from __future__ import annotations

import json
from pathlib import Path

from fastapi import APIRouter, Body, HTTPException

from backend.app.core.config import BackendConfig, CONFIG_PATH, load_config

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

# Chemin vers la config frontend
FRONTEND_CONFIG_PATH = Path(__file__).resolve().parent.parent.parent.parent / "frontend" / "config_frontend.json"


@router.get("/backend", response_model=BackendConfig)
def read_backend_config() -> BackendConfig:
    # expose la configuration backend en lecture seule
    return load_config()


@router.put("/backend", response_model=BackendConfig)
def update_backend_config(payload: dict = Body(...)) -> BackendConfig:
    current = load_config()
    try:
        # validation via Pydantic avant écriture
        updated = current.model_copy(update=payload)
        CONFIG_PATH.write_text(updated.model_dump_json(indent=2), encoding="utf-8")
        load_config.cache_clear()
        return load_config()
    except Exception as exc:  # pragma: no cover
        raise HTTPException(status_code=400, detail=str(exc))


@router.get("/frontend")
def read_frontend_config() -> dict:
    """Retourne la configuration frontend."""
    if not FRONTEND_CONFIG_PATH.exists():
        raise HTTPException(status_code=404, detail="Config frontend introuvable")
    return json.loads(FRONTEND_CONFIG_PATH.read_text(encoding="utf-8"))


@router.put("/frontend")
def update_frontend_config(payload: dict = Body(...)) -> dict:
    """Met à jour la configuration frontend."""
    try:
        # Charger la config actuelle
        current = {}
        if FRONTEND_CONFIG_PATH.exists():
            current = json.loads(FRONTEND_CONFIG_PATH.read_text(encoding="utf-8"))

        # Fusion profonde des configs
        def deep_merge(base: dict, update: dict) -> dict:
            result = base.copy()
            for key, value in update.items():
                if key in result and isinstance(result[key], dict) and isinstance(value, dict):
                    result[key] = deep_merge(result[key], value)
                else:
                    result[key] = value
            return result

        updated = deep_merge(current, payload)
        FRONTEND_CONFIG_PATH.write_text(
            json.dumps(updated, indent=2, ensure_ascii=False),
            encoding="utf-8"
        )

        # Mettre à jour aussi dans public/ pour le frontend dev
        public_config = FRONTEND_CONFIG_PATH.parent / "public" / "config_frontend.json"
        if public_config.parent.exists():
            public_config.write_text(
                json.dumps(updated, indent=2, ensure_ascii=False),
                encoding="utf-8"
            )

        return updated
    except Exception as exc:
        raise HTTPException(status_code=400, detail=str(exc))