name: Label PR Intent

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

permissions:
  issues: write
  pull-requests: read

jobs:
  label-pr:
    runs-on: ubuntu-latest
    if: >-
      github.actor != 'dependabot[bot]' &&
      github.actor != 'github-actions[bot]'
    steps:
      - name: Apply intent labels
        uses: actions/github-script@f28e40c7f34bde8b3046d885e986cb6290c5673b # v7.1.0
        with:
          script: |
            const managedLabels = {
              'targets-main': {
                color: 'B60205',
                description: 'PR targets main instead of staged'
              },
              'branched-main': {
                color: 'D93F0B',
                description: 'PR appears to include plugin files materialized from main'
              },
              'skills': {
                color: '1D76DB',
                description: 'PR touches skills'
              },
              'plugin': {
                color: '5319E7',
                description: 'PR touches plugins'
              },
              'agent': {
                color: '0E8A16',
                description: 'PR touches agents'
              },
              'instructions': {
                color: 'FBCA04',
                description: 'PR touches instructions'
              },
              'new-submission': {
                color: '006B75',
                description: 'PR adds at least one new contribution'
              },
              'website-update': {
                color: '0052CC',
                description: 'PR touches website content or code'
              },
              'external-plugin': {
                color: 'FEF2C0',
                description: 'PR updates plugins/external.json'
              },
              'hooks': {
                color: 'C2E0C6',
                description: 'PR touches hooks'
              },
              'workflow': {
                color: 'BFD4F2',
                description: 'PR touches workflow automation'
              }
            };

            const matchesAny = (filename, patterns) => patterns.some((pattern) => pattern.test(filename));

            async function listAllFiles() {
              const files = [];
              let page = 1;

              while (true) {
                const response = await github.rest.pulls.listFiles({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  pull_number: context.issue.number,
                  per_page: 100,
                  page
                });

                files.push(...response.data);

                if (response.data.length < 100) {
                  return files;
                }

                page += 1;
              }
            }

            async function ensureLabel(name, { color, description }) {
              try {
                await github.rest.issues.createLabel({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  name,
                  color,
                  description
                });
              } catch (error) {
                if (error.status !== 422) {
                  throw error;
                }
              }
            }

            const files = await listAllFiles();
            const filenames = files.map((file) => file.filename);

            const patterns = {
              branchedMain: [
                /^plugins\/[^/]+\/(?:agents|commands|skills)\//
              ],
              skills: [
                /^skills\//
              ],
              plugin: [
                /^plugins\//
              ],
              agent: [
                /^agents\/.+\.agent\.md$/
              ],
              instructions: [
                /^instructions\/.+\.instructions\.md$/
              ],
              websiteUpdate: [
                /^website\//
              ],
              externalPlugin: [
                /^plugins\/external\.json$/
              ],
              hooks: [
                /^hooks\//
              ],
              workflow: [
                /^workflows\/.+\.md$/,
                /^\.github\/workflows\/.+\.(?:ya?ml|md)$/
              ],
              newSubmission: [
                /^agents\/.+\.agent\.md$/,
                /^instructions\/.+\.instructions\.md$/,
                /^skills\/[^/]+\/SKILL\.md$/,
                /^hooks\/[^/]+\/(?:README\.md|hooks\.json)$/,
                /^plugins\/[^/]+\/\.github\/plugin\/plugin\.json$/,
                /^workflows\/.+\.md$/,
                /^\.github\/workflows\/.+\.(?:ya?ml|md)$/,
                /^website\//
              ]
            };

            const isBranchedMain = filenames.some((filename) => matchesAny(filename, patterns.branchedMain));
            const hasNewSubmission = files.some(
              (file) => file.status === 'added' && matchesAny(file.filename, patterns.newSubmission)
            );

            const desiredLabels = new Set();

            if (context.payload.pull_request.base.ref === 'main') {
              desiredLabels.add('targets-main');
            }

            if (filenames.some((filename) => matchesAny(filename, patterns.externalPlugin))) {
              desiredLabels.add('external-plugin');
            }

            if (isBranchedMain) {
              desiredLabels.add('branched-main');
            } else {
              if (filenames.some((filename) => matchesAny(filename, patterns.skills))) {
                desiredLabels.add('skills');
              }

              if (filenames.some((filename) => matchesAny(filename, patterns.plugin))) {
                desiredLabels.add('plugin');
              }

              if (filenames.some((filename) => matchesAny(filename, patterns.agent))) {
                desiredLabels.add('agent');
              }

              if (filenames.some((filename) => matchesAny(filename, patterns.instructions))) {
                desiredLabels.add('instructions');
              }

              if (filenames.some((filename) => matchesAny(filename, patterns.websiteUpdate))) {
                desiredLabels.add('website-update');
              }

              if (filenames.some((filename) => matchesAny(filename, patterns.hooks))) {
                desiredLabels.add('hooks');
              }

              if (filenames.some((filename) => matchesAny(filename, patterns.workflow))) {
                desiredLabels.add('workflow');
              }

              if (hasNewSubmission) {
                desiredLabels.add('new-submission');
              }
            }

            await Promise.all(
              Object.entries(managedLabels).map(([name, config]) => ensureLabel(name, config))
            );

            const currentLabels = await github.paginate(github.rest.issues.listLabelsOnIssue, {
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
              per_page: 100
            });

            const currentManagedLabels = currentLabels
              .map((label) => label.name)
              .filter((name) => Object.prototype.hasOwnProperty.call(managedLabels, name));

            const labelsToAdd = [...desiredLabels].filter((name) => !currentManagedLabels.includes(name));
            const labelsToRemove = currentManagedLabels.filter((name) => !desiredLabels.has(name));

            if (labelsToAdd.length > 0) {
              await github.rest.issues.addLabels({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.issue.number,
                labels: labelsToAdd
              });
            }

            for (const name of labelsToRemove) {
              await github.rest.issues.removeLabel({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.issue.number,
                name
              });
            }

            core.info(`Managed labels: ${[...desiredLabels].sort().join(', ') || 'none'}`);