// Author: simon (ynwdlxm@163.com)
// Date: 2025/9/15 18:04
// Desc:

package database

import (
	"strings"

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

// DB 数据库
type DB struct {
	index int
	data  dict.Dict
}

type ExecFunc func(db *DB, args [][]byte) resp.Reply
type CmdLine = [][]byte

func NewDB() *DB {
	return &DB{
		index: 0,
		data:  dict.NewSyncDict(),
	}
}

// Exec 执行一个redis命令
// 参数:
//   - c: 客户端连接对象，表示发送命令的客户端连接
//   - cmdLine: 命令行参数，包含命令名称和所有参数的字节切片
//
// 返回值:
//   - resp.Reply: 命令执行结果的回复
func (d *DB) Exec(c resp.Connection, cmdLine CmdLine) resp.Reply {
	// 检查命令行参数是否为空
	if len(cmdLine) == 0 {
		return reply.NewErrReply("empty command")
	}
	// ping set setnx get
	cmdName := strings.ToLower(string(cmdLine[0]))
	// 查找命令
	cmd, ok := cmdTable[cmdName]
	if !ok {
		return reply.NewUnknownErrReply(cmdName)
	}
	// 参数校验
	if !validateArity(cmd.arity, cmdLine[1:]) {
		return reply.NewArgNumErrReply(cmdName)
	}

	if cmd.executor == nil {
		return reply.NewErrReply("command not implement")
	}
	return cmd.executor(d, cmdLine[1:])
}

func validateArity(arity int, args [][]byte) bool {
	if arity >= 0 {
		return arity == len(args)
	}
	// 变长的 arity 设置为 负的最小个数
	return len(args) >= -arity
}

func (d *DB) GetEntity(key string) (*database.DataEntity, bool) {
	raw, ok := d.data.Get(key)
	if !ok {
		return nil, false
	}
	entity, _ := raw.(*database.DataEntity)
	return entity, true
}

func (d *DB) PutEntity(key string, entity *database.DataEntity) int {
	return d.data.Put(key, entity)
}

func (d *DB) Remove(key string) {
	d.data.Remove(key)
}

func (d *DB) Removes(keys ...string) (deleted int) {
	deleted = 0
	for _, key := range keys {
		if _, exists := d.data.Get(key); exists {
			d.Remove(key)
			deleted++
		}
	}
	return
}

func (d *DB) Flush() {
	d.data.Clear()
}