const Transaction = require('./transactionModel')
const Belonging = require('../belonging/belongingModel')
const AppError = require('../../globalErrorHandler/AppError')
const mongoose = require('mongoose')
const ObjectID = mongoose.Schema.Types.ObjectId
const { client } = require('../../setup/typesense')
const TsApiFeatures = require('../../utils/TsApiFeatures')

const filterObj = (obj, ...allowedFields) => {
    const newObj = {}
    Object.keys(obj).forEach((el) => {
        if (allowedFields.includes(el)) newObj[el] = obj[el]
    })

    return newObj
}

const createTransaction = async (data) => {
    if (data.type == 'withdraw') {
        // Aggregate transactions to calculate inventory
        const result = await Transaction.aggregate([
            {
                $match: {
                    belongingId: ObjectID,
                    status: 'finished',
                },
            },
            {
                $group: {
                    _id: '$belongingId',
                    totalInventory: {
                        $sum: '$value',
                    },
                },
            },
        ])

        if (result[0].totalInventory <= 0) throw new AppError('Invalid Transaction', 404, {})
    }

    return Transaction.create({
        type: data.type,
        status: data.status,
        source: data.source,
        value: data.type === 'withdraw' ? data.value * -1 : data.value,
        date: data.Date,
        description: data.description,
        userId: data.userId,
        belongingId: data.belongingId,
    })
}

const getUserTransaction = async (userId) => {
    return Transaction.find({ userId }, null, null)
}

const getTransactionByBelongingId = async (belongingId) => {
    return Transaction.find({ belongingId }, null, null)
}

const getBelongingInventory = async (belongingId) => {
    const belonging = await Belonging.findById(belongingId, null, null)

    if (!belonging) {
        throw new AppError('NoBelongingFound', 404, {})
    }

    // Simplified aggregation to calculate inventory metrics
    const result = await Transaction.aggregate([
        {
            $match: {
                belongingId: ObjectID,
                $or: [{ status: 'finished' }, { status: 'pending' }],
            },
        },
        {
            $facet: {
                // Calculate total inventory from finished transactions
                finishedInventory: [
                    { $match: { status: 'finished' } },
                    {
                        $group: {
                            _id: null,
                            total: { $sum: '$value' },
                        },
                    },
                ],
                // Calculate pending deposits
                pendingDepositsInventory: [
                    {
                        $match: {
                            status: 'pending',
                            type: 'deposit',
                        },
                    },
                    {
                        $group: {
                            _id: null,
                            total: { $sum: '$value' },
                        },
                    },
                ],
                // Calculate pending withdrawals
                pendingWithdrawsInventory: [
                    {
                        $match: {
                            status: 'pending',
                            type: 'withdraw',
                        },
                    },
                    {
                        $group: {
                            _id: null,
                            total: { $sum: '$value' },
                        },
                    },
                ],
            },
        },
        {
            // Restructure the output to get only the values
            $project: {
                finishedInventory: { $ifNull: [{ $arrayElemAt: ['$finishedInventory.total', 0] }, 0] },
                pendingDepositsInventory: { $ifNull: [{ $arrayElemAt: ['$pendingDepositsInventory.total', 0] }, 0] },
                pendingWithdrawsInventory: { $ifNull: [{ $arrayElemAt: ['$pendingWithdrawsInventory.total', 0] }, 0] },
            },
        },
    ])

    return { belongingCode: belonging.belongingCode, ...result[0] }
}

const updateTransaction = async (transactionId, data) => {
    const filteredBody = filterObj(data, 'status')
    const transaction = await Transaction.findOneAndUpdate({ _id: transactionId }, filteredBody, { new: true })

    if (!transaction) {
        throw new AppError('NoTransactionFound', 404, {})
    }

    return transaction
}

const deleteTransaction = async (transactionId) => {
    const transaction = await Transaction.findOneAndDelete({ _id: transactionId })

    if (!transaction) {
        throw AppError('NoTransactionFound', 404, {})
    }

    return null
}

const ensureCollectionExists = async () => {
    const collections = await client.collections().retrieve()
    const collectionExists = collections.some((collection) => collection.name === 'transactions')

    if (collectionExists) {
        await client.collections('transactions').delete()
    }

    const schema = getTypeSenseSchema()

    await client.collections().create(schema)
    console.log('Collection "transactions" created successfully')
}

const searchTransactions = async (inputQuery) => {
    const tsFeatures = new TsApiFeatures(client, 'transactions', inputQuery).filter().facet().sort().limitFields().paginate().search()

    let { facets, items, totalCount, pagesCount } = await tsFeatures.execute()

    return { facets, transactions: items, totalCount, pagesCount }
}

const indexAllTransactions = async () => {
    const batchSize = 20
    const count = await Transaction.countDocuments({}, null)
    const rounds = Math.ceil(count / batchSize)

    await ensureCollectionExists()

    for (let i = 1; i <= rounds; i++) {
        console.log(`Indexing ${batchSize} transactions, Round ${i}`)

        const transactions = await Transaction.find({}, null, null)
            .skip((i - 1) * batchSize)
            .limit(batchSize)

        let documents = []

        for (const transaction of transactions) {
            const data = {
                _id: transaction._id,
                type: transaction.type,
                status: transaction.status,
                source: transaction.source,
                value: transaction.value,
                description: transaction.description,
            }

            documents.push(data)
        }

        await client.collections('transactions').documents().import(documents, { action: 'emplace' })
    }

    return { totalCount: count }
}

const getTypeSenseSchema = () => {
    return {
        name: 'transactions',
        enable_nested_fields: true,
        fields: [
            { name: '_id', type: 'string', facet: false, infix: false },
            { name: 'type', type: 'string', facet: false },
            { name: 'status', type: 'string', facet: false },
            { name: 'source', type: 'string', facet: false },
            { name: 'value', type: 'int64', facet: false },
            { name: 'description', type: 'string', facet: false, infix: true },
        ],
        default_sorting_field: 'createdAt',
    }
}

module.exports = {
    createTransaction,
    getUserTransaction,
    getBelongingInventory,
    updateTransaction,
    deleteTransaction,
    getTransactionByBelongingId,
    indexAllTransactions,
    searchTransactions,
}