const DBName = "EMI_SOCIAL";

const chatDB = (DB) => {
    DB.chatMessagesCol = DB.db.db(DBName).collection("chat_messages");
    DB.chatMessagesCol.createIndex({ createdAt: -1 }).catch(console.error);

    DB.addChatMessage = async ({ senderId, senderProfileId, senderName, text, sourceLang }) => {
        const safeText = (text || "").trim();
        if (!safeText) return false;
        const message = {
            senderId: senderId ? senderId + "" : "",
            senderProfileId: senderProfileId ? senderProfileId + "" : "",
            senderName: senderName || "Anonymous",
            text: safeText,
            sourceLang: sourceLang || "en",
            translations: {},
            createdAt: new Date(),
        };
        const result = await DB.chatMessagesCol.insertOne(message).catch((err) => {
            console.log(err);
            return false;
        });
        if (!result || !result.insertedId) return false;
        return {
            ...message,
            _id: result.insertedId,
        };
    };

    DB.getChatParticipants = async () => {
        return DB.chatMessagesCol.distinct("senderProfileId").catch((err) => {
            console.log(err);
            return [];
        });
    };

    DB.getRecentChatMessages = async (limit = 100) => {
        const safeLimit = Math.min(Math.max(parseInt(limit, 10) || 100, 1), 200);
        const messages = await DB.chatMessagesCol.find({})
            .sort({ createdAt: -1 })
            .limit(safeLimit)
            .toArray()
            .catch((err) => {
                console.log(err);
                return [];
            });
        return messages.reverse();
    };

    DB.setChatMessageTranslation = async ({ messageId, targetLang, text, provider, model }) => {
        if (!messageId || !targetLang || !text) return false;
        const _id = typeof messageId === "string" ? DB.ObjectID(messageId) : messageId;
        const fieldBase = `translations.${targetLang}`;
        const update = {
            $set: {
                [`${fieldBase}.text`]: text,
                [`${fieldBase}.provider`]: provider || "openai",
                [`${fieldBase}.model`]: model || "",
                [`${fieldBase}.updatedAt`]: new Date(),
            },
        };
        return DB.chatMessagesCol.updateOne({ _id }, update).catch((err) => {
            console.log(err);
            return false;
        });
    };
};

module.exports = chatDB;