"""Сессии: создание, состояние, история.

`group_id` и `mode` принимаются с первого дня — размечать накопленные сессии
задним числом не надо (docs/arch/CONTRACT.md#http-api).
"""

from datetime import datetime
from uuid import UUID

from fastapi import APIRouter, Depends, HTTPException, Query
from pydantic import BaseModel
from sqlalchemy.ext.asyncio import AsyncSession

from app.db import repo
from app.db.base import get_session
from app.domain.events import SessionMode

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


class SessionCreate(BaseModel):
    scenario_id: str
    mode: SessionMode
    trainee: str | None = None
    group: str | None = None


class SessionOut(BaseModel):
    session_id: UUID
    scenario_id: str
    mode: SessionMode
    attempt: int
    trainee_id: UUID | None = None
    group_id: UUID | None = None
    started_at: datetime | None = None
    ended_at: datetime | None = None
    end_reason: str | None = None


def _out(session) -> SessionOut:
    return SessionOut(
        session_id=session.id,
        scenario_id=session.scenario_id,
        mode=session.mode,
        attempt=session.attempt,
        trainee_id=session.trainee_id,
        group_id=session.group_id,
        started_at=session.started_at,
        ended_at=session.ended_at,
        end_reason=session.end_reason,
    )


@router.post("", response_model=SessionOut, status_code=201)
async def create(body: SessionCreate, db: AsyncSession = Depends(get_session)) -> SessionOut:
    group = await repo.ensure_group(db, body.group) if body.group else None
    trainee = await repo.ensure_trainee(db, body.trainee, group) if body.trainee else None
    session = await repo.create_session(
        db,
        scenario_id=body.scenario_id,
        mode=body.mode.value,
        trainee_id=trainee.id if trainee else None,
        group_id=group.id if group else None,
    )
    return _out(session)


@router.get("/{session_id}", response_model=SessionOut)
async def read(session_id: UUID, db: AsyncSession = Depends(get_session)) -> SessionOut:
    session = await repo.get_session(db, session_id)
    if session is None:
        raise HTTPException(status_code=404, detail="session_not_found")
    return _out(session)


@router.get("", response_model=list[SessionOut])
async def listing(
    trainee: UUID | None = None,
    group: UUID | None = None,
    mode: SessionMode | None = None,
    since: datetime | None = Query(default=None, alias="from"),
    limit: int = 100,
    db: AsyncSession = Depends(get_session),
) -> list[SessionOut]:
    rows = await repo.history(
        db,
        trainee_id=trainee,
        group_id=group,
        mode=mode.value if mode else None,
        since=since,
        limit=limit,
    )
    return [_out(row) for row in rows]