#!/bin/sh
set -eu

: "${SWITCH_DATA_ROOT:?set the isolated app-owned Switch data root}"
: "${SWITCH_LIBRARY:?set the read-only Switch source library}"
: "${PUID:?set the non-root Eden UID}"
: "${PGID:?set the non-root Eden GID}"

case "$PUID:$PGID" in
    *[!0-9:]*|:*|*:) echo "PUID and PGID must be numeric." >&2; exit 1 ;;
esac

if [ "$PUID" -eq 0 ] || [ "$PGID" -eq 0 ]; then
    echo "Eden must use a non-root PUID and PGID." >&2
    exit 1
fi

case "$SWITCH_DATA_ROOT" in
    /*) ;;
    *) echo "SWITCH_DATA_ROOT must be absolute." >&2; exit 1 ;;
esac

case "$SWITCH_LIBRARY" in
    /*) ;;
    *) echo "SWITCH_LIBRARY must be absolute." >&2; exit 1 ;;
esac

data_parent=$(dirname -- "$SWITCH_DATA_ROOT")
data_name=$(basename -- "$SWITCH_DATA_ROOT")
if [ ! -d "$data_parent" ]; then
    echo "The SWITCH_DATA_ROOT parent must already exist: $data_parent" >&2
    exit 1
fi

data_parent=$(readlink -f -- "$data_parent")
data_root=$(readlink -m -- "$data_parent/$data_name")
library_root=$(readlink -f -- "$SWITCH_LIBRARY")

case "$data_root" in
    /|/mnt|/mnt/user|/mnt/user/appdata)
        echo "Refusing unsafe SWITCH_DATA_ROOT: $data_root" >&2
        exit 1
        ;;
esac

case "$data_root/" in
    "$library_root"/*)
        echo "SWITCH_DATA_ROOT must not be inside the source library." >&2
        exit 1
        ;;
esac

case "$library_root/" in
    "$data_root"/*)
        echo "SWITCH_LIBRARY must not be inside app-owned data." >&2
        exit 1
        ;;
esac

mkdir -p -- "$data_root/config"
data_root=$(readlink -f -- "$data_root")

# Eden must be able to read and update its own persistent config after a PUID/PGID change.
# This path is app-owned; the source library is intentionally never touched.
chown -R "$PUID:$PGID" -- "$data_root/config"
chmod 750 -- "$data_root/config"
find "$data_root/config" -type f -name qt-config.ini -exec chmod 600 {} +

printf 'Prepared %s for Eden identity %s:%s; source library untouched: %s\n' \
    "$data_root/config" "$PUID" "$PGID" "$library_root"