package service

import (
	userAgentParser "github.com/mileusna/useragent"
	"github.com/oschwald/maxminddb-golang/v2"
	"github.com/stonith404/pocket-id/backend/internal/model"
	"github.com/stonith404/pocket-id/backend/internal/utils"
	"github.com/stonith404/pocket-id/backend/internal/utils/email"
	"gorm.io/gorm"
	"log"
	"net/netip"
)

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 {
	country, city, err := s.GetIpLocation(ipAddress)
	if err != nil {
		log.Printf("Failed to get IP location: %v\n", err)
	}

	auditLog := model.AuditLog{
		Event:     event,
		IpAddress: ipAddress,
		Country:   country,
		City:      city,
		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) model.AuditLog {
	createdAuditLog := s.Create(model.AuditLogEventSignIn, ipAddress, userAgent, userID, model.AuditLogData{})

	// 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)

			err := SendEmail(s.emailService, email.Address{
				Name:  user.Username,
				Email: user.Email,
			}, NewLoginTemplate, &NewLoginTemplateData{
				IPAddress: ipAddress,
				Country:   createdAuditLog.Country,
				City:      createdAuditLog.City,
				Device:    s.DeviceStringFromUserAgent(userAgent),
				DateTime:  createdAuditLog.CreatedAt.UTC(),
			})
			if err != nil {
				log.Printf("Failed to send email to '%s': %v\n", user.Email, 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
}

func (s *AuditLogService) GetIpLocation(ipAddress string) (country, city string, err error) {
	db, err := maxminddb.Open("GeoLite2-City.mmdb")
	if err != nil {
		return "", "", err
	}
	defer db.Close()

	addr := netip.MustParseAddr(ipAddress)

	var record struct {
		City struct {
			Names map[string]string `maxminddb:"names"`
		} `maxminddb:"city"`
		Country struct {
			Names map[string]string `maxminddb:"names"`
		} `maxminddb:"country"`
	}

	err = db.Lookup(addr).Decode(&record)
	if err != nil {
		return "", "", err
	}

	return record.Country.Names["en"], record.City.Names["en"], nil
}