/*
 * ***** 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) 2009 Blender Foundation.
 * All rights reserved.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/editors/interface/interface_eyedropper_colorband.c
 *  \ingroup edinterface
 *
 * Eyedropper (Color Band).
 *
 * Operates by either:
 * - Dragging a straight line, sampling pixels formed by the line to extract a gradient.
 * - Clicking on points, adding each color to the end of the color-band.
 *
 * Defines:
 * - #UI_OT_eyedropper_colorband
 * - #UI_OT_eyedropper_colorband_point
 */

#include "MEM_guardedalloc.h"

#include "DNA_screen_types.h"

#include "BLI_bitmap_draw_2d.h"
#include "BLI_math_vector.h"

#include "BKE_context.h"
#include "BKE_colorband.h"

#include "RNA_access.h"

#include "UI_interface.h"

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

#include "interface_intern.h"

#include "interface_eyedropper_intern.h"

typedef struct Colorband_RNAUpdateCb {
	PointerRNA ptr;
	PropertyRNA *prop;
} Colorband_RNAUpdateCb;

typedef struct EyedropperColorband {
	int last_x, last_y;
	/* Alpha is currently fixed at 1.0, may support in future. */
	float (*color_buffer)[4];
	int     color_buffer_alloc;
	int     color_buffer_len;
	bool sample_start;
	ColorBand init_color_band;
	ColorBand *color_band;
	PointerRNA ptr;
	PropertyRNA *prop;
} EyedropperColorband;

/* For user-data only. */
struct EyedropperColorband_Context {
	bContext *context;
	EyedropperColorband *eye;
};

static bool eyedropper_colorband_init(bContext *C, wmOperator *op)
{
	ColorBand *band = NULL;
	EyedropperColorband *eye;

	uiBut *but = UI_context_active_but_get(C);

	if (but == NULL) {
		/* pass */
	}
	else if (but->type == UI_BTYPE_COLORBAND) {
		/* When invoked with a hotkey, we can find the band in 'but->poin'. */
		band = (ColorBand *)but->poin;
	}
	else {
		/* When invoked from a button it's in custom_data field. */
		band = (ColorBand *)but->custom_data;
	}

	if (!band)
		return false;

	op->customdata = eye = MEM_callocN(sizeof(EyedropperColorband), __func__);
	eye->color_buffer_alloc = 16;
	eye->color_buffer = MEM_mallocN(sizeof(*eye->color_buffer) * eye->color_buffer_alloc, __func__);
	eye->color_buffer_len = 0;
	eye->color_band = band;
	eye->init_color_band = *eye->color_band;
	eye->ptr = ((Colorband_RNAUpdateCb *)but->func_argN)->ptr;
	eye->prop  = ((Colorband_RNAUpdateCb *)but->func_argN)->prop;

	return true;
}

static void eyedropper_colorband_sample_point(bContext *C, EyedropperColorband *eye, int mx, int my)
{
	if (eye->last_x != mx || eye->last_y != my) {
		float col[4];
		col[3] = 1.0f;  /* TODO: sample alpha */
		eyedropper_color_sample_fl(C, mx, my, col);
		if (eye->color_buffer_len + 1 == eye->color_buffer_alloc) {
			eye->color_buffer_alloc *= 2;
			eye->color_buffer = MEM_reallocN(eye->color_buffer, sizeof(*eye->color_buffer) * eye->color_buffer_alloc);
		}
		copy_v4_v4(eye->color_buffer[eye->color_buffer_len], col);
		eye->color_buffer_len += 1;
		eye->last_x = mx;
		eye->last_y = my;
	}
}

static bool eyedropper_colorband_sample_callback(int mx, int my, void *userdata)
{
	struct EyedropperColorband_Context *data = userdata;
	bContext *C = data->context;
	EyedropperColorband *eye = data->eye;
	eyedropper_colorband_sample_point(C, eye, mx, my);
	return true;
}

static void eyedropper_colorband_sample_segment(bContext *C, EyedropperColorband *eye, int mx, int my)
{
	/* Since the mouse tends to move rather rapidly we use #BLI_bitmap_draw_2d_line_v2v2i
	 * to interpolate between the reported coordinates */
	struct EyedropperColorband_Context userdata = {C, eye};
	int p1[2] = {eye->last_x, eye->last_y};
	int p2[2] = {mx, my};
	BLI_bitmap_draw_2d_line_v2v2i(p1, p2, eyedropper_colorband_sample_callback, &userdata);
}

static void eyedropper_colorband_exit(bContext *C, wmOperator *op)
{
	WM_cursor_modal_restore(CTX_wm_window(C));

	if (op->customdata) {
		EyedropperColorband *eye = op->customdata;
		MEM_freeN(eye->color_buffer);
		MEM_freeN(eye);
		op->customdata = NULL;
	}
}

static void eyedropper_colorband_apply(bContext *C, wmOperator *op)
{
	EyedropperColorband *eye = op->customdata;
	/* Always filter, avoids noise in resulting color-band. */
	bool filter_samples = true;
	BKE_colorband_init_from_table_rgba(eye->color_band, eye->color_buffer, eye->color_buffer_len, filter_samples);
	RNA_property_update(C, &eye->ptr, eye->prop);
}

static void eyedropper_colorband_cancel(bContext *C, wmOperator *op)
{
	EyedropperColorband *eye = op->customdata;
	*eye->color_band = eye->init_color_band;
	RNA_property_update(C, &eye->ptr, eye->prop);
	eyedropper_colorband_exit(C, op);
}

/* main modal status check */
static int eyedropper_colorband_modal(bContext *C, wmOperator *op, const wmEvent *event)
{
	EyedropperColorband *eye = op->customdata;
	/* handle modal keymap */
	if (event->type == EVT_MODAL_MAP) {
		switch (event->val) {
			case EYE_MODAL_CANCEL:
				eyedropper_colorband_cancel(C, op);
				return OPERATOR_CANCELLED;
			case EYE_MODAL_SAMPLE_CONFIRM:
				eyedropper_colorband_sample_segment(C, eye, event->x, event->y);
				eyedropper_colorband_apply(C, op);
				eyedropper_colorband_exit(C, op);
				return OPERATOR_FINISHED;
			case EYE_MODAL_SAMPLE_BEGIN:
				/* enable accum and make first sample */
				eye->sample_start = true;
				eyedropper_colorband_sample_point(C, eye, event->x, event->y);
				eyedropper_colorband_apply(C, op);
				eye->last_x = event->x;
				eye->last_y = event->y;
				break;
			case EYE_MODAL_SAMPLE_RESET:
				break;
		}
	}
	else if (event->type == MOUSEMOVE) {
		if (eye->sample_start) {
			eyedropper_colorband_sample_segment(C, eye, event->x, event->y);
			eyedropper_colorband_apply(C, op);
		}
	}
	return OPERATOR_RUNNING_MODAL;
}

static int eyedropper_colorband_point_modal(bContext *C, wmOperator *op, const wmEvent *event)
{
	EyedropperColorband *eye = op->customdata;
	/* handle modal keymap */
	if (event->type == EVT_MODAL_MAP) {
		switch (event->val) {
			case EYE_MODAL_POINT_CANCEL:
				eyedropper_colorband_cancel(C, op);
				return OPERATOR_CANCELLED;
			case EYE_MODAL_POINT_CONFIRM:
				eyedropper_colorband_apply(C, op);
				eyedropper_colorband_exit(C, op);
				return OPERATOR_FINISHED;
			case EYE_MODAL_POINT_REMOVE_LAST:
				if (eye->color_buffer_len > 0) {
					eye->color_buffer_len -= 1;
					eyedropper_colorband_apply(C, op);
				}
				break;
			case EYE_MODAL_POINT_SAMPLE:
				eyedropper_colorband_sample_point(C, eye, event->x, event->y);
				eyedropper_colorband_apply(C, op);
				if (eye->color_buffer_len == MAXCOLORBAND ) {
					eyedropper_colorband_exit(C, op);
					return OPERATOR_FINISHED;
				}
				break;
			case EYE_MODAL_SAMPLE_RESET:
				*eye->color_band = eye->init_color_band;
				RNA_property_update(C, &eye->ptr, eye->prop);
				eye->color_buffer_len = 0;
				break;
		}
	}
	return OPERATOR_RUNNING_MODAL;
}


/* Modal Operator init */
static int eyedropper_colorband_invoke(bContext *C, wmOperator *op, const wmEvent *UNUSED(event))
{
	/* init */
	if (eyedropper_colorband_init(C, op)) {
		WM_cursor_modal_set(CTX_wm_window(C), BC_EYEDROPPER_CURSOR);

		/* add temp handler */
		WM_event_add_modal_handler(C, op);

		return OPERATOR_RUNNING_MODAL;
	}
	else {
		eyedropper_colorband_exit(C, op);
		return OPERATOR_CANCELLED;
	}
}

/* Repeat operator */
static int eyedropper_colorband_exec(bContext *C, wmOperator *op)
{
	/* init */
	if (eyedropper_colorband_init(C, op)) {

		/* do something */

		/* cleanup */
		eyedropper_colorband_exit(C, op);

		return OPERATOR_FINISHED;
	}
	else {
		return OPERATOR_CANCELLED;
	}
}

static bool eyedropper_colorband_poll(bContext *C)
{
	uiBut *but = UI_context_active_but_get(C);
	return (but && but->type == UI_BTYPE_COLORBAND);
}


void UI_OT_eyedropper_colorband(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Eyedropper colorband";
	ot->idname = "UI_OT_eyedropper_colorband";
	ot->description = "Sample a color band";

	/* api callbacks */
	ot->invoke = eyedropper_colorband_invoke;
	ot->modal = eyedropper_colorband_modal;
	ot->cancel = eyedropper_colorband_cancel;
	ot->exec = eyedropper_colorband_exec;
	ot->poll = eyedropper_colorband_poll;

	/* flags */
	ot->flag = OPTYPE_BLOCKING | OPTYPE_INTERNAL;

	/* properties */
}

void UI_OT_eyedropper_colorband_point(wmOperatorType *ot)
{
	/* identifiers */
	ot->name = "Eyedropper colorband (points)";
	ot->idname = "UI_OT_eyedropper_colorband_point";
	ot->description = "Pointsample a color band";

	/* api callbacks */
	ot->invoke = eyedropper_colorband_invoke;
	ot->modal = eyedropper_colorband_point_modal;
	ot->cancel = eyedropper_colorband_cancel;
	ot->exec = eyedropper_colorband_exec;
	ot->poll = eyedropper_colorband_poll;

	/* flags */
	ot->flag = OPTYPE_BLOCKING | OPTYPE_INTERNAL;

	/* properties */
}