#include <SDL.h>

#include "private.h"

#include "drawing.h"
#include "font.h"
#include "window.h"


static const char passwordPattern[] = "*";


static int utf8charlen(const char *c) {
	if (!*c) return 0;
	if ( (c[0] & 0x80) == 0x00 )
		return 1;
	if ( (c[0] & 0xE0) == 0xC0
	  && (c[1] & 0xC0) == 0x80 )
		return 2;
	if ( (c[0] & 0xF0) == 0xE0
	  && (c[1] & 0xC0) == 0x80
	  && (c[2] & 0xC0) == 0x80 )
		return 3;
	if ( (c[0] & 0xF8) == 0xF0
	  && (c[1] & 0xC0) == 0x80
	  && (c[2] & 0xC0) == 0x80
	  && (c[3] & 0xC0) == 0x80 )
		return 4;
	return -1;
}


static int utf8len(const char *c) {
	int len = 0;
	while(*c) {
		int l = utf8charlen(c);
		c += l > 0 ? l : 1;
		++len;
	}
	return len;
}


static int utf8pos(const char *c, int pos) {
	int p = 0;
	const char *end = c + pos;
	while(*c && c < end) {
		int l = utf8charlen(c);
		c += l > 0 ? l : 1;
		++p;
	}
	return p;
}


static int utf8shift(const char *s, int pos, int offset) {
	int len = strlen(s);
	if (pos > len) { offset += pos - len; pos = len; }
	if (pos < 0) { offset += pos; pos = 0; }
	
	while(offset > 0 && pos < len) {
		int l = utf8charlen(s + pos);
		if (l > 0) {
			pos += l;
		} else {
			while(pos < len && utf8charlen(s + pos) <= 0) ++pos;
		}
		--offset;
	}
	
	while(offset < 0 && pos > 0) {
		do --pos; while(pos > 0 && utf8charlen(s + pos) <= 0);
		++offset;
	}
	
	return pos;
}


static void fixPos(HeliDialog *dialog) {
	int answerLen = strlen(dialog->answer);
	if (dialog->pos < 0) dialog->pos = 0;
	if (dialog->pos > answerLen) dialog->pos = answerLen;
	if (dialog->selPos < 0) dialog->selPos = 0;
	if (dialog->selPos > answerLen) dialog->selPos = answerLen;
}


static void insert(HeliDialog *dialog, const char *text) {
	int answerLen = strlen(dialog->answer);
	fixPos(dialog);
	
	int pos0 = dialog->pos < dialog->selPos ? dialog->pos : dialog->selPos;
	int pos1 = dialog->pos < dialog->selPos ? dialog->selPos : dialog->pos;
	int selLen = pos1 - pos0;
	
	int textLen = strlen(text);
	int dl = answerLen - selLen + textLen - dialog->maxAnswerSize;
	if (dl > 0) textLen -= dl;
	if (textLen < 0) textLen = 0;
	
	int tailPos = pos0 + selLen;
	int offset = textLen - selLen;
	int tailLen = answerLen - tailPos;
	if (offset && tailLen > 0)
		memmove(
			dialog->answer + tailPos + offset,
			dialog->answer + tailPos,
			tailLen);
	tailPos += offset;
	dialog->answer[tailPos + tailLen] = 0;
	
	if (textLen > 0)
		memcpy(dialog->answer + pos0, text, textLen);
	
	dialog->pos = dialog->selPos = tailPos;
}


static void copy(HeliDialog *dialog) {
	if (!dialog->password && dialog->pos != dialog->selPos) {
		int pos0 = dialog->pos < dialog->selPos ? dialog->pos : dialog->selPos;
		int pos1 = dialog->pos < dialog->selPos ? dialog->selPos : dialog->pos;
		char c = dialog->answer[pos1];
		dialog->answer[pos1] = 0;
		SDL_SetClipboardText(dialog->answer + pos0);
		dialog->answer[pos1] = c;
	}
}


static void paste(HeliDialog *dialog) {
	const char *text = SDL_GetClipboardText();
	if (text && text[0]) insert(dialog, text);
}


static void draw(HeliDialog *dialog) {
	saveState();
	
	const double time = SDL_GetTicks()*1e-3;
	
	const double w = windowGetWidth();
	const double h = windowGetHeight();
	const double border = 16;
	
	double title = 64;
	double buttons = 32;
	double l = border;
	double t = border + title;
	double r = w - border;
	double b = h - border - buttons;
	if (!dialog->multiline && b - t > buttons) {
		t = round(0.5*(b + t - buttons));
		b = t + buttons;
		title = t - border;
	}
	
	const double cursorSrcollWidth = 64;
	const double cursorSrcollHeight = 16;
	
	const double bt = h - buttons - border + 8;
	const double bb = h - border;
	const double bh = bb - bt;
	double bw = (w - 2*border)/4;
	if (bw < bh) bw = bh;
	const double bl0 = border - 2;
	const double br0 = bl0 + bw;
	const double br1 = w - border + 2;
	const double bl1 = br1 - bw;
	
	unsigned int strokeColor  = COLOR_WHITE;
	unsigned int fillColor    = 0x4d4d4dff;
	unsigned int selTextColor = COLOR_BLACK;
	unsigned int selFillColor = COLOR_WHITE;
	strokeWidth(1);
	textFontDefault();
	textSize(16);
	
	noStroke();
	fill(fillColor);
	rect(0, 0, w, h);
	
	
	noFill();
	stroke(strokeColor);
	textAlign(HALIGN_LEFT, VALIGN_TOP);
	TextLayout layout = createTextLayout(dialog->password ? dialog->passwordText : dialog->answer);
	
	int shift = keyDown("any shift");
	if (keyWentDown("up")) {
		dialog->pos = textLayoutCursorUp(layout, dialog->pos);
		if (!shift) dialog->selPos = dialog->pos;
	}
	if (keyWentDown("down")) {
		dialog->pos = textLayoutCursorDown(layout, dialog->pos);
		if (!shift) dialog->selPos = dialog->pos;
	}
	
	int pos = dialog->pos;
	int selPos = dialog->selPos;
	if (dialog->password) {
		pos = utf8pos(dialog->answer, pos)*((int)sizeof(passwordPattern) - 1);
		selPos = utf8pos(dialog->answer, selPos)*((int)sizeof(passwordPattern) - 1);
	}
	
	cliprect(l-2, t-2, r-l+2, b-t+2);
	double tx = l;
	double ty = t;
	double cx = textLayoutCursorGetX(layout, pos) + tx;
	double cy = textLayoutCursorGetY(layout, pos) + ty;
	double ch = textLayoutCursorGetHeight(layout, pos);
	
	double minScrollY = t + ch + cursorSrcollHeight - cy;
	double maxScrollY = b - cursorSrcollHeight - cy;
	if (maxScrollY > 0) maxScrollY = 0;
	if (dialog->scrollY < minScrollY) dialog->scrollY = minScrollY;
	if (dialog->scrollY > maxScrollY) dialog->scrollY = maxScrollY;

	double minScrollX = l + cursorSrcollWidth - cx;
	double maxScrollX = r - cursorSrcollWidth - cx;
	if (maxScrollX > 0) maxScrollX = 0;
	if (dialog->scrollX < minScrollX) dialog->scrollX = minScrollX;
	if (dialog->scrollX > maxScrollX) dialog->scrollX = maxScrollX;
	
	tx += dialog->scrollX;
	ty += dialog->scrollY;
	cx += dialog->scrollX;
	cy += dialog->scrollY;
	
	if (pos == selPos) {
		textLayoutDraw(layout, tx, ty);
	} else {
		int p0 = pos < selPos ? pos : selPos;
		int p1 = pos < selPos ? selPos : pos;
		fill(selFillColor);
		stroke(selTextColor);
		textLayoutDrawSubstr(layout, tx, ty, p0, p1 - p0);
		noFill();
		stroke(strokeColor);
		textLayoutDrawSubstr(layout, tx, ty, 0, p0);
		textLayoutDrawFrom(layout, tx, ty, p1);
	}
	
	stroke(colorByRGBA(1, 1, 1, 0.5 + 0.5*sin(time/0.5*2*PI)));
	line(cx, cy, cx, cy - ch);
	
	textLayoutDestroy(layout);
	noClip();
	
	
	noFill();
	stroke(strokeColor);
	rect(l - 2, t - 2, r - l + 4, b - t + 4);
	
	textAlign(HALIGN_CENTER, VALIGN_CENTER);
	text(w/2, border + title/2, dialog->question);
	
	rect(bl0, bt, bw, bh);
	rect(bl1, bt, bw, bh);
	text((bl0 + br0)/2, (bt + bb)/2, "\u2613");
	text((bl1 + br1)/2, (bt + bb)/2, "\u2713");
	
	if (mouseWentDown("left")) {
		double x = mouseX();
		double y = mouseY();
		if (y >= bt && y <= bb) {
			if (x >= bl0 && x <= br0) dialog->shown = FALSE;
			if (x >= bl1 && x <= br1) { dialog->success = TRUE; dialog->shown = FALSE; }
		}
	}
	
	restoreState();
}


void heliDialogDraw(HeliDialog *dialog) {
	if (*textInputGet()) insert(dialog, textInputGet());
	textInputClear();
	
	int shift = keyDown("any shift");
	int ctrl = keyDown("any ctrl");
	
	if (keyWentDown("backspace")) {
		if (dialog->pos == dialog->selPos) {
			dialog->selPos = dialog->pos;
			dialog->pos = utf8shift(dialog->answer, dialog->pos, -1);
		}
		insert(dialog, "");
	}
	
	if (keyWentDown("delete")) {
		if (dialog->pos == dialog->selPos) {
			dialog->selPos = dialog->pos;
			dialog->pos = utf8shift(dialog->answer, dialog->pos, 1);
		} else
		if (shift && !dialog->password) {
			copy(dialog);
		}
		insert(dialog, "");
	}
	
	if (keyWentDown("left")) {
		dialog->pos = utf8shift(dialog->answer, dialog->pos, -1);
		if (!shift) dialog->selPos = dialog->pos;
	}
	
	if (keyWentDown("right")) {
		dialog->pos = utf8shift(dialog->answer, dialog->pos, 1);
		if (!shift) dialog->selPos = dialog->pos;
	}
	
	if (keyWentDown("home")) {
		if (ctrl) {
			dialog->pos = 0;
		} else {
			while( dialog->pos > 0
			    && dialog->answer[dialog->pos-1] != '\r'
			    && dialog->answer[dialog->pos-1] != '\n' ) --dialog->pos;
		}
		if (!shift) dialog->selPos = dialog->pos;
	}
	
	if (keyWentDown("end")) {
		if (ctrl) {
			dialog->pos = strlen(dialog->answer);
		} else {
			while( dialog->answer[dialog->pos] != 0
			    && dialog->answer[dialog->pos] != '\r'
			    && dialog->answer[dialog->pos] != '\n' ) ++dialog->pos;
		}
		if (!shift) dialog->selPos = dialog->pos;
	}
	
	if (keyWentDown("return")) {
		if (!dialog->multiline || ctrl) {
			dialog->success = TRUE;
			dialog->shown = FALSE;
		} else {
			insert(dialog, "\n");
		}
	}
	
	if (ctrl && keyWentDown("a"))
		{ dialog->selPos = 0; dialog->pos = strlen(dialog->answer); }
	if (!dialog->password && ctrl && keyWentDown("c"))
		copy(dialog);
	if (!dialog->password && ctrl && keyWentDown("insert"))
		copy(dialog);
	if (ctrl && keyWentDown("v"))
		paste(dialog);
	if (shift && keyWentDown("insert"))
		paste(dialog);
	if (!dialog->password && ctrl && keyWentDown("x"))
		{ copy(dialog); insert(dialog, ""); }
	
	if (keyWentDown("escape")) dialog->shown = FALSE;
	
	if (!dialog->multiline) {
		char *c = strpbrk(dialog->answer, "\n\r");
		if (c) *c = 0;
		fixPos(dialog);
	}
	
	if (dialog->password) {
		int len = utf8len(dialog->answer);
		char *c = dialog->passwordText;
		for(int i = 0; i < len; ++i)
			for(const char *p = passwordPattern; *p; ++p, ++c)
				*c = *p;
		*c = 0;
	}
	
	draw(dialog);
}