// Package controller 提供游戏逻辑的控制器层，负责处理各种游戏功能的请求分发。
// 包含用户、宠物、战斗、物品、地图、任务等各个模块的控制器方法。
// 通过反射和标签系统自动注册 cmd 处理方法，实现请求到处理函数的映射。
package controller

import (
	"blazing/common/rpc"
	"blazing/cool"
	"blazing/logic/service/common"
	"bytes"
	"context"
	"fmt"
	"reflect"
	"strconv"
	"strings"
	"sync"

	"github.com/gogf/gf/v2/os/glog"
	"github.com/lunixbochs/struc"
	"github.com/panjf2000/gnet/v2"
)

// Maincontroller 是控制器层共享变量。
var Maincontroller = &Controller{} //注入service

// Controller 分发cmd逻辑实现
type Controller struct {
	UID       uint32
	RPCClient *struct {
		Kick func(uint32) error

		RegisterLogic func(uint32, uint32) error

		MatchJoinOrUpdate func(rpc.PVPMatchJoinPayload) error

		MatchCancel func(uint32) error
	}
}

// ParseCmd 将字节数组数据解析到指定类型的变量中
// 该函数使用struc库进行数据解包操作
// 参数 data: 需要解析的字节数据
// 返回值: 解析后的指定类型实例
func ParseCmd[T any](data []byte) T {
	var result T
	// 使用struc.Unpack将字节数据解包到result变量中
	struc.Unpack(bytes.NewReader(data), &result)
	return result
}

// Init 初始化控制器，注册所有cmd处理方法
// 参数 isGame: 标识是否为游戏服务器(true)或登录服务器(false)
func Init(isGame bool) {
	controllerValue := reflect.ValueOf(Maincontroller)
	controllerType := controllerValue.Type()

	for i := 0; i < controllerType.NumMethod(); i++ {
		method := controllerType.Method(i)
		methodValue := controllerValue.Method(i)
		methodType := methodValue.Type()

		if methodType.NumIn() == 0 {
			continue
		}

		reqArgType := methodType.In(0)
		if reqArgType.Kind() != reflect.Ptr || reqArgType.Elem().Kind() != reflect.Struct {
			glog.Warning(context.Background(), "方法首参必须为结构体指针", method.Name, "跳过注册")
			continue
		}
		reqType := reqArgType.Elem()
		binding := getCmdBinding(reqType)

		for _, cmd := range binding.cmds {
			if cmd == 0 {
				glog.Warning(context.Background(), "方法参数必须包含CMD参数", method.Name, "跳过注册")
				continue
			}

			if methodType.NumIn() != 2 {
				glog.Warning(context.Background(), "方法参数数量必须为2", method.Name, "跳过注册")
				continue
			}

			if !isGame && cmd > 1000 {
				continue
			}

			if isGame && cmd < 1000 {
				continue
			}

			if cool.Config.ServerInfo.IsDebug != 0 {
				fmt.Println("注册方法", cmd, method.Name)
			}

			reqTypeForNew := reqType
			cmdInfo := cool.Cmd{
				Func:             methodValue,
				Req:              reqType,
				HeaderFieldIndex: append([]int(nil), binding.headerFieldIndex...),
				UseConn:          methodType.In(1) == connType,
				NewReqFunc: func() interface{} {
					return reflect.New(reqTypeForNew).Interface()
				},
				NewReqValue: func() reflect.Value {
					return reflect.New(reqTypeForNew)
				},
			}

			if _, exists := cool.CmdCache[cmd]; exists {
				panic(fmt.Sprintf("命令处理方法已存在，跳过注册 %d %s", cmd, method.Name))
			}
			cool.CmdCache[cmd] = cmdInfo
		}
	}
}

var (
	targetType   = reflect.TypeOf(common.TomeeHeader{})
	connType     = reflect.TypeOf((*gnet.Conn)(nil)).Elem()
	cmdTypeCache sync.Map
)

// 默认返回值（无匹配字段/解析失败时）
const defaultCmdValue = 0

type cmdBinding struct {
	cmds             []uint32
	headerFieldIndex []int
}

func normalizeStructType(typ reflect.Type) reflect.Type {
	for typ.Kind() == reflect.Ptr {
		typ = typ.Elem()
	}
	return typ
}

// getCmdBinding 从结构体类型中提取绑定的cmd指令和头字段位置。
func getCmdBinding(typ reflect.Type) cmdBinding {
	typ = normalizeStructType(typ)
	if cached, ok := cmdTypeCache.Load(typ); ok {
		return cached.(cmdBinding)
	}

	if typ.Kind() != reflect.Struct {
		binding := cmdBinding{cmds: []uint32{defaultCmdValue}}
		cmdTypeCache.Store(typ, binding)
		return binding
	}

	if binding, ok := findCmdBinding(typ, make(map[reflect.Type]struct{})); ok {
		cmdTypeCache.Store(typ, binding)
		return binding
	}

	binding := cmdBinding{cmds: []uint32{defaultCmdValue}}
	cmdTypeCache.Store(typ, binding)
	return binding
}

func findCmdBinding(typ reflect.Type, visiting map[reflect.Type]struct{}) (cmdBinding, bool) {
	typ = normalizeStructType(typ)
	if typ.Kind() != reflect.Struct {
		return cmdBinding{}, false
	}
	if _, seen := visiting[typ]; seen {
		return cmdBinding{}, false
	}
	visiting[typ] = struct{}{}
	defer delete(visiting, typ)

	for i := 0; i < typ.NumField(); i++ {
		field := typ.Field(i)

		cmdSlice, isHeader, err := parseCmdTagWithStructField(field)
		if isHeader && err == nil {
			return cmdBinding{
				cmds:             cmdSlice,
				headerFieldIndex: append([]int(nil), field.Index...),
			}, true
		}

		nestedTyp := normalizeStructType(field.Type)
		if nestedTyp.Kind() != reflect.Struct {
			continue
		}

		nestedBinding, ok := findCmdBinding(nestedTyp, visiting)
		if !ok {
			continue
		}

		fieldIndex := make([]int, 0, len(field.Index)+len(nestedBinding.headerFieldIndex))
		fieldIndex = append(fieldIndex, field.Index...)
		fieldIndex = append(fieldIndex, nestedBinding.headerFieldIndex...)
		nestedBinding.headerFieldIndex = fieldIndex
		return nestedBinding, true
	}

	return cmdBinding{}, false
}

// parseCmdTagWithStructField 校验字段是否为TomeeHeader（值/指针）并解析cmd标签
// 参数 field: 结构体字段元信息
// 返回值: 解析后的cmd切片，是否为目标类型，解析失败错误
func parseCmdTagWithStructField(field reflect.StructField) ([]uint32, bool, error) {
	if field.Type != targetType && !(field.Type.Kind() == reflect.Ptr && field.Type.Elem() == targetType) {
		return nil, false, nil
	}

	cmdStr := field.Tag.Get("cmd")
	if cmdStr == "" {
		return nil, true, fmt.Errorf("field %s cmd tag is empty", field.Name)
	}

	result := make([]uint32, 0, strings.Count(cmdStr, "|")+1)
	remain := cmdStr
	for idx := 0; ; idx++ {
		part, next, found := strings.Cut(remain, "|")
		s := strings.TrimSpace(part)
		if s == "" {
			return nil, true, fmt.Errorf("field %s cmd tag part %d is empty", field.Name, idx)
		}

		num, err := strconv.ParseUint(s, 10, 32)
		if err != nil {
			return nil, true, fmt.Errorf("field %s cmd tag part %d parse error: %v (value: %s)",
				field.Name, idx, err, s)
		}
		result = append(result, uint32(num))

		if !found {
			break
		}
		remain = next
	}

	return result, true, nil
}