package email

import (
	"fmt"
	"strconv"

	"github.com/avct/uasurfer"
	"github.com/ente-io/museum/pkg/controller/lock"
	"github.com/ente-io/museum/pkg/repo"
	"github.com/ente-io/museum/pkg/utils/email"
	"github.com/ente-io/museum/pkg/utils/time"
	log "github.com/sirupsen/logrus"
)

const (
	WebAppFirstUploadTemplate           = "web_app_first_upload.html"
	MobileAppFirstUploadTemplate        = "mobile_app_first_upload.html"
	FirstUploadEmailSubject             = "Congratulations! 🎉"
	StorageLimitExceededMailLock        = "storage_limit_exceeded_mail_lock"
	StorageLimitExceededTemplateID      = "storage_limit_exceeded"
	StorageLimitExceededTemplate        = "storage_limit_exceeded.html"
	FilesCollectedTemplate              = "files_collected.html"
	FilesCollectedTemplateID            = "files_collected"
	FilesCollectedSubject               = "You've got photos!"
	SubscriptionUpgradedTemplate        = "subscription_upgraded.html"
	SubscriptionUpgradedSubject         = "Thank you for choosing ente!"
	FilesCollectedMuteDurationInMinutes = 10
	StorageLimitExceededSubject         = "[Alert] You have exceeded your storage limit"
	ReferralSuccessfulTemplate          = "successful_referral.html"
	ReferralSuccessfulSubject           = "You've earned 10 GB on ente! 🎁"
)

type EmailNotificationController struct {
	UserRepo                           *repo.UserRepository
	LockController                     *lock.LockController
	NotificationHistoryRepo            *repo.NotificationHistoryRepository
	isSendingStorageLimitExceededMails bool
}

func (c *EmailNotificationController) OnFirstFileUpload(userID int64, userAgent string) {
	user, err := c.UserRepo.Get(userID)
	if err != nil {
		return
	}
	os := getOSFromUA(userAgent)
	template := WebAppFirstUploadTemplate
	if os == uasurfer.OSAndroid || os == uasurfer.OSiOS {
		template = MobileAppFirstUploadTemplate
	}
	err = email.SendTemplatedEmail([]string{user.Email}, "team@ente.io", "team@ente.io", FirstUploadEmailSubject, template, nil, nil)
	if err != nil {
		log.Error("Error sending first upload email ", err)
	}
}

func getOSFromUA(ua string) uasurfer.OSName {
	return uasurfer.Parse(ua).OS.Name
}

func (c *EmailNotificationController) OnSuccessfulReferral(userID int64) {
	user, err := c.UserRepo.Get(userID)
	if err != nil {
		return
	}
	err = email.SendTemplatedEmail([]string{user.Email}, "team@ente.io", "team@ente.io", ReferralSuccessfulSubject, ReferralSuccessfulTemplate, nil, nil)
	if err != nil {
		log.Error("Error sending first upload email ", err)
	}
}

func (c *EmailNotificationController) OnFilesCollected(userID int64) {
	user, err := c.UserRepo.Get(userID)
	if err != nil {
		return
	}
	lastNotificationTime, err := c.NotificationHistoryRepo.GetLastNotificationTime(userID, FilesCollectedTemplateID)
	logger := log.WithFields(log.Fields{
		"user_id": userID,
	})
	if err != nil {
		logger.Error("Could not fetch last notification time", err)
		return
	}
	if lastNotificationTime > time.MicrosecondsAfterMinutes(-FilesCollectedMuteDurationInMinutes) {
		logger.Info("Not notifying user about a collected file")
		return
	}
	lockName := "files_collected_" + strconv.FormatInt(userID, 10)
	lockStatus := c.LockController.TryLock(lockName, time.MicrosecondsAfterMinutes(FilesCollectedMuteDurationInMinutes))
	if !lockStatus {
		log.Error("Could not acquire lock to send file collected mails")
		return
	}
	defer c.LockController.ReleaseLock(lockName)
	logger.Info("Notifying about files collected")
	err = email.SendTemplatedEmail([]string{user.Email}, "team@ente.io", "team@ente.io", FilesCollectedSubject, FilesCollectedTemplate, nil, nil)
	if err != nil {
		log.Error("Error sending files collected email ", err)
	}
	c.NotificationHistoryRepo.SetLastNotificationTimeToNow(userID, FilesCollectedTemplateID)
}

func (c *EmailNotificationController) OnAccountUpgrade(userID int64) {
	user, err := c.UserRepo.Get(userID)
	if err != nil {
		log.Error("Could not find user to email", err)
		return
	}
	log.Info(fmt.Sprintf("Emailing on account upgrade %d", user.ID))
	err = email.SendTemplatedEmail([]string{user.Email}, "team@ente.io", "team@ente.io", SubscriptionUpgradedSubject, SubscriptionUpgradedTemplate, nil, nil)
	if err != nil {
		log.Error("Error sending files collected email ", err)
	}
}

func (c *EmailNotificationController) SendStorageLimitExceededMails() {
	if c.isSendingStorageLimitExceededMails {
		log.Info("Skipping sending storage limit exceeded mails as another instance is still running")
		return
	}
	c.setStorageLimitExceededMailerJobStatus(true)
	defer c.setStorageLimitExceededMailerJobStatus(false)
	lockStatus := c.LockController.TryLock(StorageLimitExceededMailLock, time.MicrosecondsAfterHours(24))
	if !lockStatus {
		log.Error("Could not acquire lock to send storage limit exceeded mails")
		return
	}
	defer c.LockController.ReleaseLock(StorageLimitExceededMailLock)
	users, err := c.UserRepo.GetUsersWithIndividualPlanWhoHaveExceededStorageQuota()
	if err != nil {
		log.Error("Error while fetching user list", err)
		return
	}
	for _, u := range users {
		lastNotificationTime, err := c.NotificationHistoryRepo.GetLastNotificationTime(u.ID, StorageLimitExceededTemplateID)
		logger := log.WithFields(log.Fields{
			"user_id": u.ID,
		})
		if err != nil {
			logger.Error("Could not fetch last notification time", err)
			continue
		}
		if lastNotificationTime > 0 {
			continue
		}
		logger.Info("Alerting about storage limit exceeded")
		err = email.SendTemplatedEmail([]string{u.Email}, "team@ente.io", "team@ente.io", StorageLimitExceededSubject, StorageLimitExceededTemplate, nil, nil)
		if err != nil {
			logger.Info("Error notifying", err)
			continue
		}
		c.NotificationHistoryRepo.SetLastNotificationTimeToNow(u.ID, StorageLimitExceededTemplateID)
	}
}

func (c *EmailNotificationController) setStorageLimitExceededMailerJobStatus(isSending bool) {
	c.isSendingStorageLimitExceededMails = isSending
}