name: Clean up closed PR artifacts

on:
  pull_request_target:
    types:
      - closed

permissions:
  actions: write
  pull-requests: read

jobs:
  delete-artifacts:
    name: Delete PR artifacts
    runs-on: ubuntu-latest
    timeout-minutes: 10

    steps:
      - name: Delete artifacts from PR workflow runs
        uses: actions/github-script@v9
        with:
          script: |
            const { owner, repo } = context.repo;
            const pullRequest = context.payload.pull_request;

            const workflowRuns = await github.paginate(
              github.rest.actions.listWorkflowRunsForRepo,
              {
                owner,
                repo,
                event: 'pull_request',
                branch: pullRequest.head.ref,
                per_page: 100
              }
            );

            const pullRequestRuns = [];
            const associatedPullRequestsBySha = new Map();

            for (const run of workflowRuns) {
              if (!associatedPullRequestsBySha.has(run.head_sha)) {
                const associatedPullRequests = await github.paginate(
                  github.rest.repos.listPullRequestsAssociatedWithCommit,
                  {
                    owner,
                    repo,
                    commit_sha: run.head_sha,
                    per_page: 100
                  }
                );

                associatedPullRequestsBySha.set(run.head_sha, associatedPullRequests);
              }

              const belongsToPullRequest = associatedPullRequestsBySha
                .get(run.head_sha)
                .some(pr => pr.number === pullRequest.number);

              if (belongsToPullRequest) {
                pullRequestRuns.push(run);
              }
            }

            let deletedArtifacts = 0;
            let deletedBytes = 0;

            for (const run of pullRequestRuns) {
              const artifacts = await github.paginate(
                github.rest.actions.listWorkflowRunArtifacts,
                {
                  owner,
                  repo,
                  run_id: run.id,
                  per_page: 100
                }
              );

              for (const artifact of artifacts) {
                if (artifact.expired) {
                  core.info(`Skipping expired artifact ${artifact.name} (${artifact.id}).`);
                  continue;
                }

                try {
                  await github.rest.actions.deleteArtifact({
                    owner,
                    repo,
                    artifact_id: artifact.id
                  });

                  deletedArtifacts += 1;
                  deletedBytes += artifact.size_in_bytes;
                  core.info(`Deleted artifact ${artifact.name} (${artifact.id}).`);
                } catch (error) {
                  if (error.status === 404) {
                    core.info(`Artifact ${artifact.name} (${artifact.id}) was already deleted.`);
                    continue;
                  }

                  throw error;
                }
              }
            }

            const deletedMiB = (deletedBytes / 1024 / 1024).toFixed(1);
            core.info(
              `Deleted ${deletedArtifacts} artifact(s) (${deletedMiB} MiB) ` +
              `from ${pullRequestRuns.length} workflow run(s) for PR #${pullRequest.number}.`
            );

            await core.summary
              .addHeading('PR artifact cleanup')
              .addRaw(`Pull request: #${pullRequest.number}`, true)
              .addRaw(`Workflow runs inspected: ${pullRequestRuns.length}`, true)
              .addRaw(`Artifacts deleted: ${deletedArtifacts}`, true)
              .addRaw(`Storage released: ${deletedMiB} MiB`, true)
              .write();