/*******************************************************************************
 * This file is part of SWIFT.
 * Copyright (c) 2020 Matthieu Schaller (schaller@strw.leidenuniv.nl)
 * Copyright (c) 2022 Filip Husko (filip.husko@durham.ac.uk)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/
#ifndef SWIFT_SPIN_JET_BLACK_HOLE_PART_H
#define SWIFT_SPIN_JET_BLACK_HOLE_PART_H

/*! The total number of rays used in AGN feedback */
#define spinjet_blackhole_number_of_rays 50

#include "black_holes_struct.h"
#include "chemistry_struct.h"
#include "particle_splitting_struct.h"
#include "rays_struct.h"
#include "timeline.h"

/*! The possible accretion modes every black hole can take. */
enum BH_accretion_modes {
  BH_thick_disc = 0,       /* At low Eddington ratios */
  BH_thin_disc,            /* At moderate Eddington ratios */
  BH_slim_disc,            /* Super-Eddington accretion */
  BH_accretion_modes_count /* Number of possible accretion modes */
};

/**
 * @brief Particle fields for the black hole particles.
 *
 * All quantities related to gravity are stored in the associate #gpart.
 */
struct bpart {

  /*! Particle ID. */
  long long id;

  /*! Pointer to corresponding gravity part. */
  struct gpart* gpart;

  /*! Particle position. */
  double x[3];

  /* Offset between current position and position at last tree rebuild. */
  float x_diff[3];

  /*! Particle velocity. */
  float v[3];

  /*! Black hole mass */
  float mass;

  /*! Black hole mass at the start of each step, prior to any nibbling */
  float mass_at_start_of_step;

  /* Particle cutoff radius. */
  float h;

  /*! Particle time bin */
  timebin_t time_bin;

  struct {

    /* Number of neighbours. */
    float wcount;

    /* Number of neighbours spatial derivative. */
    float wcount_dh;

  } density;

  /*! Union for the formation time and formation scale factor */
  union {

    /*! Formation time */
    float formation_time;

    /*! Formation scale factor */
    float formation_scale_factor;
  };

  /*! Subgrid mass of the black hole */
  float subgrid_mass;

  /*! Total accreted mass of the black hole (not including mass merged in
   * from other black holes) */
  float total_accreted_mass;

  /*! Energy reservoir for feedback */
  float energy_reservoir;

  /*! Instantaneous accretion rate */
  float accretion_rate;

  /*! Density of the gas surrounding the black hole. */
  float rho_gas;

  /*! Smoothed sound speed of the gas surrounding the black hole. */
  float sound_speed_gas;

  /*! Smoothed velocity of the gas surrounding the black hole,
   * in the frame of the black hole (internal units) */
  float velocity_gas[3];

  /*! Smoothed velocity dispersion (peculiar) of the gas around the
   * black hole */
  float velocity_dispersion_gas;

  /*! Circular velocity of the gas around the black hole at the smoothing
   * radius (calculated as j_gas / h_BH, where j is specific ang. mom.) */
  float circular_velocity_gas[3];

  /*! Specific angular momentum of the gas around the black hole */
  float spec_angular_momentum_gas[3];

  /*! Curl of the gas velocity around the black hole. */
  float curl_v_gas[3];

  /*! Multiplicative factor for accretion rates, from Rosas-Guevara et al.
   * (2015) angular momentum based accretion disc model */
  float f_visc;

  /*! Total mass of the gas neighbours. */
  float ngb_mass;

  /*! Integer number of neighbours */
  int num_ngbs;

  /*! Number of seeds in this BH (i.e. itself + the merged ones) */
  int cumulative_number_seeds;

  /*! Total number of BH merger events (i.e. not including all progenies) */
  int number_of_mergers;

  /*! Total number of gas particles swallowed (including particles swallowed
   * by merged-in black holes) */
  int number_of_gas_swallows;

  /*! Total number of gas particles swallowed (excluding particles swallowed
   * by merged-in black holes) */
  int number_of_direct_gas_swallows;

  /*! Total number of times the black hole has been repositioned (excluding
   * repositionings of merged-in black holes) */
  int number_of_repositions;

  /*! Total number of times a black hole attempted repositioning (including
   * cases where it was aborted because the black hole was already at a
   * lower potential than all eligible neighbours) */
  int number_of_reposition_attempts;

  /*! Total number of time steps in which the black hole was active. */
  int number_of_time_steps;

  /*! Total (physical) angular momentum accumulated by swallowing particles */
  float swallowed_angular_momentum[3];

  /*! Total (physical) angular momentum accumulated from subgrid accretion */
  float accreted_angular_momentum[3];

  /*! Integer (cumulative) number of energy injections in AGN feedback. At a
   * given time-step, an AGN-active BH may produce multiple energy injections.
   * The number of energy injections is equal to or more than the number of
   * particles heated by the BH during this time-step. */
  int AGN_number_of_energy_injections;

  /*! Integer (cumulative) number of AGN events. If a BH does feedback at a
   * given time-step, the number of its AGN events is incremented by 1. Each
   * AGN event may have multiple energy injections. */
  int AGN_number_of_AGN_events;

  /* Total energy injected into the gas in AGN feedback by this BH */
  float AGN_cumulative_energy;

  /*! Union for the last AGN event time and the last AGN event scale factor */
  union {

    /*! Last AGN event time */
    float last_AGN_event_time;

    /*! Last AGN event scale-factor */
    float last_AGN_event_scale_factor;
  };

  /*! BH accretion-limited time-step */
  float dt_heat;

  /*! Eddington fraction */
  float eddington_fraction;

  /*! BH dimensionless spin */
  float spin;

  /*! The normalized spin/angular momentum vector of the BH */
  float angular_momentum_direction[3];

  /*! The jet efficiency */
  float jet_efficiency;

  /*! The radiative efficiency */
  float radiative_efficiency;

  /*! Cosine of the angle between the spin vector and the angular momentum
      of the gas in the smoothing kernel */
  float accretion_disk_angle;

  /*! Aspect ratio of the subgrid accretion disk */
  float aspect_ratio;

  /*! Which type is the subgrid accretion disk (thick, thin or slim) */
  enum BH_accretion_modes accretion_mode;

  /*! The jet-limited time-step of the BH */
  float dt_jet;

  /*! The angular momentum evolution limited time-step of the BH */
  float dt_ang_mom;

  /*! The current jet kick velocity to be applied */
  float v_jet;

  /*! The energ in the jet reservoir */
  float jet_reservoir;

  /*! Total jet energy launched so far */
  float total_jet_energy;

  /*! Total accreted masses, radiated energies and jet energies launched
      by BHs, split by accretion mode */
  float accreted_mass_by_mode[BH_accretion_modes_count];
  float thermal_energy_by_mode[BH_accretion_modes_count];
  float jet_energy_by_mode[BH_accretion_modes_count];

  /*! Total number of jet kicks */
  int AGN_number_of_jet_injections;

  /*! Total number of jet kicking events */
  int AGN_number_of_AGN_jet_events;

  /*! Halo mass the black hole is assigned to */
  float group_mass;

  union {

    /*! Last time a jet event occurred */
    float last_AGN_jet_event_time;

    /*! Last scale factor a jet event occurred */
    float last_AGN_jet_event_scale_factor;
  };

  /*! Union for the last high Eddington ratio point in time */
  union {

    /*! Last time the BH had a a high Eddington fraction */
    float last_high_Eddington_fraction_time;

    /*! Last scale factor the BH had a a high Eddington fraction */
    float last_high_Eddington_fraction_scale_factor;
  };

  /*! Union for the last minor merger point in time */
  union {

    /*! Last time the BH had a a high Eddington fraction */
    float last_minor_merger_time;

    /*! Last scale factor the BH had a a high Eddington fraction */
    float last_minor_merger_scale_factor;
  };

  /*! Union for the last major merger point in time */
  union {

    /*! Last time the BH had a a high Eddington fraction */
    float last_major_merger_time;

    /*! Last scale factor the BH had a a high Eddington fraction */
    float last_major_merger_scale_factor;
  };

  /*! Properties used in the feedback loop to distribute to gas neighbours. */
  struct {

    /*! Energy per unit mass in a single AGN energy-injection event */
    float AGN_delta_u;

    /*! Number of energy injections per time-step */
    int AGN_number_of_energy_injections;

    /*! Number of energy injections per time-step */
    int AGN_number_of_jet_injections;

    /*! Change in energy from SNII feedback energy injection */
    float AGN_delta_u_jet;

  } to_distribute;

  struct {

    /*! Gravitational potential copied from the #gpart. */
    float potential;

    /*! Value of the minimum potential across all neighbours. */
    float min_potential;

    /*! Delta position to apply after the reposition procedure */
    double delta_x[3];

  } reposition;

  /*! Splitting structure */
  struct particle_splitting_data split_data;

  /*! Chemistry information (e.g. metal content at birth, swallowed metal
   * content, etc.) */
  struct chemistry_bpart_data chemistry_data;

  /*! Black holes merger information (e.g. merging ID) */
  struct black_holes_bpart_data merger_data;

  /*! Isotropic AGN feedback information */
  struct ray_data rays[spinjet_blackhole_number_of_rays];

  /*! Jet AGN feedback information. This ray is used to kick particles along
      the spin axis. */
  struct ray_data rays_jet[spinjet_blackhole_number_of_rays];

  /*! Jet AGN feedback information. This ray is used to kick particles in the
      oppposite direction from the spin axis. */
  struct ray_data rays_jet_pos[spinjet_blackhole_number_of_rays];

  /*! Tracer structure */
  struct tracers_bpart_data tracers_data;

#ifdef SWIFT_DEBUG_CHECKS

  /* Time of the last drift */
  integertime_t ti_drift;

  /* Time of the last kick */
  integertime_t ti_kick;

#endif

#ifdef DEBUG_INTERACTIONS_BLACK_HOLES
  /*! Number of interactions in the density SELF and PAIR */
  int num_ngb_density;

  /*! List of interacting particles in the density SELF and PAIR */
  long long ids_ngbs_density[MAX_NUM_OF_NEIGHBOURS_BLACK_HOLES];

  /*! Number of interactions in the force SELF and PAIR */
  int num_ngb_force;

  /*! List of interacting particles in the force SELF and PAIR */
  long long ids_ngbs_force[MAX_NUM_OF_NEIGHBOURS_BLACK_HOLES];
#endif

} SWIFT_STRUCT_ALIGN;

#endif /* SWIFT_SPIN_JET_BLACK_HOLE_PART_H */
