#!/usr/bin/env bash
#
# Provisions a real NeoForge dedicated server, drops the built mod into it and drives it through a
# scripted session — once with the default (zero-instrumentation) configuration and once with deep
# mode on. The resulting worlds are left in build/e2e/<mode> for ChunkInspectorE2ETest to assert on.
#
# Runnable on its own:  ./e2e/run-servers.sh
#
set -euo pipefail

project_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
neo_version="${NEO_VERSION:-$(sed -n 's/^neo_version=//p' "$project_dir/gradle.properties")}"
mod_jar="${MOD_JAR:-$(ls "$project_dir"/build/libs/chunkinspector-*.jar 2>/dev/null | head -1)}"
out_dir="${E2E_OUT:-$project_dir/build/e2e}"
cache_dir="${E2E_CACHE:-$HOME/.cache/chunkinspector-e2e}"
boot_timeout="${E2E_BOOT_TIMEOUT:-420}"

# The forceloaded square the assertions look for: chunks (100, 100)..(103, 103) — 4x4, far enough
# from spawn to form its own cluster and small enough to stay under the report's suspect cap.
# /forceload takes *block* coordinates, so these are the corners of those chunks: 100 * 16 = 1600
# and 103 * 16 + 15 = 1663.
force_from="1600 1600"
force_to="1663 1663"

if [[ -z "$mod_jar" || ! -f "$mod_jar" ]]; then
    echo "no mod jar found; run ./gradlew jar first" >&2
    exit 1
fi

log() { printf '[e2e] %s\n' "$*"; }

# --------------------------------------------------------------------- provision

installer="$cache_dir/neoforge-$neo_version-installer.jar"
template="$cache_dir/server-$neo_version"

mkdir -p "$cache_dir"
if [[ ! -f "$installer" ]]; then
    log "downloading NeoForge $neo_version installer"
    curl -fsSL -o "$installer.part" \
        "https://maven.neoforged.net/releases/net/neoforged/neoforge/$neo_version/neoforge-$neo_version-installer.jar"
    mv "$installer.part" "$installer"
fi

# The installation is cached and copied per run so the two modes can never share a world.
if [[ ! -f "$template/.installed" ]]; then
    log "installing dedicated server into $template"
    rm -rf "$template"
    mkdir -p "$template"
    # From the cache directory: the installer drops its own .log file next to the working directory.
    (cd "$cache_dir" && java -jar "$installer" --installServer "$template") > "$cache_dir/install.log" 2>&1 \
        || { tail -40 "$cache_dir/install.log" >&2; exit 1; }
    touch "$template/.installed"
fi

args_file="libraries/net/neoforged/neoforge/$neo_version/unix_args.txt"
[[ -f "$template/$args_file" ]] || { echo "missing $args_file in the installed server" >&2; exit 1; }

# ------------------------------------------------------------------------- run

# run <mode> <extra jvm properties...>
run() {
    local mode="$1"
    shift
    local dir="$out_dir/$mode"

    log "preparing $mode server in $dir"
    rm -rf "$dir"
    mkdir -p "$dir"
    cp -a "$template/." "$dir/"
    rm -f "$dir/.installed"
    mkdir -p "$dir/mods"
    cp "$mod_jar" "$dir/mods/"

    echo "eula=true" > "$dir/eula.txt"
    cat > "$dir/server.properties" <<'PROPERTIES'
level-name=world
level-type=minecraft:flat
level-seed=e2e
online-mode=false
max-players=1
view-distance=10
simulation-distance=10
spawn-protection=0
sync-chunk-writes=false
enable-jmx-monitoring=false
enable-status=false
max-tick-time=-1
PROPERTIES

    local fifo="$dir/console-in"
    mkfifo "$fifo"
    (
        cd "$dir"
        exec java -Xmx2G "$@" "@$args_file" --nogui < console-in > console.log 2>&1
    ) &
    local server=$!
    # Opening the write end unblocks the server's read end; keeping it open keeps stdin alive.
    exec 9> "$fifo"

    log "waiting for $mode server to finish loading"
    local waited=0
    until grep -q 'Done (' "$dir/console.log" 2>/dev/null; do
        if ! kill -0 "$server" 2>/dev/null; then
            exec 9>&-
            tail -40 "$dir/console.log" >&2
            echo "$mode server exited before it finished loading" >&2
            exit 1
        fi
        sleep 1
        waited=$((waited + 1))
        if [[ $waited -ge $boot_timeout ]]; then
            exec 9>&-
            kill "$server" 2>/dev/null || true
            echo "$mode server did not start within ${boot_timeout}s" >&2
            exit 1
        fi
    done

    say() { printf '%s\n' "$1" >&9; log "  > $1"; sleep "${2:-2}"; }

    # A leaking chunk loader, simulated with the one permanent ticket every vanilla server can make.
    # The pause covers generating the 4x4 square, which has never been visited before.
    say "forceload add $force_from $force_to" 5
    say "chunkinspector status"
    say "chunkinspector why 102 102"
    say "chunkinspector snapshot full" 5
    # Long enough for at least one periodic snapshot (interval is 200 ticks = 10s) to also land.
    say "chunkinspector status" 12
    say "stop" 0

    log "waiting for $mode server to shut down"
    wait "$server" || true
    exec 9>&-
    rm -f "$fifo"

    local summaries="$dir/world/chunk-summaries"
    [[ -d "$summaries" ]] || { tail -60 "$dir/console.log" >&2; echo "no $summaries produced" >&2; exit 1; }
    log "$mode done: $(ls "$summaries" | wc -l) files in chunk-summaries"
}

mkdir -p "$out_dir"

# Tier one: nothing injected into the game at all.
run light \
    -Dchunkinspector.interval=200 \
    -Dchunkinspector.retention=5

# Tier two: the opt-in expensive analysis.
run deep \
    -Dchunkinspector.deep=true \
    -Dchunkinspector.attribution=true \
    -Dchunkinspector.interval=200 \
    -Dchunkinspector.retention=5

log "all servers completed"