import { Sequelize } from 'sequelize'; import { Category, Product } from '../models'; /*   Connect to database.  NOTE: i'm connecting here to the database `typescript_in_nodejs_starter_db` on my `localhost` with username `postgres` and password 'fawzy'.  You can change this data and use your data instead.  */ /**  * A singleton instance of sequelize that will be used across the application.  *  * @summary It's important to not use any other instances of sequelize other than this instance unless you have more than one database.  */ const sequelize = new Sequelize('typescript_in_nodejs_starter_db', 'postgres', 'fawzy', { host: 'localhost', dialect: 'postgres', logging: false /* Stop logging sql queries unless your are tracing some problems. */ }); /**  * The Database helper that includes all functionalities related to the database and all of it's models.  * @summary All of this class members are static.  * @summary All database models should be registered in this class.  * @summary All database models should be accessed only through this class as central point of database functionality.  */ export class Database { /**  * A singleton instance of sequelize that will be used across the application.  *  * @summary It's important to not use any other instances of sequelize other than this instance unless you have more than one database.  */ public static readonly sequelize: Sequelize = sequelize; /**  * Tests the connection to the database using the provided credentials.  */ public static testDatabaseConnection(): Promise<void> { return sequelize.authenticate(); } /**  * Sync all defined models to the DB.  * @param force If force is true, each DAO will do DROP TABLE IF EXISTS ..., before it tries to create its own table  */ public static syncDatabase(force?: boolean): Promise<never> { return sequelize.sync({ force: force }); } /**  * The Category model that maps the `categories table` in the database.  * The model name will be `categories` also.  */ public static get Categories(): typeof Category { return Category; } /**  * The Product model that maps the `products table` in the database.  * The model name will be `products` also.  */ public static get Products(): typeof Product { return Product; } }

/**  * Represents an application http-response's body in case of success or even failure.  */ export interface AppHttpResponse { /**  * Gets or sets the data that requested or created by the user.  *  * This property will has a value only if the request was succeeded.  */ data?: unknown; /**  * Gets or sets the metadata for the http response.  */ meta?: AppHttpResponseMeta; /**  * Gets or sets a set of errors that occurs during request processing.  *  * @summary e.g. validation errors, security errors or even internal server errors.  */ errors?: AppHttpResponseError[]; }

/**  * Represents an application http-response metadata.  */ export interface AppHttpResponseMeta { /**  * Gets or sets the current pagination page.  */ page?: number; /**  * Gets or sets the maximum allowed items per-page.  */ pageSize?: number; /**  * Gets or sets the count of the actual items in the current page.  */ count?: number; /**  * Gets or sets the total count of items available in the database those match the query criteria.  */ total?: number; /**  * Gets or sets the number of the previous pagination page.  */ previousPage?: number | undefined; /**  * Gets or sets the number of the next pagination page.  */ nextPage?: number | undefined; /**  * Gets or sets the total available pagination pages those match the query criteria.  */ totalPages?: number; }

/**  * Represents an app http error that should be sent within a failed request's response.  *  * @summary All error members are optional but the more details the server sends back to the client the more easy it becomes to fix the error.  */ export interface AppHttpResponseError { /**  * Gets or sets the application-specific code for this error.  */ code?: AppErrorCode; /**  * Gets or sets the name of the source that causes this error.  *  * Usually it's the name of the property that causes the error.  *  * The property maybe a nested property,  * in this case use e.g. if we are validating a `Person` object use `address.postalCode` instead of `postalCode`.  */ source?: string; /**  * Gets or sets a generic title of the problem.  */ title?: string; /**  * Gets or sets a more descriptive details for the problem, unlike the generic @field title.  */ detail?: string; }

/**  * The application-specific error codes.  */ export enum AppErrorCode { /** Un-authenticated code. */ UnAuthenticated = 1, /** Access denied or forbidden code. */ Forbidden = 2, /** Internal server code. */ InternalServerError = 3, /** The field is required code. */ IsRequired = 4, /** The field type is invalid. */ InvalidType = 5, /** The field type is String and its length is invalid. */ InvalidLength = 6, /** The entity field value already exists in another entity. */ ValueExists = 7, /** The entity can't be deleted due to its existing relations with other entities. */ CantBeDeleted = 8, /**  * The related entity isn't found,  * @summary e.g. you are trying to create a new product in a category which is not exists in the database.  */ RelatedEntityNotFound = 9 }