/*
   GoToSocial
   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU Affero General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Affero General Public License for more details.

   You should have received a copy of the GNU Affero General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package status

import (
	"context"
	"errors"
	"fmt"

	"github.com/superseriousbusiness/gotosocial/internal/api/model"
	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
	"github.com/superseriousbusiness/gotosocial/internal/db"
	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
	"github.com/superseriousbusiness/gotosocial/internal/log"
	"github.com/superseriousbusiness/gotosocial/internal/util"
)

func (p *processor) ProcessVisibility(ctx context.Context, form *apimodel.AdvancedStatusCreateForm, accountDefaultVis gtsmodel.Visibility, status *gtsmodel.Status) error {
	// by default all flags are set to true
	federated := true
	boostable := true
	replyable := true
	likeable := true

	// If visibility isn't set on the form, then just take the account default.
	// If that's also not set, take the default for the whole instance.
	var vis gtsmodel.Visibility
	switch {
	case form.Visibility != "":
		vis = p.tc.APIVisToVis(form.Visibility)
	case accountDefaultVis != "":
		vis = accountDefaultVis
	default:
		vis = gtsmodel.VisibilityDefault
	}

	switch vis {
	case gtsmodel.VisibilityPublic:
		// for public, there's no need to change any of the advanced flags from true regardless of what the user filled out
		break
	case gtsmodel.VisibilityUnlocked:
		// for unlocked the user can set any combination of flags they like so look at them all to see if they're set and then apply them
		if form.Federated != nil {
			federated = *form.Federated
		}

		if form.Boostable != nil {
			boostable = *form.Boostable
		}

		if form.Replyable != nil {
			replyable = *form.Replyable
		}

		if form.Likeable != nil {
			likeable = *form.Likeable
		}

	case gtsmodel.VisibilityFollowersOnly, gtsmodel.VisibilityMutualsOnly:
		// for followers or mutuals only, boostable will *always* be false, but the other fields can be set so check and apply them
		boostable = false

		if form.Federated != nil {
			federated = *form.Federated
		}

		if form.Replyable != nil {
			replyable = *form.Replyable
		}

		if form.Likeable != nil {
			likeable = *form.Likeable
		}

	case gtsmodel.VisibilityDirect:
		// direct is pretty easy: there's only one possible setting so return it
		federated = true
		boostable = false
		replyable = true
		likeable = true
	}

	status.Visibility = vis
	status.Federated = &federated
	status.Boostable = &boostable
	status.Replyable = &replyable
	status.Likeable = &likeable
	return nil
}

func (p *processor) ProcessReplyToID(ctx context.Context, form *apimodel.AdvancedStatusCreateForm, thisAccountID string, status *gtsmodel.Status) gtserror.WithCode {
	if form.InReplyToID == "" {
		return nil
	}

	// If this status is a reply to another status, we need to do a bit of work to establish whether or not this status can be posted:
	//
	// 1. Does the replied status exist in the database?
	// 2. Is the replied status marked as replyable?
	// 3. Does a block exist between either the current account or the account that posted the status it's replying to?
	//
	// If this is all OK, then we fetch the repliedStatus and the repliedAccount for later processing.
	repliedStatus := &gtsmodel.Status{}
	repliedAccount := &gtsmodel.Account{}

	if err := p.db.GetByID(ctx, form.InReplyToID, repliedStatus); err != nil {
		if err == db.ErrNoEntries {
			err := fmt.Errorf("status with id %s not replyable because it doesn't exist", form.InReplyToID)
			return gtserror.NewErrorBadRequest(err, err.Error())
		}
		err := fmt.Errorf("db error fetching status with id %s: %s", form.InReplyToID, err)
		return gtserror.NewErrorInternalError(err)
	}
	if !*repliedStatus.Replyable {
		err := fmt.Errorf("status with id %s is marked as not replyable", form.InReplyToID)
		return gtserror.NewErrorForbidden(err, err.Error())
	}

	if err := p.db.GetByID(ctx, repliedStatus.AccountID, repliedAccount); err != nil {
		if err == db.ErrNoEntries {
			err := fmt.Errorf("status with id %s not replyable because account id %s is not known", form.InReplyToID, repliedStatus.AccountID)
			return gtserror.NewErrorBadRequest(err, err.Error())
		}
		err := fmt.Errorf("db error fetching account with id %s: %s", repliedStatus.AccountID, err)
		return gtserror.NewErrorInternalError(err)
	}

	if blocked, err := p.db.IsBlocked(ctx, thisAccountID, repliedAccount.ID, true); err != nil {
		err := fmt.Errorf("db error checking block: %s", err)
		return gtserror.NewErrorInternalError(err)
	} else if blocked {
		err := fmt.Errorf("status with id %s not replyable", form.InReplyToID)
		return gtserror.NewErrorNotFound(err)
	}

	status.InReplyToID = repliedStatus.ID
	status.InReplyToURI = repliedStatus.URI
	status.InReplyToAccountID = repliedAccount.ID

	return nil
}

func (p *processor) ProcessMediaIDs(ctx context.Context, form *apimodel.AdvancedStatusCreateForm, thisAccountID string, status *gtsmodel.Status) error {
	if form.MediaIDs == nil {
		return nil
	}

	gtsMediaAttachments := []*gtsmodel.MediaAttachment{}
	attachments := []string{}
	for _, mediaID := range form.MediaIDs {
		// check these attachments exist
		a := &gtsmodel.MediaAttachment{}
		if err := p.db.GetByID(ctx, mediaID, a); err != nil {
			return fmt.Errorf("invalid media type or media not found for media id %s", mediaID)
		}
		// check they belong to the requesting account id
		if a.AccountID != thisAccountID {
			return fmt.Errorf("media with id %s does not belong to account %s", mediaID, thisAccountID)
		}
		// check they're not already used in a status
		if a.StatusID != "" || a.ScheduledStatusID != "" {
			return fmt.Errorf("media with id %s is already attached to a status", mediaID)
		}
		gtsMediaAttachments = append(gtsMediaAttachments, a)
		attachments = append(attachments, a.ID)
	}
	status.Attachments = gtsMediaAttachments
	status.AttachmentIDs = attachments
	return nil
}

func (p *processor) ProcessLanguage(ctx context.Context, form *apimodel.AdvancedStatusCreateForm, accountDefaultLanguage string, status *gtsmodel.Status) error {
	if form.Language != "" {
		status.Language = form.Language
	} else {
		status.Language = accountDefaultLanguage
	}
	if status.Language == "" {
		return errors.New("no language given either in status create form or account default")
	}
	return nil
}

func (p *processor) ProcessMentions(ctx context.Context, form *apimodel.AdvancedStatusCreateForm, accountID string, status *gtsmodel.Status) error {
	mentionedAccountNames := util.DeriveMentionNamesFromText(form.Status)
	mentions := []*gtsmodel.Mention{}
	mentionIDs := []string{}

	for _, mentionedAccountName := range mentionedAccountNames {
		gtsMention, err := p.parseMention(ctx, mentionedAccountName, accountID, status.ID)
		if err != nil {
			log.Errorf("ProcessMentions: error parsing mention %s from status: %s", mentionedAccountName, err)
			continue
		}

		if err := p.db.Put(ctx, gtsMention); err != nil {
			log.Errorf("ProcessMentions: error putting mention in db: %s", err)
		}

		mentions = append(mentions, gtsMention)
		mentionIDs = append(mentionIDs, gtsMention.ID)
	}

	// add full populated gts menchies to the status for passing them around conveniently
	status.Mentions = mentions
	// add just the ids of the mentioned accounts to the status for putting in the db
	status.MentionIDs = mentionIDs

	return nil
}

func (p *processor) ProcessTags(ctx context.Context, form *apimodel.AdvancedStatusCreateForm, accountID string, status *gtsmodel.Status) error {
	tags := []string{}
	gtsTags, err := p.db.TagStringsToTags(ctx, util.DeriveHashtagsFromText(form.Status), accountID)
	if err != nil {
		return fmt.Errorf("error generating hashtags from status: %s", err)
	}
	for _, tag := range gtsTags {
		if err := p.db.Put(ctx, tag); err != nil {
			var alreadyExistsError *db.ErrAlreadyExists
			if !errors.As(err, &alreadyExistsError) {
				return fmt.Errorf("error putting tags in db: %s", err)
			}
		}
		tags = append(tags, tag.ID)
	}
	// add full populated gts tags to the status for passing them around conveniently
	status.Tags = gtsTags
	// add just the ids of the used tags to the status for putting in the db
	status.TagIDs = tags
	return nil
}

func (p *processor) ProcessEmojis(ctx context.Context, form *apimodel.AdvancedStatusCreateForm, accountID string, status *gtsmodel.Status) error {
	// for each emoji shortcode in the text, check if it's an enabled
	// emoji on this instance, and if so, add it to the status
	emojiShortcodes := util.DeriveEmojisFromText(form.Status)
	status.Emojis = make([]*gtsmodel.Emoji, 0, len(emojiShortcodes))
	status.EmojiIDs = make([]string, 0, len(emojiShortcodes))

	for _, shortcode := range emojiShortcodes {
		emoji, err := p.db.GetEmojiByShortcodeDomain(ctx, shortcode, "")
		if err != nil {
			if err != db.ErrNoEntries {
				log.Errorf("error getting local emoji with shortcode %s: %s", shortcode, err)
			}
			continue
		}

		if *emoji.VisibleInPicker && !*emoji.Disabled {
			status.Emojis = append(status.Emojis, emoji)
			status.EmojiIDs = append(status.EmojiIDs, emoji.ID)
		}
	}

	return nil
}

func (p *processor) ProcessContent(ctx context.Context, form *apimodel.AdvancedStatusCreateForm, accountID string, status *gtsmodel.Status) error {
	// if there's nothing in the status at all we can just return early
	if form.Status == "" {
		status.Content = ""
		return nil
	}

	// if format wasn't specified we should try to figure out what format this user prefers
	if form.Format == "" {
		acct, err := p.db.GetAccountByID(ctx, accountID)
		if err != nil {
			return fmt.Errorf("error processing new content: couldn't retrieve account from db to check post format: %s", err)
		}

		switch acct.StatusFormat {
		case "plain":
			form.Format = model.StatusFormatPlain
		case "markdown":
			form.Format = model.StatusFormatMarkdown
		default:
			form.Format = model.StatusFormatDefault
		}
	}

	// parse content out of the status depending on what format has been submitted
	var formatted string
	switch form.Format {
	case apimodel.StatusFormatPlain:
		formatted = p.formatter.FromPlain(ctx, form.Status, status.Mentions, status.Tags)
	case apimodel.StatusFormatMarkdown:
		formatted = p.formatter.FromMarkdown(ctx, form.Status, status.Mentions, status.Tags)
	default:
		return fmt.Errorf("format %s not recognised as a valid status format", form.Format)
	}

	status.Content = formatted
	return nil
}