package main

import (
	"context"
	"database/sql"
	"log"
	"os"
)

func openDB() (*sql.DB, error) {
	dsn := os.Getenv("MYSQL_DSN")
	if dsn == "" {
		log.Fatal("MYSQL_DSN is empty!")
	}
	return sql.Open("mysql", dsn)
}

func migrate(ctx context.Context, db *sql.DB) error {
	ddl := `
CREATE TABLE IF NOT EXISTS students (
  id BIGINT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(100) NOT NULL,
  age INT NOT NULL,
  email VARCHAR(255) NOT NULL UNIQUE,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;`
	_, err := db.ExecContext(ctx, ddl)
	return err
}