from typing import Any

from fastapi import FastAPI
from fastapi.openapi.constants import REF_PREFIX
from fastapi.openapi.utils import get_openapi

field_error_definition = {
    "title": "FieldError",
    "type": "object",
    "properties": {
        "message": {"title": "Message", "type": "string"},
        "code": {"title": "Error code", "type": "string"},
    },
    "required": ["message", "code"],
}

validation_error_response_definition = {
    "title": "HTTPValidationError",
    "type": "object",
    "properties": {
        "message": {"title": "Message", "type": "string"},
        "code": {"title": "Error code", "type": "string"},
        "fields": {
            "title": "Field errors",
            "type": "object",
            "additionalProperties": {"$ref": REF_PREFIX + "FieldError"},
        },
    },
    "required": ["message", "code", "fields"],
    "example": {
        "message": "Validation error",
        "code": "validation_error",
        "fields": {
            "name": {
                "message": "Cannot be blank",
                "code": "value_error.required",
            },
            "email": {
                "message": "Not valid email",
                "code": "value_error.invalid",
            },
        },
    },
}


def extend(app: FastAPI) -> None:
    def _openapi() -> dict[str, Any]:
        if app.openapi_schema:
            return app.openapi_schema
        openapi_schema = get_openapi(
            title=app.title,
            version=app.version,
            openapi_version=app.openapi_version,
            description=app.description,
            servers=app.servers,
            routes=app.routes,
        )
        del openapi_schema["components"]["schemas"]["ValidationError"]
        openapi_schema["components"]["schemas"].update(
            {
                "FieldError": field_error_definition,
                "HTTPValidationError": validation_error_response_definition,
            }
        )
        app.openapi_schema = openapi_schema
        return app.openapi_schema

    app.openapi = _openapi  # type: ignore[method-assign]