advsql/db.go

package advsql

import (
	"database/sql"
	"fmt"

	_ "github.com/go-sql-driver/mysql"
)

type Database struct {
	db    *sql.DB
	stmts map[string]*sql.Stmt
}

func InitDatabase(database *Database, conn *sql.DB) {
	panicOnNil(database)

	if database.db != nil {
		panic("database is initialized already")
	}

	*database = Database{
		db:    conn,
		stmts: map[string]*sql.Stmt{},
	}
	database.init()
}

func InitMysqlDatabase(database *Database, host string, port uint16, user, pass, db string) {
	panicOnNil(database)

	conn, err := sql.Open("mysql", connString(host, port, user, pass, db))
	if err != nil {
		panic(err)
	}

	InitDatabase(database, conn)
}

func panicOnNil(database *Database) {
	if database == nil {
		panic("database is nil. initialize database variable with new()")
	}
}

func (db *Database) init() {
	for _, globalQuery := range globalStmts {
		if db == globalQuery.db {
			db.stmt(globalQuery.query)
		}
	}
}

func (db *Database) stmt(query string) *sql.Stmt {
	if stmt, ok := db.stmts[query]; ok {
		return stmt
	}

	stmt, err := db.db.Prepare(query)
	if err != nil {
		panic(fmt.Errorf("compilation failed for query '%s' reason: %w", query, err))
	}
	db.stmts[query] = stmt
	return stmt
}

func (db *Database) Close() error {
	for _, stmt := range db.stmts {
		stmt.Close()
	}
	return db.db.Close()
}