name: DCO Advisor Bot

on:
  pull_request_target:
    types: [opened, reopened, synchronize]

permissions:
  pull-requests: write
  issues: write

jobs:
  dco_advisor:
    runs-on: ubuntu-latest
    steps:
      - name: Handle DCO check result
        uses: actions/github-script@v7
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const pr = context.payload.pull_request || context.payload.check_run?.pull_requests?.[0];
            if (!pr) return;

            const prNumber = pr.number;
            const baseRef = pr.base.ref;
            const headSha =
              context.payload.check_run?.head_sha ||
              pr.head?.sha;
            const username = pr.user.login;

            console.log("HEAD SHA:", headSha);

            const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));

            // Poll until DCO check has a conclusion (max 6 attempts, 30s)
            let dcoCheck = null;
            for (let attempt = 0; attempt < 6; attempt++) {
              const { data: checks } = await github.rest.checks.listForRef({
                owner: context.repo.owner,
                repo: context.repo.repo,
                ref: headSha
              });

              
              console.log("All check runs:");
                checks.check_runs.forEach(run => {
                console.log(`- ${run.name} (${run.status}/${run.conclusion}) @ ${run.head_sha}`);
              });

              dcoCheck = checks.check_runs.find(run =>
                run.name.toLowerCase().includes("dco") &&
              !run.name.toLowerCase().includes("dco_advisor") &&
                run.head_sha === headSha
              );


              if (dcoCheck?.conclusion) break;
              console.log(`Waiting for DCO check... (${attempt + 1})`);
              await sleep(5000); // wait 5 seconds
            }

            if (!dcoCheck || !dcoCheck.conclusion) {
              console.log("DCO check did not complete in time.");
              return;
            }

            const isFailure = ["failure", "action_required"].includes(dcoCheck.conclusion);
            console.log(`DCO check conclusion for ${headSha}: ${dcoCheck.conclusion} (treated as ${isFailure ? "failure" : "success"})`);

            // Parse DCO output for commit SHAs and author
            let badCommits = [];
            let authorName = "";
            let authorEmail = "";
            let moreInfo = `More info: [DCO check report](${dcoCheck?.html_url})`;

            if (isFailure) {
                const { data: commits } = await github.rest.pulls.listCommits({
                    owner: context.repo.owner,
                    repo: context.repo.repo,
                    pull_number: prNumber,
                });

                for (const commit of commits) {
                    const commitMessage = commit.commit.message;
                    const signoffMatch = commitMessage.match(/^Signed-off-by:\s+.+<.+>$/m);
                    if (!signoffMatch) {
                        console.log(`Bad commit found ${commit.sha}`)
                        badCommits.push({
                        sha: commit.sha,
                        authorName: commit.commit.author.name,
                        authorEmail: commit.commit.author.email,
                        });
                    }
                }            
            }

            // If multiple authors are present, you could adapt the message accordingly
            // For now, we'll just use the first one
            if (badCommits.length > 0) {
            authorName = badCommits[0].authorName;
            authorEmail = badCommits[0].authorEmail;
            }

            // Generate remediation commit message if needed
            let remediationSnippet = "";
            if (badCommits.length && authorEmail) {
              remediationSnippet = `git commit --allow-empty -s -m "DCO Remediation Commit for ${authorName} <${authorEmail}>\n\n` +
                badCommits.map(c => `I, ${c.authorName} <${c.authorEmail}>, hereby add my Signed-off-by to this commit: ${c.sha}`).join('\n') +
                `"`;
            } else {
              remediationSnippet = "# Unable to auto-generate remediation message. Please check the DCO check details.";
            }

            // Build comment
            const commentHeader = '<!-- dco-advice-bot -->';
            let body = "";

            if (isFailure) {
              body = [
                commentHeader,
                '❌ **DCO Check Failed**',
                '',
                `Hi @${username}, your pull request has failed the Developer Certificate of Origin (DCO) check.`,
                '',
                'This repository supports **remediation commits**, so you can fix this without rewriting history — but you must follow the required message format.',
                '',
                '---',
                '',
                '### 🛠 Quick Fix: Add a remediation commit',
                'Run this command:',
                '',
                '```bash',
                remediationSnippet,
                'git push',
                '```',
                '',
                '---',
                '',
                '<details>',
                '<summary>🔧 Advanced: Sign off each commit directly</summary>',
                '',
                '**For the latest commit:**',
                '```bash',
                'git commit --amend --signoff',
                'git push --force-with-lease',
                '```',
                '',
                '**For multiple commits:**',
                '```bash',
                `git rebase --signoff origin/${baseRef}`,
                'git push --force-with-lease',
                '```',
                '',
                '</details>',
                '',
                moreInfo
              ].join('\n');
            } else {
              body = [
                commentHeader,
                '✅ **DCO Check Passed**',
                '',
                `Thanks @${username}, all your commits are properly signed off. 🎉`
              ].join('\n');
            }

            // Get existing comments on the PR
            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: prNumber
            });

            // Look for a previous bot comment
            const existingComment = comments.find(c =>
              c.body.includes("<!-- dco-advice-bot -->")
            );

            if (existingComment) {
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: existingComment.id,
                body: body
              });
            } else {
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: prNumber,
                body: body
              });
            }