package zlog

import (
	"bytes"
	"log/slog"
	"sync"
)

type jsonHandlerPool struct {
	*sync.Pool
}

func newJsonHandlerPool(handlerOption *slog.HandlerOptions) *jsonHandlerPool {
	var handlerPool *jsonHandlerPool
	generator := &sync.Pool{
		New: func() any {
			buf := new(bytes.Buffer)
			return &jsonHandler{
				buf:         buf,
				pool:        handlerPool,
				JSONHandler: slog.NewJSONHandler(buf, handlerOption),
			}
		},
	}
	handlerPool = &jsonHandlerPool{
		generator,
	}
	return handlerPool
}

func (jhp *jsonHandlerPool) Get() *jsonHandler {
	handler := jhp.Pool.Get().(*jsonHandler)
	return handler
}

type jsonHandler struct {
	buf  *bytes.Buffer
	pool *jsonHandlerPool
	*slog.JSONHandler
}

func (j *jsonHandler) Put() {
	// Only put back to pool if buffer is smaller than 4MB in RAM size.
	if j.buf.Cap() < 1024*1024*4 {
		j.buf.Reset()
		j.pool.Put(j)
	}
}