package state

import (
	"context"
	"encoding/json"
	"errors"
	"flux/core"

	"github.com/cockroachdb/pebble/v2"
)

type pebbleStateValue struct {
	backend *PebbleStateBackend
	stateID uint8
}

func (p *pebbleStateValue) Update(ctx context.Context, newVal any) (any, error) {
	key := p.backend.deserialize(p.stateID)
	// convert newVal to []byte raw
	v, err := json.Marshal(newVal)
	if err != nil {
		return nil, err
	}

	err = p.backend.db.Set(key, v, pebble.NoSync)
	if err != nil {
		return nil, err
	}

	return newVal, nil
}

func (p *pebbleStateValue) Value(ctx context.Context) (any, error) {
	key := p.backend.deserialize(p.stateID)
	v, closer, err := p.backend.db.Get(key)
	if err != nil {
		if errors.Is(err, pebble.ErrNotFound) {
			return nil, nil 
		}
		return nil, err
	}

	defer closer.Close()

	res := core.GetBuffer(len(v))
	copy(res, v)
	return v, nil
}

func (p *pebbleStateValue) Clear(ctx context.Context) error {
	key := p.backend.deserialize(p.stateID)

	return p.backend.db.Delete(key, pebble.NoSync)
}