package db

import (
	"bytes"
	"errors"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"

	"github.com/xlgmokha/x/pkg/env"
	"github.com/xlgmokha/x/pkg/serde"
	"github.com/xlgmokha/x/pkg/x"
)

type Entity interface {
	Identifier() string
}

type Storage[T Entity] struct {
	dir string
}

func New[T Entity](dir string) *Storage[T] {
	fullPath := x.Must(filepath.Abs(dir))
	x.Check(os.MkdirAll(fullPath, 0700))

	return &Storage[T]{
		dir: fullPath,
	}
}

func (db *Storage[T]) Save(item T) error {
	if db.fileExistsFor(item) {
		return nil
	}

	w := new(bytes.Buffer)
	x.Check(serde.To(w, item, serde.YAML))
	if env.Fetch("DUMP", "") != "" {
		fmt.Println(w.String())
	}

	return ioutil.WriteFile(db.filePathFor(item), w.Bytes(), 0700)
}

func (db *Storage[T]) filePathFor(item T) string {
	return fmt.Sprintf("%v/%v.yaml", db.dir, item.Identifier())
}

func (db *Storage[T]) fileExistsFor(item T) bool {
	_, err := os.Stat(db.filePathFor(item))

	if err != nil && errors.Is(err, os.ErrNotExist) {
		return false
	}

	return true
}