser) -> SettingsOut:
    return _settings_out(user)


@router.get("/quota", response_model=QuotaOut)
async def get_quota(user: CurrentUser, db: DbSession) -> QuotaOut:
    """Storage quota and current usage (sum of stored message sizes)."""
    used = await db.scalar(
        select(func.coalesce(func.sum(Message.size_bytes), 0)).where(Message.user_id == user.id)
    )
    return QuotaOut(used_bytes=int(used or 0), quota_bytes=user.quota_bytes)


@router.patch("", response_model=SettingsOut, dependencies=[Depends(require_csrf)])
async def patch_settings(body: SettingsPatch, user: CurrentUser, db: DbSession) -> SettingsOut:
    updates = dict(user.settings)
    if body.thread_order is not None and body.thread_order in _ALLOWED_ORDER:
        updates["thread_order"] = body.thread_order
    if body.tz is not None:
        updates["tz"] = body.tz
    user.settings = updates
    await db.commit()
    return _settings_out(user)