package translation

import (
	"embed"
	"encoding/json"
	"fmt"
	"strings"

	"git.apihub24.de/admin/generic-di"
)

func init() {
	di.Injectable(newTranslationService)
}

type ITranslationService interface {
	Init(files embed.FS)
	SetDefaultCulture(culture string)
	Get(key string, culture string, args ...string) string
}

type translationService struct {
	defaultCulture   string
	translationFiles embed.FS
	sources          map[string]map[string]string
}

func newTranslationService() ITranslationService {
	return &translationService{
		defaultCulture:   "en",
		translationFiles: embed.FS{},
		sources:          make(map[string]map[string]string),
	}
}

func (translation *translationService) Init(files embed.FS) {
	translation.translationFiles = files
}

func (translation *translationService) SetDefaultCulture(culture string) {
	translation.defaultCulture = strings.ToLower(culture)
}

func (translation *translationService) Get(key string, culture string, args ...string) string {
	source, err := translation.loadSource(culture)
	if err != nil {
		return fmt.Sprintf("unknown error: %s", err.Error())
	}
	value, ok := source[key]
	if !ok {
		return fmt.Sprintf("no value for key %s found in source %s", key, culture)
	}
	if len(args) > 0 {
		var tmpArgs = make([]any, len(args))
		for idx, arg := range args {
			tmpArgs[idx] = arg
		}
		return fmt.Sprintf(value, tmpArgs...)
	}
	return value
}

func (translation *translationService) loadSource(culture string) (map[string]string, error) {
	source, ok := translation.sources[culture]
	if ok {
		return source, nil
	}
	data, err := translation.translationFiles.ReadFile(fmt.Sprintf("%s.json", strings.ToLower(culture)))
	if err != nil {
		data, err = translation.translationFiles.ReadFile(fmt.Sprintf("%s.json", translation.defaultCulture))
		if err != nil {
			return source, fmt.Errorf("can not load translation source for culture %s DefaultCulture: %s", culture, translation.defaultCulture)
		}
	}
	err = json.Unmarshal(data, &source)
	if err != nil {
		return source, fmt.Errorf("can not parse translation source %s", culture)
	}
	translation.sources[culture] = source
	return translation.sources[culture], nil
}