#!/usr/bin/env bash
#
# Single entry point for deploying from removable media.
#
#   ./install.sh                 reads deploy.conf next to this script
#   ./install.sh -c other.conf   reads a different config
#   ./install.sh --check         verify prerequisites and exit
#
# Copies itself off read-only media, installs prerequisites, and runs the
# deploy. Everything is configured in deploy.conf, so there are no flags to
# remember at the console.

set -euo pipefail

HERE="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
CONF="$HERE/deploy.conf"
CHECK_ONLY=0
WORKDIR=""

die()  { printf '\n\033[1;31merror:\033[0m %s\n\n' "$*" >&2; exit 1; }
step() { printf '\n\033[1m=== %s ===\033[0m\n\n' "$*"; }
info() { echo ">>> $*"; }
warn() { echo "    warning: $*" >&2; }

while [ $# -gt 0 ]; do
    case "$1" in
        -c|--config) CONF="${2:-}"; shift 2 ;;
        --check)     CHECK_ONLY=1; shift ;;
        -w|--workdir) WORKDIR="${2:-}"; shift 2 ;;
        -h|--help)   awk 'NR>1 && /^#/ {sub(/^# ?/,""); print; next} NR>1 {exit}' "$0"; exit 0 ;;
        *) die "unknown option: $1" ;;
    esac
done

[ "$(id -u)" -ne 0 ] || die "run this as your normal user, not root — it calls sudo itself"

# ------------------------------------------------------------------ config ---

[ -f "$CONF" ] || die "no config at $CONF
     Copy deploy.conf.example to deploy.conf and edit it first."

# shellcheck source=/dev/null
. "$CONF"

for v in PACK_NAME AUTHOR MIRROR_URL SHARE; do
    [ -n "${!v:-}" ] || die "$v is not set in $CONF"
done

MC_VERSION="${MC_VERSION:-1.21.1}"
NEOFORGE="${NEOFORGE:-latest}"
MC_PORT="${MC_PORT:-25565}"
HTTP_PORT="${HTTP_PORT:-18080}"
HTTP_BIND="${HTTP_BIND:-0.0.0.0}"
XMX="${XMX:-10G}"
XMS="${XMS:-$XMX}"
ACCEPT_EULA="${ACCEPT_EULA:-no}"
START_SERVER="${START_SERVER:-no}"
CAP_ZFS_ARC="${CAP_ZFS_ARC:-}"

# ------------------------------------------------------------- prequisites ---

step "Checking prerequisites"

MISSING=()
need() { command -v "$1" >/dev/null || MISSING+=("$2"); }
need java   java-21-openjdk-headless
need curl   curl
need go     golang
need python3 python3
need zfs    zfs
need findmnt util-linux
need mkfifo coreutils

if [ "${#MISSING[@]}" -gt 0 ]; then
    info "missing: ${MISSING[*]}"
    if (( CHECK_ONLY )); then
        die "prerequisites missing (see above)"
    fi
    info "installing with dnf"
    sudo dnf install -y "${MISSING[@]}" \
        || die "could not install: ${MISSING[*]}
     Install them by hand and re-run."
else
    info "all present"
fi

jver="$(java -version 2>&1 | head -1 | grep -oE '"[0-9]+' | tr -d '"' || echo 0)"
[ "${jver:-0}" -ge 21 ] || warn "java is $jver; NeoForge for 1.21.x wants 21"

if ! mountpoint -q "$SHARE"; then
    die "$SHARE is not a mountpoint — the ZFS dataset is not mounted.
     Import and mount the pool first:
       sudo zpool import -a && sudo zfs mount -a
     Then re-run. Deploying onto an unmounted path would fill the root disk."
fi
info "$SHARE is mounted ($(findmnt -no SOURCE "$SHARE"))"

if (( CHECK_ONLY )); then
    step "Prerequisites OK"
    exit 0
fi

# --------------------------------------------------------------- workspace ---

# The media is very likely read-only, and the deploy needs somewhere writable
# for the go build and the pack. Copy the kit onto the host first.
if [ -z "$WORKDIR" ]; then
    if [ -w "$HERE" ]; then
        WORKDIR="$HERE"
    else
        WORKDIR="$HOME/mc-packwiz-deploy"
        info "media is read-only — copying the kit to $WORKDIR"
        mkdir -p "$WORKDIR"
        cp -f "$HERE"/*.sh "$HERE"/*.py "$WORKDIR"/ 2>/dev/null || true
        cp -f "$CONF" "$WORKDIR/deploy.conf"
        chmod +x "$WORKDIR"/*.sh "$WORKDIR"/*.py 2>/dev/null || true
    fi
fi
cd "$WORKDIR"
[ -x ./deploy.sh ] || die "deploy.sh not found in $WORKDIR"

# ----------------------------------------------------------------- zfs arc ---

if [ -n "$CAP_ZFS_ARC" ]; then
    if [ ! -f /etc/modprobe.d/zfs.conf ] || ! grep -q zfs_arc_max /etc/modprobe.d/zfs.conf; then
        step "Capping the ZFS ARC at $CAP_ZFS_ARC bytes"
        echo "options zfs zfs_arc_max=$CAP_ZFS_ARC" | sudo tee /etc/modprobe.d/zfs.conf >/dev/null
        warn "the ARC cap needs a reboot (and 'sudo dracut --force') to take effect"
    else
        info "ZFS ARC already capped in /etc/modprobe.d/zfs.conf"
    fi
fi

# ------------------------------------------------------------------ deploy ---

EULA_FLAG=""
case "${ACCEPT_EULA,,}" in
    yes|true|1) EULA_FLAG="--accept-eula" ;;
    *) die "ACCEPT_EULA is not set to yes in $CONF.
     Read https://aka.ms/MinecraftEULA, then set ACCEPT_EULA=\"yes\" to accept it." ;;
esac

step "Deploying $PACK_NAME"

./deploy.sh \
    -n "$PACK_NAME" \
    -a "$AUTHOR" \
    -u "$MIRROR_URL" \
    -m "$MC_VERSION" \
    -N "$NEOFORGE" \
    -s "$SHARE" \
    -p "$MC_PORT" \
    -H "$HTTP_PORT" \
    -B "$HTTP_BIND" \
    -X "$XMX" \
    -x "$XMS" \
    $EULA_FLAG

# ------------------------------------------------------------------- start ---

case "${START_SERVER,,}" in
    yes|true|1)
        step "Starting Minecraft"
        sudo systemctl start minecraft
        sleep 3
        if systemctl is-active --quiet minecraft; then
            info "minecraft.service is running"
        else
            warn "minecraft.service did not come up — journalctl -u minecraft -n 50"
        fi
        ;;
esac

# ------------------------------------------------------------------- done ----

SITE="${MIRROR_URL%/*}"
HOSTONLY="$(sed -e 's#^[a-z]*://##' -e 's#/.*##' -e 's#:.*##' <<<"$SITE")"
[ "$MC_PORT" = "25565" ] && SHOWN="$HOSTONLY" || SHOWN="$HOSTONLY:$MC_PORT"

step "Done"
cat <<EOF
Kit installed in:   $WORKDIR
Pack HTTP server:   ${HTTP_BIND}:${HTTP_PORT}   (proxy /  ->  this)
Players connect to: $SHOWN
Setup guides:       $SITE/setup-windows-packwiz.html
                    $SITE/setup-linux-packwiz.html

Still to do by hand:
  1. Point your reverse proxy at ${HTTP_BIND}:${HTTP_PORT}
  2. Drop mod jars into $SHARE/mods
  3. Run $WORKDIR/mc-refresh-restart.sh to register them

  sudo systemctl start minecraft
  journalctl -u minecraft -f
  echo "op YourName" | sudo tee /run/minecraft/console
EOF