package node

import (
	"bytes"
	"sync"

	core "dappco.re/go/core"
)

// bufferPool provides reusable byte buffers for JSON encoding in hot paths.
// This reduces allocation overhead in message serialization.
var bufferPool = sync.Pool{
	New: func() any {
		return bytes.NewBuffer(make([]byte, 0, 1024))
	},
}

func getBuffer() *bytes.Buffer {
	buffer := bufferPool.Get().(*bytes.Buffer)
	buffer.Reset()
	return buffer
}

func putBuffer(buffer *bytes.Buffer) {
	// Don't pool buffers that grew too large (>64KB)
	if buffer.Cap() <= 65536 {
		bufferPool.Put(buffer)
	}
}

// MarshalJSON encodes a value to JSON using Core's JSON primitive and then
// restores the historical no-EscapeHTML behaviour expected by the node package.
// Returns a copy of the encoded bytes (safe to use after the function returns).
//
//	data, err := MarshalJSON(value)
func MarshalJSON(value any) ([]byte, error) {
	encoded := core.JSONMarshal(value)
	if !encoded.OK {
		return nil, encoded.Value.(error)
	}
	data := encoded.Value.([]byte)

	data = bytes.ReplaceAll(data, []byte(`\u003c`), []byte("<"))
	data = bytes.ReplaceAll(data, []byte(`\u003e`), []byte(">"))
	data = bytes.ReplaceAll(data, []byte(`\u0026`), []byte("&"))

	// Return a copy since callers may retain the slice after subsequent calls.
	out := make([]byte, len(data))
	copy(out, data)
	return out, nil
}