name: 'Codegen drift check'
description: >
  Runs a Justfile codegen recipe and reports a warning - without failing the
  build - when the committed output differs from what the recipe produces.

inputs:
  recipe:
    description: 'Justfile recipe to run (e.g. gen-fonts)'
    required: true
  paths:
    description: 'Git pathspec of the generated files to check for drift'
    required: true
  label:
    description: 'Human readable name of the generated artefact'
    required: true
  just-version:
    description: 'Version of just to install'
    default: '1.57.0'

runs:
  using: "composite"
  steps:

    - name: Install just
      shell: bash
      env:
        JUST_VERSION: ${{ inputs.just-version }}
      run: |
        # The edgetx-dev image ships wget but not curl.
        wget -qO- \
          "https://github.com/casey/just/releases/download/${JUST_VERSION}/just-${JUST_VERSION}-x86_64-unknown-linux-musl.tar.gz" \
          | tar xz -C /usr/local/bin just
        just --version

    - name: Allow git to read the workspace
      shell: bash
      run: git config --global --add safe.directory "$GITHUB_WORKSPACE"

    - name: Regenerate ${{ inputs.label }}
      shell: bash
      env:
        RECIPE: ${{ inputs.recipe }}
      run: just "${RECIPE}" 2>&1 | tee /tmp/codegen.log

    - name: Check for incomplete generation
      shell: bash
      env:
        RECIPE: ${{ inputs.recipe }}
      run: |
        # make_fonts.sh warns and carries on when a translation header yields no
        # characters, so a clean diff on its own does not prove a complete run.
        if grep -q 'No characters found' /tmp/codegen.log; then
          echo "::warning::'just ${RECIPE}' skipped one or more font sets ('No characters found' in the log), so the drift result below may be incomplete."
        fi

    - name: Check for drift
      shell: bash
      env:
        PATHS: ${{ inputs.paths }}
        RECIPE: ${{ inputs.recipe }}
        LABEL: ${{ inputs.label }}
      run: |
        # Deliberately non-failing. Contributors without the local toolchain must
        # not be blocked; this only surfaces that the committed files have drifted.
        # Word splitting on PATHS is intentional - it may hold several pathspecs.
        # shellcheck disable=SC2086
        changed=$(git status --porcelain -- ${PATHS})
        if [ -z "${changed}" ]; then
          echo "${LABEL}: up to date"
          exit 0
        fi

        echo "::warning::${LABEL} is out of date. Run 'just ${RECIPE}' and commit the result."

        # A full regeneration diff can run to megabytes (the fonts are the worst
        # case), so truncate well inside the 1 MiB step summary limit. Truncation
        # uses bash substring expansion rather than `head`: piping into `head`
        # would SIGPIPE the producer once it closed the pipe, and under `pipefail`
        # that exits 141 - failing a step that must never fail.
        # shellcheck disable=SC2086
        diff=$(git diff -- ${PATHS} || true)
        truncated="${diff:0:60000}"
        if [ "${#diff}" -gt "${#truncated}" ]; then
          truncated="${truncated}"$'\n''... diff truncated ...'
        fi

        {
          echo "### :warning: ${LABEL} is out of date"
          echo
          echo "The committed files differ from what \`just ${RECIPE}\` produces in"
          echo "\`ghcr.io/edgetx/edgetx-dev:latest\`. Run \`just ${RECIPE}\` and commit the result."
          echo
          echo '```'
          echo "${changed}"
          echo '```'
          echo
          echo "<details><summary>Diff</summary>"
          echo
          echo '```diff'
          echo "${truncated}"
          echo '```'
          echo
          echo "</details>"
        } >> "$GITHUB_STEP_SUMMARY"