package models

import (
	"errors"
	"fmt"
	"time"

	"code.nonshy.com/nonshy/website/pkg/log"
	"gorm.io/gorm"
)

// CertificationPhoto table.
type CertificationPhoto struct {
	ID                uint64 `gorm:"primaryKey"`
	UserID            uint64 `gorm:"uniqueIndex"`
	Filename          string
	Filesize          int64
	Status            CertificationPhotoStatus
	AdminComment      string
	SecondaryNeeded   bool   // a secondary form of ID has been requested
	SecondaryFilename string // photo ID upload
	SecondaryVerified bool   // mark true when ID checked so original can be deleted
	IPAddress         string // the IP they uploaded the photo from
	CreatedAt         time.Time
	UpdatedAt         time.Time
}

type CertificationPhotoStatus string

const (
	CertificationPhotoNeeded   CertificationPhotoStatus = "needed"
	CertificationPhotoPending  CertificationPhotoStatus = "pending"
	CertificationPhotoApproved CertificationPhotoStatus = "approved"
	CertificationPhotoRejected CertificationPhotoStatus = "rejected"

	// If a photo is pending approval but the admin wants to engage the
	// secondary check (prompt user for a photo ID upload)
	CertificationPhotoSecondary CertificationPhotoStatus = "secondary"
)

// GetCertificationPhoto retrieves the user's record from the DB or upserts their initial record.
func GetCertificationPhoto(userID uint64) (*CertificationPhoto, error) {
	p := &CertificationPhoto{}
	result := DB.Where("user_id = ?", userID).First(&p)
	if result.Error == gorm.ErrRecordNotFound {
		p = &CertificationPhoto{
			UserID: userID,
			Status: CertificationPhotoNeeded,
		}
		result = DB.Create(p)
		return p, result.Error
	}
	return p, result.Error
}

// CertifiedSince retrieve's the last updated date of the user's certification photo, if approved.
//
// This incurs a DB query for their cert photo.
func (u *User) CertifiedSince() (time.Time, error) {
	if !u.Certified {
		return time.Time{}, errors.New("user is not certified")
	}

	cert, err := GetCertificationPhoto(u.ID)
	if err != nil {
		return time.Time{}, err
	}

	if cert.Status != CertificationPhotoApproved {
		// The edge case can come up if a user was manually certified but didn't have an approved picture.
		// Return their CreatedAt instead.
		return u.CreatedAt, nil
	}

	return cert.UpdatedAt, nil
}

// CertificationPhotosNeedingApproval returns a pager of the pictures that require admin approval.
func CertificationPhotosNeedingApproval(status CertificationPhotoStatus, pager *Pagination) ([]*CertificationPhoto, error) {
	var p = []*CertificationPhoto{}

	query := DB.Where(
		"status = ?",
		status,
	).Order(
		pager.Sort,
	)

	// Get the total count.
	query.Model(&CertificationPhoto{}).Count(&pager.Total)

	result := query.Offset(
		pager.GetOffset(),
	).Limit(pager.PerPage).Find(&p)

	return p, result.Error
}

// CountCertificationPhotosNeedingApproval gets the count of pending photos for admin alert.
func CountCertificationPhotosNeedingApproval() int64 {
	var count int64
	DB.Where("status = ?", CertificationPhotoPending).Model(&CertificationPhoto{}).Count(&count)
	return count
}

// MaybeRevokeCertificationForEmptyGallery will delete a user's certification photo if they delete every picture from their gallery.
//
// Returns true if their certification was revoked.
func MaybeRevokeCertificationForEmptyGallery(user *User) bool {
	cert, err := GetCertificationPhoto(user.ID)
	if err != nil {
		return false
	}

	// Ignore if their cert photo status is not applicable to be revoked.
	if cert.Status == CertificationPhotoNeeded || cert.Status == CertificationPhotoRejected {
		return false
	}

	if count := CountPhotos(user.ID); count == 0 {
		// Revoke their cert status.
		cert.Status = CertificationPhotoRejected
		cert.SecondaryVerified = false
		cert.AdminComment = "Your certification photo has been automatically rejected because you have deleted every photo on your gallery. " +
			"To restore your certified status, please upload photos to your gallery and submit a new Certification Photo for approval."

		if err := cert.Save(); err != nil {
			log.Error("MaybeRevokeCertificationForEmptyGallery(%s): %s", user.Username, err)
		}

		// Update the user's Certified flag. Note: we freshly query the user here in case they had JUST deleted
		// their default profile picture - so that we don't (re)set their old ProfilePhotoID by accident!
		if user, err := GetUser(user.ID); err == nil {
			user.Certified = false
			if err := user.Save(); err != nil {
				log.Error("MaybeRevokeCertificationForEmptyGallery(%s): saving user certified flag: %s", user.Username, err)
			}
		}

		// Notify the site admin for visibility.
		fb := &Feedback{
			Intent:    "report",
			Subject:   "A certified user has deleted all their pictures",
			UserID:    user.ID,
			TableName: "users",
			TableID:   user.ID,
			Message: fmt.Sprintf(
				"The username **@%s** has deleted every picture in their gallery, and so their Certification Photo status has been revoked.",
				user.Username,
			),
		}

		// Save the feedback.
		if err := CreateFeedback(fb); err != nil {
			log.Error("Couldn't save feedback from user auto-revoking their cert photo: %s", err)
		}

		return true
	}

	return false
}

// Save photo.
func (p *CertificationPhoto) Save() error {
	result := DB.Save(p)
	return result.Error
}

// Delete the DB entry.
func (p *CertificationPhoto) Delete() error {
	return DB.Delete(p).Error
}