package models

import (
	"errors"
	"fmt"
	"strings"
	"time"

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

// Photo table.
type Photo struct {
	ID              uint64 `gorm:"primaryKey"`
	UserID          uint64 `gorm:"index"`
	Filename        string
	CroppedFilename string // if cropped, e.g. for profile photo
	Filesize        int64
	Caption         string
	Flagged         bool            // photo has been reported by the community
	Visibility      PhotoVisibility `gorm:"index"`
	Gallery         bool            `gorm:"index"` // photo appears in the public gallery (if public)
	Explicit        bool            `gorm:"index"` // is an explicit photo
	CreatedAt       time.Time       `gorm:"index"`
	UpdatedAt       time.Time
}

// PhotoVisibility settings.
type PhotoVisibility string

const (
	PhotoPublic      PhotoVisibility = "public"  // on profile page and/or public gallery
	PhotoFriends     PhotoVisibility = "friends" // only friends can see it
	PhotoPrivate     PhotoVisibility = "private" // private
	PhotoInnerCircle PhotoVisibility = "circle"  // inner circle

	// Special visibility in case, on User Gallery view, user applies a filter
	// for friends-only picture but they are not friends with the user.
	PhotoNotAvailable PhotoVisibility = "not_available"
)

// PhotoVisibility preset settings.
var (
	PhotoVisibilityAll = []PhotoVisibility{
		PhotoPublic,
		PhotoFriends,
		PhotoPrivate,
	}

	// "All" but also for Inner Circle members.
	PhotoVisibilityCircle = []PhotoVisibility{
		PhotoPublic,
		PhotoFriends,
		PhotoPrivate,
		PhotoInnerCircle,
	}

	// Site Gallery visibility for when your friends show up in the gallery.
	// Or: "Friends + Gallery" photos can appear to your friends in the Site Gallery.
	PhotoVisibilityFriends = []string{
		string(PhotoPublic),
		string(PhotoFriends),
	}
)

// CreatePhoto with most of the settings you want (not ID or timestamps) in the database.
func CreatePhoto(tmpl Photo) (*Photo, error) {
	if tmpl.UserID == 0 {
		return nil, errors.New("UserID required")
	}

	p := &Photo{
		UserID:          tmpl.UserID,
		Filename:        tmpl.Filename,
		CroppedFilename: tmpl.CroppedFilename,
		Filesize:        tmpl.Filesize,
		Caption:         tmpl.Caption,
		Visibility:      tmpl.Visibility,
		Gallery:         tmpl.Gallery,
		Explicit:        tmpl.Explicit,
	}

	result := DB.Create(p)
	return p, result.Error
}

// GetPhoto by ID.
func GetPhoto(id uint64) (*Photo, error) {
	p := &Photo{}
	result := DB.First(&p, id)
	return p, result.Error
}

// GetPhotos by an array of IDs, mapped to their IDs.
func GetPhotos(IDs []uint64) (map[uint64]*Photo, error) {
	var (
		mp = map[uint64]*Photo{}
		ps = []*Photo{}
	)

	result := DB.Model(&Photo{}).Where("id IN ?", IDs).Find(&ps)
	for _, row := range ps {
		mp[row.ID] = row
	}

	return mp, result.Error
}

// UserGallery configuration for filtering gallery pages.
type UserGallery struct {
	Explicit   string // "", "true", "false"
	Visibility []PhotoVisibility
}

/*
PaginateUserPhotos gets a page of photos belonging to a user ID.
*/
func PaginateUserPhotos(userID uint64, conf UserGallery, pager *Pagination) ([]*Photo, error) {
	var (
		p            = []*Photo{}
		wheres       = []string{}
		placeholders = []interface{}{}
	)

	var explicit = []bool{}
	switch conf.Explicit {
	case "true":
		explicit = []bool{true}
	case "false":
		explicit = []bool{false}
	}

	wheres = append(wheres, "user_id = ? AND visibility IN ?")
	placeholders = append(placeholders, userID, conf.Visibility)

	if len(explicit) > 0 {
		wheres = append(wheres, "explicit = ?")
		placeholders = append(placeholders, explicit[0])
	}

	query := DB.Where(
		strings.Join(wheres, " AND "),
		placeholders...,
	).Order(
		pager.Sort,
	)

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

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

	return p, result.Error
}

// CountPhotos returns the total number of photos on a user's account.
func CountPhotos(userID uint64) int64 {
	var count int64
	result := DB.Where(
		"user_id = ?",
		userID,
	).Model(&Photo{}).Count(&count)
	if result.Error != nil {
		log.Error("CountPhotos(%d): %s", userID, result.Error)
	}
	return count
}

/*
IsSiteGalleryThrottled returns whether the user is throttled from marking additional pictures for the Site Gallery.

The thresholds are in pkg/config but the idea is a user can only upload (say) 5 Site Gallery photos within a
24 hour time span, so that new users who sign up and immediately max out their full gallery don't end up
spamming the Site Gallery for pages and pages.

If the user has too many recent Site Gallery pictures:

  - Newly uploaded photos can NOT check the Gallery box.
  - Editing any existing photo which is NOT in the Gallery: you can not mark the box either.
  - Existing Gallery photos CAN be un-marked for the gallery, which (if it is one of the 5 recent
    photos) may put the user below the threshold again.

If the user is on the Edit page for an existing photo, provide the Photo; otherwise leave it nil
if the user is uploading a new photo for the first time.
*/
func IsSiteGalleryThrottled(user *User, editPhoto *Photo) bool {
	// If the editing photo is already in the gallery, allow the user to keep or remove it.
	if editPhoto != nil && editPhoto.Gallery {
		return false
	}

	var count = CountRecentGalleryPhotos(user, config.SiteGalleryRateLimitInterval)
	log.Debug("IsSiteGalleryThrottled(%s): they have %d recent Gallery photos", user.Username, count)
	return count >= config.SiteGalleryRateLimitMax
}

// CountRecentGalleryPhotos returns the count of recently uploaded Site Gallery photos for a user,
// within the past 24 hours, to rate limit spammy bulk uploads that will flood the gallery.
func CountRecentGalleryPhotos(user *User, duration time.Duration) (count int64) {
	result := DB.Where(
		"user_id = ? AND created_at >= ? AND gallery IS TRUE",
		user.ID,
		time.Now().Add(-duration),
	).Model(&Photo{}).Count(&count)
	if result.Error != nil {
		log.Error("CountRecentGalleryPhotos(%d): %s", user.ID, result.Error)
	}
	return
}

// AllFriendsOnlyPhotoIDs returns the listing of all friends-only photo IDs belonging to the user(s) given.
func AllFriendsOnlyPhotoIDs(users ...*User) ([]uint64, error) {
	var userIDs = []uint64{}
	for _, user := range users {
		userIDs = append(userIDs, user.ID)
	}

	if len(userIDs) == 0 {
		return nil, errors.New("no user IDs given")
	}

	var photoIDs = []uint64{}
	err := DB.Table(
		"photos",
	).Select(
		"photos.id AS id",
	).Where(
		"user_id IN ? AND visibility = ?",
		userIDs, PhotoFriends,
	).Scan(&photoIDs)

	if err.Error != nil {
		return photoIDs, fmt.Errorf("AllFriendsOnlyPhotoIDs(%+v): %s", userIDs, err.Error)
	}

	return photoIDs, nil
}

// CountPhotosICanSee returns the number of photos on an account which can be seen by the given viewer.
func CountPhotosICanSee(user *User, viewer *User) int64 {
	// Visibility filters to query by.
	var visibilities = []PhotoVisibility{
		PhotoPublic,
	}

	// Is the viewer in the inner circle?
	if viewer.IsInnerCircle() {
		visibilities = append(visibilities, PhotoInnerCircle)
	}

	// Is the viewer friends with the target?
	if AreFriends(user.ID, viewer.ID) {
		visibilities = append(visibilities, PhotoFriends)
	}

	// Is the viewer granted private access?
	if IsPrivateUnlocked(user.ID, viewer.ID) {
		visibilities = append(visibilities, PhotoPrivate)
	}

	// Get the photo count now.
	var count int64
	result := DB.Where(
		"user_id = ? AND visibility IN ?",
		user.ID, visibilities,
	).Model(&Photo{}).Count(&count)
	if result.Error != nil {
		log.Error("CountPhotosICanSee(%d, %d): %s", user.ID, viewer.ID, result.Error)
	}
	return count
}

// MapPhotoCounts returns a mapping of user ID to the CountPhotos()-equivalent result for each.
// It's used on the member directory to show photo counts on each user card.
func MapPhotoCounts(users []*User) PhotoCountMap {
	var (
		userIDs = []uint64{}
		result  = PhotoCountMap{}
	)

	for _, user := range users {
		userIDs = append(userIDs, user.ID)
	}

	type group struct {
		UserID     uint64
		PhotoCount int64
	}
	var groups = []group{}

	if res := DB.Table(
		"photos",
	).Select(
		"user_id, count(id) AS photo_count",
	).Where(
		"user_id IN ? AND visibility = ?", userIDs, PhotoPublic,
	).Group("user_id").Scan(&groups); res.Error != nil {
		log.Error("CountPhotosForUsers: %s", res.Error)
	}

	// Map the results in.
	for _, row := range groups {
		result[row.UserID] = row.PhotoCount
	}

	return result
}

// MapPhotoCounts returns a mapping of user ID to the CountPhotosICanSee()-equivalent result for each.
// It's used on the member directory to show photo counts on each user card.
/* TODO: under construction..
func MapPhotoCounts(users []*User, viewer *User) PhotoCountMap {
	var (
		userIDs = []uint64{}
		result  = PhotoCountMap{}

		wheres       = []string{}
		placeholders = []interface{}{}

		// User ID filters for the viewer's context.
		myFriendIDs         = FriendIDs(viewer.ID)
		myPrivateGrantedIDs = PrivateGrantedUserIDs(viewer.ID)
		isInnerCircle       = viewer.IsInnerCircle()
	)

	// Define "all photos visibilities"
	var (
		photosPublic = []PhotoVisibility{
			PhotoPublic,
		}
		photosFriends = []PhotoVisibility{
			PhotoPublic,
			PhotoFriends,
		}
		photosPrivate = []PhotoVisibility{
			PhotoPublic,
			PhotoPrivate,
		}
	)
	if isInnerCircle {
		photosPublic = append(photosPublic, PhotoInnerCircle)
		photosFriends = append(photosFriends, PhotoInnerCircle)
	}

	// Flatten the userIDs of all passed in users.
	for _, user := range users {
		userIDs = append(userIDs, user.ID)
	}

	// Build the where clause.
	wheres = append(wheres, "user_id IN ?")
	placeholders = append(placeholders, userIDs)

	log.Error("FRIEND IDS: %+v", myFriendIDs)

	// Filter by which photos are visible to us.
	wheres = append(wheres,
		"((user_id IN ? AND visibility IN ?) OR "+
			"(user_id IN ? AND visibility IN ?) OR "+
			"(user_id NOT IN ? AND visibility IN ?))",
	)
	placeholders = append(placeholders,
		myFriendIDs, photosFriends,
		myPrivateGrantedIDs, photosPrivate,
		myFriendIDs, photosPublic,
	)

	type group struct {
		UserID     uint64
		PhotoCount int64
	}
	var groups = []group{}

	if res := DB.Table(
		"photos",
	).Select(
		"user_id, count(id) AS photo_count",
	).Where(
		strings.Join(wheres, " AND "),
		placeholders...,
	).Group("user_id").Scan(&groups); res.Error != nil {
		log.Error("CountPhotosForUsers: %s", res.Error)
	}

	// Map the results in.
	for _, row := range groups {
		result[row.UserID] = row.PhotoCount
	}

	return result
}
*/

type PhotoCountMap map[uint64]int64

// Get a photo count for the given user ID from the map.
func (pc PhotoCountMap) Get(id uint64) int64 {
	if value, ok := pc[id]; ok {
		return value
	}
	return 0
}

// CountExplicitPhotos returns the number of explicit photos a user has (so non-explicit viewers can see some do exist)
func CountExplicitPhotos(userID uint64, visibility []PhotoVisibility) (int64, error) {
	query := DB.Where(
		"user_id = ? AND visibility IN ? AND explicit = ?",
		userID,
		visibility,
		true,
	)

	var count int64
	result := query.Model(&Photo{}).Count(&count)
	return count, result.Error
}

// CountPublicPhotos returns the number of public photos on a user's page (to control whether the "invite to circle" prompt can appear).
func CountPublicPhotos(userID uint64) int64 {
	query := DB.Where(
		"user_id = ? AND visibility = ?",
		userID,
		PhotoPublic,
	)

	var count int64
	result := query.Model(&Photo{}).Count(&count)
	if result.Error != nil {
		log.Error("CountPublicPhotos(%d): %s", userID, result.Error)
	}
	return count
}

// DistinctPhotoTypes returns types of photos the user has: a set of public, friends, or private.
//
// The result is cached on the User the first time it's queried.
func (u *User) DistinctPhotoTypes() (result map[PhotoVisibility]struct{}) {
	if u.cachePhotoTypes != nil {
		return u.cachePhotoTypes
	}

	result = map[PhotoVisibility]struct{}{}

	var results = []*Photo{}
	query := DB.Model(&Photo{}).
		Select("DISTINCT photos.visibility").
		Where("user_id = ?", u.ID).
		Group("photos.visibility").
		Find(&results)
	if query.Error != nil {
		log.Error("User.DistinctPhotoTypes(%s): %s", u.Username, query.Error)
		return
	}

	for _, row := range results {
		log.Warn("DistinctPhotoTypes(%s): got %+v", u.Username, row)
		result[row.Visibility] = struct{}{}
	}

	u.cachePhotoTypes = result
	return
}

// Gallery config for the main Gallery paginator.
type Gallery struct {
	Explicit    string // Explicit filter
	Visibility  string // Visibility filter
	AdminView   bool   // Show all images
	IsShy       bool   // Current user is like a Shy Account (or: show self/friends and private photo grants only)
	FriendsOnly bool   // Only show self/friends instead of everybody's pics
}

/*
PaginateGalleryPhotos gets a page of all public user photos for the site gallery.

Admin view returns ALL photos regardless of Gallery status.
*/
func PaginateGalleryPhotos(user *User, conf Gallery, pager *Pagination) ([]*Photo, error) {
	var (
		filterExplicit   = conf.Explicit
		filterVisibility = conf.Visibility
		adminView        = conf.AdminView
		friendsOnly      = conf.FriendsOnly // Show only self and friends pictures
		isShy            = conf.IsShy       // Self, friends, and private photo grants only
		p                = []*Photo{}
		query            *gorm.DB

		// Get the user ID and their preferences.
		userID     = user.ID
		explicitOK = user.Explicit // User opted-in for explicit content

		blocklist                = BlockedUserIDs(user)
		friendIDs                = FriendIDs(userID)
		privateUserIDs           = PrivateGrantedUserIDs(userID)
		privateUserIDsAreFriends = PrivateGrantedUserIDsAreFriends(user)
		wheres                   = []string{}
		placeholders             = []interface{}{}
	)

	// Define "all photos visibilities"
	var (
		photosPublic = []PhotoVisibility{
			PhotoPublic,
		}
		photosFriends = []PhotoVisibility{
			PhotoPublic,
			PhotoFriends,
		}
		photosPrivate = []PhotoVisibility{
			PhotoPrivate,
		}
	)
	if user.IsInnerCircle() {
		photosPublic = append(photosPublic, PhotoInnerCircle)
		photosFriends = append(photosFriends, PhotoInnerCircle)
	}

	// Admins see everything on the site (only an admin user can get an admin view).
	adminView = user.HasAdminScope(config.ScopePhotoModerator) && adminView

	// Include ourself in our friend IDs.
	friendIDs = append(friendIDs, userID)

	// What sets of User ID * Visibility filters to query under?
	var (
		visOrs          = []string{}
		visPlaceholders = []interface{}{}
	)

	// Whose photos can you see on the Site Gallery?
	if isShy {
		// Shy users can only see their Friends photos (public or friends visibility)
		// and any Private photos to whom they were granted access.
		visOrs = append(visOrs,
			"(user_id IN ? AND visibility IN ?)",
			"(user_id IN ? AND visibility IN ?)",
		)
		visPlaceholders = append(visPlaceholders,
			friendIDs, photosFriends,
			privateUserIDs, photosPrivate,
		)
	} else if friendsOnly {
		// User wants to see only self and friends photos.
		visOrs = append(visOrs, "(user_id IN ? AND visibility IN ?)")
		visPlaceholders = append(visPlaceholders, friendIDs, photosFriends)

		// If their friends granted private photos, include those too.
		if len(privateUserIDsAreFriends) > 0 {
			visOrs = append(visOrs, "(user_id IN ? AND visibility IN ?)")
			visPlaceholders = append(visPlaceholders, privateUserIDsAreFriends, photosPrivate)
		}
	} else {
		// You can see friends' Friend photos but only public for non-friends.
		visOrs = append(visOrs,
			"(user_id IN ? AND visibility IN ?)",
			"(user_id IN ? AND visibility IN ?)",
			"(user_id NOT IN ? AND visibility IN ?)",
		)
		visPlaceholders = append(placeholders,
			friendIDs, photosFriends,
			privateUserIDs, photosPrivate,
			friendIDs, photosPublic,
		)
	}

	// Join the User ID * Visibility filters into a nested "OR"
	wheres = append(wheres, fmt.Sprintf("(%s)", strings.Join(visOrs, " OR ")))
	placeholders = append(placeholders, visPlaceholders...)

	// Gallery photos only.
	wheres = append(wheres, "gallery = ?")
	placeholders = append(placeholders, true)

	// Filter blocked users.
	if len(blocklist) > 0 {
		wheres = append(wheres, "user_id NOT IN ?")
		placeholders = append(placeholders, blocklist)
	}

	// Non-explicit pics unless the user opted in. Allow explicit filter setting to override.
	if filterExplicit != "" {
		wheres = append(wheres, "explicit = ?")
		placeholders = append(placeholders, filterExplicit == "true")
	} else if !explicitOK {
		wheres = append(wheres, "explicit = ?")
		placeholders = append(placeholders, false)
	}

	// Is the user furthermore clamping the visibility filter?
	if filterVisibility != "" {
		wheres = append(wheres, "visibility = ?")
		placeholders = append(placeholders, filterVisibility)
	}

	// Only certified (and not banned) user photos.
	wheres = append(wheres,
		"EXISTS (SELECT 1 FROM users WHERE id = photos.user_id AND certified = true AND status='active')",
	)

	// Exclude private users' photos.
	wheres = append(wheres,
		"NOT EXISTS (SELECT 1 FROM users WHERE id = photos.user_id AND visibility = 'private')",
	)

	// Admin view: get ALL PHOTOS on the site, period.
	if adminView {
		query = DB

		// Admin may filter too.
		if filterVisibility != "" {
			query = query.Where("visibility = ?", filterVisibility)
		}
		if filterExplicit != "" {
			query = query.Where("explicit = ?", filterExplicit == "true")
		}
	} else {
		query = DB.Where(
			strings.Join(wheres, " AND "),
			placeholders...,
		)
	}

	query = query.Order(pager.Sort)

	query.Model(&Photo{}).Count(&pager.Total)
	result := query.Offset(pager.GetOffset()).Limit(pager.PerPage).Find(&p)
	return p, result.Error
}

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

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