name: update-inputs

on:
  schedule:
    - cron: "0 6 * * 2,5" # Tue & Fri
  workflow_dispatch:

jobs:
  update-flake-lock:
    runs-on: nixos

    env:
      BASE_BRANCH: main
      BRANCH_PREFIX: flake-lock-update
      FJ_URL: https://code.oliverdavies.uk
      GIT_AUTHOR_EMAIL: flake-bot@local
      GIT_AUTHOR_NAME: flake-bot
      GIT_COMMITTER_EMAIL: ${{ env.GIT_AUTHOR_EMAIL }}
      GIT_COMMITTER_NAME: ${{ env.GIT_AUTHOR_NAME }}

    steps:
      - uses: actions/checkout@v3
        with: { fetch-depth: 0 }

      - name: Update inputs & commit
        id: bump
        run: |
          set -o errexit
          set -o nounset
          set -o pipefail

          BRANCH="${BRANCH_PREFIX}-${GITHUB_RUN_ID}"
          git switch -c "$BRANCH"

          BEFORE=$(git rev-parse HEAD)

          # Nix updates inputs and commits if needed
          nix flake update --commit-lock-file

          AFTER=$(git rev-parse HEAD)
          if [ "$BEFORE" = "$AFTER" ]; then
            echo "changed=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          # ── Grab commit info ────────────────────────────────────────────────
          # Full message
          COMMIT_RAW=$(git log -1 --pretty=%B)

          # First line is the short summary; we keep lines AFTER the first blank
          COMMIT_BODY=$(printf '%s\n' "$COMMIT_RAW" \
            | sed '1,/^$/d' \
            | sed 's/^• */* /') # nicer Markdown bullet

          # Title becomes first line of the PR
          COMMIT_TITLE=$(printf '%s\n' "$COMMIT_RAW" | head -n1)

          # JSON-escape the body so \n etc. are valid JSON
          BODY_JSON=$(printf '%s' "$COMMIT_BODY" | jq -Rs .)

          echo "changed=true" >> "$GITHUB_OUTPUT"
          echo "branch=$BRANCH" >> "$GITHUB_OUTPUT"
          echo "title=$COMMIT_TITLE" >> "$GITHUB_OUTPUT"
          echo "body_json=$BODY_JSON" >> "$GITHUB_OUTPUT"

          git push -u origin "$BRANCH"

      - name: Open pull-request
        if: steps.bump.outputs.changed == 'true'
        env:
          TOKEN: ${{ secrets.FLAKE_UPDATE_PAT }}
          BRANCH: ${{ steps.bump.outputs.branch }}
          TITLE: ${{ steps.bump.outputs.title }}
          BODY_JSON: ${{ steps.bump.outputs.body_json }}
        run: |
          set -o errexit
          set -o nounset

          OWNER="${GITHUB_REPOSITORY%%/*}"
          REPO="${GITHUB_REPOSITORY#*/}"

          curl -fSs -X POST "$FJ_URL/api/v1/repos/$OWNER/$REPO/pulls" \
            -H "Authorization: token $TOKEN" \
            --json '{
              "base": "'"$BASE_BRANCH"'",
              "body": '"$BODY_JSON"',
              "draft": false,
              "head": "'"$BRANCH"'",
              "title": "'"$TITLE"'"
            }'