tdesktop/.github/workflows/user_agent_updater.yml

name: User-agent updater.

on:
  repository_dispatch:
    types: ["Restart user_agent_updater workflow."]
  schedule:
    # At 00:00 on day-of-month 1.
    - cron: '0 0 1 * *'
  pull_request_target:
    types: [closed]

jobs:
  User-agent:
    runs-on: ubuntu-latest

    env:
      codeFile: "Telegram/SourceFiles/mtproto/details/mtproto_domain_resolver.cpp"
      headBranchPrefix: "chrome_"
      baseBranch: "dev"
      isPull: "0"

    steps:
      - name: Set env.
        if: startsWith(github.event_name, 'pull_request')
        run: |
          echo "isPull=1" >> $GITHUB_ENV          

      - name: Clone.
        uses: actions/checkout@v2

      - name: Set up git.
        run: |
          token=${{ secrets.TOKEN_FOR_MASTER_UPDATER }}
          if [ -z "${token}" ]; then
              echo "Token is unset. Nothing to do."
              exit 1
          fi

          url=https://x-access-token:$token@github.com/$GITHUB_REPOSITORY

          git config --global user.email "action@github.com"
          git config --global user.name "GitHub Action"

          git remote set-url origin $url          

      - name: Delete branch.
        env:
          ref: ${{ github.event.pull_request.head.ref }}
        if: |
          env.isPull == '1'
            && github.event.action == 'closed'
            && startsWith(env.ref, env.headBranchPrefix)          
        run: |
          git push origin --delete $ref          

      - name: Write a new version of Google Chrome to the user-agent for DNS.
        if: env.isPull == '0'
        shell: python
        run: |
          import subprocess, os, re;

          regExpVersion = "[0-9]+.[0-9]+.[0-9]+.[0-9]+";
          chrome = "Chrome/";

          def newVersion():
            output = subprocess.check_output(["google-chrome", "--version"]);
            version = re.search(regExpVersion, output);
            if not version:
              print("Can't find a Chrome version.");
              exit();
            return version.group(0);

          newChromeVersion = newVersion();
          print(newChromeVersion);

          def setEnv(value):
            open(os.environ['GITHUB_ENV'], "a").write(value);

          def writeUserAgent():
            p = os.environ['codeFile'];
            w = open(p, "r");
            content = w.read();
            w.close();

            regExpChrome = chrome + regExpVersion;

            version = re.search(regExpChrome, content);
            if not version:
              print("Can't find an user-agent in the code.");
              exit();
            content = re.sub(regExpChrome, chrome + newChromeVersion, content);

            w = open(p, "w");
            w.write(content);

            setEnv("ChromeVersion=" + newChromeVersion);

          writeUserAgent();          

      - name: Push to a new branch.
        if: env.isPull == '0' && env.ChromeVersion != ''
        run: |
          git diff > git_diff.txt
          if [[ ! -s git_diff.txt ]]; then
            echo "Nothing to commit."
            exit 0
          fi

          git checkout -b $headBranchPrefix$ChromeVersion
          git add $codeFile
          git commit -m "Update User-Agent for DNS to Chrome $ChromeVersion."

          git push origin $headBranchPrefix$ChromeVersion
          echo "Done!"          

      - name: Close previous pull requests.
        if: env.isPull == '0' && env.ChromeVersion != ''
        uses: actions/github-script@0.4.0
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const common = {
              owner: context.repo.owner,
              repo: context.repo.repo,
            };

            github.pulls.list(common).then(response => {
              response.data.forEach((item, _) => {
                if (item.head.ref.startsWith(process.env.headBranchPrefix)) {
                  console.log(`Close ${item.title} #${item.number}.`);
                  github.pulls.update({
                    pull_number: item.number,
                    state: "closed",
                    ...common
                  });
                }
              });
            });            

      - name: Create a new pull request.
        if: env.isPull == '0' && env.ChromeVersion != ''
        uses: actions/github-script@0.4.0
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const version = process.env.ChromeVersion;
            const title = `Update User-Agent for DNS to Chrome ${version}.`;

            github.pulls.create({
              title: title,
              body: "",
              head: `${process.env.headBranchPrefix}${version}`,
              base: process.env.baseBranch,
              owner: context.repo.owner,
              repo: context.repo.repo,
            });