package config

import (
	"fmt"
	"strings"
)

// SubstituteVars replaces ${var} and $var references in a string with values
// from the vars map. This is the YAML equivalent of shorewall's params file.
func SubstituteVars(s string, vars map[string]string) string {
	if len(vars) == 0 || !strings.Contains(s, "$") {
		return s
	}
	result := s
	for k, v := range vars {
		result = strings.ReplaceAll(result, "${"+k+"}", v)
		result = strings.ReplaceAll(result, "$"+k, v)
	}
	return result
}

func (c *Config) validateVars() error {
	for k := range c.Vars {
		if k == "" {
			return fmt.Errorf("vars: empty variable name")
		}
		if strings.ContainsAny(k, " \t${}") {
			return fmt.Errorf("vars: invalid variable name %q", k)
		}
	}
	return nil
}