package service

import (
	userAgentParser "github.com/mileusna/useragent"
	"github.com/stonith404/pocket-id/backend/internal/model"
	"github.com/stonith404/pocket-id/backend/internal/utils"
	"gorm.io/gorm"
	"log"
)

type AuditLogService struct {
	db               *gorm.DB
	appConfigService *AppConfigService
	emailService     *EmailService
}

func NewAuditLogService(db *gorm.DB, appConfigService *AppConfigService, emailService *EmailService) *AuditLogService {
	return &AuditLogService{db: db, appConfigService: appConfigService, emailService: emailService}
}

// Create creates a new audit log entry in the database
func (s *AuditLogService) Create(event model.AuditLogEvent, ipAddress, userAgent, userID string, data model.AuditLogData) model.AuditLog {
	auditLog := model.AuditLog{
		Event:     event,
		IpAddress: ipAddress,
		UserAgent: userAgent,
		UserID:    userID,
		Data:      data,
	}

	// Save the audit log in the database
	if err := s.db.Create(&auditLog).Error; err != nil {
		log.Printf("Failed to create audit log: %v\n", err)
		return model.AuditLog{}
	}

	return auditLog
}

// CreateNewSignInWithEmail creates a new audit log entry in the database and sends an email if the device hasn't been used before
func (s *AuditLogService) CreateNewSignInWithEmail(ipAddress, userAgent, userID string, data model.AuditLogData) model.AuditLog {
	createdAuditLog := s.Create(model.AuditLogEventSignIn, ipAddress, userAgent, userID, data)

	// Count the number of times the user has logged in from the same device
	var count int64
	err := s.db.Model(&model.AuditLog{}).Where("user_id = ? AND ip_address = ? AND user_agent = ?", userID, ipAddress, userAgent).Count(&count).Error
	if err != nil {
		log.Printf("Failed to count audit logs: %v\n", err)
		return createdAuditLog
	}

	// If the user hasn't logged in from the same device before, send an email
	if count <= 1 {
		go func() {
			var user model.User
			s.db.Where("id = ?", userID).First(&user)

			title := "New device login with " + s.appConfigService.DbConfig.AppName.Value
			err := s.emailService.Send(user.Email, title, "login-with-new-device", map[string]interface{}{
				"ipAddress":      ipAddress,
				"device":         s.DeviceStringFromUserAgent(userAgent),
				"dateTimeString": createdAuditLog.CreatedAt.UTC().Format("2006-01-02 15:04:05 UTC"),
			})
			if err != nil {
				log.Printf("Failed to send email: %v\n", err)
			}
		}()
	}

	return createdAuditLog
}

// ListAuditLogsForUser retrieves all audit logs for a given user ID
func (s *AuditLogService) ListAuditLogsForUser(userID string, page int, pageSize int) ([]model.AuditLog, utils.PaginationResponse, error) {
	var logs []model.AuditLog
	query := s.db.Model(&model.AuditLog{}).Where("user_id = ?", userID).Order("created_at desc")

	pagination, err := utils.Paginate(page, pageSize, query, &logs)
	return logs, pagination, err
}

func (s *AuditLogService) DeviceStringFromUserAgent(userAgent string) string {
	ua := userAgentParser.Parse(userAgent)
	return ua.Name + " on " + ua.OS + " " + ua.OSVersion
}