const events = require("../lib/events.js");
const {hasFlag} = require("../lib/guildSettings.js");
const fetch = require("node-fetch");

const REGEX_GITHUB =
  /(?:\s|^)https?:\/\/(www\.)?github\.com\/.+?\/.+?\/blob\/([a-zA-Z0-9-_.#/]*)/g;
const REGEX_GITLAB =
  /(?:\s|^)https?:\/\/(www\.)?gitlab\.com\/.+?\/.+?\/-\/blob\/([a-zA-Z0-9-_.#/]*)/g;
const REGEX_GITEA =
  /(?:\s|^)https?:\/\/.+?\/.+?\/.+?\/src\/branch\/([a-zA-Z0-9-_.#/]*)/g;

function unindent(str) {
  str = str.replace(/\t/g, "    ");
  const minIndent =
    str
      .match(/^ *(?=\S)/gm)
      ?.reduce((prev, curr) => Math.min(prev, curr.length), Infinity) ?? 0;
  if (!minIndent) return str;
  return str.replace(new RegExp(`^ {${minIndent}}`, "gm"), "");
}

events.add("messageCreate", "codePreviews", async function (msg) {
  if (!msg.guildID) return;
  if (!hasFlag(msg.guildID, "codePreviews")) return;

  let out = "";

  const githubLinks = msg.content.match(REGEX_GITHUB);
  const gitlabLinks = msg.content.match(REGEX_GITLAB);
  const giteaLinks = msg.content.match(REGEX_GITEA);

  if (githubLinks?.length) {
    for (const link of githubLinks) {
      const rawLink = link.replace("/blob/", "/raw/");
      const file = await fetch(rawLink).then((res) => res.text());
      const lines = file.replace(/\r/g, "").split("\n");

      const fileName = link.substring(
        link.lastIndexOf("/") + 1,
        link.indexOf("#") == -1 ? link.length : link.indexOf("#")
      );
      const fileType =
        fileName.indexOf(".") == -1
          ? ""
          : fileName.substring(fileName.indexOf(".") + 1);

      const lineStr = link.match(/#L\d+?(-L\d+?)?/)?.[0];
      let startLine, endLine;
      let entireFile = false;

      if (lineStr) {
        let [start, end] = link.match(/L\d+?/g);
        start = parseInt(start.replace("L", ""));
        if (!end) {
          startLine = endLine = start;
        } else {
          end = parseInt(end.replace("L", ""));
          startLine = start;
          endLine = end;
        }
      } else {
        entireFile = true;
        startLine = 1;
        endLine = lines.length;
      }

      const whichLines = entireFile
        ? ""
        : startLine == endLine
        ? "Line " + startLine
        : "Lines " + startLine + "-" + endLine;

      startLine--;
      endLine--;

      const targetLines = (
        entireFile ? lines : lines.slice(startLine, endLine)
      ).join("\n");

      out +=
        "**" +
        fileName +
        ": **" +
        whichLines +
        "\n```" +
        fileType +
        "\n" +
        unindent(targetLines) +
        "\n```\n";
    }
  }

  if (out !== "")
    msg.channel.createMessage({
      content: out,
      allowedMentions: {
        repliedUser: false,
      },
      messageReference: {
        messageID: msg.id,
      },
    });
});