/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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) 2014 Blender Foundation.
 * All rights reserved.
 *
 * Contributor(s): Blender Foundation
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file dial3d_gizmo.c
 *  \ingroup edgizmolib
 *
 * \name Dial Gizmo
 *
 * 3D Gizmo
 *
 * \brief Circle shaped gizmo for circular interaction.
 * Currently no own handling, use with operator only.
 *
 * - `matrix[0]` is derived from Y and Z.
 * - `matrix[1]` is 'up' when DialGizmo.use_start_y_axis is set.
 * - `matrix[2]` is the axis the dial rotates around (all dials).
 */

#include "MEM_guardedalloc.h"

#include "BLI_math.h"

#include "BKE_context.h"

#include "BIF_gl.h"
#include "BIF_glutil.h"

#include "GPU_immediate.h"
#include "GPU_immediate_util.h"
#include "GPU_matrix.h"
#include "GPU_select.h"
#include "GPU_state.h"

#include "RNA_access.h"
#include "RNA_define.h"

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

#include "ED_screen.h"
#include "ED_view3d.h"
#include "ED_gizmo_library.h"

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

/* To use custom dials exported to geom_dial_gizmo.c */
// #define USE_GIZMO_CUSTOM_DIAL

static int gizmo_dial_modal(
        bContext *C, wmGizmo *gz, const wmEvent *event,
        eWM_GizmoFlagTweak tweak_flag);

typedef struct DialInteraction {
	struct {
		float mval[2];
		/* Only for when using properties. */
		float prop_angle;
	} init;
	struct {
		/* Cache the last angle to detect rotations bigger than -/+ PI. */
		eWM_GizmoFlagTweak tweak_flag;
		float angle;
	} prev;

	/* Number of full rotations. */
	int rotations;

	/* Final output values, used for drawing. */
	struct {
		float angle_ofs;
		float angle_delta;
	} output;
} DialInteraction;

#define DIAL_WIDTH       1.0f
#define DIAL_RESOLUTION 48

/* Could make option, negative to clip more (don't show when view aligned). */
#define DIAL_CLIP_BIAS 0.02

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

static void dial_geom_draw(
        const wmGizmo *gz, const float color[4], const bool select,
        float axis_modal_mat[4][4], float clip_plane[4], const float arc_inner_factor)
{
#ifdef USE_GIZMO_CUSTOM_DIAL
	UNUSED_VARS(gz, axis_modal_mat, clip_plane);
	wm_gizmo_geometryinfo_draw(&wm_gizmo_geom_data_dial, select, color);
#else
	const int draw_options = RNA_enum_get(gz->ptr, "draw_options");
	const bool filled = (draw_options & ED_GIZMO_DIAL_DRAW_FLAG_FILL) != 0;

	GPU_line_width(gz->line_width);

	GPUVertFormat *format = immVertexFormat();
	uint pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);

	if (clip_plane) {
		immBindBuiltinProgram(GPU_SHADER_3D_CLIPPED_UNIFORM_COLOR);
		float clip_plane_f[4] = {clip_plane[0], clip_plane[1], clip_plane[2], clip_plane[3]};
		immUniform4fv("ClipPlane", clip_plane_f);
		immUniformMatrix4fv("ModelMatrix", axis_modal_mat);
	}
	else {
		immBindBuiltinProgram(GPU_SHADER_3D_UNIFORM_COLOR);
	}

	immUniformColor4fv(color);

	if (filled) {
		imm_draw_circle_fill_2d(pos, 0, 0, 1.0, DIAL_RESOLUTION);
	}
	else {
		imm_draw_circle_wire_2d(pos, 0, 0, 1.0, DIAL_RESOLUTION);
		if (arc_inner_factor != 0.0f) {
			imm_draw_circle_wire_2d(pos, 0, 0, arc_inner_factor, DIAL_RESOLUTION);
		}
	}

	immUnbindProgram();

	UNUSED_VARS(select);
#endif
}

/**
 * Draws a line from (0, 0, 0) to \a co_outer, at \a angle.
 */
static void dial_ghostarc_draw_helpline(
        const float angle, const float co_outer[3], const float color[4])
{
	GPU_matrix_push();
	GPU_matrix_rotate_3f(RAD2DEGF(angle), 0.0f, 0.0f, -1.0f);

	uint pos = GPU_vertformat_attr_add(immVertexFormat(), "pos", GPU_COMP_F32, 3, GPU_FETCH_FLOAT);

	immBindBuiltinProgram(GPU_SHADER_3D_UNIFORM_COLOR);

	immUniformColor4fv(color);

	immBegin(GPU_PRIM_LINE_STRIP, 2);
	immVertex3f(pos, 0.0f, 0, 0.0f);
	immVertex3fv(pos, co_outer);
	immEnd();

	immUnbindProgram();

	GPU_matrix_pop();
}

static void dial_ghostarc_draw(
        const float angle_ofs, const float angle_delta,
        const float arc_inner_factor, const float color[4])
{
	const float width_inner = DIAL_WIDTH;
	GPUVertFormat *format = immVertexFormat();
	uint pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
	immBindBuiltinProgram(GPU_SHADER_3D_UNIFORM_COLOR);

	if (arc_inner_factor != 0.0) {
		float color_dark[4] = {0};
		color_dark[3] = color[3] / 2;
		immUniformColor4fv(color_dark);
		imm_draw_disk_partial_fill_2d(
		        pos, 0, 0, arc_inner_factor, width_inner, DIAL_RESOLUTION, RAD2DEGF(angle_ofs), RAD2DEGF(M_PI * 2));
	}

	immUniformColor4fv(color);
	imm_draw_disk_partial_fill_2d(
	        pos, 0, 0, arc_inner_factor, width_inner, DIAL_RESOLUTION, RAD2DEGF(angle_ofs), RAD2DEGF(angle_delta));
	immUnbindProgram();
}

static void dial_ghostarc_get_angles(
        const wmGizmo *gz,
        const wmEvent *event,
        const ARegion *ar,
        float mat[4][4], const float co_outer[3],
        float *r_start, float *r_delta)
{
	DialInteraction *inter = gz->interaction_data;
	const RegionView3D *rv3d = ar->regiondata;
	const float mval[2] = {event->x - ar->winrct.xmin, event->y - ar->winrct.ymin};

	/* We might need to invert the direction of the angles. */
	float view_vec[3], axis_vec[3];
	ED_view3d_global_to_vector(rv3d, gz->matrix_basis[3], view_vec);
	normalize_v3_v3(axis_vec, gz->matrix_basis[2]);

	float proj_outer_rel[3];
	mul_v3_project_m4_v3(proj_outer_rel, mat, co_outer);
	sub_v3_v3(proj_outer_rel, gz->matrix_basis[3]);

	float proj_mval_new_rel[3];
	float proj_mval_init_rel[3];
	float dial_plane[4];

	plane_from_point_normal_v3(dial_plane, gz->matrix_basis[3], axis_vec);

	if (!ED_view3d_win_to_3d_on_plane(ar, dial_plane, inter->init.mval, proj_mval_init_rel)) {
		goto fail;
	}
	sub_v3_v3(proj_mval_init_rel, gz->matrix_basis[3]);

	if (!ED_view3d_win_to_3d_on_plane(ar, dial_plane, mval, proj_mval_new_rel)) {
		goto fail;
	}
	sub_v3_v3(proj_mval_new_rel, gz->matrix_basis[3]);

	const int draw_options = RNA_enum_get(gz->ptr, "draw_options");

	/* Start direction from mouse or set by user. */
	const float *proj_init_rel =
	        (draw_options & ED_GIZMO_DIAL_DRAW_FLAG_ANGLE_START_Y) ?
	        gz->matrix_basis[1] : proj_mval_init_rel;

	/* Return angles. */
	const float start = angle_wrap_rad(angle_signed_on_axis_v3v3_v3(proj_outer_rel, proj_init_rel, axis_vec));
	const float delta = angle_wrap_rad(angle_signed_on_axis_v3v3_v3(proj_mval_init_rel, proj_mval_new_rel, axis_vec));

	/* Change of sign, we passed the 180 degree threshold. This means we need to add a turn
	 * to distinguish between transition from 0 to -1 and -PI to +PI, use comparison with PI/2.
	 * Logic taken from #BLI_dial_angle */
	if ((delta * inter->prev.angle < 0.0f) &&
	    (fabsf(inter->prev.angle) > (float)M_PI_2))
	{
		if (inter->prev.angle < 0.0f) {
			inter->rotations--;
		}
		else {
			inter->rotations++;
		}
	}
	inter->prev.angle = delta;

	const bool wrap_angle = RNA_boolean_get(gz->ptr, "wrap_angle");
	const double delta_final = (double)delta + ((2 * M_PI) * (double)inter->rotations);
	*r_start = start;
	*r_delta = (float)(wrap_angle ? fmod(delta_final, 2 * M_PI) : delta_final);
	return;

	/* If we can't project (unlikely). */
fail:
	*r_start = 0.0;
	*r_delta = 0.0;
}

static void dial_ghostarc_draw_with_helplines(
        const float angle_ofs, const float angle_delta,
        const float arc_inner_factor, const float color_helpline[4], const int draw_options)
{
	/* Coordinate at which the arc drawing will be started. */
	const float co_outer[4] = {0.0f, DIAL_WIDTH, 0.0f};
	dial_ghostarc_draw(angle_ofs, angle_delta, arc_inner_factor, (const float[4]){0.8f, 0.8f, 0.8f, 0.4f});
	GPU_line_width(1.0f);
	dial_ghostarc_draw_helpline(angle_ofs, co_outer, color_helpline);
	if (draw_options & ED_GIZMO_DIAL_DRAW_FLAG_ANGLE_VALUE) {
		GPU_line_width(3.0f);
	}
	dial_ghostarc_draw_helpline(angle_ofs + angle_delta, co_outer, color_helpline);
}

static void dial_draw_intern(
        const bContext *C, wmGizmo *gz,
        const bool select, const bool highlight, float clip_plane[4])
{
	float matrix_final[4][4];
	float color[4];

	BLI_assert(CTX_wm_area(C)->spacetype == SPACE_VIEW3D);

	gizmo_color_get(gz, highlight, color);

	WM_gizmo_calc_matrix_final(gz, matrix_final);

	GPU_matrix_push();
	GPU_matrix_mul(matrix_final);

	/* FIXME(campbell): look into removing this. */
	if ((gz->flag & WM_GIZMO_DRAW_VALUE) &&
	    (gz->state & WM_GIZMO_STATE_MODAL))
	{
		/* XXX, View3D rotation gizmo doesn't call modal. */
		if (!WM_gizmo_target_property_is_valid_any(gz)) {
			wmWindow *win = CTX_wm_window(C);
			gizmo_dial_modal((bContext *)C, gz, win->eventstate, 0);
		}
	}

	GPU_polygon_smooth(false);

	const float arc_inner_factor = RNA_float_get(gz->ptr, "arc_inner_factor");
	if (select == false) {
		float angle_ofs = 0.0f;
		float angle_delta = 0.0f;
		bool show_ghostarc = false;

		/* Draw rotation indicator arc first. */
		wmGizmoProperty *gz_prop = WM_gizmo_target_property_find(gz, "offset");
		const int draw_options = RNA_enum_get(gz->ptr, "draw_options");

		if (WM_gizmo_target_property_is_valid(gz_prop) &&
		    (draw_options & ED_GIZMO_DIAL_DRAW_FLAG_ANGLE_VALUE))
		{
			angle_ofs = 0.0f;
			angle_delta = WM_gizmo_target_property_float_get(gz, gz_prop);
			show_ghostarc = true;
		}
		else if ((gz->flag & WM_GIZMO_DRAW_VALUE) &&
		         (gz->state & WM_GIZMO_STATE_MODAL))
		{
			DialInteraction *inter = gz->interaction_data;
			angle_ofs = inter->output.angle_ofs;
			angle_delta = inter->output.angle_delta;
			show_ghostarc = true;
		}

		if (show_ghostarc) {
			dial_ghostarc_draw_with_helplines(angle_ofs, angle_delta, arc_inner_factor, color, draw_options);
			if ((draw_options & ED_GIZMO_DIAL_DRAW_FLAG_ANGLE_MIRROR) != 0) {
				angle_ofs += M_PI;
				dial_ghostarc_draw_with_helplines(angle_ofs, angle_delta, arc_inner_factor, color, draw_options);
			}
		}
	}

	/* Draw actual dial gizmo. */
	dial_geom_draw(gz, color, select, gz->matrix_basis, clip_plane, arc_inner_factor);

	GPU_matrix_pop();
}

static void gizmo_dial_draw_select(const bContext *C, wmGizmo *gz, int select_id)
{
	float clip_plane_buf[4];
	const int draw_options = RNA_enum_get(gz->ptr, "draw_options");
	float *clip_plane = (draw_options & ED_GIZMO_DIAL_DRAW_FLAG_CLIP) ? clip_plane_buf : NULL;

	if (clip_plane) {
		ARegion *ar = CTX_wm_region(C);
		RegionView3D *rv3d = ar->regiondata;

		copy_v3_v3(clip_plane, rv3d->viewinv[2]);
		clip_plane[3] = -dot_v3v3(rv3d->viewinv[2], gz->matrix_basis[3]);
		clip_plane[3] += DIAL_CLIP_BIAS * gz->scale_final;
		glEnable(GL_CLIP_DISTANCE0);
	}

	GPU_select_load_id(select_id);
	dial_draw_intern(C, gz, true, false, clip_plane);

	if (clip_plane) {
		glDisable(GL_CLIP_DISTANCE0);
	}
}

static void gizmo_dial_draw(const bContext *C, wmGizmo *gz)
{
	const bool is_modal = gz->state & WM_GIZMO_STATE_MODAL;
	const bool is_highlight = (gz->state & WM_GIZMO_STATE_HIGHLIGHT) != 0;
	float clip_plane_buf[4];
	const int draw_options = RNA_enum_get(gz->ptr, "draw_options");
	float *clip_plane = (!is_modal && (draw_options & ED_GIZMO_DIAL_DRAW_FLAG_CLIP)) ? clip_plane_buf : NULL;

	if (clip_plane) {
		ARegion *ar = CTX_wm_region(C);
		RegionView3D *rv3d = ar->regiondata;

		copy_v3_v3(clip_plane, rv3d->viewinv[2]);
		clip_plane[3] = -dot_v3v3(rv3d->viewinv[2], gz->matrix_basis[3]);
		clip_plane[3] += DIAL_CLIP_BIAS * gz->scale_final;

		glEnable(GL_CLIP_DISTANCE0);
	}

	GPU_blend(true);
	dial_draw_intern(C, gz, false, is_highlight, clip_plane);
	GPU_blend(false);

	if (clip_plane) {
		glDisable(GL_CLIP_DISTANCE0);
	}
}

static int gizmo_dial_modal(
        bContext *C, wmGizmo *gz, const wmEvent *event,
        eWM_GizmoFlagTweak tweak_flag)
{
	DialInteraction *inter = gz->interaction_data;
	if ((event->type != MOUSEMOVE) && (inter->prev.tweak_flag == tweak_flag)) {
		return OPERATOR_RUNNING_MODAL;
	}
	/* Coordinate at which the arc drawing will be started. */
	const float co_outer[4] = {0.0f, DIAL_WIDTH, 0.0f};
	float angle_ofs, angle_delta;

	dial_ghostarc_get_angles(
	        gz, event, CTX_wm_region(C), gz->matrix_basis, co_outer, &angle_ofs, &angle_delta);

	if (tweak_flag & WM_GIZMO_TWEAK_SNAP) {
		const double snap = DEG2RAD(5);
		angle_delta = (float)roundf((double)angle_delta / snap) * snap;
	}
	if (tweak_flag & WM_GIZMO_TWEAK_PRECISE) {
		angle_delta *= 0.1f;
	}
	inter->output.angle_delta = angle_delta;
	inter->output.angle_ofs = angle_ofs;

	/* Set the property for the operator and call its modal function. */
	wmGizmoProperty *gz_prop = WM_gizmo_target_property_find(gz, "offset");
	if (WM_gizmo_target_property_is_valid(gz_prop)) {
		WM_gizmo_target_property_float_set(C, gz, gz_prop, inter->init.prop_angle + angle_delta);
	}

	inter->prev.tweak_flag = tweak_flag;

	return OPERATOR_RUNNING_MODAL;
}


static void gizmo_dial_setup(wmGizmo *gz)
{
	const float dir_default[3] = {0.0f, 0.0f, 1.0f};

	/* defaults */
	copy_v3_v3(gz->matrix_basis[2], dir_default);
}

static int gizmo_dial_invoke(
        bContext *UNUSED(C), wmGizmo *gz, const wmEvent *event)
{
	DialInteraction *inter = MEM_callocN(sizeof(DialInteraction), __func__);

	inter->init.mval[0] = event->mval[0];
	inter->init.mval[1] = event->mval[1];

	wmGizmoProperty *gz_prop = WM_gizmo_target_property_find(gz, "offset");
	if (WM_gizmo_target_property_is_valid(gz_prop)) {
		inter->init.prop_angle = WM_gizmo_target_property_float_get(gz, gz_prop);
	}

	gz->interaction_data = inter;

	return OPERATOR_RUNNING_MODAL;
}

/* -------------------------------------------------------------------- */
/** \name Dial Gizmo API
 *
 * \{ */

static void GIZMO_GT_dial_3d(wmGizmoType *gzt)
{
	/* identifiers */
	gzt->idname = "GIZMO_GT_dial_3d";

	/* api callbacks */
	gzt->draw = gizmo_dial_draw;
	gzt->draw_select = gizmo_dial_draw_select;
	gzt->setup = gizmo_dial_setup;
	gzt->invoke = gizmo_dial_invoke;
	gzt->modal = gizmo_dial_modal;

	gzt->struct_size = sizeof(wmGizmo);

	/* rna */
	static EnumPropertyItem rna_enum_draw_options[] = {
		{ED_GIZMO_DIAL_DRAW_FLAG_CLIP, "CLIP", 0, "Clipped", ""},
		{ED_GIZMO_DIAL_DRAW_FLAG_FILL, "FILL", 0, "Filled", ""},
		{ED_GIZMO_DIAL_DRAW_FLAG_ANGLE_MIRROR, "ANGLE_MIRROR", 0, "Angle Mirror", ""},
		{ED_GIZMO_DIAL_DRAW_FLAG_ANGLE_START_Y, "ANGLE_START_Y", 0, "Angle Start Y", ""},
		{ED_GIZMO_DIAL_DRAW_FLAG_ANGLE_VALUE, "ANGLE_VALUE", 0, "Show Angle Value", ""},
		{0, NULL, 0, NULL, NULL}
	};
	RNA_def_enum_flag(gzt->srna, "draw_options", rna_enum_draw_options, 0, "Draw Options", "");
	RNA_def_boolean(gzt->srna, "wrap_angle", true, "Wrap Angle", "");
	RNA_def_float_factor(gzt->srna, "arc_inner_factor", 0.0f, 0.0f, 1.0f, "Arc Inner Factor", "", 0.0f, 1.0f);

	WM_gizmotype_target_property_def(gzt, "offset", PROP_FLOAT, 1);
}

void ED_gizmotypes_dial_3d(void)
{
	WM_gizmotype_append(GIZMO_GT_dial_3d);
}

/** \} */