pr-category-check.yml

name: PR Category Check

# Ensures every PR has at least one category checkbox checked.
# Automatically applies matching GitHub labels to the PR.
# Creates labels with custom colors if they don't exist yet.
# Uses pull_request_target so it works for fork PRs too (runs in base repo context).
# This is safe because we only read the PR body from the event payload — no fork code is checked out or executed.

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

permissions:
  pull-requests: write
  contents: read

jobs:
  check-pr-category:
    name: Validate PR Category & Auto-Label
    runs-on: ubuntu-latest
    steps:
      - name: Check categories and apply labels
        uses: actions/github-script@v7
        with:
          script: |
            const prBody = context.payload.pull_request.body || '';
            const prNumber = context.payload.pull_request.number;

            // Category checkboxes mapped to their GitHub label names, colors, and descriptions
            const categories = [
              {
                label: 'bug fix',
                color: 'D73A4A',
                description: 'Fixes a bug or incorrect behavior',
                displayName: 'Bug Fix',
                pattern: /-\s*\[x\]\s*Bug Fix/i,
              },
              {
                label: 'feature',
                color: '9333EA',
                description: 'Adds new functionality',
                displayName: 'Feature',
                pattern: /-\s*\[x\]\s*Feature/i,
              },
              {
                label: 'performance',
                color: 'F97316',
                description: 'Improves performance (load time, memory, rendering)',
                displayName: 'Performance',
                pattern: /-\s*\[x\]\s*Performance/i,
              },
              {
                label: 'tests',
                color: '3B82F6',
                description: 'Adds or updates test coverage',
                displayName: 'Tests',
                pattern: /-\s*\[x\]\s*Tests/i,
              },
              {
                label: 'documentation',
                color: '10B981',
                description: 'Updates to docs, comments, or README',
                displayName: 'Documentation',
                pattern: /-\s*\[x\]\s*Documentation/i,
              },
            ];

            const checkedCategories = categories.filter(cat => cat.pattern.test(prBody));
            const uncheckedCategories = categories.filter(cat => !cat.pattern.test(prBody));

            // --- Step 1: Fail CI if no category is selected ---
            if (checkedCategories.length === 0) {
              const message = [
                '## PR Category Required',
                '',
                'This pull request does not have any **PR Category** selected.',
                'Please edit your PR description and check **at least one** category checkbox:',
                '',
                '| Category | Description |',
                '|----------|-------------|',
                '| Bug Fix | Fixes a bug or incorrect behavior |',
                '| Feature | Adds new functionality |',
                '| Performance | Improves performance |',
                '| Tests | Adds or updates test coverage |',
                '| Documentation | Updates to docs, comments, or README |',
                '',
                'Example: Change `- [ ] Bug Fix` to `- [x] Bug Fix`',
                '',
                '> **Tip:** You can select multiple categories if your PR spans several areas.',
              ].join('\n');

              core.setFailed(message);
              return;
            }

            // --- Step 2: Ensure labels exist with proper colors ---
            const { data: existingLabels } = await github.rest.issues.listLabelsForRepo({
              owner: context.repo.owner,
              repo: context.repo.repo,
              per_page: 100,
            });
            const existingLabelNames = existingLabels.map(l => l.name);

            for (const cat of categories) {
              if (!existingLabelNames.includes(cat.label)) {
                try {
                  await github.rest.issues.createLabel({
                    owner: context.repo.owner,
                    repo: context.repo.repo,
                    name: cat.label,
                    color: cat.color,
                    description: cat.description,
                  });
                  core.info(`Created label: "${cat.label}" with color #${cat.color}`);
                } catch (error) {
                  core.warning(`Could not create label "${cat.label}". Error: ${error.message}`);
                }
              }
            }

            // --- Step 3: Auto-apply labels for checked categories ---
            const labelsToAdd = checkedCategories.map(cat => cat.label);
            const labelsToRemove = uncheckedCategories.map(cat => cat.label);

            // Get current labels on the PR
            const { data: currentLabels } = await github.rest.issues.listLabelsOnIssue({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: prNumber,
            });
            const currentLabelNames = currentLabels.map(l => l.name);

            // Add labels that are checked but not yet on the PR
            for (const label of labelsToAdd) {
              if (!currentLabelNames.includes(label)) {
                try {
                  await github.rest.issues.addLabels({
                    owner: context.repo.owner,
                    repo: context.repo.repo,
                    issue_number: prNumber,
                    labels: [label],
                  });
                  core.info(`Added label: "${label}"`);
                } catch (error) {
                  core.warning(`Could not add label "${label}". Error: ${error.message}`);
                }
              }
            }

            // Remove labels that are unchecked but still on the PR
            for (const label of labelsToRemove) {
              if (currentLabelNames.includes(label)) {
                try {
                  await github.rest.issues.removeLabel({
                    owner: context.repo.owner,
                    repo: context.repo.repo,
                    issue_number: prNumber,
                    name: label,
                  });
                  core.info(`Removed label: "${label}"`);
                } catch (error) {
                  core.warning(`Could not remove label "${label}". Error: ${error.message}`);
                }
              }
            }

            const selected = checkedCategories.map(c => c.displayName).join(', ');
            core.info(`PR categories selected: ${selected}`);
            core.info(`Labels synced: ${labelsToAdd.join(', ')}`);