name: Automated Arch ISO Build

on:
  schedule:
    - cron: "0 0 1 * *" # Runs monthly on the 1st day of the month
  workflow_dispatch: # Allows manual triggers (multiple times a month)

concurrency:
  group: iso-build
  cancel-in-progress: false # Never kill a build that is mid-flight

jobs:
  build:
    runs-on: archlinux
    permissions:
      contents: write

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Setup local AUR repo
        run: |
          set -euo pipefail
          mkdir -p /tmp/localrepo
          cp localrepo/*.pkg.tar.zst localrepo/local-aur.db* localrepo/local-aur.files* /tmp/localrepo/
          sed -i 's|file:///home/alvin/alvinarch/localrepo|file:///tmp/localrepo|' pacman.conf

      - name: Install archiso and dependencies
        run: |
          set -euo pipefail
          pacman -Syu --noconfirm --needed archiso jq zstd

      - name: Ensure /dev/stdin exists for mkinitcpio
        run: |
          set -euo pipefail
          # Docker/container environments may lack /dev/stdin; mkinitcpio needs it
          [ -e /dev/stdin ]  || ln -sf /proc/self/fd/0 /dev/stdin
          [ -e /dev/stdout ] || ln -sf /proc/self/fd/1 /dev/stdout
          [ -e /dev/stderr ] || ln -sf /proc/self/fd/2 /dev/stderr

      - name: Build Arch ISO
        run: |
          set -euo pipefail
          # Clean up immediately even if this step is interrupted (cancel/exit):
          # unmount leftovers first, then remove the multi-GB work dir.
          trap 'umount -R "$PWD/work" 2>/dev/null || true; rm -rf "$PWD/work"' EXIT HUP INT TERM
          rm -rf "$PWD/work"
          # Always start from an empty out dir so stale ISOs are never re-uploaded
          rm -rf "$PWD/out"
          mkdir -p "$PWD/out"
          mkarchiso -v -w "$PWD/work" -o "$PWD/out" -- "$PWD"

      - name: Generate Unique Dynamic Tag
        id: tag
        env:
          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
          GITEA_API: http://192.168.1.168:3000/api/v1
          REPOSITORY: ${{ github.repository }}
        run: |
          set -euo pipefail
          test -n "$GITEA_TOKEN"

          # Pre-flight: confirm the internal Gitea API is reachable so failures are clear
          if ! curl -sfS -o /dev/null "$GITEA_API/version"; then
            echo "❌ Cannot reach Gitea API at $GITEA_API" >&2
            exit 1
          fi

          BASE_DATE=$(date -u +'%Y.%m.%d')
          REVISION=1
          TAG_NAME="iso-${BASE_DATE}-r${REVISION}"

          # Check if the tag already exists via Gitea API, increment revision loop if it does
          while curl -sf -o /dev/null -H "Authorization: token $GITEA_TOKEN" \
            "$GITEA_API/repos/$REPOSITORY/releases/tags/$TAG_NAME"; do
            REVISION=$((REVISION + 1))
            TAG_NAME="iso-${BASE_DATE}-r${REVISION}"
          done

          echo "tag_name=${TAG_NAME}" >> "$GITHUB_OUTPUT"
          echo "release_name=Arch Linux ISO (${BASE_DATE} Rev ${REVISION})" >> "$GITHUB_OUTPUT"

      - name: Create Release and Upload ISO
        env:
          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
          # Use internal Gitea URL to bypass traefik proxy timeout on large uploads
          GITEA_API: http://192.168.1.168:3000/api/v1
          REPOSITORY: ${{ github.repository }}
          TAG_NAME: ${{ steps.tag.outputs.tag_name }}
          RELEASE_NAME: ${{ steps.tag.outputs.release_name }}
        run: |
          set -euo pipefail
          shopt -s nullglob
          test -n "$GITEA_TOKEN"
          test -n "$TAG_NAME"
          test -n "$RELEASE_NAME"

          # Pre-flight: confirm the internal Gitea API is reachable so failures are clear
          if ! curl -sfS -o /dev/null "$GITEA_API/version"; then
            echo "❌ Cannot reach Gitea API at $GITEA_API" >&2
            exit 1
          fi

          # Collect the ISOs produced by the build
          isos=(out/*.iso)
          if (( ${#isos[@]} == 0 )); then
            echo "❌ No ISO found in out/ — nothing to upload, aborting." >&2
            exit 1
          fi

          # Compress each ISO with zstd and record its SHA-256
          zst_files=()
          sha256sums=()
          for iso in "${isos[@]}"; do
            fname=$(basename "$iso")
            size=$(stat -c %s "$iso")
            # Sanity check: a real ISO is multi-GB; anything tiny is the wrong file
            if (( size < 100000000 )); then
              echo "❌ '$iso' is only $size bytes — refusing to upload (not an ISO)." >&2
              exit 1
            fi

            echo "Compressing $fname ($(( size / 1024 / 1024 )) MiB) with zstd..."
            zstd -T0 -19 -f "$iso" -o "$iso.zst" --rm
            sha=$(sha256sum "$iso.zst" | awk '{print $1}')
            echo "  ✅ ${fname}.zst: $(( $(stat -c %s "$iso.zst") / 1024 / 1024 )) MiB, sha256=$sha"
            zst_files+=("$iso.zst")
            sha256sums+=("$sha")
          done

          # Build the release body with SHA-256 checksums
          printf -v body 'Arch Linux live ISO %s\n\nChecksums (SHA-256):\n' "$RELEASE_NAME"
          for i in "${!zst_files[@]}"; do
            printf -v line -- '- `%s`: sha256 `%s`\n' "$(basename "${zst_files[$i]}")" "${sha256sums[$i]}"
            body+="$line"
          done

          # Create the release
          payload=$(jq -nc --arg tag "$TAG_NAME" --arg name "$RELEASE_NAME" --arg body "$body" \
            '{tag_name:$tag,name:$name,body:$body}')
          RELEASE_ID=$(curl -sf -X POST \
            -H "Authorization: token $GITEA_TOKEN" \
            -H "Content-Type: application/json" \
            "$GITEA_API/repos/$REPOSITORY/releases" \
            -d "$payload" | jq -er '.id')
          echo "  ✅ Created release $TAG_NAME (ID: $RELEASE_ID)"

          # Upload each .zst file as a release asset
          for i in "${!zst_files[@]}"; do
            fname=$(basename "${zst_files[$i]}")
            size=$(stat -c %s "${zst_files[$i]}")
            echo "Uploading $fname ($(( size / 1024 / 1024 )) MiB) to release $TAG_NAME..."
            curl -sf -X POST \
              -H "Authorization: token $GITEA_TOKEN" \
              -F "attachment=@${zst_files[$i]}" \
              "$GITEA_API/repos/$REPOSITORY/releases/$RELEASE_ID/assets" | jq -er '.browser_download_url'
            echo "  ✅ Uploaded $fname"
          done

      - name: Keep only latest 2 releases
        if: success()
        env:
          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
          GITEA_API: http://192.168.1.168:3000/api/v1
          REPOSITORY: ${{ github.repository }}
        run: |
          set -euo pipefail
          test -n "$GITEA_TOKEN"

          echo "Pruning old releases in $REPOSITORY..."
          readarray -t ids < <(curl -sf -H "Authorization: token $GITEA_TOKEN" \
            "$GITEA_API/repos/$REPOSITORY/releases" \
            | jq -er 'sort_by(.created_at) | .[].id')

          to_delete=$(( ${#ids[@]} - 2 ))
          if (( to_delete > 0 )); then
            for ((i = 0; i < to_delete; i++)); do
              id=${ids[$i]}
              echo "Deleting old release ID: $id"
              curl -sf -X DELETE -H "Authorization: token $GITEA_TOKEN" \
                "$GITEA_API/repos/$REPOSITORY/releases/$id"
            done
          fi

      - name: Cleanup mkarchiso mounts and workdirs
        if: always() # Runs on success, failure, or cancellation
        run: |
          set -eu
          # Steps run as root (pacman is used directly); fall back to sudo if not
          if [ "$(id -u)" -eq 0 ]; then
            PRIV=""
          else
            PRIV="sudo"
          fi

          # Unmount any leftover loop devices or bind mounts in the work directory
          $PRIV umount -R "$PWD/work" 2>/dev/null || true

          # Clean up loop devices if any remain attached to the work dir
          $PRIV losetup -D || true

          # Remove working directories with proper permissions
          $PRIV rm -rf "$PWD/work"

      - name: Remove built ISO
        if: always()
        run: |
          set -eu
          rm -rf "$PWD/out"