name: bot-nix-hashes

# Keeps nix/hashes.json in step with the lockfile through a pull request, using only GITHUB_TOKEN.
# - hash and compute run repository code (nix build) with a read-only token and no secrets. compute uploads only the
#   new nix/hashes.json.
# - publish holds the write token. It runs only .github/nix-hashes/ from this commit, treats the artifact as data,
#   validates its exact shape and commits only that file to bot/nix-hashes. It never runs repository code.
# - check-bot-scope.yml, a required check, fails the bot's pull request unless it changes only a valid nix/hashes.json,
#   so a tampered branch cannot auto-merge.
# This file, check-bot-scope.yml and .github/nix-hashes/ are the security boundary.

permissions:
  contents: read

on:
  workflow_dispatch:
  push:
    branches: [dev]
    # Mirrored in .github/nix-hashes/publish.sh.
    paths:
      - "bun.lock"
      - "package.json"
      - "packages/*/package.json"
      - "services/*/package.json"
      - "flake.lock"
      - "nix/node_modules.nix"
      - "nix/scripts/**"
      - "patches/**"
      - ".github/workflows/bot-nix-hashes.yml"

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

jobs:
  # Native runners required: bun install cross-compilation flags (--os/--cpu)
  # do not produce byte-identical node_modules as native installs.
  hash:
    strategy:
      fail-fast: false
      matrix:
        include:
          - system: x86_64-linux
            runner: blacksmith-4vcpu-ubuntu-2404
          - system: aarch64-linux
            runner: blacksmith-4vcpu-ubuntu-2404-arm
          - system: aarch64-darwin
            runner: macos-latest
    runs-on: ${{ matrix.runner }}

    steps:
      - name: Checkout repository
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          persist-credentials: false

      - name: Setup Nix
        uses: nixbuild/nix-quick-install-action@2c9db80fb984ceb1bcaa77cdda3fdf8cfba92035 # v34

      - name: Compute node_modules hash
        id: hash
        env:
          SYSTEM: ${{ matrix.system }}
        run: |
          set -euo pipefail

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

          HASH=""
          MAX_ATTEMPTS=3
          for ((ATTEMPT = 1; ATTEMPT <= MAX_ATTEMPTS; ATTEMPT++)); do
            # Build with fakeHash to trigger hash mismatch and reveal correct hash
            nix build ".#packages.${SYSTEM}.node_modules_updater" --no-link 2>&1 | tee "$BUILD_LOG" || true

            HASH="$(nix run --inputs-from . nixpkgs#gnugrep -- -oP 'got:\s*\Ksha256-[A-Za-z0-9+/=]+' "$BUILD_LOG" | tail -n1 || true)"

            [ -n "$HASH" ] && break

            if [ "$ATTEMPT" -lt "$MAX_ATTEMPTS" ]; then
              echo "::warning::Attempt ${ATTEMPT}/${MAX_ATTEMPTS} produced no hash for ${SYSTEM}; retrying in $((ATTEMPT * 10))s"
              sleep $((ATTEMPT * 10))
            fi
          done

          if [ -z "$HASH" ]; then
            echo "::error::Failed to compute hash for ${SYSTEM} after ${MAX_ATTEMPTS} attempts"
            cat "$BUILD_LOG"
            exit 1
          fi

          echo "$HASH" > hash.txt
          echo "Computed hash for ${SYSTEM}: $HASH"

      - name: Upload hash
        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
        with:
          name: hash-${{ matrix.system }}
          path: hash.txt
          retention-days: 1

  # Assembles nix/hashes.json from the per-system hashes and uploads it as the only input publish accepts.
  compute:
    needs: hash
    runs-on: ubuntu-24.04
    outputs:
      changed: ${{ steps.update.outputs.changed }}

    steps:
      - name: Checkout repository
        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
        with:
          persist-credentials: false

      - name: Download hash artifacts
        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
        with:
          path: ${{ runner.temp }}/hashes
          pattern: hash-*

      - name: Update hashes.json
        id: update
        env:
          HASHES: ${{ runner.temp }}/hashes
        run: |
          set -euo pipefail

          HASH_FILE="nix/hashes.json"

          [ -f "$HASH_FILE" ] || echo '{"nodeModules":{}}' > "$HASH_FILE"

          for SYSTEM in x86_64-linux aarch64-linux aarch64-darwin; do
            HASH="$(tr -d '[:space:]' < "$HASHES/hash-${SYSTEM}/hash.txt")"
            echo "${SYSTEM}: ${HASH}"
            jq --arg sys "$SYSTEM" --arg h "$HASH" '.nodeModules[$sys] = $h' "$HASH_FILE" > tmp.json
            mv tmp.json "$HASH_FILE"
          done

          cat "$HASH_FILE"
          bash .github/nix-hashes/validate.sh "$HASH_FILE"

          if git diff --quiet -- "$HASH_FILE"; then
            echo "changed=false" >> "$GITHUB_OUTPUT"
            echo "### Nix hashes" >> "$GITHUB_STEP_SUMMARY"
            echo "Status: no changes" >> "$GITHUB_STEP_SUMMARY"
          else
            echo "changed=true" >> "$GITHUB_OUTPUT"
            echo "### Nix hashes" >> "$GITHUB_STEP_SUMMARY"
            echo "Status: changed" >> "$GITHUB_STEP_SUMMARY"
          fi

      - name: Upload hashes.json
        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
        with:
          name: nix-hashes
          path: nix/hashes.json
          if-no-files-found: error
          retention-days: 1

  # Runs even when compute found no change, so an open bot pull request with stale hashes is closed, not merged.
  publish:
    needs: compute
    if: github.repository == 'anomalyco/opencode' && github.ref == 'refs/heads/dev'
    runs-on: ubuntu-24.04
    concurrency:
      group: bot-nix-hashes-publish
      cancel-in-progress: false
    permissions:
      contents: write
      pull-requests: write
      actions: write

    steps:
      - name: Check out publish scripts
        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
        with:
          ref: ${{ github.sha }}
          path: trusted
          sparse-checkout: /.github/nix-hashes/
          sparse-checkout-cone-mode: false
          persist-credentials: false

      # Holds the push credential; only nix/hashes.json is checked out and nothing in it runs.
      - name: Check out dev
        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
        with:
          ref: dev
          path: repo
          sparse-checkout: /nix/hashes.json
          sparse-checkout-cone-mode: false

      - name: Download hashes.json
        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
        with:
          name: nix-hashes
          path: ${{ runner.temp }}/nix-hashes

      - name: Publish
        working-directory: repo
        run: bash ../trusted/.github/nix-hashes/publish.sh "$RUNNER_TEMP/nix-hashes/hashes.json"
        env:
          GH_TOKEN: ${{ github.token }}
          GH_REPO: ${{ github.repository }}