"""
Classroom API - Settings Routes

Teacher settings endpoints (Feature f16).
"""

import logging

from fastapi import APIRouter, HTTPException, Depends

from classroom_engine import get_default_durations

from ..models import (
    TeacherSettingsResponse,
    UpdatePhaseDurationsRequest,
    UpdatePreferencesRequest,
)
from ..services.persistence import (
    init_db_if_needed,
    DB_ENABLED,
    SessionLocal,
)

logger = logging.getLogger(__name__)

router = APIRouter(tags=["Settings"])


def get_db():
    """Database session dependency."""
    if DB_ENABLED and SessionLocal:
        db = SessionLocal()
        try:
            yield db
        finally:
            db.close()
    else:
        yield None


@router.get("/settings/{teacher_id}", response_model=TeacherSettingsResponse)
async def get_teacher_settings(
    teacher_id: str,
    db=Depends(get_db)
):
    """
    Holt die Einstellungen eines Lehrers.

    Gibt die personalisierten Phasen-Dauern und UI-Praeferenzen zurueck.
    Falls keine Einstellungen existieren, werden Defaults erstellt.

    Args:
        teacher_id: ID des Lehrers

    Returns:
        TeacherSettingsResponse mit allen Einstellungen
    """
    if DB_ENABLED and db:
        try:
            from classroom_engine.repository import TeacherSettingsRepository
            repo = TeacherSettingsRepository(db)
            settings = repo.get_or_create(teacher_id)
            return TeacherSettingsResponse(
                teacher_id=settings.teacher_id,
                default_phase_durations=settings.default_phase_durations or get_default_durations(),
                audio_enabled=settings.audio_enabled if settings.audio_enabled is not None else True,
                high_contrast=settings.high_contrast if settings.high_contrast is not None else False,
                show_statistics=settings.show_statistics if settings.show_statistics is not None else True,
            )
        except Exception as e:
            logger.error(f"Failed to get teacher settings: {e}")
            raise HTTPException(status_code=500, detail=f"Fehler beim Laden der Einstellungen: {e}")

    # Fallback: Defaults
    return TeacherSettingsResponse(
        teacher_id=teacher_id,
        default_phase_durations=get_default_durations(),
        audio_enabled=True,
        high_contrast=False,
        show_statistics=True,
    )


@router.put("/settings/{teacher_id}/durations", response_model=TeacherSettingsResponse)
async def update_phase_durations(
    teacher_id: str,
    request: UpdatePhaseDurationsRequest,
    db=Depends(get_db)
):
    """
    Aktualisiert die Standard-Phasendauern eines Lehrers.

    Ermoeglicht Lehrern, ihre bevorzugten Phasen-Dauern zu speichern.
    Diese werden dann bei neuen Sessions als Default verwendet.

    Args:
        teacher_id: ID des Lehrers
        request: Neue Phasen-Dauern in Minuten

    Returns:
        Aktualisierte TeacherSettingsResponse
    """
    # Validierung: Nur gueltige Phasen erlauben
    valid_phases = {"einstieg", "erarbeitung", "sicherung", "transfer", "reflexion"}
    for phase in request.durations:
        if phase not in valid_phases:
            raise HTTPException(
                status_code=400,
                detail=f"Ungueltige Phase: {phase}. Erlaubt: {valid_phases}"
            )
        if request.durations[phase] < 1 or request.durations[phase] > 120:
            raise HTTPException(
                status_code=400,
                detail=f"Phasen-Dauer muss zwischen 1 und 120 Minuten liegen"
            )

    if DB_ENABLED and db:
        try:
            from classroom_engine.repository import TeacherSettingsRepository
            repo = TeacherSettingsRepository(db)
            settings = repo.update_phase_durations(teacher_id, request.durations)
            return TeacherSettingsResponse(
                teacher_id=settings.teacher_id,
                default_phase_durations=settings.default_phase_durations,
                audio_enabled=settings.audio_enabled if settings.audio_enabled is not None else True,
                high_contrast=settings.high_contrast if settings.high_contrast is not None else False,
                show_statistics=settings.show_statistics if settings.show_statistics is not None else True,
            )
        except Exception as e:
            logger.error(f"Failed to update phase durations: {e}")
            raise HTTPException(status_code=500, detail=f"Fehler beim Speichern: {e}")

    raise HTTPException(
        status_code=503,
        detail="Datenbank nicht verfuegbar - Einstellungen koennen nicht gespeichert werden"
    )


@router.put("/settings/{teacher_id}/preferences", response_model=TeacherSettingsResponse)
async def update_preferences(
    teacher_id: str,
    request: UpdatePreferencesRequest,
    db=Depends(get_db)
):
    """
    Aktualisiert die UI-Praeferenzen eines Lehrers.

    Ermoeglicht das Speichern von:
    - audio_enabled: Audio-Hinweise aktiviert
    - high_contrast: Hoher Kontrast fuer Beamer
    - show_statistics: Statistiken nach Stundenende anzeigen

    Args:
        teacher_id: ID des Lehrers
        request: Zu aktualisierende Praeferenzen

    Returns:
        Aktualisierte TeacherSettingsResponse
    """
    if DB_ENABLED and db:
        try:
            from classroom_engine.repository import TeacherSettingsRepository
            repo = TeacherSettingsRepository(db)
            settings = repo.update_preferences(
                teacher_id=teacher_id,
                audio_enabled=request.audio_enabled,
                high_contrast=request.high_contrast,
                show_statistics=request.show_statistics
            )
            return TeacherSettingsResponse(
                teacher_id=settings.teacher_id,
                default_phase_durations=settings.default_phase_durations or get_default_durations(),
                audio_enabled=settings.audio_enabled if settings.audio_enabled is not None else True,
                high_contrast=settings.high_contrast if settings.high_contrast is not None else False,
                show_statistics=settings.show_statistics if settings.show_statistics is not None else True,
            )
        except Exception as e:
            logger.error(f"Failed to update preferences: {e}")
            raise HTTPException(status_code=500, detail=f"Fehler beim Speichern: {e}")

    raise HTTPException(
        status_code=503,
        detail="Datenbank nicht verfuegbar - Einstellungen koennen nicht gespeichert werden"
    )