core/config/loader.go

package config

import (
	"os"
	"reflect"
	"regexp"
	"strings"

	"gitea.meta-tech.academy/go/core/style"
	"gopkg.in/yaml.v3"
)

type Cfg interface {
	GetVar() []VarConfig
	GetStylesDef() []string
	SetStyles(*style.Styles)
}

type VarConfig struct {
	Name  string `yaml:"name"`
	Value string `yaml:"value"`
}

type ConfigLoader struct {
	Var    []VarConfig
	Config interface{}
	varDef *VarPattern
	refstr []*reflect.Value
}

func LoadConfig(path string, out Cfg, varPattern *VarPattern) {
	cl := &ConfigLoader{varDef: varPattern, refstr: []*reflect.Value{}}
	data, err := os.ReadFile(path)
	if err != nil {
		panic(err)
	}
	if err = yaml.Unmarshal(data, out); err != nil {
		panic(err)
	}
	cl.Var = out.GetVar()
	cl.Config = out
	cl.parse()
	cl.refstr = []*reflect.Value{}
	cl.buildStyles(out)
}

func (cl *ConfigLoader) buildStyles(out Cfg) {
	styles := style.NewStyles()
	for _, def := range out.GetStylesDef() {
		s := style.NewStyleByDef(def)
		styles.List[s.Name] = s
	}
	out.SetStyles(styles)
}

func (cl *ConfigLoader) findVarName(match string) string {
	re := regexp.MustCompile(cl.varDef.getPatternCaptureName())
	parts := re.FindStringSubmatch(match)
	if len(parts) > 0 {
		match = parts[1]
	}
	return match
}

func (cl *ConfigLoader) findVarValue(v string) string {
	names := strings.SplitN(v, ".", 2)
	if names[0] == "var" {
		for _, varConfig := range cl.Var {
			if varConfig.Name == names[1] {
				v = varConfig.Value
			}
		}
	}
	return v
}

func (cl *ConfigLoader) findStringRef(ref reflect.Value) {
	switch ref.Kind() {
	case reflect.Ptr, reflect.Interface:
		cl.findStringRef(ref.Elem())
	case reflect.Struct:
		for i := 0; i < ref.NumField(); i++ {
			refc := ref.Field(i)
			cl.findStringRef(refc)
		}
	case reflect.Slice:
		if !ref.IsNil() {
			for i := 0; i < ref.Len(); i++ {
				refc := ref.Index(i)
				cl.findStringRef(refc)
			}
		}
	case reflect.String:
		if ref.Len() > 0 {
			cl.refstr = append(cl.refstr, &ref)
		}
	}
}

func (cl *ConfigLoader) parse() {
	var name string
	var tmp string
	var parts []string
	var re2 *regexp.Regexp

	cl.findStringRef(reflect.ValueOf(&cl))

	re := regexp.MustCompile(cl.varDef.getPatternVar())
	for _, ref := range cl.refstr {
		tmp = ref.String()
		parts = re.FindStringSubmatch(tmp)
		if len(parts) > 0 {
			s := strings.SplitAfter(parts[1], cl.varDef.Close)
			for _, part := range s {
				name = cl.findVarName(part)
				re2 = regexp.MustCompile(cl.varDef.getPatternVarName(name))
				tmp = re2.ReplaceAllString(tmp, cl.findVarValue(name))
			}
			ref.SetString(tmp)
		}
	}
}