'use strict';

const config = require('config');
const Promise = require('bluebird');
const path = require('path');
const fs = require('fs-extra');
const bhttp = require('bhttp');
const mime = require('mime');
const sharp = require('sharp');
const blake2 = require('blake2');

const knex = require('./knex');

function getHash(buffer) {
    const hash = blake2.createHash('blake2b', { digestLength: 24 });

    hash.update(buffer);

    return hash.digest('hex');
}

function pluckPhotos(photos, specifiedLimit) {
    const limit = specifiedLimit || config.media.limit;

    if (photos.length <= limit) {
        return photos;
    }

    const plucked = [1]
        .concat(
            Array.from({ length: limit - 1 }, (value, index) => Math.round((index + 1) * (photos.length / (limit - 1)))),
        );

    return Array.from(new Set(plucked)).map(photoIndex => photos[photoIndex - 1]); // remove duplicates, may happen when photo total and photo limit are close
}

async function createThumbnail(buffer) {
    return sharp(buffer)
        .resize({
            height: config.media.thumbnailSize,
            withoutEnlargement: true,
        })
        .toBuffer();
}

async function createMediaDirectory(domain, subpath) {
    const filepath = path.join(config.media.path, domain, subpath);

    await fs.mkdir(filepath, { recursive: true });
    return filepath;
}

function curatePhotoEntries(files, domain = 'releases', role = 'photo', targetId) {
    return files.map((file, index) => ({
        path: file.filepath,
        thumbnail: file.thumbpath,
        mime: file.mimetype,
        hash: file.hash,
        source: file.source,
        index,
        domain,
        target_id: targetId,
        role: file.role || role,
    }));
}

// before fetching
async function filterSourceDuplicates(photos, domains = ['releases'], roles = ['photo'], identifier) {
    const photoSourceEntries = await knex('media')
        .whereIn('source', photos.flat())
        .whereIn('domain', domains)
        .whereIn('role', roles); // accept string argument

    const photoSources = new Set(photoSourceEntries.map(photo => photo.source));
    const newPhotos = photos.filter(source => (Array.isArray(source) // fallbacks provided?
        ? !source.some(sourceX => photoSources.has(sourceX)) // ensure none of the sources match
        : !photoSources.has(source)));

    if (photoSourceEntries.length > 0) {
        console.log(`Ignoring ${photoSourceEntries.length} ${roles} items already present by source for ${identifier}`);
    }

    return newPhotos;
}

// after fetching
async function filterHashDuplicates(files, domains = ['releases'], roles = ['photo'], identifier) {
    const photoHashEntries = await knex('media')
        .whereIn('hash', files.map(file => file.hash))
        .whereIn('domain', [].concat(domains))
        .whereIn('role', [].concat(roles)); // accept string argument

    const photoHashes = new Set(photoHashEntries.map(entry => entry.hash));

    if (photoHashEntries.length > 0) {
        console.log(`Ignoring ${photoHashEntries.length} ${roles} items already present by hash for ${identifier}`);
    }

    return files.filter(file => file && !photoHashes.has(file.hash));
}

async function fetchPhoto(photoUrl, index, identifier, attempt = 1) {
    if (Array.isArray(photoUrl)) {
        return photoUrl.reduce(async (outcome, url) => outcome.catch(async () => {
            const photo = await fetchPhoto(url, index, identifier);

            if (photo) {
                return photo;
            }

            throw new Error('Photo not available');
        }), Promise.reject(new Error()));
    }

    try {
        const { pathname } = new URL(photoUrl);
        const mimetype = mime.getType(pathname);

        const res = await bhttp.get(photoUrl);

        if (res.statusCode === 200) {
            const extension = mime.getExtension(mimetype);
            const hash = getHash(res.body);

            return {
                photo: res.body,
                mimetype,
                extension,
                hash,
                source: photoUrl,
            };
        }

        throw new Error(`Response ${res.statusCode} not OK`);
    } catch (error) {
        console.warn(`Failed attempt ${attempt}/3 to fetch photo ${index + 1} for ${identifier} (${photoUrl}): ${error}`);

        if (attempt < 3) {
            await Promise.delay(1000);
            return fetchPhoto(photoUrl, index, identifier, attempt + 1);
        }

        return null;
    }
}

async function savePhotos(files, {
    domain = 'releases',
    subpath,
    role = 'photo',
    naming = 'index',
}) {
    return Promise.map(files, async (file, index) => {
        const timestamp = new Date().getTime();
        const thumbnail = await createThumbnail(file.photo);

        const filename = naming === 'index'
            ? `${file.role || role}-${index + 1}`
            : `${timestamp + index}`;

        const filepath = path.join(domain, subpath, `${filename}.${file.extension}`);
        const thumbpath = path.join(domain, subpath, `${filename}_thumb.${file.extension}`);

        await Promise.all([
            fs.writeFile(path.join(config.media.path, filepath), file.photo),
            fs.writeFile(path.join(config.media.path, thumbpath), thumbnail),
        ]);

        return {
            ...file,
            thumbnail,
            filepath,
            thumbpath,
        };
    });
}

async function storePhotos(photos, {
    domain = 'releases',
    role = 'photo',
    naming = 'index',
    targetId,
    subpath,
    primaryRole, // role to assign to first photo if not already in database, used mainly for avatars
}, identifier) {
    if (!photos || photos.length === 0) {
        console.warn(`No ${role}s available for ${identifier}`);
        return;
    }

    const pluckedPhotos = pluckPhotos(photos);
    const roles = primaryRole ? [role, primaryRole] : [role];

    const newPhotos = await filterSourceDuplicates(pluckedPhotos, [domain], roles, identifier);

    if (newPhotos.length === 0) return;

    console.log(`Fetching ${newPhotos.length} ${role}s for ${identifier}`);

    const metaFiles = await Promise.map(newPhotos, async (photoUrl, index) => fetchPhoto(photoUrl, index, identifier), {
        concurrency: 10,
    }).filter(photo => photo);

    const [uniquePhotos, primaryPhoto] = await Promise.all([
        filterHashDuplicates(metaFiles, [domain], roles, identifier),
        primaryRole
            ? await knex('media')
                .where('domain', domain)
                .where('target_id', targetId)
                .where('role', primaryRole)
                .first()
            : null,
    ]);

    if (primaryRole && !primaryPhoto) {
        console.log(`Setting first photo as ${primaryRole} for ${identifier}`);

        uniquePhotos[0].role = primaryRole;
    }

    const savedPhotos = await savePhotos(uniquePhotos, {
        domain,
        role,
        targetId,
        subpath,
        naming,
    });

    const curatedPhotoEntries = curatePhotoEntries(savedPhotos, domain, role, targetId);

    await knex('media').insert(curatedPhotoEntries);

    console.log(`Stored ${newPhotos.length} ${role}s for ${identifier}`);
}

async function storeTrailer(trailers, {
    domain = 'releases',
    role = 'trailer',
    targetId,
    subpath,
}, identifier) {
    // support scrapers supplying multiple qualities
    const trailer = Array.isArray(trailers)
        ? trailers.find(trailerX => [1080, 720].includes(trailerX.quality)) || trailers[0]
        : trailers;

    if (!trailer || !trailer.src) {
        console.warn(`No trailer available for ${identifier}`);
        return;
    }

    console.log(`Storing trailer for ${identifier}`);

    const { pathname } = new URL(trailer.src);
    const mimetype = trailer.type || mime.getType(pathname);

    const res = await bhttp.get(trailer.src);
    const filepath = path.join('releases', subpath, `trailer${trailer.quality ? `_${trailer.quality}` : ''}.${mime.getExtension(mimetype)}`);

    await Promise.all([
        fs.writeFile(path.join(config.media.path, filepath), res.body),
        knex('media').insert({
            path: filepath,
            mime: mimetype,
            source: trailer.src,
            domain,
            target_id: targetId,
            role,
            quality: trailer.quality || null,
        }),
    ]);
}

async function findAvatar(actorId, domain = 'actors') {
    return knex('media')
        .where('domain', domain)
        .where('target_id', actorId)
        .where('role', 'avatar');
}

module.exports = {
    createMediaDirectory,
    findAvatar,
    storePhotos,
    storeTrailer,
};