/* SPDX-License-Identifier: MIT */
/*
 * kontextbox.c
 *
 * Copyright (c) 2026 KonAki
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "kontextbox.h"

#include <math.h>
#include <string.h>

static int iround(float v)
{
	return (int)floorf(v + 0.5f);
}

/* the alpha of a colour times a share from 0 to 1 */
static uint32_t fade(uint32_t color, float alpha)
{
	uint32_t a = color >> 24;

	if (!(alpha > 0.0f)) return 0;
	if (alpha >= 1.0f) return color;
	a = (uint32_t)((float)a * alpha + 0.5f);
	return (a << 24) | (color & 0x00FFFFFFu);
}

static kon_rect_t wholeOf(const kon_image *image, kon_rect_t src)
{
	if (src.w > 0 && src.h > 0) return src;
	src.x = src.y = 0;
	src.w = image->width;
	src.h = image->height;
	return src;
}

/*** panels ***/

static void drawPatch(kon_framebuffer_t *fb, const kon_image *image, kon_rect_t src, int x, int y, int w, int h, uint32_t tint)
{
	if (src.w <= 0 || src.h <= 0 || w <= 0 || h <= 0) return;
	kon_drawImageTint(fb, image, src, (float)x, (float)y, 0.0f, 0.0f, (float)w / (float)src.w, (float)h / (float)src.h, 0.0f, KON_FILTER_NEAREST, tint);
}

void kon_drawPanel(kon_framebuffer_t *fb, const kon_panel_t *panel, int x, int y, int width, int height, float alpha)
{
	int b = panel->borderWidth;
	uint32_t color;

	if (!fb || width <= 0 || height <= 0 || !(alpha > 0.0f)) return;

	color = fade(panel->fill, alpha);
	if (color >> 24) kon_fillRectangle(fb, x, y, width, height, color);

	if (panel->image) {
		kon_rect_t src = wholeOf(panel->image, panel->src);
		uint32_t tint = fade(0xFFFFFFFFu, alpha);

		if (panel->mode == KON_PANEL_SLICE && panel->slice > 0) {
			int m = panel->slice, mw = m, mh = m, i, j;
			int sx[4], sy[4], dx[4], dy[4];

			if (mw * 2 > src.w) mw = src.w / 2;
			if (mh * 2 > src.h) mh = src.h / 2;
			sx[0] = src.x; sx[1] = src.x + mw; sx[2] = src.x + src.w - mw; sx[3] = src.x + src.w;
			sy[0] = src.y; sy[1] = src.y + mh; sy[2] = src.y + src.h - mh; sy[3] = src.y + src.h;
			if (mw * 2 > width) mw = width / 2;
			if (mh * 2 > height) mh = height / 2;
			dx[0] = x; dx[1] = x + mw; dx[2] = x + width - mw; dx[3] = x + width;
			dy[0] = y; dy[1] = y + mh; dy[2] = y + height - mh; dy[3] = y + height;
			for (j = 0; j < 3; j++) {
				for (i = 0; i < 3; i++) {
					kon_rect_t part = KON_RECT(sx[i], sy[j], sx[i + 1] - sx[i], sy[j + 1] - sy[j]);

					drawPatch(fb, panel->image, part, dx[i], dy[j], dx[i + 1] - dx[i], dy[j + 1] - dy[j], tint);
				}
			}
		} else {
			drawPatch(fb, panel->image, src, x, y, width, height, tint);
		}
	}

	color = fade(panel->border, alpha);
	if (b > 0 && (color >> 24)) {
		if (b * 2 > width) b = width / 2;
		if (b * 2 > height) b = height / 2;
		kon_fillRectangle(fb, x, y, width, b, color);
		kon_fillRectangle(fb, x, y + height - b, width, b, color);
		kon_fillRectangle(fb, x, y + b, b, height - b * 2, color);
		kon_fillRectangle(fb, x + width - b, y + b, b, height - b * 2, color);
	}
}

/*** layout ***/

typedef struct layout {
	int x, y, width, height; /* the room for text */
	int boxX, boxY;
	int innerX, innerY, innerWidth, innerHeight;
	int lineHeight, ascent;
} layout_t;

static int fontHeight(const kon_textbox_t *box)
{
	int h = 0;

	kon_measureText(box->font, "A", NULL, &h);
	return h > 0 ? h : 8;
}

static void layoutOf(const kon_textbox_t *box, layout_t *l)
{
	int edge = box->padding + (box->panel.borderWidth > 0 ? box->panel.borderWidth : 0);
	int h = fontHeight(box);

	l->boxX = iround(kon_tweenValue(&box->x));
	l->boxY = iround(kon_tweenValue(&box->y));
	l->innerX = l->boxX + edge;
	l->innerY = l->boxY + edge;
	l->innerWidth = box->width - edge * 2;
	l->innerHeight = box->height - edge * 2;
	if (l->innerWidth < 1) l->innerWidth = 1;
	if (l->innerHeight < 1) l->innerHeight = 1;
	l->x = l->innerX + (box->marginLeft > 0 ? box->marginLeft : 0);
	l->y = l->innerY;
	l->width = l->innerWidth - (box->marginLeft > 0 ? box->marginLeft : 0) - (box->marginRight > 0 ? box->marginRight : 0);
	l->height = l->innerHeight;
	if (l->width < 1) l->width = 1;
	if (box->portrait) {
		int pw = wholeOf(box->portrait, box->portraitSrc).w;

		l->width -= pw + box->padding;
		if (l->width < 1) l->width = 1;
		if (box->portraitSide == KON_SIDE_LEFT) l->x += pw + box->padding;
	}
	l->lineHeight = h + box->lineSpacing;
	if (l->lineHeight < 1) l->lineHeight = 1;
	l->ascent = h * 4 / 5;
}

/*** wrapping ***/

static int widthOf(kon_textbox_t *box, int start, int end)
{
	char saved = box->text[end];
	int w = 0;

	box->text[end] = '\0';
	kon_measureText(box->font, &box->text[start], &w, NULL);
	box->text[end] = saved;
	return w;
}

/* where text of that width starts in a room of width, for an alignment */
static int alignedX(int x, int room, int width, kon_align_t align)
{
	if (align == KON_ALIGN_CENTER) return x + (room - width) / 2;
	if (align == KON_ALIGN_RIGHT) return x + room - width;
	return x;
}

static void wrap(kon_textbox_t *box, int avail)
{
	int i = 0, len = box->length;

	box->lineCount = 0;
	if (avail < 1) avail = 1;
	while (i < len && box->lineCount < KON_TEXTBOX_LINES) {
		int start = i, fit = i, j = i, n;

		for (;;) {
			int k = j;

			while (k < len && box->text[k] != ' ' && box->text[k] != '\n') k++;
			if (k > start && widthOf(box, start, k) > avail) {
				if (fit == start) {
					/* one word wider than the box, it is cut where it runs out */
					fit = start + 1;
					while (fit < k && widthOf(box, start, fit + 1) <= avail) fit++;
				}
				break;
			}
			fit = k;
			if (k >= len || box->text[k] == '\n') break;
			j = k;
			while (j < len && box->text[j] == ' ') j++;
			if (j >= len) break;
		}

		n = fit - start;
		while (n > 0 && box->text[start + n - 1] == ' ') n--;
		box->lineStart[box->lineCount] = start;
		box->lineLength[box->lineCount] = n;
		box->lineCount++;

		i = fit;
		while (i < len && box->text[i] == ' ') i++;
		if (i < len && box->text[i] == '\n') i++;
	}
}

static int linesOnPage(const kon_textbox_t *box)
{
	int first = box->page * box->linesPerPage, n = box->lineCount - first;

	if (n > box->linesPerPage) n = box->linesPerPage;
	return n > 0 ? n : 0;
}

static void startPage(kon_textbox_t *box)
{
	int first = box->page * box->linesPerPage, n = linesOnPage(box), i;

	box->pageChars = 0;
	for (i = 0; i < n; i++) box->pageChars += box->lineLength[first + i];
	box->shown = 0.0f;
	box->state = KON_TEXTBOX_TYPING;
	if (!(box->speed > 0.0f) || box->pageChars == 0) {
		box->shown = (float)box->pageChars;
		box->state = KON_TEXTBOX_WAITING;
	}
}

static void rewrap(kon_textbox_t *box)
{
	layout_t l;

	layoutOf(box, &l);
	wrap(box, l.width);
	box->linesPerPage = l.height / l.lineHeight;
	if (box->linesPerPage < 1) box->linesPerPage = 1;
	box->pageCount = (box->lineCount + box->linesPerPage - 1) / box->linesPerPage;
}

/*** text box ***/

void kon_textboxInit(kon_textbox_t *box, kon_font_t *font, int x, int y, int width, int height)
{
	kon_textbox_t zero = {0};

	*box = zero;
	box->font = font;
	box->width = width;
	box->height = height;
	kon_tweenSet(&box->x, (float)x);
	kon_tweenSet(&box->y, (float)y);
	kon_tweenSet(&box->alpha, 1.0f);

	box->panel.fill = 0xE026223Au;
	box->panel.border = 0xFF9A93B3u;
	box->panel.borderWidth = 1;
	box->plate.fill = 0xF0332E4Eu;
	box->plate.border = 0xFF9A93B3u;
	box->plate.borderWidth = 1;
	box->padding = 8;
	box->button.fill = 0xE026223Au;
	box->button.border = 0xFF9A93B3u;
	box->button.borderWidth = 1;
	box->buttonSelected = box->button;
	box->buttonSelected.fill = 0xFFF2A7C3u;
	box->buttonGap = 6;
	box->platePadding = 4;
	box->plateOffsetX = 8;
	box->textColor = 0xFFE4DDF0u;
	box->nameColor = 0xFFF2A7C3u;
	box->choiceColor = 0xFFE4DDF0u;
	box->selectColor = 0xFF1B1826u;
	box->selectFill = 0xFFF2A7C3u;
	box->speed = 40.0f;
	box->lineSpacing = 2;
}

void kon_textboxClear(kon_textbox_t *box)
{
	box->state = KON_TEXTBOX_EMPTY;
	box->text[0] = '\0';
	box->name[0] = '\0';
	box->length = 0;
	box->lineCount = box->page = box->pageCount = box->pageChars = 0;
	box->shown = 0.0f;
	box->choiceCount = box->selected = 0;
}

static void copyString(char *to, size_t size, const char *from)
{
	size_t n = strlen(from);

	if (n >= size) n = size - 1;
	memcpy(to, from, n);
	to[n] = '\0';
}

void kon_textboxSay(kon_textbox_t *box, const char *name, const char *text)
{
	size_t i, n = 0;

	kon_textboxClear(box);
	if (name) copyString(box->name, sizeof box->name, name);
	if (!text) text = "";
	for (i = 0; text[i] && n < KON_TEXTBOX_TEXT - 1; i++) {
		if (text[i] == '\r') continue;
		box->text[n++] = text[i];
	}
	box->text[n] = '\0';
	box->length = (int)n;

	rewrap(box);
	startPage(box);
}

void kon_textboxPortrait(kon_textbox_t *box, const kon_image *image, const kon_rect_t *src, kon_side_t side, kon_portraitMode_t mode)
{
	box->portrait = image;
	box->portraitSrc = src ? *src : (kon_rect_t){0, 0, 0, 0};
	box->portraitSide = side;
	box->portraitMode = mode;

	if (box->state == KON_TEXTBOX_TYPING || box->state == KON_TEXTBOX_WAITING) {
		rewrap(box);
		if (box->page >= box->pageCount) box->page = box->pageCount > 0 ? box->pageCount - 1 : 0;
		startPage(box);
		box->shown = (float)box->pageChars;
		box->state = KON_TEXTBOX_WAITING;
	}
}

void kon_textboxFace(kon_textbox_t *box, const kon_image *sheet, int frameWidth, int frameHeight, int index, kon_side_t side)
{
	kon_rect_t src = {0, 0, 0, 0};

	if (sheet) src = kon_frameRect(sheet, frameWidth, frameHeight, index);
	if (!sheet || src.w <= 0 || src.x + src.w > sheet->width || src.y + src.h > sheet->height) {
		kon_textboxPortrait(box, NULL, NULL, side, KON_PORTRAIT_INSIDE);
		return;
	}
	kon_textboxPortrait(box, sheet, &src, side, KON_PORTRAIT_INSIDE);
}

int kon_textboxAdvance(kon_textbox_t *box)
{
	switch (box->state) {
	case KON_TEXTBOX_TYPING:
		box->shown = (float)box->pageChars;
		box->state = KON_TEXTBOX_WAITING;
		return 0;
	case KON_TEXTBOX_WAITING:
		if (box->page + 1 < box->pageCount) {
			box->page++;
			startPage(box);
			return 0;
		}
		kon_textboxClear(box);
		return 1;
	case KON_TEXTBOX_EMPTY:
	case KON_TEXTBOX_CHOOSING:
		break;
	}
	return 0;
}

int kon_textboxWaiting(const kon_textbox_t *box)
{
	return box->state == KON_TEXTBOX_WAITING;
}

int kon_textboxMore(const kon_textbox_t *box)
{
	return box->state == KON_TEXTBOX_WAITING && box->page + 1 < box->pageCount;
}

int kon_textboxUpdate(kon_textbox_t *box, float dt)
{
	kon_tweenStep(&box->x, dt);
	kon_tweenStep(&box->y, dt);
	kon_tweenStep(&box->alpha, dt);

	if (box->state != KON_TEXTBOX_TYPING || !(dt > 0.0f)) return 0;
	box->shown += box->speed * dt;
	if (box->shown < (float)box->pageChars) return 0;
	box->shown = (float)box->pageChars;
	box->state = KON_TEXTBOX_WAITING;
	return 1;
}

void kon_textboxPlaceX(kon_textbox_t *box, int viewWidth, kon_align_t align, int margin)
{
	int x = margin;

	if (align == KON_ALIGN_CENTER) x = (viewWidth - box->width) / 2;
	else if (align == KON_ALIGN_RIGHT) x = viewWidth - box->width - margin;
	kon_tweenSet(&box->x, (float)x);
}

void kon_textboxCenter(kon_textbox_t *box, int viewWidth, int viewHeight, int horizontal, int vertical)
{
	if (horizontal) kon_tweenSet(&box->x, (float)((viewWidth - box->width) / 2));
	if (vertical) kon_tweenSet(&box->y, (float)((viewHeight - box->height) / 2));
}

void kon_textboxMove(kon_textbox_t *box, float x, float y, float seconds, kon_ease_t ease)
{
	kon_tweenTo(&box->x, x, seconds, ease);
	kon_tweenTo(&box->y, y, seconds, ease);
}

void kon_textboxFade(kon_textbox_t *box, float alpha, float seconds, kon_ease_t ease)
{
	kon_tweenTo(&box->alpha, alpha, seconds, ease);
}

/*** choices ***/

void kon_textboxChoices(kon_textbox_t *box, const char *const *labels, int count)
{
	int i;

	kon_textboxClear(box);
	if (!labels || count < 1) return;
	if (count > KON_TEXTBOX_CHOICES) count = KON_TEXTBOX_CHOICES;
	for (i = 0; i < count; i++) copyString(box->labels[i], sizeof box->labels[i], labels[i] ? labels[i] : "");
	box->choiceCount = count;
	box->selected = 0;
	box->state = KON_TEXTBOX_CHOOSING;
}

/* where choice i is drawn */
static kon_rect_t choiceRect(const kon_textbox_t *box, const layout_t *l, int i)
{
	kon_rect_t r;

	if (box->choiceMode == KON_CHOICES_BUTTONS) {
		int rowHeight = l->lineHeight + box->padding * 2;

		r = KON_RECT(l->boxX, l->boxY + i * (rowHeight + box->buttonGap), box->width, rowHeight);
	} else {
		r = KON_RECT(l->innerX, l->innerY + i * l->lineHeight, l->innerWidth, l->lineHeight);
	}
	return r;
}

void kon_textboxFitChoices(kon_textbox_t *box, int minWidth)
{
	layout_t l;
	int i, widest = 0, fit;

	if (box->state != KON_TEXTBOX_CHOOSING) return;
	layoutOf(box, &l);
	for (i = 0; i < box->choiceCount; i++) {
		int w = 0;

		kon_measureText(box->font, box->labels[i], &w, NULL);
		if (w > widest) widest = w;
	}
	if (box->choiceMode == KON_CHOICES_BUTTONS) {
		int rowHeight = l.lineHeight + box->padding * 2;

		fit = widest + (box->padding + (box->button.borderWidth > 0 ? box->button.borderWidth : 0)) * 2;
		box->height = box->choiceCount * rowHeight + (box->choiceCount - 1) * box->buttonGap;
	} else {
		int edge = box->padding + (box->panel.borderWidth > 0 ? box->panel.borderWidth : 0);

		fit = widest + edge * 2;
		box->height = box->choiceCount * l.lineHeight + edge * 2;
	}
	box->width = fit > minWidth ? fit : minWidth;
}

void kon_textboxSelect(kon_textbox_t *box, int delta)
{
	if (box->state != KON_TEXTBOX_CHOOSING || box->choiceCount < 1) return;
	box->selected = (box->selected + delta % box->choiceCount + box->choiceCount) % box->choiceCount;
}

void kon_textboxHighlight(kon_textbox_t *box, int index)
{
	if (box->state == KON_TEXTBOX_CHOOSING && index >= 0 && index < box->choiceCount) box->selected = index;
}

int kon_textboxChoiceAt(const kon_textbox_t *box, int x, int y)
{
	layout_t l;
	int i;

	if (box->state != KON_TEXTBOX_CHOOSING) return -1;
	layoutOf(box, &l);
	for (i = 0; i < box->choiceCount; i++) {
		kon_rect_t r = choiceRect(box, &l, i);

		if (x >= r.x && x < r.x + r.w && y >= r.y && y < r.y + r.h) return i;
	}
	return -1;
}

int kon_textboxConfirm(kon_textbox_t *box)
{
	int chosen;

	if (box->state != KON_TEXTBOX_CHOOSING) return -1;
	chosen = box->selected;
	kon_textboxClear(box);
	return chosen;
}

/*** drawing ***/

/* the line is cut off with a terminator for a moment */
static void drawLine(kon_textbox_t *box, kon_framebuffer_t *fb, int x, int baseline, int start, int length, uint32_t color)
{
	char saved = box->text[start + length];

	box->text[start + length] = '\0';
	kon_drawText(fb, box->font, x, baseline, &box->text[start], color);
	box->text[start + length] = saved;
}

void kon_textboxDraw(kon_textbox_t *box, kon_framebuffer_t *fb)
{
	layout_t l;
	float alpha = kon_tweenValue(&box->alpha);
	int bx = iround(kon_tweenValue(&box->x)), by = iround(kon_tweenValue(&box->y));
	int i;

	if (!fb || !box->font || !(alpha > 0.0f)) return;
	if (box->state == KON_TEXTBOX_EMPTY && !box->showEmpty) return;
	layoutOf(box, &l);

	if (!(box->state == KON_TEXTBOX_CHOOSING && box->choiceMode == KON_CHOICES_BUTTONS)) kon_drawPanel(fb, &box->panel, bx, by, box->width, box->height, alpha);

	if (box->name[0] && box->state != KON_TEXTBOX_CHOOSING) {
		int w = 0, h = fontHeight(box);
		int pad = box->platePadding;

		kon_measureText(box->font, box->name, &w, NULL);
		kon_drawPanel(fb, &box->plate, bx + box->plateOffsetX, by - (h + pad * 2) + box->plateOffsetY, w + pad * 2, h + pad * 2, alpha);
		kon_drawText(fb, box->font, bx + box->plateOffsetX + pad, by - (h + pad * 2) + box->plateOffsetY + pad + l.ascent, box->name, fade(box->nameColor, alpha));
	}

	if (box->portrait) {
		kon_rect_t src = wholeOf(box->portrait, box->portraitSrc);
		int px = box->portraitSide == KON_SIDE_LEFT ? l.innerX : l.innerX + l.innerWidth - src.w;
		int py = box->portraitMode == KON_PORTRAIT_HANG ? by + box->height - src.h : l.innerY + (l.innerHeight - src.h) / 2;

		kon_drawImageTint(fb, box->portrait, src, (float)px, (float)py, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, KON_FILTER_NEAREST, fade(0xFFFFFFFFu, alpha));
	}

	if (box->state == KON_TEXTBOX_CHOOSING) {
		int buttons = box->choiceMode == KON_CHOICES_BUTTONS;

		for (i = 0; i < box->choiceCount; i++) {
			kon_rect_t r = choiceRect(box, &l, i);
			int chosen = i == box->selected, inset = buttons ? box->padding : 2, w = 0;

			if (!buttons && r.y + r.h > by + box->height) break;
			if (buttons) kon_drawPanel(fb, chosen ? &box->buttonSelected : &box->button, r.x, r.y, r.w, r.h, alpha);
			else if (chosen) kon_fillRectangle(fb, r.x, r.y, r.w, r.h, fade(box->selectFill, alpha));
			kon_measureText(box->font, box->labels[i], &w, NULL);
			kon_drawText(fb, box->font, alignedX(r.x + inset, r.w - inset * 2, w, box->choiceAlign), r.y + (r.h - fontHeight(box)) / 2 + l.ascent,
			    box->labels[i], fade(chosen ? box->selectColor : box->choiceColor, alpha));
		}
		return;
	}

	if (box->state == KON_TEXTBOX_TYPING || box->state == KON_TEXTBOX_WAITING) {
		int first = box->page * box->linesPerPage, n = linesOnPage(box);
		int left = (int)box->shown;

		for (i = 0; i < n && left > 0; i++) {
			int len = box->lineLength[first + i];

			if (len > left) len = left;
			drawLine(box, fb, alignedX(l.x, l.width, widthOf(box, box->lineStart[first + i], box->lineStart[first + i] + box->lineLength[first + i]), box->align),
			    l.y + i * l.lineHeight + (l.lineHeight - fontHeight(box)) / 2 + l.ascent, box->lineStart[first + i], len, fade(box->textColor, alpha));
			left -= box->lineLength[first + i];
		}
	}
}