import crypto from "crypto";
import util from "util";
import db from "./sql.mjs";

const scrypt = util.promisify(crypto.scrypt);

const epochs = [
  ["year", 31536000],
  ["month", 2592000],
  ["day", 86400],
  ["hour", 3600],
  ["minute", 60],
  ["second", 1]
];
const getDuration = timeAgoInSeconds => {
  for(let [name, seconds] of epochs) {
    const interval = ~~(timeAgoInSeconds / seconds);
    if(interval >= 1) return {
      interval: interval,
      epoch: name
    };
  }
};

export default new class {
  formatSize(size, i = ~~(Math.log(size) / Math.log(1024))) {
    return (size / Math.pow(1024, i)).toFixed(2) * 1 + " " + ["B", "kB", "MB", "GB", "TB"][i];
  };
  calcSpeed(b, s) {
    return (Math.round((b * 8 / s / 1e6) * 1e4) / 1e4);
  };
  timeAgo(date) {
    const { interval, epoch } = getDuration(~~((new Date() - new Date(date)) / 1e3));
    return `${interval} ${epoch}${interval === 1 ? "" : "s"} ago`;
  };
  md5(str) {
    return crypto.createHash('md5').update(str).digest("hex");
  };
  getMode(mode) {
    let tmp;
    switch(mode) {
      case 1: // nsfw
        tmp = "items.id in (select item_id from tags_assign where tag_id = 2 group by item_id)";
      break;
      case 2: // untagged
        tmp = "items.id not in (select item_id from tags_assign group by item_id)";
      break;
      case 3: // all
        tmp = "1 = 1";
      break;
      default: // sfw
        tmp = "items.id in (select item_id from tags_assign where tag_id = 1 group by item_id)";
      break;
    }
    return tmp;
  };
  createID() {
    return crypto.randomBytes(16).toString("hex") + Date.now().toString(24);
  };
  genLink(env) {
    const link = [];
    if(env.tag) link.push("tag", env.tag);
    if(env.user) link.push("user", env.user, env.type ?? 'f0cks');
    if(env.mime.length > 2) link.push(env.mime);
    if(env.page) link.push("p", env.page);
    return link.join("/");
  };
  parseTag(tag) {
    if(!tag)
      return null;
    return decodeURI(tag);
  }

  // async funcs
  async countf0cks() {
    const tagged = (await db`
      select count(*) as total
      from "items"
      where id in (select item_id from tags_assign group by item_id)
    `)[0].total;
    const untagged = (await db`
      select count(*) as total
      from "items"
      where id not in (select item_id from tags_assign group by item_id)
    `)[0].total;
    const sfw = (await db`
      select count(*) as total
      from "items"
      where id in (select item_id from tags_assign where tag_id = 1 group by item_id)
    `)[0].total;
    const nsfw = (await db`
      select count(*) as total
      from "items"
      where id in (select item_id from tags_assign where tag_id = 2 group by item_id)
    `)[0].total;
    return {
      tagged,
      untagged,
      total: +tagged + +untagged,
      sfw,
      nsfw
    };
  };
  async hash(str) {
    const salt = crypto.randomBytes(16).toString("hex");
    const derivedKey = await scrypt(str, salt, 64);
    return "$f0ck$" + salt + ":" + derivedKey.toString("hex");
  };
  async verify(str, hash) {
    const [ salt, key ] = hash.substring(6).split(":");
    const keyBuffer = Buffer.from(key, "hex");
    const derivedKey = await scrypt(str, salt, 64);
    return crypto.timingSafeEqual(keyBuffer, derivedKey);
  };
  async auth(req, res, next) {
    if(!req.session) {
      return res.reply({
        code: 401,
        body: "401 - Unauthorized"
      });
    }
    return next();
  };
  async getTags(itemid) {
    const tags = await db`
      select "tags".id, "tags".tag, "tags".normalized, "user".user
      from "tags_assign"
      left join "tags" on "tags".id = "tags_assign".tag_id
      left join "user" on "user".id = "tags_assign".user_id
      where "tags_assign".item_id = ${+itemid}
      order by "tags".id asc
    `;
    for(let t = 0; t < tags.length; t++) {
      if(tags[t].tag.startsWith(">"))
        tags[t].badge = "badge-greentext badge-light";
      else if(tags[t].normalized === "ukraine")
        tags[t].badge = "badge-ukraine badge-light";
      else if(/[а-яё]/.test(tags[t].normalized) || tags[t].normalized === "russia")
        tags[t].badge = "badge-russia badge-light";
      else if(tags[t].normalized === "german")
        tags[t].badge = "badge-german badge-light";
      else if(tags[t].normalized === "dutch")
        tags[t].badge = "badge-dutch badge-light";
      else if(tags[t].normalized === "sfw")
        tags[t].badge = "badge-success";
      else if(tags[t].normalized === "nsfw")
        tags[t].badge = "badge-danger";
      else
        tags[t].badge = "badge-light";
    }
    return tags;
  };

};