#!/usr/bin/env bash
# Second Coat on a Steam Deck, or any Linux PC with Steam: the launcher in
# ~/SecondCoat, and the launcher and each game in the Steam library with
# their artwork, to start from Gaming Mode.
#
# The installer file on secondcoat.dev/steam-deck/ runs this in a terminal
# from Desktop Mode:
#
#   curl -fsSL https://secondcoat.dev/steam-deck/install.sh | bash
#
# It needs no password: everything goes in your home folder. Steam closes
# while the launcher adds itself to the library (`--steam-setup`), and
# starts again after. Running it again updates the launcher and puts the
# tiles back.
set -euo pipefail

manifest="https://files.secondcoat.dev/launcher/latest.json"
dir="$HOME/SecondCoat"
app="$dir/Second-Coat.AppImage"

say() { printf '\n\033[1;33m%s\033[0m\n' "$*"; }
fail() {
  printf '\n\033[1;31m%s\033[0m\n' "$*" >&2
  exit 1
}

[ "$(uname -s)-$(uname -m)" = Linux-x86_64 ] || fail "Second Coat runs on x86-64 Linux here (a Steam Deck is one)."
for tool in curl sha256sum python3; do
  command -v "$tool" >/dev/null || fail "This needs $tool, which is missing."
done

say "Looking up the latest launcher…"
json="$(curl -fsSL "$manifest")" || fail "files.secondcoat.dev cannot be reached. Check the connection and try again."
# The AppImage of the launcher's release manifest: version, file, SHA-256.
read -r version file sha256 < <(python3 -c '
import json, sys
m = json.loads(sys.argv[1])
b = m.get("builds", {}).get("linux", {}).get("appimage")
if b: print(m["version"], b["file"], b["sha256"])
' "$json") || fail "There is no launcher for Linux to download yet."

mkdir -p "$dir"
part="$dir/.Second-Coat.AppImage.part"
say "Downloading the Second Coat launcher $version…"
curl -fL --progress-bar -o "$part" "https://files.secondcoat.dev/launcher/$version/$file" \
  || fail "The download stopped. Run the installer again to try once more."
if ! echo "$sha256  $part" | sha256sum -c --status; then
  rm -f "$part"
  fail "The download is damaged (its SHA-256 does not match). Run the installer again."
fi
chmod +x "$part"
mv -f "$part" "$app"
echo "$app"

# An AppImage mounts itself with FUSE 2; without it, it unpacks itself
# to a temporary folder instead.
if ! { [ -e /dev/fuse ] && /sbin/ldconfig -p 2>/dev/null | grep -q 'libfuse\.so\.2'; }; then
  export APPIMAGE_EXTRACT_AND_RUN=1
fi

say "Adding Second Coat to Steam. Steam closes, and opens again after…"
"$app" --steam-setup || fail "Second Coat could not be added to Steam (see above)."

if grep -qs '^ID=steamos' /etc/os-release; then
  say "Done. Double-click Return to Gaming Mode on the desktop: Second Coat is in your library, under Non-Steam."
else
  say "Done: Second Coat is in your Steam library."
fi