/*
 * Copyright (C) 2025 Yidhra Studio. - All Rights Reserved
 * Updated : 25/04/2025 10:52
 *
 * Unauthorized copying or redistribution of this file in source and binary forms via any medium
 * is strictly prohibited.
 */

import {
	Injectable,
	Logger,
	OnModuleDestroy,
	OnModuleInit,
} from "@nestjs/common";
import { ConfigService } from "@nestjs/config";
import { drizzle } from "drizzle-orm/node-postgres";
import { migrate } from "drizzle-orm/node-postgres/migrator";
import { Pool } from "pg";
import * as schema from "./schemas";

@Injectable()
export class DatabaseService implements OnModuleInit, OnModuleDestroy {
	private readonly logger = new Logger(DatabaseService.name);
	private readonly pool!: Pool;
	public readonly db: ReturnType<typeof drizzle>;

	constructor(private configService: ConfigService) {
		// Create the PostgreSQL client
		const connectionString = this.getDatabaseConnectionString();
		this.pool = new Pool({ connectionString });
		// Recreate drizzle with initialized pool
		this.db = drizzle(this.pool, { schema });
	}

	async onModuleInit() {
		try {
			// Run migrations if in production mode
			if (this.configService.get("NODE_ENV") === "production") {
				this.logger.log("Running database migrations...");
				await migrate(this.db, { migrationsFolder: ".migrations" });
				this.logger.log("Database migrations completed successfully");
			} else {
				this.logger.debug("Skipping migrations in non-production environment");
			}
			this.logger.log("Database connection established successfully");
		} catch (error) {
			this.logger.error("Failed to initialize database connection", error);
			throw error;
		}
	}

	async onModuleDestroy() {
		try {
			// Close the database connection
			await this.pool.end();
			this.logger.log("Database connection closed successfully");
		} catch (error) {
			this.logger.error("Error closing database connection", error);
		}
	}

	// Get the database connection string from environment variables
	private getDatabaseConnectionString(): string {
		this.logger.debug(
			"Getting database connection string from environment variables",
		);

		const password = this.configService.get<string>("POSTGRES_PASSWORD");
		const username = this.configService.get<string>("POSTGRES_USER");
		const host = this.configService.get<string>("POSTGRES_HOST");
		const port = this.configService.get<string>("POSTGRES_PORT");
		const database = this.configService.get<string>("POSTGRES_DB");

		const missingVars: string[] = [];
		if (!password) missingVars.push("POSTGRES_PASSWORD");
		if (!username) missingVars.push("POSTGRES_USER");
		if (!host) missingVars.push("POSTGRES_HOST");
		if (!port) missingVars.push("POSTGRES_PORT");
		if (!database) missingVars.push("POSTGRES_DB");

		if (missingVars.length > 0) {
			const errorMessage = `Database configuration is missing. Missing variables: ${missingVars.join(", ")}. Please check your .env file.`;
			this.logger.error(errorMessage);
			throw new Error(errorMessage);
		}

		this.logger.debug(
			`Database connection configured for ${username}@${host}:${port}/${database}`,
		);
		return `postgres://${username}:${password}@${host}:${port}/${database}`;
	}
}