/*
 * 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 2
 * 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 General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2015 Blender Foundation.
 * All rights reserved.
 */

/** \file gizmo_library_utils.c
 *  \ingroup edgizmolib
 *
 * \name Gizmo Library Utilities
 *
 * \brief This file contains functions for common behaviors of gizmos.
 */

#include "BLI_math.h"

#include "DNA_view3d_types.h"
#include "DNA_screen_types.h"

#include "BKE_context.h"

#include "RNA_access.h"

#include "WM_api.h"
#include "WM_types.h"

#include "ED_view3d.h"

/* own includes */
#include "gizmo_library_intern.h"

/* factor for precision tweaking */
#define GIZMO_PRECISION_FAC 0.05f


BLI_INLINE float gizmo_offset_from_value_constr(
        const float range_fac, const float min, const float range, const float value,
        const bool inverted)
{
	return inverted ? (range_fac * (min + range - value) / range) : (range_fac * (value / range));
}

BLI_INLINE float gizmo_value_from_offset_constr(
        const float range_fac, const float min, const float range, const float value,
        const bool inverted)
{
	return inverted ? (min + range - (value * range / range_fac)) : (value * range / range_fac);
}

float gizmo_offset_from_value(
        GizmoCommonData *data, const float value, const bool constrained, const bool inverted)
{
	if (constrained)
		return gizmo_offset_from_value_constr(data->range_fac, data->min, data->range, value, inverted);

	return value;
}

float gizmo_value_from_offset(
        GizmoCommonData *data, GizmoInteraction *inter, const float offset,
        const bool constrained, const bool inverted, const bool use_precision)
{
	const float max = data->min + data->range;

	if (use_precision) {
		/* add delta offset of this step to total precision_offset */
		inter->precision_offset += offset - inter->prev_offset;
	}
	inter->prev_offset = offset;

	float ofs_new = inter->init_offset + offset - inter->precision_offset * (1.0f - GIZMO_PRECISION_FAC);
	float value;

	if (constrained) {
		value = gizmo_value_from_offset_constr(data->range_fac, data->min, data->range, ofs_new, inverted);
	}
	else {
		value = ofs_new;
	}

	/* clamp to custom range */
	if (data->is_custom_range_set) {
		CLAMP(value, data->min, max);
	}

	return value;
}

void gizmo_property_data_update(
        wmGizmo *gz, GizmoCommonData *data, wmGizmoProperty *gz_prop,
        const bool constrained, const bool inverted)
{
	if (gz_prop->custom_func.value_get_fn != NULL) {
		/* pass  */
	}
	else if (gz_prop->prop != NULL) {
		/* pass  */
	}
	else {
		data->offset = 0.0f;
		return;
	}

	float value = WM_gizmo_target_property_float_get(gz, gz_prop);

	if (constrained) {
		if (data->is_custom_range_set == false) {
			float range[2];
			if (WM_gizmo_target_property_float_range_get(gz, gz_prop, range)) {
				data->range = range[1] - range[0];
				data->min = range[0];
			}
			else {
				BLI_assert(0);
			}
		}
		data->offset = gizmo_offset_from_value_constr(data->range_fac, data->min, data->range, value, inverted);
	}
	else {
		data->offset = value;
	}
}

void gizmo_property_value_reset(
        bContext *C, const wmGizmo *gz, GizmoInteraction *inter,
        wmGizmoProperty *gz_prop)
{
	WM_gizmo_target_property_float_set(C, gz, gz_prop, inter->init_value);
}

/* -------------------------------------------------------------------- */

void gizmo_color_get(
        const wmGizmo *gz, const bool highlight,
        float r_col[4])
{
	if (highlight && !(gz->flag & WM_GIZMO_DRAW_HOVER)) {
		copy_v4_v4(r_col, gz->color_hi);
	}
	else {
		copy_v4_v4(r_col, gz->color);
	}
}

/* -------------------------------------------------------------------- */

/**
 * Takes mouse coordinates and returns them in relation to the gizmo.
 * Both 2D & 3D supported, use so we can use 2D gizmos in the 3D view.
 */
bool gizmo_window_project_2d(
        bContext *C, const struct wmGizmo *gz, const float mval[2], int axis, bool use_offset,
        float r_co[2])
{
	float mat[4][4];
	{
		float mat_identity[4][4];
		struct WM_GizmoMatrixParams params = {NULL};
		if (use_offset == false) {
			unit_m4(mat_identity);
			params.matrix_offset = mat_identity;
		}
		WM_gizmo_calc_matrix_final_params(gz, &params, mat);
	}

	/* rotate mouse in relation to the center and relocate it */
	if (gz->parent_gzgroup->type->flag & WM_GIZMOGROUPTYPE_3D) {
		/* For 3d views, transform 2D mouse pos onto plane. */
		ARegion *ar = CTX_wm_region(C);

		float plane[4], co[3];
		plane_from_point_normal_v3(plane, mat[3], mat[2]);
		bool clip_ray = ((RegionView3D *)ar->regiondata)->is_persp;
		if (ED_view3d_win_to_3d_on_plane(ar, plane, mval, clip_ray, co)) {
			float imat[4][4];
			invert_m4_m4(imat, mat);
			mul_m4_v3(imat, co);
			r_co[0] = co[(axis + 1) % 3];
			r_co[1] = co[(axis + 2) % 3];
			return true;
		}
		return false;
	}
	else {
		float co[3] = {mval[0], mval[1], 0.0f};
		float imat[4][4];
		invert_m4_m4(imat, mat);
		mul_m4_v3(imat, co);
		copy_v2_v2(r_co, co);
		return true;
	}
}

bool gizmo_window_project_3d(
        bContext *C, const struct wmGizmo *gz, const float mval[2], bool use_offset,
        float r_co[3])
{
	float mat[4][4];
	{
		float mat_identity[4][4];
		struct WM_GizmoMatrixParams params = {NULL};
		if (use_offset == false) {
			unit_m4(mat_identity);
			params.matrix_offset = mat_identity;
		}
		WM_gizmo_calc_matrix_final_params(gz, &params, mat);
	}

	if (gz->parent_gzgroup->type->flag & WM_GIZMOGROUPTYPE_3D) {
		View3D *v3d = CTX_wm_view3d(C);
		ARegion *ar = CTX_wm_region(C);
		/* Note: we might want a custom reference point passed in,
		 * instead of the gizmo center. */
		ED_view3d_win_to_3d(v3d, ar, mat[3], mval, r_co);
		invert_m4(mat);
		mul_m4_v3(mat, r_co);
		return true;
	}
	else {
		float co[3] = {mval[0], mval[1], 0.0f};
		float imat[4][4];
		invert_m4_m4(imat, mat);
		mul_m4_v3(imat, co);
		copy_v2_v2(r_co, co);
		return true;
	}
}