#include <sdl.h></sdl.h>

#include "private.h"

#include "drawing.h"

#include "font.h"

#include "world.h"

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 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->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) {

	pushDrawingState();

	const double time = SDL_GetTicks()*1e-3;

	const double w = worldGetWidth();

	const double h = worldGetHeight();

	const double border = 16;

	const double scroll = 16;

	const double title = 64;

	const double buttons = 32;

	const double l = border;

	const double t = border + title;

	const double r = w - border - scroll;

	const double b = h - border - scroll - buttons;

	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;

	const char *strokeColor = "white";

	const char *fillColor = "0.3 0.3 0.3";

	const char *selTextColor = "black";

	const char *selFillColor = "white";

	strokeWeight(1);

	textFontDefault();

	textSize(16);

	noStroke();

	fill(fillColor);

	rect(0, 0, w, h);

	noFill();

	stroke(strokeColor);

	textAlign(HALIGN_LEFT, VALIGN_TOP);

	TextLayout layout = createTextLayout(dialog->answer);

	double tx = l + dialog->scrollX;

	double ty = t + dialog->scrollY;

	double cx = textLayoutCursorGetX(layout, dialog->pos) + tx;

	double cy = textLayoutCursorGetY(layout, dialog->pos) + ty;

	double ch = textLayoutCursorGetHeight(layout, dialog->pos);

	cliprect(l-1, t-1, r-l+2, b-t+2);

	if (dialog->pos == dialog->selPos) {

		textLayoutDraw(layout, tx, ty);

	} else {

		int p0 = dialog->pos < dialog->selPos ? dialog->pos : dialog->selPos;

		int p1 = dialog->pos < dialog->selPos ? dialog->selPos : dialog->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(rgba(1, 1, 1, 0.5 + 0.5*sin(time/0.5*2*PI)));

	line(cx, cy, cx, cy - ch);

	int shift = keyDown("left shift") || keyDown("right 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;

	}

	textLayoutDestroy(layout);

	noClip();

	noFill();

	stroke(strokeColor);

	rect(l - 2, t - 2, r - l + 4, b - t + 4);

	textAlign(HALIGN_CENTER, VALIGN_CENTER);

	text(dialog->question, w/2, title/2);

	rect(bl0, bt, bw, bh);

	rect(bl1, bt, bw, bh);

	text("<<", (bl0 + br0)/2, (bt + bb)/2);

	text("\u23CE", (bl1 + br1)/2, (bt + bb)/2);

	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; }

		}

	}

	popDrawingState();

}

void heliDialogDraw(HeliDialog *dialog) {

	if (dialog->newText[0]) insert(dialog, dialog->newText);

	int shift = keyDown("left shift") || keyDown("right shift");

	int ctrl = keyDown("left ctrl") || keyDown("right 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) {

			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 (ctrl && keyWentDown("c"))

		copy(dialog);

	if (ctrl && keyWentDown("insert"))

		copy(dialog);

	if (ctrl && keyWentDown("v"))

		paste(dialog);

	if (shift && keyWentDown("insert"))

		paste(dialog);

	if (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);

	}

	draw(dialog);

}