const CosmosClient = require("@azure/cosmos").CosmosClient;
const config = require("../config");

class BaseDao {
    /**
     * Manages reading, adding, and updating Tasks in Cosmos DB
     * @param {string} collectionId
     */
    constructor(collectionId){
        this.client = config.cosmosClient;
        this.databaseId = config.databaseId;
        this.collectionId = collectionId;

        this.database = null;
        this.container = null;

        this.init(err => {
            console.error(err);
        })
            .catch(err => {
                console.error(err);
                console.error("Shutting down because there was an error setting up the database.");
                process.exit(1);
            });
    }

    async init() {
        console.log("Setting up the database...");
        const dbResponse = await this.client.databases.createIfNotExists({
            id: this.databaseId
        });
        this.database = dbResponse.database;
        console.log("Setting up the database...done!");
        console.log("Setting up the container...");
        const coResponse = await this.database.containers.createIfNotExists({
            id: this.collectionId
        });
        this.container = coResponse.container;
        console.log("Setting up the container...done!");
    }

    async find(querySpec) {
        console.log("Querying for items from the database");
        if (!this.container) {
            throw new Error("Collection is not initialized.");
        }
        const { result: results } = await this.container.items
            .query(querySpec)
            .toArray();
        return results;
    }

    async addItem(item) {
        console.log("Adding an item to the database");
        const { body: doc } = await this.container.items.create(item);
        return doc;
    }

    async updateItem(item) {
        console.log("Update an item in the database");
        const { body: replaced } = await this.container.item(item.id).replace(item);
        return replaced;
    }

    async getItem(itemId) {
        const { body } = await this.container.item(itemId).read();
        return body;
    }

    async getAllItems() {
        const { body } = await this.container.items.read();
        return body;
    }

}

module.exports = BaseDao;