package dbx

import (
	"fmt"
	"strconv"
	"strings"
)

// DBConfig provides a template for database connection configuration compatible
// with go-toolkit/config. If used as a field in a struct, remember to include
// the `validate:"dive"` tag to ensure that the validator checks sub-fields.
type DBConfig struct {
	User        string `validate:"required"`
	Password    string `validate:"required"`
	URI         string `validate:"hostname_port,required"`
	Name        string `validate:"required"`
	MaxConn     int    `validate:"min=1,max=1000"`
	AutoMigrate bool
	DebugLog    bool
}

// ConnectionString returns a connection string compatible with the given
// SQL dialect.
func (cfg *DBConfig) ConnectionString(dialect Dialect) string {
	switch dialect {
	case DialectPostgres:
		return fmt.Sprintf("postgres://%s:%s@%s/%s?sslmode=disable",
			cfg.User, cfg.Password, cfg.URI, cfg.Name)
	case DialectMySQL:
		return fmt.Sprintf("%s:%s@tcp(%s)/%s?parseTime=true&loc=Local",
			cfg.User, cfg.Password, cfg.URI, cfg.Name)
	default:
		panic("unsupported dialect: " + string(dialect))
	}
}

// Host returns the host portion of the database URI.
func (cfg *DBConfig) Host() (string, error) {
	host, _, err := cfg.split()
	return host, err
}

// Port returns the port portion of the database URI.
func (cfg *DBConfig) Port() (int, error) {
	_, port, err := cfg.split()
	if err != nil {
		return 0, err
	}

	portInt, err := strconv.Atoi(port)
	if err != nil {
		return 0, fmt.Errorf("invalid port: %w", err)
	}
	return portInt, nil
}

// splits the URI into host and port.
func (cfg *DBConfig) split() (string, string, error) {
	split := strings.Split(cfg.URI, ":")
	if len(split) != 2 {
		return "", "", fmt.Errorf("invalid URI format")
	}
	return split[0], split[1], nil
}