package login

import (
	"encoding/binary"
	"errors"
	"fmt"
	"log"
	"math/rand"

	"github.com/CPunch/gopenfusion/cnet"
	"github.com/CPunch/gopenfusion/config"
	"github.com/CPunch/gopenfusion/internal/db"
	"github.com/CPunch/gopenfusion/internal/protocol"
	"github.com/CPunch/gopenfusion/internal/redis"
	"github.com/CPunch/gopenfusion/util"
)

const (
	LOGIN_DATABASE_ERROR                        = 0
	LOGIN_ID_DOESNT_EXIST                       = 1
	LOGIN_ID_AND_PASSWORD_DO_NOT_MATCH          = 2
	LOGIN_ID_ALREADY_IN_USE                     = 3
	LOGIN_ERROR                                 = 4
	LOGIN_CLIENT_VERSION_OUTDATED               = 6
	LOGIN_YOU_ARE_NOT_AN_AUTHORIZED_BETA_TESTER = 7
	LOGIN_AUTHENTICATION_CONNECTION_ERROR       = 8
	LOGIN_UPDATED_EUALA_REQUIRED                = 9
)

func (server *LoginServer) AcceptLogin(peer *cnet.CNPeer, SzID string, IClientVerC int32, ISlotNum int8, data []protocol.SP_LS2CL_REP_CHAR_INFO) error {
	resp := protocol.SP_LS2CL_REP_LOGIN_SUCC{
		SzID:          SzID,
		ICharCount:    int8(len(data)),
		ISlotNum:      ISlotNum,
		IPaymentFlag:  1,
		IOpenBetaFlag: 0,
		UiSvrTime:     util.GetTime(),
	}

	if err := peer.Send(protocol.P_LS2CL_REP_LOGIN_SUCC, resp); err != nil {
		return err
	}

	// swap keys
	peer.E_key = protocol.CreateNewKey(
		resp.UiSvrTime,
		uint64(resp.ICharCount+1),
		uint64(resp.ISlotNum+1),
	)
	peer.FE_key = protocol.CreateNewKey(
		binary.LittleEndian.Uint64([]byte(protocol.DEFAULT_KEY)),
		uint64(IClientVerC),
		1,
	)

	// send characters (if any)
	for i := 0; i < len(data); i++ {
		if err := peer.Send(protocol.P_LS2CL_REP_CHAR_INFO, &data[i]); err != nil {
			return err
		}
	}

	return nil
}

func (server *LoginServer) Login(peer *cnet.CNPeer, pkt protocol.Packet) error {
	var loginPkt protocol.SP_CL2LS_REQ_LOGIN
	pkt.Decode(&loginPkt)

	SendError := func(e int32) {
		peer.Send(protocol.P_LS2CL_REP_LOGIN_FAIL, protocol.SP_LS2CL_REP_LOGIN_FAIL{
			IErrorCode: e,
			SzID:       loginPkt.SzID,
		})
	}

	// client is resending a login packet??
	if peer.UserData() != nil {
		SendError(LOGIN_ERROR)
		return fmt.Errorf("out of order P_CL2LS_REQ_LOGIN: %v", peer.UserData())
	}

	// attempt login
	account, err := server.dbHndlr.TryLogin(loginPkt.SzID, loginPkt.SzPassword)
	if errors.Is(err, db.ErrLoginInvalidID) {
		// this is the default behavior, auto create the account if the ID isn't in use
		account, err = server.dbHndlr.NewAccount(loginPkt.SzID, loginPkt.SzPassword)
		if err != nil {
			// respond with a dummy login error packet so the client doesn't get softlocked
			SendError(LOGIN_DATABASE_ERROR)
			return err
		}
	} else if errors.Is(err, db.ErrLoginInvalidPassword) {
		// respond with invalid password
		SendError(LOGIN_ID_AND_PASSWORD_DO_NOT_MATCH)
		return nil
	} else if err != nil { // wtf?
		SendError(LOGIN_DATABASE_ERROR)
		return err
	}

	// grab player data
	peer.SetUserData(account)
	plrs, err := server.dbHndlr.GetPlayers(account.AccountID)
	if err != nil {
		SendError(LOGIN_DATABASE_ERROR)
		return err
	}
	log.Printf("Account (%d) %s has logged in", account.AccountID, account.Login)

	// truncate plrs
	if len(plrs) > 3 {
		plrs = plrs[:4]
	}

	// build character list
	charInfo := [4]protocol.SP_LS2CL_REP_CHAR_INFO{}
	for i, plr := range plrs {
		info := protocol.SP_LS2CL_REP_CHAR_INFO{
			ISlot:      int8(plr.Slot),
			ILevel:     int16(plr.Level),
			SPC_Style:  plr.PCStyle,
			SPC_Style2: plr.PCStyle2,
			IX:         int32(plr.X),
			IY:         int32(plr.Y),
			IZ:         int32(plr.Z),
		}

		AEquip, err := server.dbHndlr.GetPlayerInventorySlots(plr.PlayerID, 0, config.AEQUIP_COUNT-1)
		if err != nil {
			SendError(LOGIN_DATABASE_ERROR)
			return err
		}

		copy(info.AEquip[:], AEquip)
		charInfo[i] = info
	}

	return server.AcceptLogin(peer, loginPkt.SzID, loginPkt.IClientVerC, 1, charInfo[:len(plrs)])
}

func (server *LoginServer) CheckCharacterName(peer *cnet.CNPeer, pkt protocol.Packet) error {
	var charPkt protocol.SP_CL2LS_REQ_CHECK_CHAR_NAME
	pkt.Decode(&charPkt)

	// just auto accept, client resends this data later
	return peer.Send(protocol.P_LS2CL_REP_CHECK_CHAR_NAME_SUCC, protocol.SP_LS2CL_REP_CHECK_CHAR_NAME_SUCC{
		SzFirstName: charPkt.SzFirstName,
		SzLastName:  charPkt.SzLastName,
	})
}

func (server *LoginServer) SaveCharacterName(peer *cnet.CNPeer, pkt protocol.Packet) error {
	var charPkt protocol.SP_CL2LS_REQ_SAVE_CHAR_NAME
	pkt.Decode(&charPkt)

	account, ok := peer.UserData().(*db.Account)
	if !ok || account == nil {
		peer.Send(protocol.P_LS2CL_REP_SAVE_CHAR_NAME_FAIL, protocol.SP_LS2CL_REP_SAVE_CHAR_NAME_FAIL{})
		return fmt.Errorf("out of order P_LS2CL_REP_SAVE_CHAR_NAME_FAIL")
	}

	// TODO: sanity check SzFirstName && SzLastName
	PlayerID, err := server.dbHndlr.NewPlayer(account.AccountID, charPkt.SzFirstName, charPkt.SzLastName, int(charPkt.ISlotNum))
	if err != nil {
		peer.Send(protocol.P_LS2CL_REP_SAVE_CHAR_NAME_FAIL, protocol.SP_LS2CL_REP_SAVE_CHAR_NAME_FAIL{})
		return err
	}

	return peer.Send(protocol.P_LS2CL_REP_SAVE_CHAR_NAME_SUCC, protocol.SP_LS2CL_REP_SAVE_CHAR_NAME_SUCC{
		IPC_UID:     int64(PlayerID),
		ISlotNum:    charPkt.ISlotNum,
		IGender:     charPkt.IGender,
		SzFirstName: charPkt.SzFirstName,
		SzLastName:  charPkt.SzLastName,
	})
}

func validateCharacterCreation(character *protocol.SP_CL2LS_REQ_CHAR_CREATE) bool {
	// thanks openfusion!
	// all the values have been determined from analyzing client code and xdt
	// and double checked using cheat engine

	// check base parameters
	style := &character.PCStyle
	if !(style.IBody >= 0 && style.IBody <= 2 &&
		style.IEyeColor >= 1 && style.IEyeColor <= 5 &&
		style.IGender >= 1 && style.IGender <= 2 &&
		style.IHairColor >= 1 && style.IHairColor <= 18) &&
		style.IHeight >= 0 && style.IHeight <= 4 &&
		style.INameCheck >= 0 && style.INameCheck <= 2 &&
		style.ISkinColor >= 1 && style.ISkinColor <= 12 {
		return false
	}

	// facestyle and hairstyle are gender dependent
	if !(style.IGender == 1 && style.IFaceStyle >= 1 && style.IFaceStyle <= 5 && style.IHairStyle >= 1 && style.IHairStyle <= 23) &&
		!(style.IGender == 2 && style.IFaceStyle >= 6 && style.IFaceStyle <= 10 && style.IHairStyle >= 25 && style.IHairStyle <= 45) {
		return false
	}

	// TODO: sanity check items in SOn_Item; see db.FinishPlayer()
	return true
}

func SendFail(peer *cnet.CNPeer) error {
	if err := peer.Send(protocol.P_LS2CL_REP_SHARD_SELECT_FAIL, protocol.SP_LS2CL_REP_SHARD_SELECT_FAIL{
		IErrorCode: 2,
	}); err != nil {
		return err
	}

	return nil
}

func (server *LoginServer) CharacterCreate(peer *cnet.CNPeer, pkt protocol.Packet) error {
	var charPkt protocol.SP_CL2LS_REQ_CHAR_CREATE
	pkt.Decode(&charPkt)

	account, ok := peer.UserData().(*db.Account)
	if !ok || account == nil {
		return SendFail(peer)
	}

	if !validateCharacterCreation(&charPkt) {
		log.Printf("Invalid character creation packet: %+v", charPkt)
		return SendFail(peer)
	}

	if err := server.dbHndlr.FinishPlayer(&charPkt, account.AccountID); err != nil {
		log.Printf("Error finishing player: %v", err)
		return SendFail(peer)
	}

	plr, err := server.dbHndlr.GetPlayer(int(charPkt.PCStyle.IPC_UID))
	if err != nil {
		log.Printf("Error getting player: %v", err)
		return SendFail(peer)
	}

	return peer.Send(protocol.P_LS2CL_REP_CHAR_CREATE_SUCC, protocol.SP_LS2CL_REP_CHAR_CREATE_SUCC{
		ILevel:     int16(plr.Level),
		SPC_Style:  plr.PCStyle,
		SPC_Style2: plr.PCStyle2,
		SOn_Item:   charPkt.SOn_Item, // if items were faked, we don't really care since the db only stores the sanitized fields
	})
}

func (server *LoginServer) CharacterDelete(peer *cnet.CNPeer, pkt protocol.Packet) error {
	var charPkt protocol.SP_CL2LS_REQ_CHAR_DELETE
	pkt.Decode(&charPkt)

	account, ok := peer.UserData().(*db.Account)
	if !ok || account == nil {
		return SendFail(peer)
	}

	slot, err := server.dbHndlr.DeletePlayer(int(charPkt.IPC_UID), account.AccountID)
	if err != nil {
		return SendFail(peer)
	}

	return peer.Send(protocol.P_LS2CL_REP_CHAR_DELETE_SUCC, protocol.SP_LS2CL_REP_CHAR_DELETE_SUCC{
		ISlotNum: int8(slot),
	})
}

func (server *LoginServer) ShardSelect(peer *cnet.CNPeer, pkt protocol.Packet) error {
	var selection protocol.SP_CL2LS_REQ_CHAR_SELECT
	pkt.Decode(&selection)

	account, ok := peer.UserData().(*db.Account)
	if !ok || account == nil {
		return SendFail(peer)
	}

	shards := server.redisHndlr.GetShards()
	if len(shards) == 0 {
		SendFail(peer)
		return fmt.Errorf("loginServer has found no linked shards")
	}

	key, err := protocol.GenSerialKey()
	if err != nil {
		return err
	}

	// TODO: better shard selection logic pls
	// for now, pick random shard
	shard := shards[rand.Intn(len(shards))]

	// make sure the player is owned by the account
	plr, err := server.dbHndlr.GetPlayer(int(selection.IPC_UID))
	if err != nil {
		log.Printf("Error getting player: %v", err)
		return SendFail(peer)
	}
	accountID := account.AccountID

	if plr.AccountID != accountID {
		log.Printf("HACK: player %d tried to join shard as player %d", accountID, plr.AccountID)
		return SendFail(peer)
	}

	// share the login attempt
	server.redisHndlr.QueueLogin(key, redis.LoginMetadata{
		FEKey:     peer.FE_key,
		PlayerID:  int32(selection.IPC_UID),
		AccountID: accountID,
	})

	// craft response
	resp := protocol.SP_LS2CL_REP_SHARD_SELECT_SUCC{
		G_FE_ServerPort: int32(shard.Port),
		IEnterSerialKey: key,
	}

	// the rest of the bytes in G_FE_ServerIP will be zero'd, so there's no need to write the NULL byte
	copy(resp.G_FE_ServerIP[:], []byte(shard.IP))

	return peer.Send(protocol.P_LS2CL_REP_SHARD_SELECT_SUCC, resp)
}

func (server *LoginServer) FinishTutorial(peer *cnet.CNPeer, pkt protocol.Packet) error {
	var charPkt protocol.SP_CL2LS_REQ_SAVE_CHAR_TUTOR
	pkt.Decode(&charPkt)

	account, ok := peer.UserData().(*db.Account)
	if !ok || account == nil {
		return SendFail(peer)
	}

	if err := server.dbHndlr.FinishTutorial(int(charPkt.IPC_UID), account.AccountID); err != nil {
		return SendFail(peer)
	}

	// no response
	return nil
}