package str

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"strings"

	"github.com/Shugyousha/stasher/filter"
	"github.com/Shugyousha/stasher/registry"
	"github.com/Shugyousha/stasher/work"
)

func init() {
	registry.Filterregistry["string"] = New
}

type Replacer interface {
	Replace(string) string
}

type StringFilter struct {
	FilterFuncMap map[string]Replacer
}

func New(kv map[string]string) filter.Filter {
	replmap := make(map[string]Replacer, len(kv))

	for field, repl := range kv {
		replmap[field] = strings.NewReplacer(strings.Split(repl, "/")...)
	}

	return &StringFilter{FilterFuncMap: replmap}
}

func (f *StringFilter) Filter(w *work.Work) *work.Work {
	dec := json.NewDecoder(bytes.NewReader(w.Data))
	jm := make(map[string]string, 10)

	err := dec.Decode(&jm)
	if err == io.EOF {
		fmt.Printf("EOF jm: %v\n", jm)
		return w
	}
	if err != nil {
		fmt.Printf("Error when decoding JSON: %q\n", err)
		w.Err = err
		return w
	}

	changed := false
	for field, repl := range f.FilterFuncMap {
		str, ok := jm[field]
		if !ok {
			continue
		}

		jm[field] = repl.Replace(str)
		changed = true
	}
	if changed {
		bs, err := json.Marshal(jm)
		if err != nil {
			fmt.Printf("Error when marshalling JSON: %q\n", err)
			w.Err = err
		} else {
			w.Data = bs
		}
	}

	return w
}