#!/usr/bin/env bash
set -euo pipefail

ROOT_DIR=$(CDPATH= cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)
DIST_DIR="${DIST_DIR:-$ROOT_DIR/dist}"
APPDIR="${APPDIR:-$DIST_DIR/AppDir}"
APP_NAME="Mice"
APP_ID="mice"
ARCH_EXPECTED="aarch64"
APPIMAGETOOL_BIN="${APPIMAGETOOL_BIN:-appimagetool}"
PYTHON_BIN="${PYTHON_BIN:-python3}"
OUTPUT_APPIMAGE="${OUTPUT_APPIMAGE:-$DIST_DIR/${APP_NAME}-${ARCH_EXPECTED}.AppImage}"

PYTHON_DIR="$APPDIR/usr/opt/python"
GAME_DIR="$APPDIR/usr/share/mice"
LIB_DIR="$APPDIR/usr/lib"

require_command() {
    if ! command -v "$1" >/dev/null 2>&1; then
        printf 'Missing required command: %s\n' "$1" >&2
        exit 1
    fi
}

find_system_library() {
    local soname="$1"
    ldconfig -p | awk -v target="$soname" '$1 == target { print $NF; exit }'
}

should_bundle_soname() {
    case "$1" in
        linux-vdso.so.*|libc.so.*|libm.so.*|libpthread.so.*|libdl.so.*|librt.so.*|libutil.so.*|libresolv.so.*|ld-linux*.so.*)
            return 1
            ;;
        *)
            return 0
            ;;
    esac
}

copy_dependency_tree() {
    local binary="$1"
    local dep
    local soname

    while IFS= read -r dep; do
        [ -n "$dep" ] || continue
        [ -f "$dep" ] || continue
        soname=$(basename "$dep")
        if ! should_bundle_soname "$soname"; then
            continue
        fi
        if [ ! -e "$LIB_DIR/$soname" ]; then
            cp -a "$dep" "$LIB_DIR/$soname"
            chmod 755 "$LIB_DIR/$soname" || true
            copy_dependency_tree "$dep"
        fi
    done < <(
        ldd "$binary" 2>/dev/null | awk '
            /=>/ && $3 ~ /^\// { print $3 }
            $1 ~ /^\// { print $1 }
        ' | sort -u
    )
}

copy_system_library() {
    local soname="$1"
    local path
    path=$(find_system_library "$soname")
    if [ -z "$path" ]; then
        printf 'Unable to locate required system library: %s\n' "$soname" >&2
        exit 1
    fi
    cp -a "$path" "$LIB_DIR/$(basename "$path")"
    chmod 755 "$LIB_DIR/$(basename "$path")" || true
    copy_dependency_tree "$path"
}

printf '==> Checking build prerequisites\n'
require_command rsync
require_command "$PYTHON_BIN"
require_command "$APPIMAGETOOL_BIN"
require_command ldconfig
require_command ldd

if [ "$(uname -m)" != "$ARCH_EXPECTED" ]; then
    printf 'This builder must run on %s. Current architecture: %s\n' "$ARCH_EXPECTED" "$(uname -m)" >&2
    exit 1
fi

printf '==> Creating AppDir at %s\n' "$APPDIR"
rm -rf "$APPDIR"
mkdir -p "$DIST_DIR" "$LIB_DIR" "$GAME_DIR"

printf '==> Building bundled Python environment with %s\n' "$PYTHON_BIN"
"$PYTHON_BIN" -m venv --copies "$PYTHON_DIR"
"$PYTHON_DIR/bin/pip" install --upgrade pip setuptools wheel
"$PYTHON_DIR/bin/pip" install -r "$ROOT_DIR/requirements.txt"

printf '==> Syncing game files\n'
rsync -a \
    --delete \
    --exclude '.git' \
    --exclude '.github' \
    --exclude '.venv' \
    --exclude '__pycache__' \
    --exclude '*.pyc' \
    --exclude '.mypy_cache' \
    --exclude '.pytest_cache' \
    --exclude 'build' \
    --exclude 'dist' \
    --exclude 'packaging' \
    "$ROOT_DIR/" "$GAME_DIR/"

rm -f "$GAME_DIR/user_profiles.json" "$GAME_DIR/scores.txt"

printf '==> Installing AppImage metadata\n'
install -Dm755 "$ROOT_DIR/packaging/appimage/AppRun" "$APPDIR/AppRun"
install -Dm644 "$ROOT_DIR/packaging/appimage/mice.desktop" "$APPDIR/$APP_ID.desktop"
install -Dm644 "$ROOT_DIR/packaging/appimage/mice.desktop" "$APPDIR/usr/share/applications/$APP_ID.desktop"
install -Dm644 "$ROOT_DIR/assets/Rat/BMP_WEWIN.png" "$APPDIR/$APP_ID.png"
install -Dm644 "$ROOT_DIR/assets/Rat/BMP_WEWIN.png" "$APPDIR/usr/share/icons/hicolor/256x256/apps/$APP_ID.png"

printf '==> Bundling native dependencies\n'
copy_system_library libSDL2-2.0.so.0
copy_system_library libSDL2_ttf-2.0.so.0
copy_dependency_tree "$PYTHON_DIR/bin/python"

while IFS= read -r -d '' candidate; do
    copy_dependency_tree "$candidate"
done < <(find "$PYTHON_DIR" -type f \( -name '*.so' -o -name '*.so.*' -o -perm -u+x \) -print0)

printf '==> Building AppImage %s\n' "$OUTPUT_APPIMAGE"
ARCH="$ARCH_EXPECTED" "$APPIMAGETOOL_BIN" --appimage-extract-and-run "$APPDIR" "$OUTPUT_APPIMAGE"

printf 'AppImage created at %s\n' "$OUTPUT_APPIMAGE"