name: Update Nix Hashes

permissions:
  contents: write

on:
  workflow_dispatch:
  push:
    paths:
      - "bun.lock"
      - "package.json"
      - "packages/*/package.json"
      - ".github/workflows/update-nix-hashes.yml"
  pull_request:
    paths:
      - "bun.lock"
      - "package.json"
      - "packages/*/package.json"
      - ".github/workflows/update-nix-hashes.yml"

jobs:
  compute-node-modules-hash:
    if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository
    strategy:
      fail-fast: false
      matrix:
        include:
          - system: x86_64-linux
            host: blacksmith-4vcpu-ubuntu-2404
          - system: aarch64-linux
            host: blacksmith-4vcpu-ubuntu-2404-arm
          - system: x86_64-darwin
            host: macos-15-intel
          - system: aarch64-darwin
            host: macos-latest
    runs-on: ${{ matrix.host }}
    env:
      SYSTEM: ${{ matrix.system }}

    steps:
      - name: Checkout repository
        uses: actions/checkout@v6
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
          fetch-depth: 0
          ref: ${{ github.head_ref || github.ref_name }}
          repository: ${{ github.event.pull_request.head.repo.full_name || github.repository }}

      - name: Setup Nix
        uses: nixbuild/nix-quick-install-action@v34

      - name: Compute node_modules hash
        run: |
          set -euo pipefail

          DUMMY="sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA="
          HASH_FILE="nix/hashes.json"
          OUTPUT_FILE="hash-${SYSTEM}.txt"

          export NIX_KEEP_OUTPUTS=1
          export NIX_KEEP_DERIVATIONS=1

          BUILD_LOG=$(mktemp)
          TMP_JSON=$(mktemp)
          trap 'rm -f "$BUILD_LOG" "$TMP_JSON"' EXIT

          if [ ! -f "$HASH_FILE" ]; then
            mkdir -p "$(dirname "$HASH_FILE")"
            echo '{"nodeModules":{}}' > "$HASH_FILE"
          fi

          # Set dummy hash to force nix to rebuild and reveal correct hash
          jq --arg system "$SYSTEM" --arg value "$DUMMY" \
            '.nodeModules = (.nodeModules // {}) | .nodeModules[$system] = $value' "$HASH_FILE" > "$TMP_JSON"
          mv "$TMP_JSON" "$HASH_FILE"

          MODULES_ATTR=".#packages.${SYSTEM}.default.node_modules"
          DRV_PATH="$(nix eval --raw "${MODULES_ATTR}.drvPath")"

          echo "Building node_modules for ${SYSTEM} to discover correct hash..."
          echo "Attempting to realize derivation: ${DRV_PATH}"
          REALISE_OUT=$(nix-store --realise "$DRV_PATH" --keep-failed 2>&1 | tee "$BUILD_LOG" || true)

          BUILD_PATH=$(echo "$REALISE_OUT" | grep "^/nix/store/" | head -n1 || true)
          CORRECT_HASH=""

          if [ -n "$BUILD_PATH" ] && [ -d "$BUILD_PATH" ]; then
            echo "Realized node_modules output: $BUILD_PATH"
            CORRECT_HASH=$(nix hash path --sri "$BUILD_PATH" 2>/dev/null || true)
          fi

          # Try to extract hash from build log
          if [ -z "$CORRECT_HASH" ]; then
            CORRECT_HASH="$(grep -E 'got:\s+sha256-[A-Za-z0-9+/=]+' "$BUILD_LOG" | awk '{print $2}' | head -n1 || true)"
          fi

          if [ -z "$CORRECT_HASH" ]; then
            CORRECT_HASH="$(grep -A2 'hash mismatch' "$BUILD_LOG" | grep 'got:' | awk '{print $2}' | sed 's/sha256:/sha256-/' || true)"
          fi

          # Try to hash from kept failed build directory
          if [ -z "$CORRECT_HASH" ]; then
            KEPT_DIR=$(grep -oE "build directory.*'[^']+'" "$BUILD_LOG" | grep -oE "'/[^']+'" | tr -d "'" | head -n1 || true)
            if [ -z "$KEPT_DIR" ]; then
              KEPT_DIR=$(grep -oE '/nix/var/nix/builds/[^ ]+' "$BUILD_LOG" | head -n1 || true)
            fi

            if [ -n "$KEPT_DIR" ] && [ -d "$KEPT_DIR" ]; then
              HASH_PATH="$KEPT_DIR"
              [ -d "$KEPT_DIR/build" ] && HASH_PATH="$KEPT_DIR/build"

              if [ -d "$HASH_PATH/node_modules" ]; then
                CORRECT_HASH=$(nix hash path --sri "$HASH_PATH" 2>/dev/null || true)
              fi
            fi
          fi

          if [ -z "$CORRECT_HASH" ]; then
            echo "Failed to determine correct node_modules hash for ${SYSTEM}."
            cat "$BUILD_LOG"
            exit 1
          fi

          echo "$CORRECT_HASH" > "$OUTPUT_FILE"
          echo "Hash for ${SYSTEM}: $CORRECT_HASH"

      - name: Upload hash artifact
        uses: actions/upload-artifact@v6
        with:
          name: hash-${{ matrix.system }}
          path: hash-${{ matrix.system }}.txt
          retention-days: 1

  commit-node-modules-hashes:
    needs: compute-node-modules-hash
    if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository
    runs-on: blacksmith-4vcpu-ubuntu-2404
    env:
      TITLE: node_modules hashes

    steps:
      - name: Checkout repository
        uses: actions/checkout@v6
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
          fetch-depth: 0
          ref: ${{ github.head_ref || github.ref_name }}
          repository: ${{ github.event.pull_request.head.repo.full_name || github.repository }}

      - name: Configure git
        run: |
          git config --global user.email "action@github.com"
          git config --global user.name "Github Action"

      - name: Pull latest changes
        env:
          TARGET_BRANCH: ${{ github.head_ref || github.ref_name }}
        run: |
          BRANCH="${TARGET_BRANCH:-${GITHUB_REF_NAME}}"
          git pull --rebase --autostash origin "$BRANCH"

      - name: Download all hash artifacts
        uses: actions/download-artifact@v7
        with:
          pattern: hash-*
          merge-multiple: true

      - name: Merge hashes into hashes.json
        run: |
          set -euo pipefail

          HASH_FILE="nix/hashes.json"

          if [ ! -f "$HASH_FILE" ]; then
            mkdir -p "$(dirname "$HASH_FILE")"
            echo '{"nodeModules":{}}' > "$HASH_FILE"
          fi

          echo "Merging hashes into ${HASH_FILE}..."

          shopt -s nullglob
          files=(hash-*.txt)
          if [ ${#files[@]} -eq 0 ]; then
            echo "No hash files found, nothing to update"
            exit 0
          fi

          EXPECTED_SYSTEMS="x86_64-linux aarch64-linux x86_64-darwin aarch64-darwin"
          for sys in $EXPECTED_SYSTEMS; do
            if [ ! -f "hash-${sys}.txt" ]; then
              echo "WARNING: Missing hash file for $sys"
            fi
          done

          for f in "${files[@]}"; do
            system="${f#hash-}"
            system="${system%.txt}"
            hash=$(cat "$f")
            if [ -z "$hash" ]; then
              echo "WARNING: Empty hash for $system, skipping"
              continue
            fi
            echo "  $system: $hash"
            jq --arg sys "$system" --arg h "$hash" \
              '.nodeModules = (.nodeModules // {}) | .nodeModules[$sys] = $h' "$HASH_FILE" > "${HASH_FILE}.tmp"
            mv "${HASH_FILE}.tmp" "$HASH_FILE"
          done

          echo "All hashes merged:"
          cat "$HASH_FILE"

      - name: Commit ${{ env.TITLE }} changes
        env:
          TARGET_BRANCH: ${{ github.head_ref || github.ref_name }}
        run: |
          set -euo pipefail

          HASH_FILE="nix/hashes.json"
          echo "Checking for changes..."

          summarize() {
            local status="$1"
            {
              echo "### Nix $TITLE"
              echo ""
              echo "- ref: ${GITHUB_REF_NAME}"
              echo "- status: ${status}"
            } >> "$GITHUB_STEP_SUMMARY"
            if [ -n "${GITHUB_SERVER_URL:-}" ] && [ -n "${GITHUB_REPOSITORY:-}" ] && [ -n "${GITHUB_RUN_ID:-}" ]; then
              echo "- run: ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}/actions/runs/${GITHUB_RUN_ID}" >> "$GITHUB_STEP_SUMMARY"
            fi
            echo "" >> "$GITHUB_STEP_SUMMARY"
          }

          FILES=("$HASH_FILE")
          STATUS="$(git status --short -- "${FILES[@]}" || true)"
          if [ -z "$STATUS" ]; then
            echo "No changes detected."
            summarize "no changes"
            exit 0
          fi

          echo "Changes detected:"
          echo "$STATUS"
          git add "${FILES[@]}"
          git commit -m "Update $TITLE"

          BRANCH="${TARGET_BRANCH:-${GITHUB_REF_NAME}}"
          git pull --rebase --autostash origin "$BRANCH"
          git push origin HEAD:"$BRANCH"
          echo "Changes pushed successfully"

          summarize "committed $(git rev-parse --short HEAD)"