mostlymatter/server/public/model/post.go

// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

package model

import (
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"regexp"
	"sort"
	"strings"
	"sync"
	"unicode/utf8"

	"github.com/hashicorp/go-multierror"
	"github.com/mattermost/mattermost/server/public/shared/markdown"
	"github.com/mattermost/mattermost/server/public/shared/mlog"
)

const (
	PostSystemMessagePrefix      = "system_"
	PostTypeDefault              = ""
	PostTypeSlackAttachment      = "slack_attachment"
	PostTypeSystemGeneric        = "system_generic"
	PostTypeJoinLeave            = "system_join_leave" // Deprecated, use PostJoinChannel or PostLeaveChannel instead
	PostTypeJoinChannel          = "system_join_channel"
	PostTypeGuestJoinChannel     = "system_guest_join_channel"
	PostTypeLeaveChannel         = "system_leave_channel"
	PostTypeJoinTeam             = "system_join_team"
	PostTypeLeaveTeam            = "system_leave_team"
	PostTypeAutoResponder        = "system_auto_responder"
	PostTypeAddRemove            = "system_add_remove" // Deprecated, use PostAddToChannel or PostRemoveFromChannel instead
	PostTypeAddToChannel         = "system_add_to_channel"
	PostTypeAddGuestToChannel    = "system_add_guest_to_chan"
	PostTypeRemoveFromChannel    = "system_remove_from_channel"
	PostTypeMoveChannel          = "system_move_channel"
	PostTypeAddToTeam            = "system_add_to_team"
	PostTypeRemoveFromTeam       = "system_remove_from_team"
	PostTypeHeaderChange         = "system_header_change"
	PostTypeDisplaynameChange    = "system_displayname_change"
	PostTypeConvertChannel       = "system_convert_channel"
	PostTypePurposeChange        = "system_purpose_change"
	PostTypeChannelDeleted       = "system_channel_deleted"
	PostTypeChannelRestored      = "system_channel_restored"
	PostTypeEphemeral            = "system_ephemeral"
	PostTypeChangeChannelPrivacy = "system_change_chan_privacy"
	PostTypeWrangler             = "system_wrangler"
	PostTypeGMConvertedToChannel = "system_gm_to_channel"
	PostTypeAddBotTeamsChannels  = "add_bot_teams_channels"
	PostTypeMe                   = "me"
	PostCustomTypePrefix         = "custom_"
	PostTypeReminder             = "reminder"

	PostFileidsMaxRunes   = 300
	PostFilenamesMaxRunes = 4000
	PostHashtagsMaxRunes  = 1000
	PostMessageMaxRunesV1 = 4000
	PostMessageMaxBytesV2 = 65535                     // Maximum size of a TEXT column in MySQL
	PostMessageMaxRunesV2 = PostMessageMaxBytesV2 / 4 // Assume a worst-case representation
	PostPropsMaxRunes     = 800000
	PostPropsMaxUserRunes = PostPropsMaxRunes - 40000 // Leave some room for system / pre-save modifications

	PropsAddChannelMember = "add_channel_member"

	PostPropsAddedUserId              = "addedUserId"
	PostPropsDeleteBy                 = "deleteBy"
	PostPropsOverrideIconURL          = "override_icon_url"
	PostPropsOverrideIconEmoji        = "override_icon_emoji"
	PostPropsOverrideUsername         = "override_username"
	PostPropsFromWebhook              = "from_webhook"
	PostPropsFromBot                  = "from_bot"
	PostPropsFromOAuthApp             = "from_oauth_app"
	PostPropsWebhookDisplayName       = "webhook_display_name"
	PostPropsAttachments              = "attachments"
	PostPropsFromPlugin               = "from_plugin"
	PostPropsMentionHighlightDisabled = "mentionHighlightDisabled"
	PostPropsGroupHighlightDisabled   = "disable_group_highlight"
	PostPropsPreviewedPost            = "previewed_post"
	PostPropsForceNotification        = "force_notification"
	PostPropsChannelMentions          = "channel_mentions"
	PostPropsUnsafeLinks              = "unsafe_links"

	PostPriorityUrgent = "urgent"
)

type Post struct {
	Id         string `json:"id"`
	CreateAt   int64  `json:"create_at"`
	UpdateAt   int64  `json:"update_at"`
	EditAt     int64  `json:"edit_at"`
	DeleteAt   int64  `json:"delete_at"`
	IsPinned   bool   `json:"is_pinned"`
	UserId     string `json:"user_id"`
	ChannelId  string `json:"channel_id"`
	RootId     string `json:"root_id"`
	OriginalId string `json:"original_id"`

	Message string `json:"message"`
	// MessageSource will contain the message as submitted by the user if Message has been modified
	// by Mattermost for presentation (e.g if an image proxy is being used). It should be used to
	// populate edit boxes if present.
	MessageSource string `json:"message_source,omitempty"`

	Type          string          `json:"type"`
	propsMu       sync.RWMutex    `db:"-"`       // Unexported mutex used to guard Post.Props.
	Props         StringInterface `json:"props"` // Deprecated: use GetProps()
	Hashtags      string          `json:"hashtags"`
	Filenames     StringArray     `json:"-"` // Deprecated, do not use this field any more
	FileIds       StringArray     `json:"file_ids"`
	PendingPostId string          `json:"pending_post_id"`
	HasReactions  bool            `json:"has_reactions,omitempty"`
	RemoteId      *string         `json:"remote_id,omitempty"`

	// Transient data populated before sending a post to the client
	ReplyCount   int64         `json:"reply_count"`
	LastReplyAt  int64         `json:"last_reply_at"`
	Participants []*User       `json:"participants"`
	IsFollowing  *bool         `json:"is_following,omitempty"` // for root posts in collapsed thread mode indicates if the current user is following this thread
	Metadata     *PostMetadata `json:"metadata,omitempty"`
}

func (o *Post) Auditable() map[string]any {
	var metaData map[string]any
	if o.Metadata != nil {
		metaData = o.Metadata.Auditable()
	}

	return map[string]any{
		"id":              o.Id,
		"create_at":       o.CreateAt,
		"update_at":       o.UpdateAt,
		"edit_at":         o.EditAt,
		"delete_at":       o.DeleteAt,
		"is_pinned":       o.IsPinned,
		"user_id":         o.UserId,
		"channel_id":      o.ChannelId,
		"root_id":         o.RootId,
		"original_id":     o.OriginalId,
		"type":            o.Type,
		"props":           o.GetProps(),
		"file_ids":        o.FileIds,
		"pending_post_id": o.PendingPostId,
		"remote_id":       o.RemoteId,
		"reply_count":     o.ReplyCount,
		"last_reply_at":   o.LastReplyAt,
		"is_following":    o.IsFollowing,
		"metadata":        metaData,
	}
}

func (o *Post) LogClone() any {
	return o.Auditable()
}

type PostEphemeral struct {
	UserID string `json:"user_id"`
	Post   *Post  `json:"post"`
}

type PostPatch struct {
	IsPinned     *bool            `json:"is_pinned"`
	Message      *string          `json:"message"`
	Props        *StringInterface `json:"props"`
	FileIds      *StringArray     `json:"file_ids"`
	HasReactions *bool            `json:"has_reactions"`
}

type PostReminder struct {
	TargetTime int64 `json:"target_time"`
	// These fields are only used internally for interacting with DB.
	PostId string `json:",omitempty"`
	UserId string `json:",omitempty"`
}

type PostPriority struct {
	Priority                *string `json:"priority"`
	RequestedAck            *bool   `json:"requested_ack"`
	PersistentNotifications *bool   `json:"persistent_notifications"`
	// These fields are only used internally for interacting with DB.
	PostId    string `json:",omitempty"`
	ChannelId string `json:",omitempty"`
}

type PostPersistentNotifications struct {
	PostId     string
	CreateAt   int64
	LastSentAt int64
	DeleteAt   int64
	SentCount  int16
}

type GetPersistentNotificationsPostsParams struct {
	MaxTime      int64
	MaxSentCount int16
	PerPage      int
}

type MoveThreadParams struct {
	ChannelId string `json:"channel_id"`
}

type SearchParameter struct {
	Terms                  *string `json:"terms"`
	IsOrSearch             *bool   `json:"is_or_search"`
	TimeZoneOffset         *int    `json:"time_zone_offset"`
	Page                   *int    `json:"page"`
	PerPage                *int    `json:"per_page"`
	IncludeDeletedChannels *bool   `json:"include_deleted_channels"`
}

func (sp SearchParameter) Auditable() map[string]any {
	return map[string]any{
		"terms":                    sp.Terms,
		"is_or_search":             sp.IsOrSearch,
		"time_zone_offset":         sp.TimeZoneOffset,
		"page":                     sp.Page,
		"per_page":                 sp.PerPage,
		"include_deleted_channels": sp.IncludeDeletedChannels,
	}
}

func (sp SearchParameter) LogClone() any {
	return sp.Auditable()
}

type AnalyticsPostCountsOptions struct {
	TeamId        string
	BotsOnly      bool
	YesterdayOnly bool
}

func (o *PostPatch) WithRewrittenImageURLs(f func(string) string) *PostPatch {
	pCopy := *o //nolint:revive
	if pCopy.Message != nil {
		*pCopy.Message = RewriteImageURLs(*o.Message, f)
	}
	return &pCopy
}

func (o *PostPatch) Auditable() map[string]any {
	return map[string]any{
		"is_pinned":     o.IsPinned,
		"props":         o.Props,
		"file_ids":      o.FileIds,
		"has_reactions": o.HasReactions,
	}
}

type PostForExport struct {
	Post
	TeamName    string
	ChannelName string
	Username    string
	ReplyCount  int
	FlaggedBy   StringArray
}

type DirectPostForExport struct {
	Post
	User           string
	ChannelMembers *[]string
	FlaggedBy      StringArray
}

type ReplyForExport struct {
	Post
	Username  string
	FlaggedBy StringArray
}

type PostForIndexing struct {
	Post
	TeamId         string `json:"team_id"`
	ParentCreateAt *int64 `json:"parent_create_at"`
}

type FileForIndexing struct {
	FileInfo
	ChannelId string `json:"channel_id"`
	Content   string `json:"content"`
}

// ShouldIndex tells if a file should be indexed or not.
// index files which are-
// a. not deleted
// b. have an associated post ID, if no post ID, then,
// b.i. the file should belong to the channel's bookmarks, as indicated by the "CreatorId" field.
//
// Files not passing this criteria will be deleted from ES index.
// We're deleting those files from ES index instead of simply skipping them while fetching a batch of files
// because existing ES indexes might have these files already indexed, so we need to remove them from index.
func (file *FileForIndexing) ShouldIndex() bool {
	// NOTE - this function is used in server as well as Enterprise code.
	// Make sure to update public package dependency in both server and Enterprise code when
	// updating the logic here and to test both places.
	return file != nil && file.DeleteAt == 0 && (file.PostId != "" || file.CreatorId == BookmarkFileOwner)
}

// ShallowCopy is an utility function to shallow copy a Post to the given
// destination without touching the internal RWMutex.
func (o *Post) ShallowCopy(dst *Post) error {
	if dst == nil {
		return errors.New("dst cannot be nil")
	}
	o.propsMu.RLock()
	defer o.propsMu.RUnlock()
	dst.propsMu.Lock()
	defer dst.propsMu.Unlock()
	dst.Id = o.Id
	dst.CreateAt = o.CreateAt
	dst.UpdateAt = o.UpdateAt
	dst.EditAt = o.EditAt
	dst.DeleteAt = o.DeleteAt
	dst.IsPinned = o.IsPinned
	dst.UserId = o.UserId
	dst.ChannelId = o.ChannelId
	dst.RootId = o.RootId
	dst.OriginalId = o.OriginalId
	dst.Message = o.Message
	dst.MessageSource = o.MessageSource
	dst.Type = o.Type
	dst.Props = o.Props
	dst.Hashtags = o.Hashtags
	dst.Filenames = o.Filenames
	dst.FileIds = o.FileIds
	dst.PendingPostId = o.PendingPostId
	dst.HasReactions = o.HasReactions
	dst.ReplyCount = o.ReplyCount
	dst.Participants = o.Participants
	dst.LastReplyAt = o.LastReplyAt
	dst.Metadata = o.Metadata
	if o.IsFollowing != nil {
		dst.IsFollowing = NewPointer(*o.IsFollowing)
	}
	dst.RemoteId = o.RemoteId
	return nil
}

// Clone shallowly copies the post and returns the copy.
func (o *Post) Clone() *Post {
	pCopy := &Post{} //nolint:revive
	o.ShallowCopy(pCopy)
	return pCopy
}

func (o *Post) ToJSON() (string, error) {
	pCopy := o.Clone() //nolint:revive
	pCopy.StripActionIntegrations()
	b, err := json.Marshal(pCopy)
	return string(b), err
}

func (o *Post) EncodeJSON(w io.Writer) error {
	o.StripActionIntegrations()
	return json.NewEncoder(w).Encode(o)
}

type CreatePostFlags struct {
	TriggerWebhooks   bool
	SetOnline         bool
	ForceNotification bool
}

type GetPostsSinceOptions struct {
	UserId                   string
	ChannelId                string
	Time                     int64
	SkipFetchThreads         bool
	CollapsedThreads         bool
	CollapsedThreadsExtended bool
	SortAscending            bool
}

type GetPostsSinceForSyncCursor struct {
	LastPostUpdateAt int64
	LastPostUpdateID string
	LastPostCreateAt int64
	LastPostCreateID string
}

func (c GetPostsSinceForSyncCursor) IsEmpty() bool {
	return c.LastPostCreateAt == 0 && c.LastPostCreateID == "" && c.LastPostUpdateAt == 0 && c.LastPostUpdateID == ""
}

type GetPostsSinceForSyncOptions struct {
	ChannelId       string
	ExcludeRemoteId string
	IncludeDeleted  bool
	SinceCreateAt   bool // determines whether the cursor will be based on CreateAt or UpdateAt
}

type GetPostsOptions struct {
	UserId                   string
	ChannelId                string
	PostId                   string
	Page                     int
	PerPage                  int
	SkipFetchThreads         bool
	CollapsedThreads         bool
	CollapsedThreadsExtended bool
	FromPost                 string // PostId after which to send the items
	FromCreateAt             int64  // CreateAt after which to send the items
	FromUpdateAt             int64  // UpdateAt after which to send the items. This cannot be used with FromCreateAt.
	Direction                string // Only accepts up|down. Indicates the order in which to send the items.
	UpdatesOnly              bool   // This flag is used to make the API work with the updateAt value.
	IncludeDeleted           bool
	IncludePostPriority      bool
}

type PostCountOptions struct {
	// Only include posts on a specific team. "" for any team.
	TeamId             string
	MustHaveFile       bool
	MustHaveHashtag    bool
	ExcludeDeleted     bool
	ExcludeSystemPosts bool
	UsersPostsOnly     bool
	// AllowFromCache looks up cache only when ExcludeDeleted and UsersPostsOnly are true and rest are falsy.
	AllowFromCache bool

	// retrieves posts in the inclusive range: [SinceUpdateAt + LastPostId, UntilUpdateAt]
	SincePostID   string
	SinceUpdateAt int64
	UntilUpdateAt int64
}

func (o *Post) Etag() string {
	return Etag(o.Id, o.UpdateAt)
}

func (o *Post) IsValid(maxPostSize int) *AppError {
	if !IsValidId(o.Id) {
		return NewAppError("Post.IsValid", "model.post.is_valid.id.app_error", nil, "", http.StatusBadRequest)
	}

	if o.CreateAt == 0 {
		return NewAppError("Post.IsValid", "model.post.is_valid.create_at.app_error", nil, "id="+o.Id, http.StatusBadRequest)
	}

	if o.UpdateAt == 0 {
		return NewAppError("Post.IsValid", "model.post.is_valid.update_at.app_error", nil, "id="+o.Id, http.StatusBadRequest)
	}

	if !IsValidId(o.UserId) {
		return NewAppError("Post.IsValid", "model.post.is_valid.user_id.app_error", nil, "", http.StatusBadRequest)
	}

	if !IsValidId(o.ChannelId) {
		return NewAppError("Post.IsValid", "model.post.is_valid.channel_id.app_error", nil, "", http.StatusBadRequest)
	}

	if !(IsValidId(o.RootId) || o.RootId == "") {
		return NewAppError("Post.IsValid", "model.post.is_valid.root_id.app_error", nil, "", http.StatusBadRequest)
	}

	if !(len(o.OriginalId) == 26 || o.OriginalId == "") {
		return NewAppError("Post.IsValid", "model.post.is_valid.original_id.app_error", nil, "", http.StatusBadRequest)
	}

	if utf8.RuneCountInString(o.Message) > maxPostSize {
		return NewAppError("Post.IsValid", "model.post.is_valid.message_length.app_error",
			map[string]any{"Length": utf8.RuneCountInString(o.Message), "MaxLength": maxPostSize}, "id="+o.Id, http.StatusBadRequest)
	}

	if utf8.RuneCountInString(o.Hashtags) > PostHashtagsMaxRunes {
		return NewAppError("Post.IsValid", "model.post.is_valid.hashtags.app_error", nil, "id="+o.Id, http.StatusBadRequest)
	}

	switch o.Type {
	case
		PostTypeDefault,
		PostTypeSystemGeneric,
		PostTypeJoinLeave,
		PostTypeAutoResponder,
		PostTypeAddRemove,
		PostTypeJoinChannel,
		PostTypeGuestJoinChannel,
		PostTypeLeaveChannel,
		PostTypeJoinTeam,
		PostTypeLeaveTeam,
		PostTypeAddToChannel,
		PostTypeAddGuestToChannel,
		PostTypeRemoveFromChannel,
		PostTypeMoveChannel,
		PostTypeAddToTeam,
		PostTypeRemoveFromTeam,
		PostTypeSlackAttachment,
		PostTypeHeaderChange,
		PostTypePurposeChange,
		PostTypeDisplaynameChange,
		PostTypeConvertChannel,
		PostTypeChannelDeleted,
		PostTypeChannelRestored,
		PostTypeChangeChannelPrivacy,
		PostTypeAddBotTeamsChannels,
		PostTypeReminder,
		PostTypeMe,
		PostTypeWrangler,
		PostTypeGMConvertedToChannel:
	default:
		if !strings.HasPrefix(o.Type, PostCustomTypePrefix) {
			return NewAppError("Post.IsValid", "model.post.is_valid.type.app_error", nil, "id="+o.Type, http.StatusBadRequest)
		}
	}

	if utf8.RuneCountInString(ArrayToJSON(o.Filenames)) > PostFilenamesMaxRunes {
		return NewAppError("Post.IsValid", "model.post.is_valid.filenames.app_error", nil, "id="+o.Id, http.StatusBadRequest)
	}

	if utf8.RuneCountInString(ArrayToJSON(o.FileIds)) > PostFileidsMaxRunes {
		return NewAppError("Post.IsValid", "model.post.is_valid.file_ids.app_error", nil, "id="+o.Id, http.StatusBadRequest)
	}

	if utf8.RuneCountInString(StringInterfaceToJSON(o.GetProps())) > PostPropsMaxRunes {
		return NewAppError("Post.IsValid", "model.post.is_valid.props.app_error", nil, "id="+o.Id, http.StatusBadRequest)
	}

	return nil
}

func (o *Post) SanitizeProps() {
	if o == nil {
		return
	}
	membersToSanitize := []string{
		PropsAddChannelMember,
		PostPropsForceNotification,
	}

	for _, member := range membersToSanitize {
		if _, ok := o.GetProps()[member]; ok {
			o.DelProp(member)
		}
	}
	for _, p := range o.Participants {
		p.Sanitize(map[string]bool{})
	}
}

// Remove any input data from the post object that is not user controlled
func (o *Post) SanitizeInput() {
	o.DeleteAt = 0
	o.RemoteId = NewPointer("")

	if o.Metadata != nil {
		o.Metadata.Embeds = nil
	}
}

func (o *Post) ContainsIntegrationsReservedProps() []string {
	return ContainsIntegrationsReservedProps(o.GetProps())
}

func (o *PostPatch) ContainsIntegrationsReservedProps() []string {
	if o == nil || o.Props == nil {
		return nil
	}
	return ContainsIntegrationsReservedProps(*o.Props)
}

func ContainsIntegrationsReservedProps(props StringInterface) []string {
	foundProps := []string{}

	if props != nil {
		reservedProps := []string{
			PostPropsFromWebhook,
			PostPropsOverrideUsername,
			PostPropsWebhookDisplayName,
			PostPropsOverrideIconURL,
			PostPropsOverrideIconEmoji,
		}

		for _, key := range reservedProps {
			if _, ok := props[key]; ok {
				foundProps = append(foundProps, key)
			}
		}
	}

	return foundProps
}

func (o *Post) PreSave() {
	if o.Id == "" {
		o.Id = NewId()
	}

	o.OriginalId = ""

	if o.CreateAt == 0 {
		o.CreateAt = GetMillis()
	}

	o.UpdateAt = o.CreateAt
	o.PreCommit()
}

func (o *Post) PreCommit() {
	if o.GetProps() == nil {
		o.SetProps(make(map[string]any))
	}

	if o.Filenames == nil {
		o.Filenames = []string{}
	}

	if o.FileIds == nil {
		o.FileIds = []string{}
	}

	o.GenerateActionIds()

	// There's a rare bug where the client sends up duplicate FileIds so protect against that
	o.FileIds = RemoveDuplicateStrings(o.FileIds)
}

func (o *Post) MakeNonNil() {
	if o.GetProps() == nil {
		o.SetProps(make(map[string]any))
	}
}

func (o *Post) DelProp(key string) {
	o.propsMu.Lock()
	defer o.propsMu.Unlock()
	propsCopy := make(map[string]any, len(o.Props)-1)
	for k, v := range o.Props {
		propsCopy[k] = v
	}
	delete(propsCopy, key)
	o.Props = propsCopy
}

func (o *Post) AddProp(key string, value any) {
	o.propsMu.Lock()
	defer o.propsMu.Unlock()
	propsCopy := make(map[string]any, len(o.Props)+1)
	for k, v := range o.Props {
		propsCopy[k] = v
	}
	propsCopy[key] = value
	o.Props = propsCopy
}

func (o *Post) GetProps() StringInterface {
	o.propsMu.RLock()
	defer o.propsMu.RUnlock()
	return o.Props
}

func (o *Post) SetProps(props StringInterface) {
	o.propsMu.Lock()
	defer o.propsMu.Unlock()
	o.Props = props
}

func (o *Post) GetProp(key string) any {
	o.propsMu.RLock()
	defer o.propsMu.RUnlock()
	return o.Props[key]
}

// ValidateProps checks all known props for validity.
// Currently, it logs warnings for invalid props rather than returning an error.
// In a future version, this will be updated to return errors for invalid props.
func (o *Post) ValidateProps(logger mlog.LoggerIFace) {
	if err := o.propsIsValid(); err != nil {
		logger.Warn(
			"Invalid post props. In a future version this will result in an error. Please update your integration to be compliant.",
			mlog.String("post_id", o.Id),
			mlog.Err(err),
		)
	}
}

func (o *Post) propsIsValid() error {
	var multiErr *multierror.Error

	props := o.GetProps()

	// Check basic props validity
	if props == nil {
		return nil
	}

	if props[PostPropsAddedUserId] != nil {
		if addedUserID, ok := props[PostPropsAddedUserId].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("added_user_id prop must be a string"))
		} else if !IsValidId(addedUserID) {
			multiErr = multierror.Append(multiErr, fmt.Errorf("added_user_id prop must be a valid user ID"))
		}
	}
	if props[PostPropsDeleteBy] != nil {
		if deleteByID, ok := props[PostPropsDeleteBy].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("delete_by prop must be a string"))
		} else if !IsValidId(deleteByID) {
			multiErr = multierror.Append(multiErr, fmt.Errorf("delete_by prop must be a valid user ID"))
		}
	}

	// Validate integration props
	if props[PostPropsOverrideIconURL] != nil {
		if iconURL, ok := props[PostPropsOverrideIconURL].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("override_icon_url prop must be a string"))
		} else if iconURL == "" || !IsValidHTTPURL(iconURL) {
			multiErr = multierror.Append(multiErr, fmt.Errorf("override_icon_url prop must be a valid URL"))
		}
	}
	if props[PostPropsOverrideIconEmoji] != nil {
		if _, ok := props[PostPropsOverrideIconEmoji].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("override_icon_emoji prop must be a string"))
		}
	}
	if props[PostPropsOverrideUsername] != nil {
		if _, ok := props[PostPropsOverrideUsername].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("override_username prop must be a string"))
		}
	}
	if props[PostPropsFromWebhook] != nil {
		if fromWebhook, ok := props[PostPropsFromWebhook].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("from_webhook prop must be a string"))
		} else if fromWebhook != "true" {
			multiErr = multierror.Append(multiErr, fmt.Errorf("from_webhook prop must be \"true\""))
		}
	}
	if props[PostPropsFromBot] != nil {
		if fromBot, ok := props[PostPropsFromBot].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("from_bot prop must be a string"))
		} else if fromBot != "true" {
			multiErr = multierror.Append(multiErr, fmt.Errorf("from_bot prop must be \"true\""))
		}
	}
	if props[PostPropsFromOAuthApp] != nil {
		if fromOAuthApp, ok := props[PostPropsFromOAuthApp].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("from_oauth_app prop must be a string"))
		} else if fromOAuthApp != "true" {
			multiErr = multierror.Append(multiErr, fmt.Errorf("from_oauth_app prop must be \"true\""))
		}
	}
	if props[PostPropsFromPlugin] != nil {
		if fromPlugin, ok := props[PostPropsFromPlugin].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("from_plugin prop must be a string"))
		} else if fromPlugin != "true" {
			multiErr = multierror.Append(multiErr, fmt.Errorf("from_plugin prop must be \"true\""))
		}
	}
	if props[PostPropsUnsafeLinks] != nil {
		if unsafeLinks, ok := props[PostPropsUnsafeLinks].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("unsafe_links prop must be a string"))
		} else if unsafeLinks != "true" {
			multiErr = multierror.Append(multiErr, fmt.Errorf("unsafe_links prop must be \"true\""))
		}
	}
	if props[PostPropsWebhookDisplayName] != nil {
		if _, ok := props[PostPropsWebhookDisplayName].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("webhook_display_name prop must be a string"))
		}
	}

	if props[PostPropsMentionHighlightDisabled] != nil {
		if _, ok := props[PostPropsMentionHighlightDisabled].(bool); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("mention_highlight_disabled prop must be a boolean"))
		}
	}
	if props[PostPropsGroupHighlightDisabled] != nil {
		if _, ok := props[PostPropsGroupHighlightDisabled].(bool); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("disable_group_highlight prop must be a boolean"))
		}
	}

	if props[PostPropsPreviewedPost] != nil {
		if previewedPostID, ok := props[PostPropsPreviewedPost].(string); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("previewed_post prop must be a string"))
		} else if !IsValidId(previewedPostID) {
			multiErr = multierror.Append(multiErr, fmt.Errorf("previewed_post prop must be a valid post ID"))
		}
	}

	if props[PostPropsForceNotification] != nil {
		if _, ok := props[PostPropsForceNotification].(bool); !ok {
			multiErr = multierror.Append(multiErr, fmt.Errorf("force_notification prop must be a boolean"))
		}
	}

	for i, a := range o.Attachments() {
		if err := a.IsValid(); err != nil {
			multiErr = multierror.Append(multiErr, multierror.Prefix(err, fmt.Sprintf("message attachtment at index %d is invalid:", i)))
		}
	}

	return multiErr.ErrorOrNil()
}

func (o *Post) IsSystemMessage() bool {
	return len(o.Type) >= len(PostSystemMessagePrefix) && o.Type[:len(PostSystemMessagePrefix)] == PostSystemMessagePrefix
}

// IsRemote returns true if the post originated on a remote cluster.
func (o *Post) IsRemote() bool {
	return o.RemoteId != nil && *o.RemoteId != ""
}

// GetRemoteID safely returns the remoteID or empty string if not remote.
func (o *Post) GetRemoteID() string {
	if o.RemoteId != nil {
		return *o.RemoteId
	}
	return ""
}

func (o *Post) IsJoinLeaveMessage() bool {
	return o.Type == PostTypeJoinLeave ||
		o.Type == PostTypeAddRemove ||
		o.Type == PostTypeJoinChannel ||
		o.Type == PostTypeLeaveChannel ||
		o.Type == PostTypeJoinTeam ||
		o.Type == PostTypeLeaveTeam ||
		o.Type == PostTypeAddToChannel ||
		o.Type == PostTypeRemoveFromChannel ||
		o.Type == PostTypeAddToTeam ||
		o.Type == PostTypeRemoveFromTeam
}

func (o *Post) Patch(patch *PostPatch) {
	if patch.IsPinned != nil {
		o.IsPinned = *patch.IsPinned
	}

	if patch.Message != nil {
		o.Message = *patch.Message
	}

	if patch.Props != nil {
		newProps := *patch.Props
		o.SetProps(newProps)
	}

	if patch.FileIds != nil {
		o.FileIds = *patch.FileIds
	}

	if patch.HasReactions != nil {
		o.HasReactions = *patch.HasReactions
	}
}

func (o *Post) ChannelMentions() []string {
	return ChannelMentions(o.Message)
}

// DisableMentionHighlights disables a posts mention highlighting and returns the first channel mention that was present in the message.
func (o *Post) DisableMentionHighlights() string {
	mention, hasMentions := findAtChannelMention(o.Message)
	if hasMentions {
		o.AddProp(PostPropsMentionHighlightDisabled, true)
	}
	return mention
}

// DisableMentionHighlights disables mention highlighting for a post patch if required.
func (o *PostPatch) DisableMentionHighlights() {
	if o.Message == nil {
		return
	}
	if _, hasMentions := findAtChannelMention(*o.Message); hasMentions {
		if o.Props == nil {
			o.Props = &StringInterface{}
		}
		(*o.Props)[PostPropsMentionHighlightDisabled] = true
	}
}

func findAtChannelMention(message string) (mention string, found bool) {
	re := regexp.MustCompile(`(?i)\B@(channel|all|here)\b`)
	matched := re.FindStringSubmatch(message)
	if found = (len(matched) > 0); found {
		mention = strings.ToLower(matched[0])
	}
	return
}

func (o *Post) Attachments() []*SlackAttachment {
	if attachments, ok := o.GetProp(PostPropsAttachments).([]*SlackAttachment); ok {
		return attachments
	}
	var ret []*SlackAttachment
	if attachments, ok := o.GetProp(PostPropsAttachments).([]any); ok {
		for _, attachment := range attachments {
			if enc, err := json.Marshal(attachment); err == nil {
				var decoded SlackAttachment
				if json.Unmarshal(enc, &decoded) == nil {
					// Ignoring nil actions
					i := 0
					for _, action := range decoded.Actions {
						if action != nil {
							decoded.Actions[i] = action
							i++
						}
					}
					decoded.Actions = decoded.Actions[:i]

					// Ignoring nil fields
					i = 0
					for _, field := range decoded.Fields {
						if field != nil {
							decoded.Fields[i] = field
							i++
						}
					}
					decoded.Fields = decoded.Fields[:i]
					ret = append(ret, &decoded)
				}
			}
		}
	}
	return ret
}

func (o *Post) AttachmentsEqual(input *Post) bool {
	attachments := o.Attachments()
	inputAttachments := input.Attachments()

	if len(attachments) != len(inputAttachments) {
		return false
	}

	for i := range attachments {
		if !attachments[i].Equals(inputAttachments[i]) {
			return false
		}
	}

	return true
}

var markdownDestinationEscaper = strings.NewReplacer(
	`\`, `\\`,
	`<`, `\<`,
	`>`, `\>`,
	`(`, `\(`,
	`)`, `\)`,
)

// WithRewrittenImageURLs returns a new shallow copy of the post where the message has been
// rewritten via RewriteImageURLs.
func (o *Post) WithRewrittenImageURLs(f func(string) string) *Post {
	pCopy := o.Clone()
	pCopy.Message = RewriteImageURLs(o.Message, f)
	if pCopy.MessageSource == "" && pCopy.Message != o.Message {
		pCopy.MessageSource = o.Message
	}
	return pCopy
}

// RewriteImageURLs takes a message and returns a copy that has all of the image URLs replaced
// according to the function f. For each image URL, f will be invoked, and the resulting markdown
// will contain the URL returned by that invocation instead.
//
// Image URLs are destination URLs used in inline images or reference definitions that are used
// anywhere in the input markdown as an image.
func RewriteImageURLs(message string, f func(string) string) string {
	if !strings.Contains(message, "![") {
		return message
	}

	var ranges []markdown.Range

	markdown.Inspect(message, func(blockOrInline any) bool {
		switch v := blockOrInline.(type) {
		case *markdown.ReferenceImage:
			ranges = append(ranges, v.ReferenceDefinition.RawDestination)
		case *markdown.InlineImage:
			ranges = append(ranges, v.RawDestination)
		default:
			return true
		}
		return true
	})

	if ranges == nil {
		return message
	}

	sort.Slice(ranges, func(i, j int) bool {
		return ranges[i].Position < ranges[j].Position
	})

	copyRanges := make([]markdown.Range, 0, len(ranges))
	urls := make([]string, 0, len(ranges))
	resultLength := len(message)

	start := 0
	for i, r := range ranges {
		switch {
		case i == 0:
		case r.Position != ranges[i-1].Position:
			start = ranges[i-1].End
		default:
			continue
		}
		original := message[r.Position:r.End]
		replacement := markdownDestinationEscaper.Replace(f(markdown.Unescape(original)))
		resultLength += len(replacement) - len(original)
		copyRanges = append(copyRanges, markdown.Range{Position: start, End: r.Position})
		urls = append(urls, replacement)
	}

	result := make([]byte, resultLength)

	offset := 0
	for i, r := range copyRanges {
		offset += copy(result[offset:], message[r.Position:r.End])
		offset += copy(result[offset:], urls[i])
	}
	copy(result[offset:], message[ranges[len(ranges)-1].End:])

	return string(result)
}

func (o *Post) IsFromOAuthBot() bool {
	props := o.GetProps()
	return props[PostPropsFromWebhook] == "true" && props[PostPropsOverrideUsername] != ""
}

func (o *Post) ToNilIfInvalid() *Post {
	if o.Id == "" {
		return nil
	}
	return o
}

func (o *Post) ForPlugin() *Post {
	p := o.Clone()
	p.Metadata = nil
	if p.Type == fmt.Sprintf("%sup_notification", PostCustomTypePrefix) {
		p.DelProp("requested_features")
	}
	return p
}

func (o *Post) GetPreviewPost() *PreviewPost {
	if o.Metadata == nil {
		return nil
	}
	for _, embed := range o.Metadata.Embeds {
		if embed != nil && embed.Type == PostEmbedPermalink {
			if previewPost, ok := embed.Data.(*PreviewPost); ok {
				return previewPost
			}
		}
	}
	return nil
}

func (o *Post) GetPreviewedPostProp() string {
	if val, ok := o.GetProp(PostPropsPreviewedPost).(string); ok {
		return val
	}
	return ""
}

func (o *Post) GetPriority() *PostPriority {
	if o.Metadata == nil {
		return nil
	}
	return o.Metadata.Priority
}

func (o *Post) GetPersistentNotification() *bool {
	priority := o.GetPriority()
	if priority == nil {
		return nil
	}
	return priority.PersistentNotifications
}

func (o *Post) GetRequestedAck() *bool {
	priority := o.GetPriority()
	if priority == nil {
		return nil
	}
	return priority.RequestedAck
}

func (o *Post) IsUrgent() bool {
	postPriority := o.GetPriority()
	if postPriority == nil {
		return false
	}

	if postPriority.Priority == nil {
		return false
	}

	return *postPriority.Priority == PostPriorityUrgent
}

func (o *Post) CleanPost() *Post {
	o.Id = ""
	o.CreateAt = 0
	o.UpdateAt = 0
	o.EditAt = 0
	return o
}

type UpdatePostOptions struct {
	SafeUpdate    bool
	IsRestorePost bool
}

func DefaultUpdatePostOptions() *UpdatePostOptions {
	return &UpdatePostOptions{
		SafeUpdate:    false,
		IsRestorePost: false,
	}
}