#!/command/with-contenv bash
# shellcheck shell=bash
# Remap the frigate user to PUID/PGID and register EXTRA_GROUPS.
# No-op when: started with --user (euid != 0), FRIGATE_RUN_AS_ROOT=true,
# or PUID/PGID already match. FRIGATE_ROOT_SERVICES is validated here too.

set -o errexit -o nounset -o pipefail

if [[ "$(id -u)" -ne 0 ]]; then
    # Started with docker --user; the host owns UID mapping entirely.
    exit 0
fi

if [[ "${FRIGATE_RUN_AS_ROOT:-false}" == "true" ]]; then
    if [[ -n "${FRIGATE_ROOT_SERVICES:-}" ]]; then
        echo "[INFO] FRIGATE_RUN_AS_ROOT=true: ignoring FRIGATE_ROOT_SERVICES"
    fi
    echo "[INFO] FRIGATE_RUN_AS_ROOT=true: skipping user remapping"
    exit 0
fi

# a typo must fail the boot, not silently drop a service to non-root
if [[ -n "${FRIGATE_ROOT_SERVICES:-}" ]]; then
    IFS=',' read -ra root_services <<< "${FRIGATE_ROOT_SERVICES}"
    for entry in "${root_services[@]}"; do
        entry="${entry//[[:space:]]/}"
        if [[ -z "$entry" ]]; then
            continue
        fi
        case "$entry" in
            frigate|go2rtc|nginx) ;;
            *)
                echo "[ERROR] FRIGATE_ROOT_SERVICES contains unknown service '${entry}'; valid names are frigate, go2rtc, nginx" >&2
                exit 1
                ;;
        esac
    done
fi

puid="${PUID:-1000}"
pgid="${PGID:-1000}"

if ! [[ "$puid" =~ ^[0-9]+$ && "$pgid" =~ ^[0-9]+$ ]]; then
    echo "[ERROR] PUID and PGID must be numeric, got '${puid}' and '${pgid}'" >&2
    exit 1
fi

# Remapping to 0 would make the frigate user root, so every service would keep
# full privilege while reporting a successful migration.
if [[ "$puid" -eq 0 || "$pgid" -eq 0 ]]; then
    echo "[ERROR] PUID/PGID 0 would run the services as root and defeat the privilege separation." >&2
    echo "[ERROR] Set FRIGATE_RUN_AS_ROOT=true if you want to keep running as root." >&2
    exit 1
fi

# Colliding with the go2rtc ids would merge the two users and collapse the
# separation between the main process and the network-facing restreamer.
go2rtc_uid="$(id -u go2rtc)"
go2rtc_gid="$(id -g go2rtc)"
if [[ "$puid" -eq "$go2rtc_uid" || "$pgid" -eq "$go2rtc_gid" ]]; then
    echo "[ERROR] PUID/PGID must not equal the go2rtc service ids (${go2rtc_uid}:${go2rtc_gid})." >&2
    exit 1
fi

current_uid="$(id -u frigate)"
current_gid="$(id -g frigate)"

if [[ "$puid" != "$current_uid" || "$pgid" != "$current_gid" ]]; then
    if [[ ! -w /etc/passwd ]]; then
        echo "[ERROR] PUID/PGID remapping needs a writable /etc and is not compatible with read_only: true." >&2
        echo "[ERROR] Either remove read_only and keep PUID, or drop PUID/PGID and use docker's user: ${puid}:${pgid} instead." >&2
        echo "[ERROR] See https://docs.frigate.video/configuration/non_root for the compatibility matrix." >&2
        exit 1
    fi
    echo "[INFO] Remapping frigate user to ${puid}:${pgid}"
    groupmod -o -g "$pgid" frigate
    usermod -o -u "$puid" frigate
fi

# EXTRA_GROUPS: numeric host GIDs granting device access (e.g. host render/video)
if [[ -n "${EXTRA_GROUPS:-}" ]]; then
    # groupadd and usermod -aG both write /etc/group. Checked up front so a
    # read-only rootfs reports the real problem instead of dying mid-loop.
    if [[ ! -w /etc/group ]]; then
        echo "[ERROR] EXTRA_GROUPS needs a writable /etc and is not compatible with read_only: true." >&2
        echo "[ERROR] Use docker's group_add: with the same GIDs instead; it needs no writes inside the container." >&2
        echo "[ERROR] See https://docs.frigate.video/configuration/non_root for the compatibility matrix." >&2
        exit 1
    fi

    for gid in ${EXTRA_GROUPS//,/ }; do
        if ! [[ "$gid" =~ ^[0-9]+$ ]] || [[ "$gid" -eq 0 ]]; then
            echo "[ERROR] EXTRA_GROUPS must be nonzero numeric GIDs, got '${gid}'" >&2
            exit 1
        fi
        if ! getent group "$gid" >/dev/null; then
            groupadd -o -g "$gid" "frigate-extra-${gid}"
        fi
        group_name="$(getent group "$gid" | cut -d: -f1)"
        usermod -aG "$group_name" frigate
        usermod -aG "$group_name" go2rtc
        echo "[INFO] Added frigate and go2rtc to supplementary group ${group_name} (gid ${gid})"
    done
fi