pr-issue-check.yml

name: PR Issue Link & Assignment Check

on:
  pull_request_target:
    types: [opened, edited, reopened, synchronize]
  workflow_dispatch:
    inputs:
      pr_number:
        description: 'PR Number to check (optional. If empty, checks all open PRs)'
        required: false
        type: string

permissions:
  issues: write
  pull-requests: write

jobs:
  check-issue-link:
    name: Verify PR is Linked to an Assigned Issue
    runs-on: ubuntu-latest

    steps:
      - name: Check linked issue and assignment
        uses: actions/github-script@v7
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const { owner, repo } = context.repo;
            let pullRequests = [];

            const prInput = context.payload.inputs?.pr_number;
            if (prInput) {
              try {
                const { data: pr } = await github.rest.pulls.get({
                  owner, repo, pull_number: parseInt(prInput, 10),
                });
                pullRequests.push(pr);
              } catch (err) {
                core.setFailed(`Failed to fetch PR #${prInput}: ${err.message}`);
                return;
              }
            } else if (context.eventName === 'workflow_dispatch') {
              const { data: prs } = await github.rest.pulls.list({
                owner, repo, state: 'open', per_page: 100,
              });
              pullRequests = prs;
              core.info(`Fetched ${prs.length} open PR(s) to verify.`);
            } else {
              pullRequests.push(context.payload.pull_request);
            }

            const SENTINEL_NO_LINK  = '<!-- pr-issue-check: no-link -->';
            const SENTINEL_NOT_ASSIGNED = '<!-- pr-issue-check: not-assigned -->';

            // Helper: fetch existing bot comments on this PR
            async function getBotComments(number) {
              const { data: comments } = await github.rest.issues.listComments({
                owner, repo, issue_number: number, per_page: 100,
              });
              return comments.filter(c => c.user?.login === 'github-actions[bot]');
            }

            // Helper: check whether we already posted a specific sentinel
            async function alreadyPosted(number, sentinel) {
              const comments = await getBotComments(number);
              return comments.some(c => c.body?.includes(sentinel));
            }

            for (const pr of pullRequests) {
              const prNumber = pr.number;
              const prAuthor = pr.user.login;
              const prBody = pr.body ?? '';

              core.info(`Checking PR #${prNumber} by @${prAuthor}...`);

              // ----------------------------------------------------------------
              // 1. Parse a linked issue number from the PR body.
              //    Matches: closes/fixes/resolves #123  (case-insensitive)
              // ----------------------------------------------------------------
              const LINK_REGEX =
                /(?:close[sd]?|fix(?:e[sd])?|resolve[sd]?)\s+#(\d+)/gi;

              const issueNumbers = [];
              let match;
              while ((match = LINK_REGEX.exec(prBody)) !== null) {
                issueNumbers.push(parseInt(match[1], 10));
              }

              // ----------------------------------------------------------------
              // 2. NO linked issue found → warn, close the PR, and stop
              // ----------------------------------------------------------------
              if (issueNumbers.length === 0) {
                const already = await alreadyPosted(prNumber, SENTINEL_NO_LINK);
                if (!already) {
                  await github.rest.issues.createComment({
                    owner, repo, issue_number: prNumber,
                    body: `👋 Hey @${prAuthor}! Thanks for your contribution! 🎉

            ${SENTINEL_NO_LINK}
            Unfortunately, this PR has been **automatically closed** because it is not linked to any open issue.

            To resolve this, please do the following:
            1. **Link a valid open issue** by editing your PR description to include a closing keyword (e.g., \`Fixes #<issue-number>\`).
            2. **Reopen this PR** once the link is added.

            > 💡 You can link multiple issues if needed (e.g. \`Fixes #12, Closes #34\`).
            > If you're working on something that doesn't have an issue yet, please [open one first](https://github.com/${owner}/${repo}/issues/new/choose) and then link it here.

            We look forward to reviewing your PR once an issue is linked! 🚀`,
                  });
                }

                // Close the PR
                await github.rest.pulls.update({
                  owner, repo, pull_number: prNumber, state: 'closed',
                });

                continue; // check next PR
              }

              // ----------------------------------------------------------------
              // 3. Linked issue(s) found — check assignment for each one.
              //    We validate all linked issues and act on the first violation.
              // ----------------------------------------------------------------
              let prViolation = false;
              for (const issueNumber of issueNumbers) {
                let issue;
                try {
                  const { data } = await github.rest.issues.get({
                    owner, repo, issue_number: issueNumber,
                  });
                  issue = data;
                } catch (err) {
                  if (err.status === 404) {
                    // Linked issue doesn't exist — treat same as no-link
                    const already = await alreadyPosted(prNumber, SENTINEL_NO_LINK);
                    if (!already) {
                      await github.rest.issues.createComment({
                        owner, repo, issue_number: prNumber,
                        body: `👋 Hey @${prAuthor}!

            ${SENTINEL_NO_LINK}
            Unfortunately, this PR has been **automatically closed** because the referenced issue **#${issueNumber}** does not exist (or was deleted).

            To resolve this, please do the following:
            1. **Link a valid open issue** by editing your PR description to include a closing keyword (e.g., \`Fixes #<issue-number>\`).
            2. **Reopen this PR** once the link is added.

            Please link a valid open issue before this PR can be reviewed. 🙏`,
                      });
                    }

                    // Close the PR
                    await github.rest.pulls.update({
                      owner, repo, pull_number: prNumber, state: 'closed',
                    });

                    prViolation = true;
                    break;
                  }
                  throw err;
                }

                // Is the PR author assigned to this issue?
                const assignees = issue.assignees.map(a => a.login.toLowerCase());
                const isAssigned = assignees.includes(prAuthor.toLowerCase());

                if (!isAssigned) {
                  // Close the PR with a polite explanation
                  const already = await alreadyPosted(prNumber, SENTINEL_NOT_ASSIGNED);
                  if (!already) {
                    await github.rest.issues.createComment({
                      owner, repo, issue_number: prNumber,
                      body: `👋 Hey @${prAuthor}! Thanks for your interest in contributing to CommitPulse! 🙏

            ${SENTINEL_NOT_ASSIGNED}
            Unfortunately, this PR has been **automatically closed** because you are not assigned to the linked issue **[#${issueNumber} — ${issue.title}](${issue.html_url})**.

            To avoid this in the future, please follow these steps:

            1. **Claim the issue** — Comment \`/claim\` on [#${issueNumber}](${issue.html_url}) if you are the issue author, or ask a maintainer to \`/assign\` you.
            2. **Wait for confirmation** — The bot will confirm your assignment with a ✅ reply.
            3. **Then open your PR** — Link the issue with \`Fixes #${issueNumber}\` in your description.

            > 💡 You can be assigned to up to **5** open issues at a time. Check your current assignments before claiming a new one.

            We look forward to your contribution once you're assigned! 🚀`,
                    });
                  }

                  // Close the PR
                  await github.rest.pulls.update({
                    owner, repo, pull_number: prNumber, state: 'closed',
                  });

                  prViolation = true;
                  break; // stop after first violation
                }
              }

              if (!prViolation) {
                core.info(`✅ PR #${prNumber} by @${prAuthor} is properly linked and assigned.`);
              }
            }