"""FastAPI application entrypoint.

Thin by design: wire settings, routers, and error handling, and expose the
OpenAPI contract. All domain logic lives in the service layer; the privacy
engine is the single enforcement point for reads.
"""

from fastapi import FastAPI, Request
from fastapi.responses import JSONResponse

from app.api.health import router as health_router
from app.api.v1 import api_router
from app.core.config import get_settings
from app.services.exceptions import Conflict, Forbidden, NotFound


def _register_error_handlers(app: FastAPI) -> None:
    @app.exception_handler(NotFound)
    async def _not_found(request: Request, exc: NotFound) -> JSONResponse:
        return JSONResponse(status_code=404, content={"detail": str(exc) or "not found"})

    @app.exception_handler(Forbidden)
    async def _forbidden(request: Request, exc: Forbidden) -> JSONResponse:
        return JSONResponse(status_code=403, content={"detail": str(exc) or "forbidden"})

    @app.exception_handler(Conflict)
    async def _conflict(request: Request, exc: Conflict) -> JSONResponse:
        return JSONResponse(status_code=409, content={"detail": str(exc) or "conflict"})


def create_app() -> FastAPI:
    settings = get_settings()
    app = FastAPI(
        title=settings.app_name,
        version=settings.version,
        description="Provenance API — family and land provenance.",
    )
    app.include_router(health_router)
    app.include_router(api_router)
    _register_error_handlers(app)
    return app


app = create_app()