"""
User Language Preferences API — Stores native language + learning level.

Each user (student, parent, teacher) can set their native language.
This drives: UI language, third-language display in flashcards,
parent portal language, and translation generation.

Supported languages: de, en, tr, ar, uk, ru, pl
"""

import logging
import os
from typing import Any, Dict, Optional

from fastapi import APIRouter, HTTPException, Query
from pydantic import BaseModel

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/user", tags=["user-language"])

# Supported native languages with metadata
SUPPORTED_LANGUAGES = {
    "de": {"name": "Deutsch", "name_native": "Deutsch", "flag": "de", "rtl": False},
    "en": {"name": "English", "name_native": "English", "flag": "gb", "rtl": False},
    "tr": {"name": "Tuerkisch", "name_native": "Turkce", "flag": "tr", "rtl": False},
    "ar": {"name": "Arabisch", "name_native": "\u0627\u0644\u0639\u0631\u0628\u064a\u0629", "flag": "sy", "rtl": True},
    "uk": {"name": "Ukrainisch", "name_native": "\u0423\u043a\u0440\u0430\u0457\u043d\u0441\u044c\u043a\u0430", "flag": "ua", "rtl": False},
    "ru": {"name": "Russisch", "name_native": "\u0420\u0443\u0441\u0441\u043a\u0438\u0439", "flag": "ru", "rtl": False},
    "pl": {"name": "Polnisch", "name_native": "Polski", "flag": "pl", "rtl": False},
}

# In-memory store (will be replaced with DB later)
_preferences: Dict[str, Dict[str, Any]] = {}


class LanguagePreference(BaseModel):
    native_language: str  # ISO 639-1 code
    role: str = "student"  # student, parent, teacher
    learning_level: str = "A1"  # A1, A2, B1, B2, C1


@router.get("/languages")
def get_supported_languages():
    """List all supported native languages with metadata."""
    return {
        "languages": [
            {"code": code, **meta}
            for code, meta in SUPPORTED_LANGUAGES.items()
        ]
    }


@router.get("/language-preference")
def get_language_preference(user_id: str = Query("default")):
    """Get user's language preference."""
    pref = _preferences.get(user_id)
    if not pref:
        return {"user_id": user_id, "native_language": "de", "role": "student", "learning_level": "A1", "is_default": True}
    return {**pref, "is_default": False}


@router.put("/language-preference")
def set_language_preference(
    pref: LanguagePreference,
    user_id: str = Query("default"),
):
    """Set user's native language and learning level."""
    if pref.native_language not in SUPPORTED_LANGUAGES:
        raise HTTPException(
            status_code=400,
            detail=f"Sprache '{pref.native_language}' nicht unterstuetzt. "
                   f"Verfuegbar: {', '.join(SUPPORTED_LANGUAGES.keys())}",
        )

    _preferences[user_id] = {
        "user_id": user_id,
        "native_language": pref.native_language,
        "role": pref.role,
        "learning_level": pref.learning_level,
    }

    lang_meta = SUPPORTED_LANGUAGES[pref.native_language]
    logger.info(f"Language preference set: user={user_id} lang={pref.native_language} ({lang_meta['name']})")

    return {**_preferences[user_id], "language_meta": lang_meta}