path: root/handlers.go

package main

import (
	"errors"
	"net"
	"strconv"
	"time"
)

func handleGet(conn net.Conn, args []string) {
	if len(args) != 2 {
        err := errors.New("wrong number of arguments for 'GET'")
        conn.Write(serializeRESP(err))
		return
    }
    
	key := args[1]

	result := db.ExecuteRead(key, func(s *Shard) interface{}{
		item, exists := s.data[key]
		if !exists {
			return nil
		}

		if item.ExpiresAt != nil && time.Now().After(*item.ExpiresAt) {
			delete(s.data, key)
			return nil
		}

		strValue, ok := item.Value.(string)
		if !ok {
			err := errors.New("WRONGTYPE Operation against a key holding the wrong kind of value")
			return err
		}
		return strValue
	})


	conn.Write(serializeRESP(result))
}

func handleExists(conn net.Conn, args []string) {
	if len(args) != 2 {
        err := errors.New("wrong number of arguments for 'EXISTS'")
        conn.Write(serializeRESP(err))
		return
    }

	key := args[1]
	result := db.ExecuteRead(key, func(s *Shard) interface{}{
		_, exists := s.data[key]
		if exists {
			return 1
		} else {
			return 0
		}
	})

	conn.Write(serializeRESP(result))
}

func handleSet(conn net.Conn, args []string) {
	if len(args) != 3 {
        err := errors.New("wrong number of arguments for 'SET'")
        conn.Write(serializeRESP(err))
		return
    }

	key := args[1]
	result := db.Execute(key, func(s *Shard) interface{}{
		item := Item{Value: args[2]}
		s.data[key] = item
		return SimpleString("OK")
	})

	conn.Write(serializeRESP(result))
}

func handleDel(conn net.Conn, args []string) {

	if len(args) < 2 {
        err := errors.New("wrong number of arguments for 'DEL'")
        conn.Write(serializeRESP(err))
		return
    }
	keys := args[1:]
	deletedKeys := db.ExecuteMulti(keys, func(shards []*Shard) interface{}{
		count := 0
		for _, key := range keys{
			shard := db.getShard(key)
			_, exists := shard.data[key]
			if exists {
				delete(shard.data, key)
				count += 1
			} 
		}
		return count
	})
	conn.Write(serializeRESP(deletedKeys))
}


func handleIncr(conn net.Conn, args []string) {

	if len(args) != 2 {
        err := errors.New("wrong number of arguments for 'INCR'")
        conn.Write(serializeRESP(err))
		return
    }

	key := args[1]
	result := db.Execute(key, func(s *Shard)interface{}{
		item, exists := s.data[key]
		if exists {
			strValue, ok := item.Value.(string)
			if !ok {
				err := errors.New("value is not an integer or out of range")
				return err
			}

			currentInt, err := strconv.Atoi(strValue)
			if err != nil {
				err := errors.New("value is not an integer or out of range")
				return err
			}

			newValueStr := strconv.Itoa(currentInt + 1)
			s.data[key] = Item{Value: newValueStr}
			return currentInt + 1
		} else {
			s.data[key] = Item{Value: "1"}
			return 1
		}

	})

	conn.Write(serializeRESP(result))
}

func handleDecr(conn net.Conn, args []string) {

	if len(args) != 2 {
        err := errors.New("wrong number of arguments for 'DECR'")
        conn.Write(serializeRESP(err))
		return
    }

	key := args[1]
	result := db.Execute(key, func(s *Shard)interface{}{
		item, exists := s.data[key]
		if exists {
			strValue, ok := item.Value.(string)
			if !ok {
				err := errors.New("value is not an integer or out of range")
				return err
			}

			currentInt, err := strconv.Atoi(strValue)
			if err != nil {
				err := errors.New("value is not an integer or out of range")
				return err
			}

			newValueStr := strconv.Itoa(currentInt + 1)
			s.data[key] = Item{Value: newValueStr}
			return currentInt - 1
		} else {
			s.data[key] = Item{Value: "1"}
			return -1
		}

	})

	conn.Write(serializeRESP(result))
}

func handlePing(conn net.Conn, args []string) {
	if