package server

import (
	"sync"

	protocolpkg "github.com/noahlann/nnet/pkg/protocol"
	unpackerpkg "github.com/noahlann/nnet/pkg/unpacker"
)

// unpackerInfo 拆包器信息
type unpackerInfo struct {
	unpacker unpackerpkg.Unpacker
}

// unpackerManager 拆包器管理器（每个连接一个unpacker）
type unpackerManager struct {
	unpackers map[string]*unpackerInfo
	mu        sync.RWMutex
}

// newUnpackerManager 创建拆包器管理器
func newUnpackerManager() *unpackerManager {
	return &unpackerManager{
		unpackers: make(map[string]*unpackerInfo),
	}
}

// getOrCreateUnpacker 获取或创建连接的拆包器
func (m *unpackerManager) getOrCreateUnpacker(connID string, protocol protocolpkg.Protocol) unpackerpkg.Unpacker {
	m.mu.RLock()
	info, exists := m.unpackers[connID]
	m.mu.RUnlock()

	if exists {
		return info.unpacker
	}

	if protocol == nil {
		return nil
	}

	withUnpacker, ok := interface{}(protocol).(interface {
		Unpacker() unpackerpkg.Unpacker
	})
	if !ok {
		return nil
	}

	unpacker := withUnpacker.Unpacker()
	if unpacker == nil {
		return nil
	}

	m.mu.Lock()
	defer m.mu.Unlock()

	if existing, ok := m.unpackers[connID]; ok {
		return existing.unpacker
	}

	m.unpackers[connID] = &unpackerInfo{unpacker: unpacker}
	return unpacker
}

// removeUnpacker 移除连接的拆包器
func (m *unpackerManager) removeUnpacker(connID string) {
	m.mu.Lock()
	delete(m.unpackers, connID)
	m.mu.Unlock()
}