#!/bin/sh /etc/rc.common
# shellcheck disable=SC2034,SC3043

USE_PROCD=1
START=99

NAME="ua3f"
PROG="/usr/bin/$NAME"
SERVER_MODE=""
UA3F_GROUP="nogroup"
LOG_FILE="/var/log/ua3f/ua3f.log"

LOG() {
    if [ -n "${1}" ]; then
        printf '[%s] %s\n' "$(date "+%Y-%m-%d %H:%M:%S")" "$1" >>"$LOG_FILE"
    fi
}

opkg_available() { command -v opkg >/dev/null 2>&1; }

openclash_exists() {
    if opkg_available; then
        if opkg list-installed luci-app-openclash | grep -q 'luci-app-openclash'; then
            return 0
        fi
    fi
    return 1
}

openclash_running() {
    if pgrep -f "openclash" >/dev/null 2>&1; then
        return 0
    fi
    return 1
}

shellclash_exists() {
    if id -u shellclash >/dev/null 2>&1; then
        return 0
    fi
    if id -u shellcrash >/dev/null 2>&1; then
        return 0
    fi
    return 1
}

shellclash_running() {
    if pgrep -f "ShellCrash" >/dev/null 2>&1; then
        return 0
    fi
    return 1
}

set_ua3f_group() {
    if [ "$SERVER_MODE" = "REDIRECT" ]; then
        UA3F_GROUP="root"
        return
    elif [ "$SERVER_MODE" = "NFQUEUE" ]; then
        UA3F_GROUP="root"
        return
    fi
    if openclash_running; then
        UA3F_GROUP="nogroup"
    elif shellclash_running; then
        UA3F_GROUP="shellcrash"
    elif openclash_exists; then
        UA3F_GROUP="nogroup"
    elif shellclash_exists; then
        UA3F_GROUP="shellcrash"
    else
        UA3F_GROUP="nogroup"
    fi
}

start_service() {
    config_load "$NAME"

    mkdir -p /var/log/ua3f
    chmod o+w /var/log/ua3f
    touch /var/log/ua3f/ua3f.log

    local enabled
    config_get_bool enabled "enabled" "enabled" "0"
    [ "$enabled" -eq "1" ] || return 0

    local port bind ua log_level ua_regex partial_replace
    local rewrite_mode rewrite_rules
    local set_ttl set_ipid del_tcpts
    config_get SERVER_MODE "main" "server_mode" "TPROXY"
    config_get port "main" "port" "1080"
    config_get bind "main" "bind" "127.0.0.1"
    config_get ua "main" "ua" "FFF"
    config_get ua_regex "main" "ua_regex" ""
    config_get_bool partial_replace "main" "partial_replace" 0
    config_get log_level "main" "log_level" "ERROR"
    config_get rewrite_mode "main" "rewrite_mode" "GLOBAL"
    config_get rewrite_rules "main" "rewrite_rules" ""
    config_get_bool set_ttl "main" "set_ttl" 0
    config_get_bool set_ipid "main" "set_ipid" 0
    config_get_bool del_tcpts "main" "del_tcpts" 0

    # compose set_ttl set_ipid del_tcpts with others ",ttl,ipid,tcpts,"
    local others=","
    [ "$set_ipid" -eq "1" ] && others="${others}ipid,"
    [ "$del_tcpts" -eq "1" ] && others="${others}tcpts,"
    [ "$set_ttl" -eq "1" ] && others="${others}ttl,"

    SERVER_MODE="$(echo "$SERVER_MODE" | tr '[:lower:]' '[:upper:]')"

    set_ua3f_group
    LOG "Server Mode: $SERVER_MODE"
    LOG "Group: $UA3F_GROUP"

    procd_open_instance "$NAME"
    procd_set_param command "$PROG"
    procd_append_param command -m "$SERVER_MODE"
    procd_append_param command -p "$port"
    procd_append_param command -b "$bind"
    procd_append_param command -f "$ua"
    procd_append_param command -r "$ua_regex"
    procd_append_param command -l "$log_level"
    procd_append_param command -x "$rewrite_mode"
    procd_append_param command -z "$rewrite_rules"
    procd_append_param command -o "$others"
    [ "$partial_replace" = "1" ] && procd_append_param command -s

    procd_set_param respawn
    procd_set_param stdout 1
    procd_set_param stderr 1
    procd_set_param limits nproc="unlimited" as="unlimited" memlock="unlimited" nofile="65535 65535"
    procd_set_param group $UA3F_GROUP

    procd_close_instance

    LOG "$NAME service started"
}

service_triggers() {
    procd_add_reload_trigger "$NAME"
}