/*
 * CSB Nemesis Mode
 * Copyright (C) 2026 counter-strike-boost.com
 *
 * A self-contained "Nemesis" boss round: with a configurable chance, one random
 * player is turned into a super-soldier boss with scaled-up HP, a red glow,
 * higher speed, knife only and heavy damage reduction. Everyone else has to gun
 * it down together; a HUD bar shows the Nemesis' remaining HP. This build does
 * NOT depend on any external zombie-mod core - it stands on its own.
 *
 * Inspired by the Nemesis round from Zombie Plague by MeRcyLeZZ. This is an
 * independent GPL re-implementation; no original code is reused.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option)
 * any later version. It is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
 * Public License for more details: <https://www.gnu.org/licenses/>.
 */

#include <amxmodx>
#include <amxmisc>
#include <fun>
#include <hamsandwich>

new const PLUGIN[] = "CSB Nemesis Mode"
new const VERSION[] = "1.0.0"
new const AUTHOR[]  = "counter-strike-boost.com"

new bool:g_bNemesis[33]
new g_iNemesis = 0
new g_iNemesisMaxHP = 0

new g_pEnabled, g_pChance, g_pHpPerPlayer, g_pHpBase, g_pSpeed, g_pReduction
new g_iHudSync

public plugin_init()
{
    register_plugin(PLUGIN, VERSION, AUTHOR)

    g_pEnabled     = register_cvar("csb_nemesis_enabled", "1")
    g_pChance      = register_cvar("csb_nemesis_chance", "20")     // percent chance per round
    g_pHpBase      = register_cvar("csb_nemesis_hp_base", "2000")
    g_pHpPerPlayer = register_cvar("csb_nemesis_hp_perplayer", "800")
    g_pSpeed       = register_cvar("csb_nemesis_speed", "320")
    g_pReduction   = register_cvar("csb_nemesis_reduction", "0.35") // fraction of damage the boss actually takes

    RegisterHam(Ham_TakeDamage, "player", "fwTakeDamage")
    RegisterHam(Ham_Killed, "player", "fwKilled", 1)

    register_event("HLTV", "eNewRound", "a", "1=0", "2=0")

    register_clcmd("csb_nemesis", "cmdForce", ADMIN_LEVEL_A, "- force a Nemesis round next spawn")

    g_iHudSync = CreateHudSyncObj()
}

public eNewRound()
{
    clearNemesis()

    if (!get_pcvar_num(g_pEnabled))
        return

    if (random_num(1, 100) <= get_pcvar_num(g_pChance))
        set_task(2.0, "taskPickNemesis")
}

public cmdForce(id, level, cid)
{
    if (!cmd_access(id, level, cid, 1))
        return PLUGIN_HANDLED

    set_task(0.5, "taskPickNemesis")
    client_print(id, print_chat, "[CSB] A Nemesis will be chosen now.")
    return PLUGIN_HANDLED
}

public taskPickNemesis()
{
    new players[32], num
    get_players(players, num, "ah")   // alive, humans (skip bots? include - "a" alive only)

    if (num < 2)
        return

    new pick = players[random_num(0, num - 1)]
    makeNemesis(pick, num)
}

makeNemesis(id, playerCount)
{
    if (!is_user_alive(id))
        return

    g_iNemesis = id
    g_bNemesis[id] = true

    new hp = get_pcvar_num(g_pHpBase) + get_pcvar_num(g_pHpPerPlayer) * (playerCount - 1)
    g_iNemesisMaxHP = hp

    set_user_health(id, hp)
    set_user_maxspeed(id, float(get_pcvar_num(g_pSpeed)))
    set_user_gravity(id, 0.85)
    set_user_rendering(id, kRenderFxGlowShell, 255, 0, 0, kRenderNormal, 20)

    strip_user_weapons(id)
    give_item(id, "weapon_knife")

    new name[32]
    get_user_name(id, name, charsmax(name))

    set_hudmessage(255, 0, 0, -1.0, 0.20, 2, 0.5, 4.0, 0.1, 0.2, -1)
    show_hudmessage(0, "### NEMESIS ROUND ###^n%s is the Nemesis - %d HP!^nGun it down!", name, hp)

    client_print(0, print_chat, "[CSB] %s became the NEMESIS (%d HP). Everyone else: kill it!", name, hp)

    set_task(0.5, "taskHpBar", 771, _, _, "b")
}

public taskHpBar()
{
    if (!g_iNemesis || !is_user_alive(g_iNemesis))
    {
        clearNemesis()
        return
    }

    new hp = get_user_health(g_iNemesis)
    new pct = g_iNemesisMaxHP ? (hp * 100) / g_iNemesisMaxHP : 0

    new bar[24], filled = pct / 10
    new i
    for (i = 0; i < filled && i < 10; i++)
        bar[i] = '|'
    for (; i < 10; i++)
        bar[i] = '.'
    bar[10] = 0

    new name[32]
    get_user_name(g_iNemesis, name, charsmax(name))

    set_hudmessage(255, 60, 60, 0.02, 0.15, 0, 0.0, 0.6, 0.0, 0.1, -1)
    ShowSyncHudMsg(0, g_iHudSync, "NEMESIS %s^n[%s] %d HP", name, bar, hp)
}

public fwTakeDamage(victim, inflictor, attacker, Float:damage, damagebits)
{
    if (victim == g_iNemesis && g_bNemesis[victim])
    {
        new Float:reduction = get_pcvar_float(g_pReduction)

        if (reduction < 0.0) reduction = 0.0
        if (reduction > 1.0) reduction = 1.0

        SetHamParamFloat(4, damage * reduction)
    }

    return HAM_IGNORED
}

public fwKilled(victim, attacker, shouldgib)
{
    if (victim == g_iNemesis && g_bNemesis[victim])
    {
        new aname[32]

        if (attacker >= 1 && attacker <= 32 && is_user_connected(attacker))
        {
            get_user_name(attacker, aname, charsmax(aname))
            client_print(0, print_chat, "[CSB] %s took down the Nemesis! Humans win the round.", aname)
        }
        else
        {
            client_print(0, print_chat, "[CSB] The Nemesis is down. Humans win the round.")
        }

        clearNemesis()
    }

    return HAM_IGNORED
}

public client_disconnected(id)
{
    if (id == g_iNemesis)
        clearNemesis()

    g_bNemesis[id] = false
}

clearNemesis()
{
    remove_task(771)

    if (g_iNemesis && is_user_connected(g_iNemesis))
    {
        g_bNemesis[g_iNemesis] = false
        set_user_rendering(g_iNemesis, kRenderFxNone, 0, 0, 0, kRenderNormal, 0)
    }

    g_iNemesis = 0
    g_iNemesisMaxHP = 0
}