const axios = require('axios');
const uuid = require('uuid');
const fs = require('fs/promises');
const {createWriteStream} = require('fs');
const path = require('path');
const gm = require('gm');

module.exports = Self => {
    Self.remoteMethod('download', {
        description: 'Processes the image download queue',
        accessType: 'WRITE',
        http: {
            path: `/download`,
            verb: 'POST'
        }
    });

    Self.download = async() => {
        const models = Self.app.models;
        const tempContainer = await models.TempContainer.container('salix-image');
        const tempPath = path.join(tempContainer.client.root, tempContainer.name);
        const maxAttempts = 3;
        const collectionName = 'catalog';

        const tx = await Self.beginTransaction({});

        let tempFilePath;
        let queueRow;
        try {
            const myOptions = {transaction: tx};

            queueRow = await Self.findOne({
                fields: [
                    'id',
                    'itemFk',
                    'url',
                    'attempts'
                ],
                where: {
                    url: {neq: null},
                    attempts: {
                        lt: maxAttempts
                    }
                },
                order: 'priority, attempts, updated'
            }, myOptions);

            if (!queueRow) return;

            const collection = await models.ImageCollection.findOne({
                fields: [
                    'id',
                    'maxWidth',
                    'maxHeight',
                    'model',
                    'property'
                ],
                where: {name: collectionName},
                include: {
                    relation: 'sizes',
                    scope: {
                        fields: ['width', 'height', 'crop']
                    }
                }
            }, myOptions);

            const fileName = `${uuid.v4()}.png`;
            tempFilePath = path.join(tempPath, fileName);

            // Insert image row
            await models.Image.create({
                name: fileName,
                collectionFk: collectionName,
                updated: Date.vnNow()
            }, myOptions);

            // Update item
            const model = models[collection.model];
            if (!model)
                throw new Error('No matching model found');

            const item = await model.findById(queueRow.itemFk, null, myOptions);
            if (item) {
                await item.updateAttribute(
                    collection.property,
                    fileName,
                    myOptions
                );
            }

            // Download remote image
            const response = await axios.get(queueRow.url, {
                responseType: 'stream',
            });

            const writeStream = createWriteStream(tempFilePath);
            await new Promise((resolve, reject) => {
                writeStream.on('open', () => response.data.pipe(writeStream));
                writeStream.on('finish', () => resolve());
                writeStream.on('error', error => reject(error));
            });

            // Resize
            const container = await models.ImageContainer.container(collectionName);
            const rootPath = container.client.root;
            const collectionDir = path.join(rootPath, collectionName);

            // To max size
            const {maxWidth, maxHeight} = collection;
            const fullSizePath = path.join(collectionDir, 'full');
            const toFullSizePath = `${fullSizePath}/${fileName}`;

            await fs.mkdir(fullSizePath, {recursive: true});
            await new Promise((resolve, reject) => {
                gm(tempFilePath)
                    .resize(maxWidth, maxHeight, '>')
                    .setFormat('png')
                    .write(toFullSizePath, function(err) {
                        if (err) reject(err);
                        if (!err) resolve();
                    });
            });

            // To collection sizes
            for (const size of collection.sizes()) {
                const {width, height} = size;

                const sizePath = path.join(collectionDir, `${width}x${height}`);
                const toSizePath = `${sizePath}/${fileName}`;

                await fs.mkdir(sizePath, {recursive: true});
                await new Promise((resolve, reject) => {
                    const gmInstance = gm(tempFilePath);

                    if (size.crop) {
                        gmInstance
                            .resize(width, height, '^')
                            .gravity('Center')
                            .crop(width, height);
                    }

                    if (!size.crop)
                        gmInstance.resize(width, height, '>');

                    gmInstance
                        .setFormat('png')
                        .write(toSizePath, function(err) {
                            if (err) reject(err);
                            if (!err) resolve();
                        });
                });
            }

            if (await fs.stat(tempFilePath))
                await fs.unlink(tempFilePath);

            await queueRow.destroy(myOptions);

            // Restart queue
            Self.download();

            await tx.commit();
        } catch (error) {
            await tx.rollback();

            if (queueRow.attempts < maxAttempts) {
                await queueRow.updateAttributes({
                    error: error,
                    attempts: queueRow.attempts + 1,
                    updated: Date.vnNew()
                });
            }

            try {
                await fs.unlink(tempFilePath);
            } catch (error) {}

            Self.download();
        }
    };
};