name: Publish to CloudFront
description: Syncs frontend assets to S3 and invalidates the CloudFront distribution

inputs:
  dist_dir:
    description: Path to the frontend dist directory
    required: false
    default: frontend/dist
  s3_bucket_name:
    description: Name of the S3 bucket to sync assets to
    required: true
  cloudfront_distribution_ids:
    description: Space-separated list of CloudFront distribution IDs to invalidate
    required: false
    default: ''
  versioning:
    description: >
      When set to true, enables versioned builds: assets are synced with
      "public, max-age=31536000, immutable" and old versions older than 7 days
      are deleted, keeping at least the 2 newest.
    required: false
    default: 'false'
  versioning_prefix:
    description: >
      S3 prefix under which versioned builds are stored
      (e.g. "_static" → _static/1234567890/). When omitted, versions are
      stored at the bucket root. Requires versioning to be true.
    required: false
    default: ''
  cache_rules:
    description: >
      JSON array of per-file cache overrides. Each matched file is uploaded
      individually with the given headers and excluded from the bulk sync.
      content_type is optional. Applied independently of versioning.
      When versioning is enabled and cache_rules is empty, defaults to
      short-caching index.html — the standard SPA behaviour.
      Example:
        cache_rules: |
          [
            {"file": "index.html", "cache_control": "no-cache, no-store, must-revalidate", "content_type": "text/html"},
            {"file": "sw.js", "cache_control": "no-cache, no-store, must-revalidate", "content_type": "application/javascript"},
            {"file": "manifest.webmanifest", "cache_control": "no-cache, max-age=300", "content_type": "application/manifest+json"}
          ]
    required: false
    default: '[]'

runs:
  using: composite
  steps:
    - name: Install AWS CLI
      shell: bash
      run: |
        if ! command -v aws &> /dev/null; then
          curl -fsSL "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o /tmp/awscliv2.zip
          unzip -q /tmp/awscliv2.zip -d /tmp
          sudo /tmp/aws/install
          rm -rf /tmp/awscliv2.zip /tmp/aws
        fi

    - name: Publish frontend assets
      shell: bash
      env:
        INPUT_DIST_DIR: ${{ inputs.dist_dir }}
        INPUT_S3_BUCKET_NAME: ${{ inputs.s3_bucket_name }}
        INPUT_VERSIONING: ${{ inputs.versioning }}
        INPUT_VERSIONING_PREFIX: ${{ inputs.versioning_prefix }}
        INPUT_CACHE_RULES: ${{ inputs.cache_rules }}
      run: |
        # When versioning is active and no cache_rules provided, short-cache index.html by default
        EFFECTIVE_CACHE_RULES="${INPUT_CACHE_RULES}"
        if [[ "${INPUT_VERSIONING}" == "true" && "${EFFECTIVE_CACHE_RULES}" == "[]" && -f "${INPUT_DIST_DIR}/index.html" ]]; then
          EFFECTIVE_CACHE_RULES='[{"file": "index.html", "cache_control": "no-cache, max-age=300", "content_type": "text/html"}]'
        fi

        # Upload each file from cache_rules with its own headers,
        # and collect --exclude args so the bulk sync skips them
        EXCLUDE_ARGS=()
        if [[ "${EFFECTIVE_CACHE_RULES}" != "[]" ]]; then
          while IFS= read -r rule; do
            file=$(echo "$rule" | jq -r '.file')
            cache_control=$(echo "$rule" | jq -r '.cache_control')
            content_type=$(echo "$rule" | jq -r '.content_type // empty')

            EXCLUDE_ARGS+=("--exclude" "$file")

            if [[ -f "${INPUT_DIST_DIR}/${file}" ]]; then
              CT_ARG=()
              if [[ -n "$content_type" ]]; then
                CT_ARG=("--content-type" "$content_type")
              fi
              aws s3 cp "${INPUT_DIST_DIR}/${file}" "s3://${INPUT_S3_BUCKET_NAME}/${file}" \
                --cache-control "$cache_control" \
                --metadata-directive REPLACE \
                "${CT_ARG[@]}"
            fi
          done < <(echo "$EFFECTIVE_CACHE_RULES" | jq -c '.[]')
        fi

        # Bulk sync remaining files; versioned builds get immutable cache headers
        CACHE_CONTROL_ARG=()
        if [[ "${INPUT_VERSIONING}" == "true" ]]; then
          CACHE_CONTROL_ARG=("--cache-control" "public, max-age=31536000, immutable")
        fi

        aws s3 sync "${INPUT_DIST_DIR}" "s3://${INPUT_S3_BUCKET_NAME}" "${CACHE_CONTROL_ARG[@]}" "${EXCLUDE_ARGS[@]}"

    - name: Clean up old versioned static builds
      if: ${{ inputs.versioning == 'true' }}
      shell: bash
      env:
        INPUT_S3_BUCKET_NAME: ${{ inputs.s3_bucket_name }}
        INPUT_VERSIONING_PREFIX: ${{ inputs.versioning_prefix }}
      run: |
        S3_PATH="s3://$INPUT_S3_BUCKET_NAME"
        if [[ -n "${INPUT_VERSIONING_PREFIX}" ]]; then
          S3_PATH="s3://$INPUT_S3_BUCKET_NAME/$INPUT_VERSIONING_PREFIX"
        fi

        aws s3 ls "${S3_PATH}/" \
          | grep -oP '(?<=PRE )[0-9]+' \
          | sort --stable --reverse \
          | tail -n +3 \
          | while read version; do
              now=$(($(date +%s%N)/1000000))
              diff=$(($now-$version))
              # delete if older than 7 days
              if [ $diff -gt 604800000 ]; then
                echo "Deleting $version"
                aws s3 rm --recursive "${S3_PATH}/$version"
              fi
            done

    - name: Invalidate CloudFront
      if: ${{ inputs.cloudfront_distribution_ids != '' }}
      shell: bash
      env:
        INPUT_CLOUDFRONT_DISTRIBUTION_IDS: ${{ inputs.cloudfront_distribution_ids }}
      run: |
        echo "$INPUT_CLOUDFRONT_DISTRIBUTION_IDS" \
          | tr ' ' '\n' \
          | xargs -I% aws cloudfront create-invalidation --distribution-id % --paths '/*'