/*
   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 bundb

import (
	"context"
	"strings"

	"github.com/superseriousbusiness/gotosocial/internal/cache"
	"github.com/superseriousbusiness/gotosocial/internal/db"
	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
	"github.com/superseriousbusiness/gotosocial/internal/log"
	"github.com/uptrace/bun"
)

type emojiDB struct {
	conn  *DBConn
	cache *cache.EmojiCache
}

func (e *emojiDB) newEmojiQ(emoji *gtsmodel.Emoji) *bun.SelectQuery {
	return e.conn.
		NewSelect().
		Model(emoji)
}

func (e *emojiDB) PutEmoji(ctx context.Context, emoji *gtsmodel.Emoji) db.Error {
	if _, err := e.conn.NewInsert().Model(emoji).Exec(ctx); err != nil {
		return e.conn.ProcessError(err)
	}

	e.cache.Put(emoji)
	return nil
}

func (e *emojiDB) GetCustomEmojis(ctx context.Context) ([]*gtsmodel.Emoji, db.Error) {
	emojiIDs := []string{}

	q := e.conn.
		NewSelect().
		Table("emojis").
		Column("id").
		Where("visible_in_picker = true").
		Where("disabled = false").
		Where("domain IS NULL").
		Order("shortcode ASC")

	if err := q.Scan(ctx, &emojiIDs); err != nil {
		return nil, e.conn.ProcessError(err)
	}

	return e.emojisFromIDs(ctx, emojiIDs)
}

func (e *emojiDB) GetEmojiByID(ctx context.Context, id string) (*gtsmodel.Emoji, db.Error) {
	return e.getEmoji(
		ctx,
		func() (*gtsmodel.Emoji, bool) {
			return e.cache.GetByID(id)
		},
		func(emoji *gtsmodel.Emoji) error {
			return e.newEmojiQ(emoji).Where("emoji.id = ?", id).Scan(ctx)
		},
	)
}

func (e *emojiDB) GetEmojiByURI(ctx context.Context, uri string) (*gtsmodel.Emoji, db.Error) {
	return e.getEmoji(
		ctx,
		func() (*gtsmodel.Emoji, bool) {
			return e.cache.GetByURI(uri)
		},
		func(emoji *gtsmodel.Emoji) error {
			return e.newEmojiQ(emoji).Where("emoji.uri = ?", uri).Scan(ctx)
		},
	)
}

func (e *emojiDB) GetEmojiByShortcodeDomain(ctx context.Context, shortcode string, domain string) (*gtsmodel.Emoji, db.Error) {
	return e.getEmoji(
		ctx,
		func() (*gtsmodel.Emoji, bool) {
			return e.cache.GetByShortcodeDomain(shortcode, domain)
		},
		func(emoji *gtsmodel.Emoji) error {
			q := e.newEmojiQ(emoji)

			if domain != "" {
				q = q.Where("emoji.shortcode = ?", shortcode)
				q = q.Where("emoji.domain = ?", domain)
			} else {
				q = q.Where("emoji.shortcode = ?", strings.ToLower(shortcode))
				q = q.Where("emoji.domain IS NULL")
			}

			return q.Scan(ctx)
		},
	)
}

func (e *emojiDB) getEmoji(ctx context.Context, cacheGet func() (*gtsmodel.Emoji, bool), dbQuery func(*gtsmodel.Emoji) error) (*gtsmodel.Emoji, db.Error) {
	// Attempt to fetch cached emoji
	emoji, cached := cacheGet()

	if !cached {
		emoji = &gtsmodel.Emoji{}

		// Not cached! Perform database query
		err := dbQuery(emoji)
		if err != nil {
			return nil, e.conn.ProcessError(err)
		}

		// Place in the cache
		e.cache.Put(emoji)
	}

	return emoji, nil
}

func (e *emojiDB) emojisFromIDs(ctx context.Context, emojiIDs []string) ([]*gtsmodel.Emoji, db.Error) {
	// Catch case of no emojis early
	if len(emojiIDs) == 0 {
		return nil, db.ErrNoEntries
	}

	emojis := make([]*gtsmodel.Emoji, 0, len(emojiIDs))

	for _, id := range emojiIDs {
		emoji, err := e.GetEmojiByID(ctx, id)
		if err != nil {
			log.Errorf("emojisFromIDs: error getting emoji %q: %v", id, err)
		}

		emojis = append(emojis, emoji)
	}

	return emojis, nil
}