score-tracker/database/database.js

const app = require('../app');
const { Client } = require('pg');
const fs = require('fs');

if (process.env.NODE_ENV !== 'production' || process.env.NODE_ENV !== 'testing') {
  require('dotenv').config();
}

const client = new Client();
client.connect();

async function executeQuery(query, values = []) {
    const result = await client.query({
        rowMode: 'array',
        text: query,
        values: values
    });
    return result.rows;
}

async function Initialize() {
    console.log("Initializing database...")
    const sql = fs.readFileSync('database/init_database.sql').toString();
    await executeQuery(sql);
    console.log("Database initialized.")
}


async function checkForDatabaseInitialization() {
    const databaseIsSetupQuery = `SELECT schema_name FROM information_schema.schemata WHERE schema_name = 'scores'`;
    let result = await executeQuery(databaseIsSetupQuery);
    
    const databaseIsSetup = result.length !== 0;

    if(!databaseIsSetup) {
        await Initialize();
    }


    let latestMigration;
    try {
        const latestMigrationQuery = `SELECT value FROM metadata WHERE property = 'latest_migration';`;
        latestMigration = +((await executeQuery(latestMigrationQuery))[0][0]);
    } catch {
        latestMigration = 0;
    }


    await performMigrations(latestMigration);
}
const initializationStatus = checkForDatabaseInitialization();

async function performMigrations(currentMigration) {
    const migrationFileList = fs.readdirSync('database/migrations');
    const latestMigration = +migrationFileList[migrationFileList.length - 1].slice(0, 1);

    for(let i = +currentMigration + 1; i <= latestMigration; i++) {
        const sql = fs.readFileSync(`database/migrations/${i}.sql`).toString();
        await executeQuery(sql);
        console.log(`Performed database migration ${i}`);
    }
}





exports.executeQuery = executeQuery;
exports.initializationStatus = initializationStatus;