package formatters

import (
	"context"
	"errors"
	"fmt"
	"sync"

	"codeberg.org/danjones000/my-log/config"
	"github.com/spf13/viper"
)

var mut sync.RWMutex

type FormatInit func(config *viper.Viper) (Formatter, error)

var formatterMap = map[string]FormatInit{
	FormatPlain: newPlain,
	FormatJSON:  newJson,
	FormatNull:  newNull,
}

func Preferred(ctx context.Context) (f Formatter, err error) {
	_, c := config.RetrieveFromContext(ctx)
	return New(ctx, c.Formatters.Preferred)
}

func New(ctx context.Context, kind string) (f Formatter, err error) {
	v, _ := config.RetrieveFromContext(ctx)
	formatterConf := v.Sub("formatters." + kind)

	mut.RLock()
	defer mut.RUnlock()
	if maker, ok := formatterMap[kind]; ok {
		return maker(formatterConf)
	}

	return nil, fmt.Errorf("unimplemented format: %s", kind)
}

func Kinds() []string {
	r := []string{}

	mut.RLock()
	defer mut.RUnlock()
	for kind, _ := range formatterMap {
		r = append(r, kind)
	}
	return r
}

var ErrAlreadyAdded = errors.New("formatter already present")

func AddFormatter(key string, f FormatInit) error {
	mut.Lock()
	defer mut.Unlock()
	if _, present := formatterMap[key]; present {
		return fmt.Errorf("%w: %s", ErrAlreadyAdded, key)
	}

	formatterMap[key] = f
	return nil
}