#!/usr/bin/env bash
# Extracts the game data Shockolate needs out of a purchased System Shock:
# Enhanced Edition installer from gog.com, into ./ss_ee/{data,sound}.
#
# Usage:
#   1. Buy System Shock: Enhanced Edition on gog.com and download the
#      offline installer (a Windows .exe, e.g.
#      setup_system_shock_enhanced_edition_1.2.16_(64bit)_(44378).exe).
#   2. Drop it in this directory (res/assets/).
#   3. Run this script: ./extract_assets.sh
#
# The installer is an Inno Setup package; the actual game data lives
# inside it in sshock.kpf, which is just a zip file. Its res/pc/hd/ and
# res/pc/cdrom/ trees together hold every classic-game data/sound file
# Shockolate's res/ folder expects (res/pc/hd wins the couple of
# filenames present in both: intro.res, objprop.dat), EXCEPT
# mfdfrn.res/mfdger.res (French/German MFD art - see CONFIG.md/README.md),
# which that installer doesn't include at all - see "Optional: French/
# German MFD art" below for where those instead come from. Needs
# innoextract and unzip; if they're not installed locally, this script
# does the extraction inside a throwaway Ubuntu container instead (needs
# docker in that case, nothing else).
#
# Optional: French/German MFD art
#   The Enhanced Edition installer's data set doesn't include
#   mfdfrn.res/mfdger.res, so French/German are otherwise missing their
#   MFD (Multi-Function Display) art and the game refuses to switch to
#   them (see CONFIG.md). System Shock: Classic (also gog.com) does
#   include both files. If you also own it, drop its offline installer
#   (e.g. setup_system_shock_classic_2.0.0.3.exe) in this directory too -
#   entirely optional, this script still runs fine without it - and this
#   script pulls just those two files out of it into ss_ee/data/ as well.
set -euo pipefail

cd "$(dirname "${BASH_SOURCE[0]}")"
ASSETS_DIR="$(pwd)"
OUT_DIR="$ASSETS_DIR/ss_ee"

fail() { echo "PREFLIGHT FAIL: $*" >&2; exit 1; }

shopt -s nullglob
installers=(setup_system_shock_enhanced_edition*.exe)
classic_installers=(setup_system_shock_classic*.exe)
shopt -u nullglob
case "${#installers[@]}" in
    0) fail "no setup_system_shock_enhanced_edition*.exe found in $ASSETS_DIR - buy System Shock: Enhanced Edition on gog.com, download the offline installer, and drop it here" ;;
    1) ;;
    *) fail "multiple installer .exe files found in $ASSETS_DIR - keep only one: ${installers[*]}" ;;
esac
INSTALLER="${installers[0]}"

# Optional - see "Optional: French/German MFD art" above. Empty (not
# missing/failed) when absent; only a genuine ambiguity (more than one
# candidate file) is a hard failure.
case "${#classic_installers[@]}" in
    0) CLASSIC_INSTALLER="" ;;
    1) CLASSIC_INSTALLER="${classic_installers[0]}" ;;
    *) fail "multiple setup_system_shock_classic*.exe files found in $ASSETS_DIR - keep only one: ${classic_installers[*]}" ;;
esac

# Extracts sshock.kpf from $1 (an installer .exe) and assembles $2 (an
# ss_ee output directory) from its res/pc/{hd,cdrom} trees. Defined as a
# function so the exact same logic can run either natively or, via
# `declare -f`, inside a throwaway container.
run_extraction() {
    set -euo pipefail
    local installer="$1" out_dir="$2"
    # Deliberately not `local`: an EXIT trap set here fires when the whole
    # shell process exits, which is after this function - and this
    # function's own scope - has already returned, so a `local` var would
    # already be unset by then (unbound-variable error under `set -u`).
    work="$(mktemp -d)"
    trap 'rm -rf "${work:-}"' EXIT

    echo "== Extracting sshock.kpf from installer =="
    innoextract --silent --include sshock.kpf -d "$work/installer" "$installer"

    echo "== Unpacking sshock.kpf (data/sound trees only) =="
    mkdir -p "$work/kpf"
    unzip -q "$work/installer/sshock.kpf" \
        'res/pc/hd/data/*' 'res/pc/hd/sound/*' 'res/pc/cdrom/data/*' \
        -d "$work/kpf"

    echo "== Assembling $out_dir =="
    rm -rf "$out_dir"
    mkdir -p "$out_dir/data" "$out_dir/sound"
    # cdrom/data first (cutscenes, audio logs, and shared tables only it
    # has), then hd/data on top (wins the 2 overlapping filenames:
    # intro.res, objprop.dat - the hd install's own copies).
    cp -a "$work/kpf/res/pc/cdrom/data/." "$out_dir/data/"
    cp -a "$work/kpf/res/pc/hd/data/." "$out_dir/data/"
    cp -a "$work/kpf/res/pc/hd/sound/." "$out_dir/sound/"
}

# Extracts mfdfrn.res/mfdger.res from $1 (a System Shock: Classic installer
# .exe) into $2 (an existing ss_ee output directory's data/ subfolder) -
# see "Optional: French/German MFD art" above. Unlike the Enhanced Edition
# installer, Classic's data files sit directly in the Inno Setup package
# (no intermediate zip), so this is just a targeted innoextract --include,
# no unzip step needed. Same declare -f-into-docker structure as
# run_extraction() above.
run_classic_mfd_extraction() {
    set -euo pipefail
    local installer="$1" out_dir="$2"
    work="$(mktemp -d)"
    trap 'rm -rf "${work:-}"' EXIT

    echo "== Extracting mfdfrn.res/mfdger.res from classic installer =="
    innoextract --silent \
        --include 'app/SSHOCK/DATA/MFDFRN.RES' --include 'app/SSHOCK/DATA/MFDGER.RES' \
        -d "$work/classic" "$installer"

    # Original DOS-era filenames are uppercase; Shockolate's resource
    # loader expects the lowercase names already used for every other
    # res/data/*.res file (case-sensitive on Linux, unlike the DOS/Windows
    # filesystems these came from).
    cp "$work/classic/app/SSHOCK/DATA/MFDFRN.RES" "$out_dir/data/mfdfrn.res"
    cp "$work/classic/app/SSHOCK/DATA/MFDGER.RES" "$out_dir/data/mfdger.res"
}

if command -v innoextract >/dev/null 2>&1 && command -v unzip >/dev/null 2>&1; then
    echo "== Using local innoextract/unzip =="
    run_extraction "$ASSETS_DIR/$INSTALLER" "$OUT_DIR"
    if [ -n "$CLASSIC_INSTALLER" ]; then
        run_classic_mfd_extraction "$ASSETS_DIR/$CLASSIC_INSTALLER" "$OUT_DIR"
    fi
else
    echo "== innoextract/unzip not found locally - using a throwaway docker container =="
    command -v docker >/dev/null 2>&1 \
        || fail "docker not found in PATH (needed since innoextract/unzip aren't installed locally)"
    docker run --rm \
        -v "$ASSETS_DIR:/assets" \
        -e HOST_UID="$(id -u)" \
        -e HOST_GID="$(id -g)" \
        ubuntu:22.04 \
        bash -c "
            set -euo pipefail
            apt-get update -qq >/dev/null
            apt-get install -y -qq innoextract unzip >/dev/null
            $(declare -f run_extraction)
            $(declare -f run_classic_mfd_extraction)
            run_extraction '/assets/$INSTALLER' '/assets/ss_ee'
            $([ -n "$CLASSIC_INSTALLER" ] && echo "run_classic_mfd_extraction '/assets/$CLASSIC_INSTALLER' '/assets/ss_ee'")
            chown -R \"\$HOST_UID:\$HOST_GID\" /assets/ss_ee
        "
fi

echo "== Done =="
echo "Assets extracted to $OUT_DIR"
if [ -n "$CLASSIC_INSTALLER" ]; then
    echo "Also extracted mfdfrn.res/mfdger.res (French/German MFD art) from $CLASSIC_INSTALLER."
else
    echo "Note: mfdfrn.res/mfdger.res (French/German MFD art) are not present - only needed for"
    echo "French/German (see CONFIG.md); drop a System Shock: Classic installer here too to get them."
fi