/*  Starshatter: The Open Source Project
    Copyright (c) 2021-2024, Starshatter: The Open Source Project Contributors
    Copyright (c) 2011-2012, Starshatter OpenSource Distribution Contributors
    Copyright (c) 1997-2006, Destroyer Studios LLC.

    AUTHOR:       John DiCamillo


    OVERVIEW
    ========
    Weapon class
*/

#include "Shield.h"
#include "Shot.h"
#include "WeaponDesign.h"

#include "Game.h"
#include "ContentBundle.h"

// +----------------------------------------------------------------------+

static char*   shield_name[] = {
    "sys.shield.none",
    "sys.shield.deflector",
    "sys.shield.grav",
    "sys.shield.hyper"
};

static int     shield_value[] = {
    0, 2, 2, 3
};

// +----------------------------------------------------------------------+

Shield::Shield(SUBTYPE shield_type)
: System(SHIELD, shield_type, "shield", shield_value[shield_type], 100, 0),
shield_cutoff(0.0f), shield_capacitor(false), shield_bubble(false),
deflection_cost(1.0f), shield_curve(0.05f)
{
    name = ContentBundle::GetInstance()->GetText(shield_name[shield_type]);
    abrv = ContentBundle::GetInstance()->GetText("sys.shield.abrv");

    power_flags  = POWER_WATTS | POWER_CRITICAL;
    energy       = 0.0f;
    power_level  = 0.0f;
    shield_level = 0.0f;

    switch (shield_type) {
    default:
    case DEFLECTOR:
        capacity = sink_rate = 2.0e3f;
        shield_factor        = 0.05f;
        break;

    case GRAV_SHIELD:
        capacity = sink_rate = 7.0e3f;
        shield_factor        = 0.01f;
        break;

    case HYPER_SHIELD:
        capacity = sink_rate = 10.0e3f;
        shield_factor        = 0.003f;
        break;
    }

    emcon_power[0] = 0;
    emcon_power[1] = 0;
    emcon_power[2] = 100;
}

// +----------------------------------------------------------------------+

Shield::Shield(const Shield& s)
: System(s), shield_factor(s.shield_factor), requested_power_level(0.0f),
shield_cutoff(s.shield_cutoff), shield_capacitor(s.shield_capacitor),
shield_bubble(s.shield_bubble), deflection_cost(s.deflection_cost),
shield_curve(s.shield_curve)
{
    power_flags  = s.power_flags;
    energy       = 0.0f;
    power_level  = 0.0f;
    shield_level = 0.0f;

    Mount(s);
}

// +--------------------------------------------------------------------+

Shield::~Shield()
{ }

void
Shield::SetShieldCapacitor(bool c)
{
    shield_capacitor = c;

    if (shield_capacitor) {
        power_flags = POWER_CRITICAL;
        shield_curve = 0.05f;
    }
    else {
        power_flags = POWER_WATTS | POWER_CRITICAL;
        shield_curve = 0.25f;
    }
}

// +--------------------------------------------------------------------+

void
Shield::ExecFrame(double seconds)
{
    System::ExecFrame(seconds);

    if (power_level < requested_power_level) {
        power_level += (float) (seconds * 0.10);     // ten seconds to charge up

        if (power_level > requested_power_level)
        power_level = (float) requested_power_level;
    }
    else if (power_level > requested_power_level) {
        power_level -= (float) (seconds * 0.20);     // five seconds to power down

        if (power_level < requested_power_level)
        power_level = (float) requested_power_level;
    }

    if (power_level < 0.01 && !shield_capacitor) {
        shield_level = 0.0f;
        energy       = 0.0f;
    }
}

// +----------------------------------------------------------------------+

void
Shield::Distribute(double delivered_energy, double seconds)
{
    System::Distribute(delivered_energy, seconds);

    if (shield_capacitor) {
        if (shield_cutoff > 0 && shield_cutoff < 0.999) {
            float cutoff = shield_cutoff * capacity;

            if (energy > cutoff)
            shield_level = (energy-cutoff)/(capacity-cutoff);
            else
            shield_level = 0.0f;
        }

        else {
            shield_level = energy/capacity;
        }
    }
    else {
        shield_level = energy/sink_rate;
        energy       = 0.0f;
    }

    if (shield_level < 0)
    shield_level = 0;
}

// +--------------------------------------------------------------------+

double
Shield::DeflectDamage(Shot* shot, double damage)
{
    double filter      = 1;
    double penetration = 5;
    double leak        = 0;

    if (shot)
    penetration = shot->Design()->penetration;

    filter = 1 - shield_factor * penetration;

    if (filter < 0)
    filter = 0;

    else if (filter > 1)
    filter = 1;

    if (shield_capacitor) {
        if (shield_cutoff > 0 && shield_level < 1e-6) {
            leak = damage;
            energy -= (float) (damage * deflection_cost);
        }

        else {
            leak = damage * (1 - pow(shield_level, shield_curve) * filter * availability);

            double deflected = damage - leak;
            energy -= (float) deflected * deflection_cost;
        }

    }
    else {
        leak = damage * (1 - pow(shield_level, shield_curve) * filter * availability);
    }

    return leak;
}

// +--------------------------------------------------------------------+

void
Shield::SetPowerLevel(double level)
{
    if (level > 100)
    level = 100;
    else if (level < 0)
    level = 0;

    level /= 100;

    if (requested_power_level != level) {
        // if the system is on emergency override power,
        // do not let the EMCON system use this method
        // to drop it back to normal power:
        if (power_level > 1 && level == 1) {
            requested_power_level = (float) power_level;
            return;
        }

        requested_power_level = (float) level;
    }
}

void
Shield::SetNetShieldLevel(int level)
{
    if (level > 100)     level = 100;
    else if (level < 0)  level =   0;

    requested_power_level = (float) (level/100.0);
    power_level           = requested_power_level;
}

void
Shield::DoEMCON(int index)
{
    int e = GetEMCONPower(index);

    if (power_level * 100 > e || emcon != index) {
        if (e == 0) {
            PowerOff();
        }
        else if (emcon != index) {
            PowerOn();

            if (power_level * 100 > e)
            SetPowerLevel(e);
        }
    }

    emcon = index;
}