# Validates Scriban template syntax in PR-changed Markdown files under docs/en/,
# so escape issues are caught before they reach the published documentation.

name: Check Docs Syntax

on:
  pull_request:
    paths:
      - 'docs/en/**/*.md'
      - 'docs/en/docs-params.json'
      - '.github/scripts/CheckDocsSyntax/**'
      - '.github/workflows/check-docs-syntax.yml'

permissions:
  contents: read
  pull-requests: write

jobs:
  check-scriban-syntax:
    name: Validate Scriban syntax in docs/en
    runs-on: ubuntu-latest

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Setup .NET
        uses: actions/setup-dotnet@v4
        with:
          dotnet-version: '10.0.x'

      - name: Build syntax checker
        run: dotnet build .github/scripts/CheckDocsSyntax/CheckDocsSyntax.csproj -c Release --nologo -v minimal

      - name: Get changed markdown files
        id: changed
        uses: actions/github-script@v7
        with:
          script: |
            const prNumber = context.payload.pull_request.number;
            const changed = [];
            let paramsChanged = false;
            let page = 1;
            while (true) {
              const { data: files } = await github.rest.pulls.listFiles({
                owner: context.repo.owner,
                repo: context.repo.repo,
                pull_number: prNumber,
                per_page: 100,
                page,
              });
              const PARAMS_PATH = 'docs/en/docs-params.json';
              for (const f of files) {
                const isMutation =
                  f.status === 'added' || f.status === 'modified' || f.status === 'renamed';
                if (!isMutation) continue;
                // For renames, GitHub puts the new path in `filename` and the
                // old one in `previous_filename`. Detect docs-params.json on
                // either side so renames into / out of that path still trigger
                // the parameter-file validation path.
                if (f.filename === PARAMS_PATH || f.previous_filename === PARAMS_PATH) {
                  paramsChanged = true;
                }
                if (f.filename.startsWith('docs/en/') && f.filename.endsWith('.md')) {
                  changed.push(f.filename);
                }
              }
              if (files.length < 100) break;
              page++;
            }
            core.setOutput('files', changed.join('\n'));
            core.setOutput('count', changed.length.toString());
            core.setOutput('paramsChanged', paramsChanged ? 'true' : 'false');
            core.info(`Markdown files to check: ${changed.length}`);
            core.info(`docs-params.json changed: ${paramsChanged}`);
            for (const f of changed) {
              core.info(`  - ${f}`);
            }

      - name: Run syntax checker
        id: checker
        if: steps.changed.outputs.count != '0' || steps.changed.outputs.paramsChanged == 'true'
        env:
          CHANGED_FILES: ${{ steps.changed.outputs.files }}
          PARAMS_CHANGED: ${{ steps.changed.outputs.paramsChanged }}
        run: |
          mapfile -t files <<< "$CHANGED_FILES"
          args=()
          for f in "${files[@]}"; do
            if [ -n "$f" ] && [ -f "$f" ]; then
              args+=("$f")
            fi
          done

          if [ ${#args[@]} -eq 0 ]; then
            if [ "$PARAMS_CHANGED" = "true" ] && [ -f "docs/en/index.md" ]; then
              # No markdown changed, but docs-params.json did. Run the checker
              # against a single known-clean page so BuildRenderParameters /
              # docs-params.json parsing actually executes and fails fast on a
              # malformed parameter file.
              echo "docs-params.json changed but no markdown changed; validating params via docs/en/index.md."
              args+=("docs/en/index.md")
            else
              echo "No existing markdown files to check (all changes are deletions)."
              exit 0
            fi
          fi

          # Capture the checker's stdout so a follow-up step can post it as a PR
          # comment when the run fails, while still streaming it to the job log.
          set -o pipefail
          dotnet run --project .github/scripts/CheckDocsSyntax/CheckDocsSyntax.csproj \
            -c Release --no-build -- "${args[@]}" 2>&1 | tee checker-output.txt

      - name: Upsert PR comment on failure
        if: failure() && steps.checker.conclusion == 'failure'
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');
            const MARKER = '<!-- check-docs-syntax-bot -->';
            const prNumber = context.payload.pull_request.number;

            let report = '';
            try {
              report = fs.readFileSync('checker-output.txt', 'utf8').trim();
            } catch (e) {
              report = '(checker output was not captured)';
            }

            const runUrl = `${context.serverUrl}/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}`;
            const body = [
              MARKER,
              '### Docs syntax check failed',
              '',
              'The Scriban syntax checker reported issues in the Markdown files this PR changes. Wrap inline Scriban-looking text with `{%{{{ ... }}}%}` or wrap whole code blocks with `{%{` ... `}%}` to keep it from being parsed as a template.',
              '',
              '<details><summary>Checker output</summary>',
              '',
              '```',
              report,
              '```',
              '',
              '</details>',
              '',
              `[Full run log](${runUrl})`,
            ].join('\n');

            // Find an existing bot comment to update (idempotent across re-runs).
            let existing = null;
            for (let page = 1; ; page++) {
              const { data } = await github.rest.issues.listComments({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: prNumber,
                per_page: 100,
                page,
              });
              existing = data.find(c => c.body && c.body.startsWith(MARKER));
              if (existing || data.length < 100) break;
            }

            if (existing) {
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: existing.id,
                body,
              });
              core.info(`Updated existing bot comment (#${existing.id}).`);
            } else {
              const { data: created } = await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: prNumber,
                body,
              });
              core.info(`Created bot comment (#${created.id}).`);
            }

      - name: Resolve previous failure comment on success
        # Clear any stale failure comment whenever this workflow run is green,
        # even if the syntax checker step was skipped (e.g. when a later
        # commit reverts the earlier failure so no markdown files appear in
        # the PR's net diff).
        if: success()
        uses: actions/github-script@v7
        with:
          script: |
            const MARKER = '<!-- check-docs-syntax-bot -->';
            const prNumber = context.payload.pull_request.number;

            for (let page = 1; ; page++) {
              const { data } = await github.rest.issues.listComments({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: prNumber,
                per_page: 100,
                page,
              });

              const existing = data.find(c => c.body && c.body.startsWith(MARKER));
              if (existing) {
                const body = [
                  MARKER,
                  '### Docs syntax check passed',
                  '',
                  'The previously reported issues are no longer present in this PR.',
                ].join('\n');
                await github.rest.issues.updateComment({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  comment_id: existing.id,
                  body,
                });
                core.info(`Cleared bot comment (#${existing.id}).`);
                break;
              }

              if (data.length < 100) break;
            }