release.yml

name: Release

on:
  push:
    tags:
      - 'v*'
  workflow_dispatch:
    inputs:
      tag:
        description: 'Tag to release (e.g. v0.1.0)'
        required: true

permissions:
  contents: write

jobs:
  release:
    name: Build and Upload Firmware
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Get version from tag
        run: |
          VERSION="${{ github.event.inputs.tag || github.ref_name }}"
          echo "VERSION=${VERSION}" >> "$GITHUB_ENV"
          echo "VERSION_CLEAN=${VERSION#v}" >> "$GITHUB_ENV"

      - name: Cache PlatformIO
        uses: actions/cache@v4
        with:
          path: ~/.platformio
          key: pio-${{ runner.os }}-${{ hashFiles('platformio.ini') }}

      - name: Install PlatformIO
        run: pipx install platformio

      - name: Build firmware
        id: build
        run: |
          BUILD_OUTPUT=$(pio run -e ATmega2560 2>&1)
          echo "$BUILD_OUTPUT"

          RAM_LINE=$(echo "$BUILD_OUTPUT"  | grep -E "^RAM:")
          FLASH_LINE=$(echo "$BUILD_OUTPUT" | grep -E "^Flash:")

          RAM_PCT=$(echo   "$RAM_LINE"   | grep -oP '\d+\.\d+(?=%)' | head -1)
          FLASH_PCT=$(echo "$FLASH_LINE" | grep -oP '\d+\.\d+(?=%)' | head -1)
          RAM_USED=$(echo   "$RAM_LINE"   | grep -oP 'used \K\d+')
          RAM_TOTAL=$(echo  "$RAM_LINE"   | grep -oP 'from \K\d+')
          FLASH_USED=$(echo "$FLASH_LINE" | grep -oP 'used \K\d+')
          FLASH_TOTAL=$(echo "$FLASH_LINE" | grep -oP 'from \K\d+')

          echo "ram_pct=${RAM_PCT}"       >> "$GITHUB_OUTPUT"
          echo "flash_pct=${FLASH_PCT}"   >> "$GITHUB_OUTPUT"
          echo "ram_used=${RAM_USED}"     >> "$GITHUB_OUTPUT"
          echo "ram_total=${RAM_TOTAL}"   >> "$GITHUB_OUTPUT"
          echo "flash_used=${FLASH_USED}" >> "$GITHUB_OUTPUT"
          echo "flash_total=${FLASH_TOTAL}" >> "$GITHUB_OUTPUT"

      - name: Collect artifacts
        run: |
          cp .pio/build/ATmega2560/firmware.hex "OBDisplay-Emu-${{ env.VERSION_CLEAN }}.hex"
          cp .pio/build/ATmega2560/firmware.elf "OBDisplay-Emu-${{ env.VERSION_CLEAN }}.elf"

      - name: Generate release notes
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          SHA=$(git rev-parse HEAD)
          DATE=$(date -u '+%Y-%m-%d %H:%M UTC')

          CHANGELOG=$(gh api "repos/${{ github.repository }}/releases/generate-notes" \
            --method POST \
            -f tag_name="${{ env.VERSION }}" \
            --jq '.body' 2>/dev/null || echo "")

          {
            if [ -n "$CHANGELOG" ]; then
              echo "$CHANGELOG"
              echo ""
              echo "---"
              echo ""
            fi
            cat <<ENDBUILDINFO
          ## OBDisplay-Emu ${{ env.VERSION }}

          ### Build info

          | | |
          |---|---|
          | Version | ${{ env.VERSION }} |
          | Commit | \`${SHA}\` |
          | Built | ${DATE} |
          | Target | Arduino Mega (ATmega2560, 16 MHz) |
          | Flash | ${{ steps.build.outputs.flash_used }} / ${{ steps.build.outputs.flash_total }} bytes (${{ steps.build.outputs.flash_pct }}%) |
          | RAM | ${{ steps.build.outputs.ram_used }} / ${{ steps.build.outputs.ram_total }} bytes (${{ steps.build.outputs.ram_pct }}%) |

          ### Flashing

          Download \`OBDisplay-Emu-${{ env.VERSION_CLEAN }}.hex\` and flash with avrdude:

          \`\`\`bash
          avrdude -c arduino -p atmega2560 -P /dev/ttyUSB0 -b 115200 \\
            -U flash:w:OBDisplay-Emu-${{ env.VERSION_CLEAN }}.hex:i
          \`\`\`

          Replace \`/dev/ttyUSB0\` with your port (\`COM3\` on Windows).

          The \`.elf\` file is a developer artifact (debug symbols, flash analysis). It cannot be flashed directly — use the \`.hex\` above.

          ENDBUILDINFO
          } > release-notes.md

      - name: Create or update GitHub release
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          gh release create "${{ env.VERSION }}" \
            --title "${{ env.VERSION }}" \
            --notes-file release-notes.md \
            "OBDisplay-Emu-${{ env.VERSION_CLEAN }}.hex" \
            "OBDisplay-Emu-${{ env.VERSION_CLEAN }}.elf" \
          || gh release upload "${{ env.VERSION }}" \
            "OBDisplay-Emu-${{ env.VERSION_CLEAN }}.hex" \
            "OBDisplay-Emu-${{ env.VERSION_CLEAN }}.elf" \
            --clobber