"use strict";

const Promise = require("bluebird");
const path = require("path");
const knex = require("knex");
const { knexSnakeCaseMappers } = require("objection");
const prometheusClient = require("prom-client");

const models = require("./models");

let migrationsFolder = path.join(__dirname, "../migrations");

module.exports = function initialize({ knexfile }) {
	let prometheusRegistry = new prometheusClient.Registry();
	prometheusClient.collectDefaultMetrics({ register: prometheusRegistry });

	let knexInstance = knex({
		... knexfile,
		... knexSnakeCaseMappers()
	});

	let state = {
		knex: knexInstance,
		prometheusRegistry: prometheusRegistry,
		metrics: {
			storedItems: new prometheusClient.Counter({
				registers: [ prometheusRegistry ],
				name: "srap_stored_items_total",
				help: "Amount of items that have been created or updated",
				labelNames: [ "tag" ]
			}),
			successfulItems: new prometheusClient.Counter({
				registers: [ prometheusRegistry ],
				name: "srap_successful_items_total",
				help: "Amount of items that have been successfully processed",
				labelNames: [ "task" ]
			}),
			failedItems: new prometheusClient.Counter({
				registers: [ prometheusRegistry ],
				name: "srap_failed_items_total",
				help: "Amount of items that have failed during processing",
				labelNames: [ "task" ]
			}),
			taskFetchTime: new prometheusClient.Gauge({
				registers: [ prometheusRegistry ],
				name: "srap_task_fetch_seconds",
				help: "Time needed for the most recent attempt at fetching new scraping tasks",
				labelNames: [ "task" ]
			}),
			taskFetchResults: new prometheusClient.Gauge({
				registers: [ prometheusRegistry ],
				name: "srap_task_fetch_results_count",
				help: "Amount of new scraping tasks fetched during the most recent attempt",
				labelNames: [ "task" ]
			})
		}
	};

	return Promise.try(() => {
		return knexInstance.migrate.latest({
			directory: migrationsFolder
		});
	}).then(() => {
		return {
			... state,
			db: models(state)
		};
	});
};