let UserError = require('vn-loopback/util/user-error');

module.exports = Self => {
    Self.remoteMethod('clone', {
        description: 'clone item',
        accessType: 'WRITE',
        accepts: [{
            arg: 'id',
            type: 'number',
            required: true,
            description: 'origin itemId',
            http: {source: 'path'}
        }],
        returns: {
            type: 'object',
            description: 'new cloned itemId',
            root: true,
        },
        http: {
            path: `/:id/clone`,
            verb: 'post'
        }
    });

    Self.clone = async(itemId, options) => {
        let tx;
        const myOptions = {};

        if (typeof options == 'object')
            Object.assign(myOptions, options);

        if (!myOptions.transaction) {
            tx = await Self.beginTransaction({});
            myOptions.transaction = tx;
        }

        try {
            const origin = await Self.findById(itemId, null, myOptions);

            if (!origin)
                throw new UserError(`This item doesn't exists`);

            origin.itemTag = undefined;
            origin.description = undefined;
            origin.comment = undefined;
            origin.size = undefined;

            const newItem = await Self.create(origin, myOptions);

            await cloneTaxes(origin.id, newItem.id, myOptions);
            await cloneBotanical(origin.id, newItem.id, myOptions);
            await cloneTags(origin.id, newItem.id, myOptions);

            if (tx) await tx.commit();

            return newItem;
        } catch (e) {
            if (tx) await tx.rollback();
            throw e;
        }
    };

    /**
     * Clone original taxes to new item
     * @param {Integer} originalId - Original item id
     * @param {Integer} newId - New item id
     * @param {Object} options - Transaction options
     */
    async function cloneTaxes(originalId, newId, options) {
        const models = Self.app.models;
        const originalTaxes = await models.ItemTaxCountry.find({
            where: {itemFk: originalId},
            fields: ['countryFk', 'taxClassFk']
        }, options);

        const promises = [];
        for (tax of originalTaxes) {
            tax.itemFk = newId;

            const newTax = models.ItemTaxCountry.upsertWithWhere({
                itemFk: newId,
                countryFk: tax.countryFk,
            }, tax, options);

            promises.push(newTax);
        }

        await Promise.all(promises);
    }

    /**
     * Clone original botanical to new item
     * @param {Integer} originalId - Original item id
     * @param {Integer} newId - New item id
     * @param {Object} options - Transaction options
     */
    async function cloneBotanical(originalId, newId, options) {
        const models = Self.app.models;
        const botanical = await models.ItemBotanical.findOne({
            where: {itemFk: originalId},
            fields: ['genusFk', 'specieFk']
        }, options);

        if (botanical) {
            botanical.itemFk = newId;

            await models.ItemBotanical.create(botanical, options);
        }
    }

    /**
     * Clone original item tags to new item
     * @param {Integer} originalId - Original item id
     * @param {Integer} newId - New item id
     * @param {Object} options - Transaction options
     */
    async function cloneTags(originalId, newId, options) {
        const models = Self.app.models;
        const originalTags = await models.ItemTag.find({
            where: {
                itemFk: originalId
            },
            fields: ['tagFk', 'value', 'priority']
        }, options);

        const promises = [];
        for (tag of originalTags) {
            tag.itemFk = newId;
            const newItemTag = models.ItemTag.create(tag, options);

            promises.push(newItemTag);
        }

        await Promise.all(promises);
    }
};