/* SPDX-License-Identifier: GPL-2.0-or-later
 * Copyright 2001-2002 NaN Holding BV. All rights reserved. */

/** \file
 * \ingroup edtransform
 */

#include <stdlib.h>

#include "BLI_math.h"
#include "BLI_task.h"

#include "BKE_context.h"
#include "BKE_report.h"
#include "BKE_unit.h"

#include "ED_screen.h"

#include "UI_interface.h"

#include "transform.h"
#include "transform_convert.h"
#include "transform_snap.h"

#include "transform_mode.h"

/* -------------------------------------------------------------------- */
/** \name Transform (Rotation) Matrix Cache
 * \{ */

struct RotateMatrixCache {
  /**
   * Counter for needed updates (when we need to update to non-default matrix,
   * we also need another update on next iteration to go back to default matrix,
   * hence the '2' value used here, instead of a mere boolean).
   */
  short do_update_matrix;
  float mat[3][3];
};

static void rmat_cache_init(struct RotateMatrixCache *rmc, const float angle, const float axis[3])
{
  axis_angle_normalized_to_mat3(rmc->mat, axis, angle);
  rmc->do_update_matrix = 0;
}

static void rmat_cache_reset(struct RotateMatrixCache *rmc)
{
  rmc->do_update_matrix = 2;
}

static void rmat_cache_update(struct RotateMatrixCache *rmc,
                              const float axis[3],
                              const float angle)
{
  if (rmc->do_update_matrix > 0) {
    axis_angle_normalized_to_mat3(rmc->mat, axis, angle);
    rmc->do_update_matrix--;
  }
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Transform (Rotation) Element
 * \{ */

/**
 * \note Small arrays / data-structures should be stored copied for faster memory access.
 */
struct TransDataArgs_Rotate {
  const TransInfo *t;
  const TransDataContainer *tc;
  const float axis[3];
  float angle;
  float angle_step;
  bool is_large_rotation;
};

struct TransDataArgs_RotateTLS {
  struct RotateMatrixCache rmc;
};

static void transdata_elem_rotate(const TransInfo *t,
                                  const TransDataContainer *tc,
                                  TransData *td,
                                  const float axis[3],
                                  const float angle,
                                  const float angle_step,
                                  const bool is_large_rotation,
                                  struct RotateMatrixCache *rmc)
{
  float axis_buffer[3];
  const float *axis_final = axis;

  float angle_final = angle;
  if (t->con.applyRot) {
    copy_v3_v3(axis_buffer, axis);
    axis_final = axis_buffer;
    t->con.applyRot(t, tc, td, axis_buffer, NULL);
    angle_final = angle * td->factor;
    /* Even though final angle might be identical to orig value,
     * we have to update the rotation matrix in that case... */
    rmat_cache_reset(rmc);
  }
  else if (t->flag & T_PROP_EDIT) {
    angle_final = angle * td->factor;
  }

  /* Rotation is very likely to be above 180°, we need to do rotation by steps.
   * Note that this is only needed when doing 'absolute' rotation
   * (i.e. from initial rotation again, typically when using numinput).
   * regular incremental rotation (from mouse/widget/...) will be called often enough,
   * hence steps are small enough to be properly handled without that complicated trick.
   * Note that we can only do that kind of stepped rotation if we have initial rotation values
   * (and access to some actual rotation value storage).
   * Otherwise, just assume it's useless (e.g. in case of mesh/UV/etc. editing).
   * Also need to be in Euler rotation mode, the others never allow more than one turn anyway.
   */
  if (is_large_rotation && td->ext != NULL && td->ext->rotOrder == ROT_MODE_EUL) {
    copy_v3_v3(td->ext->rot, td->ext->irot);
    for (float angle_progress = angle_step; fabsf(angle_progress) < fabsf(angle_final);
         angle_progress += angle_step) {
      axis_angle_normalized_to_mat3(rmc->mat, axis_final, angle_progress);
      ElementRotation(t, tc, td, rmc->mat, t->around);
    }
    rmat_cache_reset(rmc);
  }
  else if (angle_final != angle) {
    rmat_cache_reset(rmc);
  }

  rmat_cache_update(rmc, axis_final, angle_final);

  ElementRotation(t, tc, td, rmc->mat, t->around);
}

static void transdata_elem_rotate_fn(void *__restrict iter_data_v,
                                     const int iter,
                                     const TaskParallelTLS *__restrict tls)
{
  struct TransDataArgs_Rotate *data = iter_data_v;
  struct TransDataArgs_RotateTLS *tls_data = tls->userdata_chunk;

  TransData *td = &data->tc->data[iter];
  if (td->flag & TD_SKIP) {
    return;
  }
  transdata_elem_rotate(data->t,
                        data->tc,
                        td,
                        data->axis,
                        data->angle,
                        data->angle_step,
                        data->is_large_rotation,
                        &tls_data->rmc);
}

/** \} */

/* -------------------------------------------------------------------- */
/** \name Transform (Rotation)
 * \{ */

static float RotationBetween(TransInfo *t, const float p1[3], const float p2[3])
{
  float angle, start[3], end[3];

  sub_v3_v3v3(start, p1, t->center_global);
  sub_v3_v3v3(end, p2, t->center_global);

  /* Angle around a constraint axis (error prone, will need debug). */
  if (t->con.applyRot != NULL && (t->con.mode & CON_APPLY)) {
    float axis[3], tmp[3];

    t->con.applyRot(t, NULL, NULL, axis, NULL);

    project_v3_v3v3(tmp, end, axis);
    sub_v3_v3v3(end, end, tmp);

    project_v3_v3v3(tmp, start, axis);
    sub_v3_v3v3(start, start, tmp);

    normalize_v3(end);
    normalize_v3(start);

    cross_v3_v3v3(tmp, start, end);

    if (dot_v3v3(tmp, axis) < 0.0f) {
      angle = -acosf(dot_v3v3(start, end));
    }
    else {
      angle = acosf(dot_v3v3(start, end));
    }
  }
  else {
    float mtx[3][3];

    copy_m3_m4(mtx, t->viewmat);

    mul_m3_v3(mtx, end);
    mul_m3_v3(mtx, start);

    angle = atan2f(start[1], start[0]) - atan2f(end[1], end[0]);
  }

  if (angle > (float)M_PI) {
    angle = angle - 2 * (float)M_PI;
  }
  else if (angle < -((float)M_PI)) {
    angle = 2.0f * (float)M_PI + angle;
  }

  return angle;
}

static void ApplySnapRotation(TransInfo *t, float *value)
{
  float point[3];
  getSnapPoint(t, point);

  float dist = RotationBetween(t, t->tsnap.snapTarget, point);
  *value = dist;
}

static float large_rotation_limit(float angle)
{
  /* Limit rotation to 1001 turns max
   * (otherwise iterative handling of 'large' rotations would become too slow). */
  const float angle_max = (float)(M_PI * 2000.0);
  if (fabsf(angle) > angle_max) {
    const float angle_sign = angle < 0.0f ? -1.0f : 1.0f;
    angle = angle_sign * (fmodf(fabsf(angle), (float)(M_PI * 2.0)) + angle_max);
  }
  return angle;
}

static void applyRotationValue(TransInfo *t,
                               float angle,
                               const float axis[3],
                               const bool is_large_rotation)
{
  const float angle_sign = angle < 0.0f ? -1.0f : 1.0f;
  /* We cannot use something too close to 180°, or 'continuous' rotation may fail
   * due to computing error... */
  const float angle_step = angle_sign * (float)(0.9 * M_PI);

  if (is_large_rotation) {
    /* Just in case, calling code should have already done that in practice
     * (for UI feedback reasons). */
    angle = large_rotation_limit(angle);
  }

  struct RotateMatrixCache rmc = {0};
  rmat_cache_init(&rmc, angle, axis);

  FOREACH_TRANS_DATA_CONTAINER (t, tc) {
    if (tc->data_len < TRANSDATA_THREAD_LIMIT) {
      TransData *td = tc->data;
      for (int i = 0; i < tc->data_len; i++, td++) {
        if (td->flag & TD_SKIP) {
          continue;
        }
        transdata_elem_rotate(t, tc, td, axis, angle, angle_step, is_large_rotation, &rmc);
      }
    }
    else {
      struct TransDataArgs_Rotate data = {
          .t = t,
          .tc = tc,
          .axis = {UNPACK3(axis)},
          .angle = angle,
          .angle_step = angle_step,
          .is_large_rotation = is_large_rotation,
      };
      struct TransDataArgs_RotateTLS tls_data = {
          .rmc = rmc,
      };

      TaskParallelSettings settings;
      BLI_parallel_range_settings_defaults(&settings);
      settings.userdata_chunk = &tls_data;
      settings.userdata_chunk_size = sizeof(tls_data);
      BLI_task_parallel_range(0, tc->data_len, &data, transdata_elem_rotate_fn, &settings);
    }
  }
}

static void applyRotation(TransInfo *t, const int UNUSED(mval[2]))
{
  char str[UI_MAX_DRAW_STR];
  float axis_final[3];
  float final = t->values[0] + t->values_modal_offset[0];

  if ((t->con.mode & CON_APPLY) && t->con.applyRot) {
    t->con.applyRot(t, NULL, NULL, axis_final, &final);
  }
  else {
    negate_v3_v3(axis_final, t->spacemtx[t->orient_axis]);
  }

  if (applyNumInput(&t->num, &final)) {
    /* We have to limit the amount of turns to a reasonable number here,
     * to avoid things getting *very* slow, see how applyRotationValue() handles those... */
    final = large_rotation_limit(final);
  }
  else {
    applySnapping(t, &final);
    if (!(activeSnap(t) && validSnap(t))) {
      transform_snap_increment(t, &final);
    }
  }

  t->values_final[0] = final;

  headerRotation(t, str, sizeof(str), final);

  const bool is_large_rotation = hasNumInput(&t->num);
  applyRotationValue(t, final, axis_final, is_large_rotation);

  recalcData(t);

  ED_area_status_text(t->area, str);
}

static void applyRotationMatrix(TransInfo *t, float mat_xform[4][4])
{
  float axis_final[3];
  const float angle_final = t->values_final[0];
  if ((t->con.mode & CON_APPLY) && t->con.applyRot) {
    t->con.applyRot(t, NULL, NULL, axis_final, NULL);
  }
  else {
    negate_v3_v3(axis_final, t->spacemtx[t->orient_axis]);
  }

  float mat3[3][3];
  float mat4[4][4];
  axis_angle_normalized_to_mat3(mat3, axis_final, angle_final);
  copy_m4_m3(mat4, mat3);
  transform_pivot_set_m4(mat4, t->center_global);
  mul_m4_m4m4(mat_xform, mat4, mat_xform);
}

void initRotation(TransInfo *t)
{
  if (t->spacetype == SPACE_ACTION) {
    BKE_report(t->reports, RPT_ERROR, "Rotation is not supported in the Dope Sheet Editor");
    t->state = TRANS_CANCEL;
  }

  t->mode = TFM_ROTATION;
  t->transform = applyRotation;
  t->transform_matrix = applyRotationMatrix;
  t->tsnap.applySnap = ApplySnapRotation;
  t->tsnap.distance = RotationBetween;

  initMouseInputMode(t, &t->mouse, INPUT_ANGLE);

  t->idx_max = 0;
  t->num.idx_max = 0;
  t->snap[0] = DEG2RAD(5.0);
  t->snap[1] = DEG2RAD(1.0);

  copy_v3_fl(t->num.val_inc, t->snap[1]);
  t->num.unit_sys = t->scene->unit.system;
  t->num.unit_use_radians = (t->scene->unit.system_rotation == USER_UNIT_ROT_RADIANS);
  t->num.unit_type[0] = B_UNIT_ROTATION;

  if (t->flag & T_2D_EDIT) {
    t->flag |= T_NO_CONSTRAINT;
  }

  transform_mode_default_modal_orientation_set(t, V3D_ORIENT_VIEW);
}

/** \} */