/*
 * CSB Parachute
 * Copyright (C) 2026 counter-strike-boost.com
 *
 * Hold +use while falling to deploy a parachute. In PlayerPreThink the plugin
 * clamps the downward velocity to a configurable speed and shows a parachute
 * model attached above the player (pev_aiment / MOVETYPE_FOLLOW); it is removed
 * the moment the player lands or lets go of +use. Cvars control the fall speed,
 * a VIP-only flag and a per-round use limit.
 *
 * Inspired by the well-known "Parachute" plugin by KRoTaL and later VEN. 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 <https://www.gnu.org/licenses/> for details.
 */

#include <amxmodx>
#include <fakemeta>

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

#define PARA_MODEL "models/csb_parachute.mdl"

new g_iChute[33]
new g_iUsed[33]
new bool:g_bModelOk

new g_pEnabled, g_pFallSpeed, g_pVipFlag, g_pMaxPerRound

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

    g_pEnabled     = register_cvar("csb_para_enabled", "1")
    g_pFallSpeed   = register_cvar("csb_para_fallspeed", "100")
    g_pVipFlag     = register_cvar("csb_para_vipflag", "")
    g_pMaxPerRound = register_cvar("csb_para_maxperround", "0")   /* 0 = unlimited */

    register_forward(FM_PlayerPreThink, "fwPreThink")

    register_event("ResetHUD", "evSpawn", "b")
    register_event("HLTV", "evNewRound", "a", "1=0", "2=0")
}

public plugin_precache()
{
    if (file_exists(PARA_MODEL))
    {
        precache_model(PARA_MODEL)
        g_bModelOk = true
    }
    else
    {
        log_amx("[CSB Parachute] %s not found - the parachute will slow the fall but show no model.", PARA_MODEL)
    }
}

public client_putinserver(id)
{
    g_iChute[id] = 0
    g_iUsed[id] = 0
}

public client_disconnected(id)
{
    removeChute(id)
    g_iChute[id] = 0
}

public evSpawn(id)
{
    removeChute(id)
    g_iUsed[id] = 0
}

public evNewRound()
{
    for (new i = 1; i <= 32; i++)
        g_iUsed[i] = 0
}

vipAllowed(id)
{
    new flagStr[8]
    get_pcvar_string(g_pVipFlag, flagStr, charsmax(flagStr))

    if (!flagStr[0])
        return 1

    new need = read_flags(flagStr)

    return (get_user_flags(id) & need) ? 1 : 0
}

public fwPreThink(id)
{
    if (!get_pcvar_num(g_pEnabled) || !is_user_alive(id))
    {
        if (g_iChute[id])
            removeChute(id)
        return
    }

    new flags = pev(id, pev_flags)

    if (flags & FL_ONGROUND)
    {
        if (g_iChute[id])
            removeChute(id)
        return
    }

    new Float:vel[3]
    pev(id, pev_velocity, vel)

    new button = pev(id, pev_button)

    /* deploy only while +use is held and the player is actually descending */
    if ((button & IN_USE) && vel[2] < 0.0 && vipAllowed(id))
    {
        new maxUse = get_pcvar_num(g_pMaxPerRound)

        if (!g_iChute[id])
        {
            if (maxUse > 0 && g_iUsed[id] >= maxUse)
                return

            deployChute(id)
            g_iUsed[id]++
        }

        new Float:fall = get_pcvar_float(g_pFallSpeed)

        if (fall < 10.0)
            fall = 10.0

        vel[2] = -fall
        set_pev(id, pev_velocity, vel)
    }
    else if (g_iChute[id])
    {
        removeChute(id)
    }
}

deployChute(id)
{
    if (!g_bModelOk)
    {
        g_iChute[id] = -1   /* marker: active but no visible model */
        return
    }

    new ent = engfunc(EngFunc_CreateNamedEntity, engfunc(EngFunc_AllocString, "info_target"))

    if (!pev_valid(ent))
    {
        g_iChute[id] = -1
        return
    }

    engfunc(EngFunc_SetModel, ent, PARA_MODEL)

    set_pev(ent, pev_movetype, MOVETYPE_FOLLOW)
    set_pev(ent, pev_aiment, id)
    set_pev(ent, pev_owner, id)
    set_pev(ent, pev_sequence, 0)
    set_pev(ent, pev_frame, 0.0)
    set_pev(ent, pev_framerate, 1.0)
    set_pev(ent, pev_animtime, get_gametime())

    new Float:origin[3]
    pev(id, pev_origin, origin)
    set_pev(ent, pev_origin, origin)

    g_iChute[id] = ent
}

removeChute(id)
{
    new ent = g_iChute[id]

    if (ent > 0 && pev_valid(ent))
        engfunc(EngFunc_RemoveEntity, ent)

    g_iChute[id] = 0
}