import Knex from 'knex';

export type EndpointHandler = (req: any, res: any, knex: Knex) => Promise<void>;

export interface EndpointError extends Error {
    name: "EndpointError",
    message: string;
    httpStatus: Number;
}

export enum DBErrorKind {
    Unknown = "Unknown",
    ResourceNotFound = "ResourceNotFound",
    ResourceConflict = "ResourceConflict",
}

export interface DBError extends Error {
    name: "DBError",
    kind: DBErrorKind,
    message: string,
}

export function isEndpointError(obj: any): obj is EndpointError {
    return obj.name === "EndpointError";
}

export function isDBError(obj: any): obj is DBError {
    return obj.name === "DBError";
}

export function toEndpointError(e: Error): EndpointError {
    if (isEndpointError(e)) { return e; }
    else if (isDBError(e) && e.kind === DBErrorKind.ResourceNotFound) {
        return {
            name: "EndpointError",
            message: e.message,
            httpStatus: 404,
        }
    } else if (isDBError(e) && e.kind === DBErrorKind.ResourceConflict) {
        return {
            name: "EndpointError",
            message: e.message,
            httpStatus: 409,
        }
    }

    return {
        name: "EndpointError",
        message: e.message,
        httpStatus: 500,
    }
}

export const handleErrorsInEndpoint = (_e: any) => {
    throw toEndpointError(_e);
}