#!/usr/bin/bash

set -euo pipefail

file=/usr/libexec/os-branch-select

if [[ ! -f "$file" ]]; then
  echo "Unable to locate Bazzite OS branch selector: $file" >&2
  exit 1
fi

old='      branch=$(cut -d ":" -f4 <<< "$(rpm-ostree status --booted | grep -m 1 $ID)")'
if ! grep -Fxq "$old" "$file"; then
  echo "Bazzite OS branch selector changed; review the downstream patch" >&2
  exit 1
fi

patched_file=$(mktemp)
awk -v old="$old" '
  $0 == old {
    print "      # Read the booted deployment directly; its image name need not match os-release ID."
    print "      image_ref=$(rpm-ostree status --booted --json | jq -r '\''[.deployments[] | select(.booted) | .[\"container-image-reference\"] // empty][0] // empty'\'')"
    print "      branch=\"\""
    print "      if [[ $image_ref =~ :([^/:]+)$ ]]; then"
    print "        branch=${BASH_REMATCH[1]}"
    print "      fi"
    found++
    next
  }
  { print }
  END { if (found != 1) exit 1 }
' "$file" > "$patched_file"

install -m 0755 "$patched_file" "$file"
rm -f "$patched_file"

# Match the channel names used by Bazzite's Game Mode announcement feeds.
# Steam's rc/beta and bc/main aliases still select the same image branches.
python3 - "$file" <<'PY'
from pathlib import Path
import sys

path = Path(sys.argv[1])
text = path.read_text()
replacements = {
    "        testing)\n          echo rc\n": "        testing)\n          echo beta\n",
    "        unstable)\n          echo main\n": "        unstable)\n          echo preview\n",
    "      echo rc\n      echo beta\n      echo bc\n      echo main\n":
        "      echo rc\n      echo beta\n      echo bc\n      echo preview\n      echo main\n",
    "    bc|main|unstable)\n": "    bc|preview|main|unstable)\n",
}
for old in replacements:
    if text.count(old) != 1:
        raise SystemExit(f"Bazzite branch selector changed; expected exactly one {old!r}")
for old, new in replacements.items():
    text = text.replace(old, new, 1)
path.write_text(text)
PY