const {MessageFlags} = require("@projectdysnomia/dysnomia").Constants;

const events = require("../lib/events.js");
const {hasFlag} = require("../lib/guildSettings.js");
const REGEX_GITHUB =
  /(?:\s|^)(\|\|\s*)?https?:\/\/(www\.)?github\.com\/[a-z0-9-]+\/[a-z0-9-]+\/blob\/([a-z0-9-_.#/]*)(\s*\|\|)?/gi;
const REGEX_GITLAB =
  /(?:\s|^)(\|\|\s*)?https?:\/\/.+?\/[a-z0-9-]+\/[a-z0-9-]+\/-\/blob\/([a-z0-9-_.#/]*)(\s*\|\|)?/gi;
const REGEX_GITEA =
  /(?:\s|^)(\|\|\s*)?https?:\/\/.+?\/[a-z0-9-]+\/[a-z0-9-]+\/src\/branch\/([a-z0-9-_.#/]*)(\s*\|\|)?/gi;
const REGEX_SPOILER = /(?:\s|^)\|\|([\s\S]+?)\|\|/;

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"), "");
}

async function processFile(link, spoiler = false) {
  link = link.replaceAll("||", "").trim();
  const res = await fetch(link);
  if (!res.ok) return "";
  if (!res.headers.get("Content-Type").startsWith("text/plain")) return "";
  const file = await 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.lastIndexOf(".") == -1
      ? ""
      : fileName.substring(fileName.lastIndexOf(".") + 1);

  if (fileType == "md") return "";

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

  if (lineStr) {
    const [start, end] = lineStr.match(/\d+/g);
    if (!end) {
      startLine = endLine = start;
    } else {
      startLine = start;
      endLine = end;
    }
  } else {
    entireFile = true;
    startLine = 0;
    endLine = lines.length;
  }

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

  if (entireFile && lines.length > 20) return "";

  let targetLines = (
    entireFile ? lines : lines.slice(startLine - 1, endLine)
  ).join("\n");

  let warning = "";
  if (spoiler && targetLines.includes("||")) {
    targetLines = targetLines.replaceAll("||", "|\u200b|");
    warning = " - :warning: Zero width spaces present";
  }
  if (targetLines.includes("``")) {
    targetLines = targetLines.replaceAll("``", "`\u200b`");
    warning = " - :warning: Zero width spaces present";
  }

  return `**${fileName}: **${whichLines}${warning}\n${
    spoiler ? "||" : ""
  }\`\`\`${fileType}\n${unindent(targetLines)}\n\`\`\`${spoiler ? "||" : ""}`;
}

events.add("messageCreate", "codePreviews", async function (msg) {
  if (msg.author.id == hf.bot.user.id) return;
  if (!msg.guildID) return;
  if (!(await hasFlag(msg.guildID, "codePreviews"))) return;

  const files = [];

  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 spoiler = REGEX_SPOILER.test(link);
      files.push(await processFile(link.replace("/blob/", "/raw/"), spoiler));
    }
  }

  if (gitlabLinks?.length) {
    for (const link of gitlabLinks) {
      const spoiler = REGEX_SPOILER.test(link);
      files.push(await processFile(link.replace("/blob/", "/raw/"), spoiler));
    }
  }

  if (giteaLinks?.length) {
    for (const link of giteaLinks) {
      const spoiler = REGEX_SPOILER.test(link);
      files.push(await processFile(link.replace("/src/", "/raw/"), spoiler));
    }
  }

  let out = "";
  const allFiles = files.join("\n").trim();
  if (allFiles !== "" && allFiles.length <= 2000) {
    await msg.edit({flags: MessageFlags.SUPPRESS_EMBEDS}).catch(() => {});
  }
  for (let i = 0; i < files.length; i++) {
    const file = files[i];
    if (file === "") continue;

    if (out.length + file.length > 2000) {
      await msg.channel.createMessage({
        content: out,
        allowedMentions: {
          repliedUser: false,
        },
        messageReference: {
          messageID: msg.id,
        },
      });

      out = file;
    } else {
      out += "\n" + file;
      out = out.trim();
    }

    if (i == files.length - 1 && out.length <= 2000) {
      await msg.channel.createMessage({
        content: out,
        allowedMentions: {
          repliedUser: false,
        },
        messageReference: {
          messageID: msg.id,
        },
      });
    }
  }
});

// TODO: maybe all command outputs should have this ability
events.add(
  "messageReactionAdd",
  "codePreviews",
  async function (msg, reaction, reactor) {
    if (!msg.guildID) return;
    if (!(await hasFlag(msg.guildID, "codePreviews"))) return;
    if (reaction.name != "\u274c") return;

    let channel = msg.channel;
    if (!channel.name) {
      channel = hf.bot.getChannel(channel.id);
    }
    if (!msg.messageReference) {
      msg = await channel.getMessage(msg.id);
    }

    if (!msg.messageReference) return;

    const ref = await channel.getMessage(msg.messageReference.messageID);
    if (!ref) return;
    if (
      ref.author.id != reactor.id &&
      !channel.permissionsOf(reactor.id).has("manageMessages")
    )
      return;
    if (
      !REGEX_GITHUB.test(ref.content) &&
      !REGEX_GITLAB.test(ref.content) &&
      !REGEX_GITEA.test(ref.content)
    )
      return;

    await msg.delete("Author requested code preview deletion");
  }
);