from typing import Dict, List
from sqlmodel import Session, select
from datetime import datetime
from app.models import Language, Translation

DEFAULT_LANGUAGES: List[Dict[str, object]] = [
    {"code": "de", "name": "Deutsch", "is_default": True},
    {"code": "en", "name": "English", "is_default": False},
]

TRANSLATION_BLUEPRINT: List[Dict[str, object]] = [
    {
        "key": "layout.header.title",
        "label": "App Titel",
        "description": "Titel im Kopfbereich der Anwendung.",
        "defaults": {"de": "Team Chat", "en": "Team Chat"},
    },
    {
        "key": "layout.nav.chat",
        "label": "Navigation Chat",
        "description": "Link zur Chat-Übersicht in der Navigation.",
        "defaults": {"de": "Chat", "en": "Chat"},
    },
    {
        "key": "layout.nav.snippets",
        "label": "Navigation Snippets",
        "description": "Link zur Snippet-Bibliothek in der Navigation.",
        "defaults": {"de": "Snippets", "en": "Snippets"},
    },
    {
        "key": "layout.nav.admin",
        "label": "Navigation Admin",
        "description": "Link zum Adminbereich in der Navigation.",
        "defaults": {"de": "Admin", "en": "Admin"},
    },
    {
        "key": "login.title",
        "label": "Login Titel",
        "description": "Überschrift des Login-Formulars.",
        "defaults": {"de": "Anmeldung", "en": "Login"},
    },
]


def ensure_default_languages(session: Session) -> List[Language]:
    """Ensure default languages exist and return current list."""
    existing = session.exec(select(Language)).all()
    if not existing:
        for language_data in DEFAULT_LANGUAGES:
            session.add(Language(**language_data))
        session.commit()
        existing = session.exec(select(Language)).all()
    return existing


def ensure_translation_entries(session: Session) -> None:
    """Ensure translation entries exist for all languages and blueprint keys."""
    languages = ensure_default_languages(session)
    has_changes = False

    for blueprint in TRANSLATION_BLUEPRINT:
        defaults: Dict[str, str] = blueprint.get("defaults", {})  # type: ignore[assignment]
        for language in languages:
            stmt = select(Translation).where(
                Translation.key == blueprint["key"],
                Translation.language_id == language.id,
            )
            translation = session.exec(stmt).first()
            if translation:
                continue
            value = defaults.get(language.code, "")
            session.add(
                Translation(
                    key=blueprint["key"],
                    value=value,
                    language_id=language.id,
                )
            )
            has_changes = True

    if has_changes:
        session.commit()


def ensure_translations_for_language(session: Session, language: Language) -> None:
    """Create translation entries for a newly added language."""
    defaults_by_key = {bp["key"]: bp.get("defaults", {}) for bp in TRANSLATION_BLUEPRINT}
    has_changes = False

    for key, defaults in defaults_by_key.items():
        stmt = select(Translation).where(
            Translation.key == key,
            Translation.language_id == language.id,
        )
        translation = session.exec(stmt).first()
        if translation:
            continue
        value = defaults.get(language.code, "") if isinstance(defaults, dict) else ""
        session.add(
            Translation(
                key=key,
                value=value,
                language_id=language.id,
            )
        )
        has_changes = True

    if has_changes:
        session.commit()


def get_translation_blueprint() -> List[Dict[str, object]]:
    return TRANSLATION_BLUEPRINT


def update_translation_timestamp(translation: Translation) -> None:
    translation.updated_at = datetime.utcnow()