// SPDX-License-Identifier: GPL-2.0-only

#define _POSIX_C_SOURCE 200809L
#include <assert.h>
#include <string.h>
#include "labwc.h"
#include "ssd.h"
#include "theme.h"
#include "common/font.h"
#include "common/scene-helpers.h"

#define FOR_EACH_STATE(view, tmp) FOR_EACH(tmp, \
	&(view)->ssd.titlebar.active, \
	&(view)->ssd.titlebar.inactive)

void
ssd_titlebar_create(struct view *view)
{
	struct theme *theme = view->server->theme;
	int width = view->w;

	float *color;
	struct wlr_scene_tree *parent;
	struct wlr_buffer *corner_top_left;
	struct wlr_buffer *corner_top_right;

	struct ssd_sub_tree *subtree;
	FOR_EACH_STATE(view, subtree) {
		subtree->tree = wlr_scene_tree_create(view->ssd.tree);
		parent = subtree->tree;
		wlr_scene_node_set_position(&parent->node, 0, -theme->title_height);
		if (subtree == &view->ssd.titlebar.active) {
			color = theme->window_active_title_bg_color;
			corner_top_left = &theme->corner_top_left_active_normal->base;
			corner_top_right = &theme->corner_top_right_active_normal->base;
		} else {
			color = theme->window_inactive_title_bg_color;
			corner_top_left = &theme->corner_top_left_inactive_normal->base;
			corner_top_right = &theme->corner_top_right_inactive_normal->base;
			wlr_scene_node_set_enabled(&parent->node, false);
		}
		wl_list_init(&subtree->parts);

		/* Title */
		add_scene_rect(&subtree->parts, LAB_SSD_PART_TITLEBAR, parent,
			width - BUTTON_WIDTH * BUTTON_COUNT, theme->title_height,
			BUTTON_WIDTH, 0, color);
		/* Buttons */
		add_scene_button_corner(&subtree->parts,
			LAB_SSD_BUTTON_WINDOW_MENU, LAB_SSD_PART_CORNER_TOP_LEFT, parent,
			corner_top_left, &theme->xbm_menu_active_unpressed->base, 0, view);
		add_scene_button(&subtree->parts, LAB_SSD_BUTTON_ICONIFY, parent,
			color, &theme->xbm_iconify_active_unpressed->base,
			width - BUTTON_WIDTH * 3, view);
		add_scene_button(&subtree->parts, LAB_SSD_BUTTON_MAXIMIZE, parent,
			color, &theme->xbm_maximize_active_unpressed->base,
			width - BUTTON_WIDTH * 2, view);
		add_scene_button_corner(&subtree->parts,
			LAB_SSD_BUTTON_CLOSE, LAB_SSD_PART_CORNER_TOP_RIGHT, parent,
			corner_top_right, &theme->xbm_close_active_unpressed->base,
			width - BUTTON_WIDTH * 1, view);
	} FOR_EACH_END
	ssd_update_title(view);
}

static bool
is_direct_child(struct wlr_scene_node *node, struct ssd_sub_tree *subtree)
{
	return node->parent == subtree->tree;
}

void
ssd_titlebar_update(struct view *view)
{
	int width = view->w;
	if (width == view->ssd.state.width) {
		return;
	}
	struct theme *theme = view->server->theme;

	struct ssd_part *part;
	struct ssd_sub_tree *subtree;
	FOR_EACH_STATE(view, subtree) {
		wl_list_for_each(part, &subtree->parts, link) {
			switch (part->type) {
			case LAB_SSD_PART_TITLEBAR:
				wlr_scene_rect_set_size(
					lab_wlr_scene_get_rect(part->node),
					width - BUTTON_WIDTH * BUTTON_COUNT,
					theme->title_height);
				continue;
			case LAB_SSD_BUTTON_ICONIFY:
				if (is_direct_child(part->node, subtree)) {
					wlr_scene_node_set_position(part->node,
						width - BUTTON_WIDTH * 3, 0);
				}
				continue;
			case  LAB_SSD_BUTTON_MAXIMIZE:
				if (is_direct_child(part->node, subtree)) {
					wlr_scene_node_set_position(part->node,
						width - BUTTON_WIDTH * 2, 0);
				}
				continue;
			case LAB_SSD_PART_CORNER_TOP_RIGHT:
				if (is_direct_child(part->node, subtree)) {
					wlr_scene_node_set_position(part->node,
						width - BUTTON_WIDTH * 1, 0);
				}
				continue;
			default:
				continue;
			}
		}
	} FOR_EACH_END
	ssd_update_title(view);
}

void
ssd_titlebar_destroy(struct view *view)
{
	if (!view->ssd.titlebar.active.tree) {
		return;
	}

	struct ssd_sub_tree *subtree;
	FOR_EACH_STATE(view, subtree) {
		ssd_destroy_parts(&subtree->parts);
		wlr_scene_node_destroy(&subtree->tree->node);
		subtree->tree = NULL;
	} FOR_EACH_END

	if (view->ssd.state.title.text) {
		free(view->ssd.state.title.text);
		view->ssd.state.title.text = NULL;
	}
}

/*
 * For ssd_update_title* we do not early out because
 * .active and .inactive may result in different sizes
 * of the title (font family/size) or background of
 * the title (different button/border width).
 */

static void
ssd_update_title_positions(struct view *view)
{
	struct theme *theme = view->server->theme;
	int width = view->w;
	int title_bg_width = width - BUTTON_WIDTH * BUTTON_COUNT;

	int x, y;
	int buffer_height, buffer_width;
	struct ssd_part *part;
	struct ssd_sub_tree *subtree;
	FOR_EACH_STATE(view, subtree) {
		part = ssd_get_part(&subtree->parts, LAB_SSD_PART_TITLE);
		if (!part) {
			/* view->surface never been mapped */
			continue;
		}

		buffer_width = part->buffer ? part->buffer->base.width : 0;
		buffer_height = part->buffer ? part->buffer->base.height : 0;
		x = BUTTON_WIDTH;
		y = (theme->title_height - buffer_height) / 2;
		if (title_bg_width <= 0) {
			wlr_scene_node_set_position(part->node, x, y);
			continue;
		}

		if (theme->window_label_text_justify == LAB_JUSTIFY_CENTER) {
			if (buffer_width + BUTTON_WIDTH * 2 <= title_bg_width) {
				/* Center based on the full width */
				x = (width - buffer_width) / 2;
			} else {
				/*
				 * Center based on the width between the buttons.
				 * Title jumps around once this is hit but its still
				 * better than to hide behind the buttons on the right.
				 */
				x += (title_bg_width - buffer_width) / 2;
			}
		} else if (theme->window_label_text_justify == LAB_JUSTIFY_RIGHT) {
			x += title_bg_width - buffer_width;
		} else if (theme->window_label_text_justify == LAB_JUSTIFY_LEFT) {
			/* TODO: maybe add some theme x padding here? */
		}
		wlr_scene_node_set_position(part->node, x, y);
	} FOR_EACH_END
}

void
ssd_update_title(struct view *view)
{
	if (!view->ssd.tree) {
		return;
	}

	char *title = (char *)view_get_string_prop(view, "title");
	if (!title || !*title) {
		return;
	}

	struct theme *theme = view->server->theme;
	struct ssd_state_title *state = &view->ssd.state.title;
	bool title_unchanged = state->text && !strcmp(title, state->text);

	/* TODO: Do we only have active window fonts? */
	struct font font = {
		.name = rc.font_name_activewindow,
		.size = rc.font_size_activewindow,
	};

	float *text_color;
	struct ssd_part *part;
	struct ssd_sub_tree *subtree;
	struct ssd_state_title_width *dstate;
	int title_bg_width = view->w - BUTTON_WIDTH * BUTTON_COUNT;

	FOR_EACH_STATE(view, subtree) {
		if (subtree == &view->ssd.titlebar.active) {
			dstate = &state->active;
			text_color = theme->window_active_label_text_color;
		} else {
			dstate = &state->inactive;
			text_color = theme->window_inactive_label_text_color;
		}

		if (title_bg_width <= 0) {
			dstate->truncated = true;
			continue;
		}

		if (title_unchanged
				&& !dstate->truncated && dstate->width < title_bg_width) {
			/* title the same + we don't need to resize title */
			continue;
		}

		part = ssd_get_part(&subtree->parts, LAB_SSD_PART_TITLE);
		if (!part) {
			/* Initialize part and wlr_scene_buffer without attaching a buffer */
			part = add_scene_part(&subtree->parts, LAB_SSD_PART_TITLE);
			part->node = &wlr_scene_buffer_create(subtree->tree, NULL)->node;
		}

		/* Generate and update the lab_data_buffer, drops the old buffer */
		font_buffer_update(&part->buffer, title_bg_width, title, &font, text_color);
		if (!part->buffer) {
			/* This can happen for example by defining a font size of 0 */
			wlr_log(WLR_ERROR, "Failed to create title buffer");
		}

		/* (Re)set the buffer */
		wlr_scene_buffer_set_buffer(
			wlr_scene_buffer_from_node(part->node),
			part->buffer ? &part->buffer->base : NULL);

		/* And finally update the cache */
		dstate->width = part->buffer ? part->buffer->base.width : 0;
		dstate->truncated = title_bg_width <= dstate->width;
	} FOR_EACH_END

	if (!title_unchanged) {
		if (state->text) {
			free(state->text);
		}
		state->text = strdup(title);
	}
	ssd_update_title_positions(view);
}

/*
 * Returns the wlr_scene_node for hover effect.
 * To disable the hover effect later on just call
 * wlr_scene_node_set_enabled(node, false).
 */
struct wlr_scene_node *
ssd_button_hover_enable(struct view *view, enum ssd_part_type type)
{
	if (!view->ssd.tree) {
		wlr_log(WLR_ERROR, "%s() for destroyed view", __func__);
		return NULL;
	}

	assert(ssd_is_button(type));
	struct ssd_part *part;
	struct ssd_sub_tree *subtree;
	FOR_EACH_STATE(view, subtree) {
		if (subtree->tree->node.enabled) {
			/*
			 * TODO: This function makes too many magic assumptions:
			 * - It expects the returned part to be the tree for the button
			 * - It expects the last node in that tree to be the hover overlay
			 *
			 * Both assumptions are valid as long as ssd_parts.c isn't changing
			 * the way a button is created but this cries for introducing bugs
			 * in the future if the button creation process or ssd_get_part()
			 * lookup routine would ever change.
			 */
			part = ssd_get_part(&subtree->parts, type);
			if (!part) {
				wlr_log(WLR_ERROR, "hover enable failed to find button");
				return NULL;
			}
			struct wlr_scene_node *child;
			struct wlr_scene_tree *button = lab_scene_tree_from_node(part->node);
			wl_list_for_each_reverse(child, &button->children, link) {
				if (child->type == WLR_SCENE_NODE_RECT) {
					wlr_scene_node_set_enabled(child, true);
					return child;
				}
			}
		}
	} FOR_EACH_END

	wlr_log(WLR_ERROR, "hover enable failed to find button");
	return NULL;
}

#undef FOR_EACH_STATE