const fs = require('fs-extra');
const path = require('path');
const UserError = require('vn-loopback/util/user-error');

module.exports = Self => {
    Self.remoteMethodCtx('download', {
        description: 'Download an invoice PDF',
        accessType: 'READ',
        accepts: [
            {
                arg: 'id',
                type: 'string',
                description: 'The invoice id',
                http: {source: 'path'}
            }
        ],
        returns: [
            {
                arg: 'body',
                type: 'file',
                root: true
            }, {
                arg: 'Content-Type',
                type: 'string',
                http: {target: 'header'}
            }, {
                arg: 'Content-Disposition',
                type: 'string',
                http: {target: 'header'}
            }
        ],
        http: {
            path: '/:id/download',
            verb: 'GET'
        }
    });

    Self.download = async function(ctx, id, options) {
        const models = Self.app.models;
        const myOptions = {};

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

        try {
            const invoiceOut = await models.InvoiceOut.findById(id, null, myOptions);

            const issued = invoiceOut.issued;
            const year = issued.getFullYear().toString();
            const month = (issued.getMonth() + 1).toString();
            const day = issued.getDate().toString();

            const container = await models.InvoiceContainer.container(year);
            const rootPath = container.client.root;
            const src = path.join(rootPath, year, month, day);
            const fileName = `${year}${invoiceOut.ref}.pdf`;
            const fileSrc = path.join(src, fileName);

            const file = {
                path: fileSrc,
                contentType: 'application/pdf',
                name: fileName
            };

            try {
                await fs.access(file.path);
            } catch (error) {
                await Self.createPdf(ctx, id);
            }

            const stream = fs.createReadStream(file.path);

            return [stream, file.contentType, `filename="${file.name}"`];
        } catch (error) {
            if (error.code === 'ENOENT')
                throw new UserError('The PDF document does not exists');

            throw error;
        }
    };
};