import { Pool } from 'pg';
import { env } from '$env/dynamic/private';

// Get DATABASE_URL with fallback
const getDatabaseUrl = () => {
	return (
		env.DATABASE_URL ||
		process.env.DATABASE_URL ||
		'postgresql://postgres:password@localhost:5432/egentrening'
	);
};

// Lazy pool creation - only create when actually needed
let pool: Pool | null = null;

const getPool = () => {
	if (!pool) {
		pool = new Pool({
			connectionString: getDatabaseUrl(),
			ssl: process.env.NODE_ENV === 'production' ? { rejectUnauthorized: false } : false
		});
	}
	return pool;
};

// Simple database client
export const db = {
	// Execute a query
	async query(text: string, params?: any[]) {
		try {
			const poolInstance = getPool();
			const client = await poolInstance.connect();
			try {
				const result = await client.query(text, params);
				return result;
			} finally {
				client.release();
			}
		} catch (error) {
			console.error('Database query failed:', error);
			throw error;
		}
	},

	// Test connection
	async testConnection() {
		try {
			const result = await this.query('SELECT NOW() as current_time');
			console.log('Database connected successfully:', result.rows[0]);
			return true;
		} catch (error) {
			console.error('Database connection failed:', error);
			return false;
		}
	},

	// Create tables for tracking daily exercises
	async createTables() {
		// Create exercises table with all activities in one table
		await this.query(`
			CREATE TABLE IF NOT EXISTS daily_exercises (
				id BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
				date DATE NOT NULL UNIQUE,
				pushups INTEGER DEFAULT 0,
				situps INTEGER DEFAULT 0,
				plank_time_seconds INTEGER DEFAULT 0,
				run_distance_km DECIMAL(5,2) DEFAULT 0.0,
				created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
				updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
			)
		`);

		// Create index for faster date lookups
		await this.query(`
			CREATE INDEX IF NOT EXISTS idx_daily_exercises_date
			ON daily_exercises(date)
		`);

		// Create trigger to update updated_at timestamp
		await this.query(`
			CREATE OR REPLACE FUNCTION update_updated_at_column()
			RETURNS TRIGGER AS $$
			BEGIN
				NEW.updated_at = CURRENT_TIMESTAMP;
				RETURN NEW;
			END;
			$$ language 'plpgsql'
		`);

		await this.query(`
			DROP TRIGGER IF EXISTS update_daily_exercises_updated_at ON daily_exercises;
			CREATE TRIGGER update_daily_exercises_updated_at
				BEFORE UPDATE ON daily_exercises
				FOR EACH ROW
				EXECUTE FUNCTION update_updated_at_column()
		`);
	},

	// Close all connections
	async close() {
		if (pool) {
			await pool.end();
			pool = null;
		}
	}
};