name: 'Codegen drift check'
description: >
  Runs a Justfile codegen recipe and fails the job when the committed output
  differs from what the recipe produces. The job is deliberately not a
  required status check, so drift is visible on the PR without blocking a
  contributor who lacks the local toolchain from merging.

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

runs:
  using: "composite"
  steps:

    - 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: ${{ inputs.label }}
      run: |
        # This job is not a required status check (see description above), so
        # failing here surfaces real drift on the PR without blocking a
        # contributor who lacks the local toolchain from merging.
        # Word splitting on PATHS is intentional - it may hold several pathspecs.
        # shellcheck disable=SC2086
        changed=$(git status --porcelain -- ${PATHS})
        if [ -z "${changed}" ]; then
          echo "${LABEL}: up to date"
          exit 0
        fi

        echo "::error::${LABEL} is out of date.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 would clobber the exit 1 below with a 141.
        # shellcheck disable=SC2086
        diff=$(git diff -- ${PATHS} || true)
        truncated="${diff:0:60000}"
        if [ "${#diff}" -gt "${#truncated}" ]; then
          truncated="${truncated}"$'\n''... diff truncated ...'
        fi

        {
          echo "### :x: ${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"

        exit 1