'use strict';

const config = require('config');
const bhttp = require('bhttp');
const blake2 = require('blake2');
const phash = require('sharp-phash');
// const phashDistance = require('sharp-phash/distance');

const logger = require('../logger')(__filename);
const limiter = require('../limiter').items;

async function fetchItem(url, attempt, context) {
    async function retry(error) {
        logger.warn(`Failed to fetch '${url}', ${attempt < config.fetch.retries ? 'retrying' : 'giving up'}: ${error.message} (${context.post ? context.post.permalink : 'no post'})`);

        if (attempt < config.fetch.retries) {
            return fetchItem(url, attempt + 1, context);
        }

        return null;
    }

    try {
        // throw new Error('Failed it!');
        const res = await limiter.schedule(async () => bhttp.get(url, { headers: context.headers }));

        if (res.statusCode !== 200) {
            throw new Error(`Response not OK for ${url} (${res.statusCode})`);
        }

        if (!Buffer.isBuffer(res.body)) {
            throw new Error(`Unexpected response for ${url} (${res.statusCode}): ${res.body}`);
        }

        logger.debug(`Fetched '${context.host?.url || url}' (${context.post?.permalink || 'no post'})`);

        const hash = blake2.createHash('blake2b', { digestLength: 24 });
        hash.update(res.body);
        const contentHash = hash.digest('hex');

        const phashResult = context.item?.type?.includes('image/')
            ? await phash(res.body)
            : null;

        return {
            buffer: res.body,
            hash: contentHash,
            phash: phashResult,
        };
    } catch (error) {
        return retry(error);
    }
}

module.exports = fetchItem;