'use strict';

const config = require('config');
const Promise = require('bluebird');
const fs = require('fs-extra');
const csvParse = Promise.promisify(require('csv').parse);

const getArchivePostIds = require('../archives/getArchivePostIds.js');
const curateUser = require('../curate/user.js');
const interpolate = require('../interpolate.js');

async function getUser(username, reddit) {
    try {
        const user = await reddit.getUser(username).fetch();

        return curateUser(user);
    } catch (error) {
        console.log('\x1b[31m%s\x1b[0m', `Failed to fetch reddit user '${username}': ${error.message} (https://reddit.com/user/${username})`);

        return {
            name: username,
            fallback: true,
        };
    }
}

async function getPosts(username, reddit, args) {
    try {
        const user = await reddit.getUser(username).getSubmissions({
            sort: args.sort,
            limit: Infinity,
        });

        return user;
    } catch (error) {
        console.log('\x1b[31m%s\x1b[0m', `Failed to fetch posts from reddit user '${username}': ${error.message} (https://reddit.com/user/${username})`);

        return [];
    }
}

async function getArchivedPosts(username, posts, reddit) {
    const postIds = await getArchivePostIds(username, posts.map(post => post.id));

    return Promise.all(postIds.map(postId => reddit.getSubmission(postId).fetch()));
}

async function getIndexedPosts(user) {
    const indexFilePath = interpolate(config.library.index.file, user, null, null, false);

    try {
        const indexFile = await fs.readFile(indexFilePath, 'utf8');

        return await csvParse(indexFile, { delimiter: '\t', columns: true, cast: true });
    } catch (error) {
        console.log('\x1b[33m%s\x1b[0m', `Could not load index file for '${user.name}' at '${indexFilePath}': ${error}`);

        return [];
    }
}

function getUserPostsWrap(reddit, args) {
    return async function getUserPosts(usernames) {
        const users = await Promise.map(usernames, async (username) => {
            const [user, posts] = await Promise.all([
                getUser(username, reddit),
                getPosts(username, reddit, args),
            ]);

            const indexed = await getIndexedPosts(user);

            if (args.archives) {
                posts.push(...await getArchivedPosts(username, posts, reddit));
            }

            if (posts.length) {
                return { ...user, posts, indexed };
            }

            return null;
        });

        return users.reduce((userPosts, user) => (user ? { ...userPosts, [user.name]: user } : userPosts), {});
    };
}

module.exports = getUserPostsWrap;