package service

import (
	"crypto/sha512"
	"electricity_bill_calc/cache"
	"electricity_bill_calc/config"
	"electricity_bill_calc/exceptions"
	"electricity_bill_calc/model"
	"electricity_bill_calc/repository"
	"fmt"
	"time"

	"github.com/google/uuid"
)

type _UserService struct{}

var UserService _UserService

func (_UserService) ProcessEnterpriseUserLogin(username, password string) (*model.Session, error) {
	user, err := repository.UserRepo.FindUserByUsername(username)

	if err != nil {
		return nil, err
	}
	if user == nil {
		return nil, exceptions.NewAuthenticationError(404, "用户不存在。")
	}
	if user.Type != 0 {
		return nil, exceptions.NewAuthenticationError(401, "用户类型不正确。")
	}
	hash := sha512.New512_256()
	hash.Write([]byte(password))
	hashedPassword := fmt.Sprintf("%x", hash.Sum(nil))
	if hashedPassword != user.Password {
		return nil, exceptions.NewAuthenticationError(401, "用户凭据不正确。")
	}
	if user.ResetNeeded {
		authErr := exceptions.NewAuthenticationError(401, "用户凭据已失效。")
		authErr.NeedReset = true
		return nil, authErr
	}
	session := &model.Session{
		Token:     uuid.New().String(),
		Uid:       user.Id,
		Type:      user.Type,
		Name:      user.Username,
		ExpiresAt: time.Now().Add(config.ServiceSettings.MaxSessionLife),
	}
	userDetial, _ := repository.UserRepo.RetreiveUserDetail(user.Id)
	if userDetial != nil {
		session.Name = *userDetial.Name
	}
	cache.CacheSession(session)
	return session, nil
}

func (_UserService) ProcessManagementUserLogin(username, password string) (*model.Session, error) {
	user, err := repository.UserRepo.FindUserByUsername(username)

	if err != nil {
		return nil, err
	}
	if user == nil {
		return nil, exceptions.NewAuthenticationError(404, "用户不存在。")
	}
	if user.Type != 1 && user.Type != 2 {
		return nil, exceptions.NewAuthenticationError(401, "用户类型不正确。")
	}
	hash := sha512.New512_256()
	hash.Write([]byte(password))
	hashedPassword := fmt.Sprintf("%x", hash.Sum(nil))
	if hashedPassword != user.Password {
		return nil, exceptions.NewAuthenticationError(401, "用户凭据不正确。")
	}
	if user.ResetNeeded {
		authErr := exceptions.NewAuthenticationError(401, "用户凭据已失效。")
		authErr.NeedReset = true
		return nil, authErr
	}
	session := &model.Session{
		Token:     uuid.New().String(),
		Uid:       user.Id,
		Type:      user.Type,
		Name:      user.Username,
		ExpiresAt: time.Now().Add(config.ServiceSettings.MaxSessionLife),
	}
	userDetial, _ := repository.UserRepo.RetreiveUserDetail(user.Id)
	if userDetial != nil {
		session.Name = *userDetial.Name
	}
	cache.CacheSession(session)
	return session, nil
}