// Author: simon (ynwdlxm@163.com)
// Date: 2025/10/20 14:51
// Desc:

package cluster

import (
	"errors"

	"github.com/runningwater/go-redis/interface/resp"
	"github.com/runningwater/go-redis/resp/reply"
)

type CmdFunc func(cdb *Database, conn resp.Connection, args [][]byte) resp.Reply

var defaultFuncMap map[string]CmdFunc

func init() {
	defaultFuncMap = map[string]CmdFunc{
		"get":      defaultFunc,
		"getset":   defaultFunc,
		"set":      defaultFunc,
		"setnx":    defaultFunc,
		"exists":   defaultFunc,
		"del":      delFunc,
		"type":     defaultFunc,
		"ping":     pingFunc,
		"select":   selectFunc,
		"rename":   renameFunc,
		"renamenx": renameFunc,
		"flushdb":  flushdbFunc,
	}
}

// 默认命令处理函数，转发到对应的节点执行
// GET key
// SEt key value
func defaultFunc(cdb *Database, conn resp.Connection, args [][]byte) resp.Reply {
	key := string(args[1])
	// 获取 key 所在的节点
	peer := cdb.peerPicker.PickNode(key)

	return cdb.relay(peer, conn, args)
}

// PING 命令处理函数，不转发，本节点执行
func pingFunc(cdb *Database, conn resp.Connection, args [][]byte) resp.Reply {
	// 不能转发，只能执行
	return cdb.db.Exec(conn, args)
}
func selectFunc(cdb *Database, conn resp.Connection, args [][]byte) resp.Reply {
	return pingFunc(cdb, conn, args)
}

// rename k1 k2
func renameFunc(cdb *Database, conn resp.Connection, args [][]byte) resp.Reply {
	if len(args) != 3 {
		return reply.NewErrReply("ERR wrong number of arguments for 'rename' command")
	}
	src := string(args[1])
	dest := string(args[2])

	peerSrc := cdb.peerPicker.PickNode(src)
	peerDest := cdb.peerPicker.PickNode(dest)

	if peerSrc != peerDest {
		return reply.NewErrReply("ERR rename command not supported in cluster mode")
	}

	return cdb.relay(peerSrc, conn, args)
}

func flushdbFunc(cdb *Database, conn resp.Connection, args [][]byte) resp.Reply {
	replies := cdb.broadcast(conn, args)
	var errReply resp.Reply
	for _, r := range replies {
		if reply.IsErrReply(r) {
			errors.As(r, &errReply)
			break
		}
	}
	if errReply == nil {
		return reply.NewOkReply()
	}

	return reply.NewErrReply("err: " + errReply.Error())
}

func delFunc(cdb *Database, conn resp.Connection, args [][]byte) resp.Reply {
	replies := cdb.broadcast(conn, args)
	var errReply resp.Reply
	var deleted int64 = 0
	for _, r := range replies {
		if reply.IsErrReply(r) {
			errors.As(r, &errReply)
			break
		}
		var intReply *reply.IntReply
		ok := errors.As(r, &intReply)
		if !ok {
			errReply = reply.NewErrReply("err:  convert to IntReply not ok")
		}
		deleted += intReply.Code
	}
	if errReply == nil {
		return reply.NewIntReply(deleted)
	}

	return reply.NewErrReply("err: " + errReply.Error())
}