package service

import (
	"context"
	"crypto/md5"
	"database/sql"
	"encoding/hex"
	"errors"
	"fmt"
	"strings"
	"time"

	"github.com/google/uuid"
	"github.com/xmdhs/authlib-skin/db/ent/user"
	"github.com/xmdhs/authlib-skin/model"
	"github.com/xmdhs/authlib-skin/utils"
)

var (
	ErrExistUser = errors.New("邮箱已存在")
	ErrExitsName = errors.New("用户名已存在")
)

func (w *WebService) Reg(ctx context.Context, u model.User) error {
	tx, err := w.client.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelReadCommitted})
	if err != nil {
		return fmt.Errorf("Reg: %w", err)
	}
	defer tx.Rollback()
	count, err := tx.User.Query().Where(user.EmailEQ(u.Email)).ForUpdate().Count(ctx)
	if err != nil {
		return fmt.Errorf("Reg: %w", err)
	}
	if count != 0 {
		return fmt.Errorf("Reg: %w", ErrExistUser)
	}
	p, s := utils.Argon2ID(u.Password)

	du, err := w.client.User.Create().
		SetEmail(u.Email).
		SetPassword(p).
		SetSalt(s).
		SetRegTime(time.Now().Unix()).
		SetState(0).Save(ctx)
	if err != nil {
		return fmt.Errorf("Reg: %w", err)
	}

	var userUuid string
	if w.config.OfflineUUID {
		userUuid = uuidGen(u.Name)
	} else {
		userUuid = strings.ReplaceAll(uuid.New().String(), "-", "")
	}

	_, err = w.client.UserProfile.Create().
		SetUser(du).
		SetName(u.Name).
		SetUUID(userUuid).
		Save(ctx)
	if err != nil {
		return fmt.Errorf("Reg: %w", err)
	}
	err = tx.Commit()
	if err != nil {
		return fmt.Errorf("Reg: %w", err)
	}
	return nil
}

func uuidGen(t string) string {
	data := []byte("OfflinePlayer:" + t)
	h := md5.New()
	h.Write(data)
	uuid := h.Sum(nil)
	uuid[6] = (uuid[6] & 0x0f) | uint8((3&0xf)<<4)
	uuid[8] = (uuid[8] & 0x3f) | 0x80
	return hex.EncodeToString(uuid)
}