#include "textwindow.h"

#include "../utils/math.h"

TextWindow::TextWindow(unsigned from_col, unsigned to_col, unsigned from_row,
					   unsigned to_row, bool use_cursor)
	: from_col(from_col),
	  to_col(to_col),
	  from_row(from_row),
	  to_row(to_row),
	  use_cursor(use_cursor),
	  pos_x(from_col),
	  pos_y(from_row) {
	if (to_col > from_col && to_row > from_row) {
		reset();
	}
}

void TextWindow::setPos(unsigned rel_x, unsigned rel_y) {
	unsigned abs_x = rel_x + from_col;
	unsigned abs_y = rel_y + from_row;

	// Check if visible
	if (abs_x < to_col && abs_y < to_row) {
		if (use_cursor) {
			CGA::setCursor(abs_x, abs_y);
		} else {
			pos_x = abs_x;
			pos_y = abs_y;
		}
	}
}

void TextWindow::getPos(unsigned& rel_x, unsigned& rel_y) const {
	unsigned abs_x = pos_x;
	unsigned abs_y = pos_y;

	if (use_cursor) {
		CGA::getCursor(abs_x, abs_y);
	}

	rel_x = Math::min(Math::max(abs_x, from_col), to_col - 1) - from_col;
	rel_y = Math::min(Math::max(abs_y, from_row), to_row - 1) - from_row;
}

void TextWindow::setPos(int rel_x, int rel_y) {
	int x = rel_x < 0 ? rel_x + to_col - from_col : rel_x;
	int y = rel_y < 0 ? rel_y + to_row - from_row : rel_y;

	if (x >= 0 && y >= 0) {
		setPos(static_cast<unsigned>(x), static_cast<unsigned>(y));
	}
}

void TextWindow::getPos(int& rel_x, int& rel_y) const {
	unsigned x;
	unsigned y;
	getPos(x, y);
	rel_x = static_cast<int>(x);
	rel_y = static_cast<int>(y);
}

void TextWindow::print(const char* str, size_t length, CGA::Attribute attrib) {
	// Get position
	unsigned abs_x = pos_x;
	unsigned abs_y = pos_y;

	if (use_cursor) {
		CGA::getCursor(abs_x, abs_y);
	}

	// Print each character
	while (length > 0) {
		switch (*str) {
			case '\n':
				abs_x = from_col;
				abs_y++;
				break;

			case '\r':
				abs_x = from_col;
				break;

			default:
				show(abs_x, abs_y, *str, attrib);
				abs_x++;
				if (abs_x >= to_col) {
					abs_x = from_col;
					abs_y++;
				}
				break;
		}
		str++;
		if (abs_y >= to_row) {
			scrollUp();
			abs_y--;
		}
		length--;
	}
	// Write position back
	if (use_cursor) {
		CGA::setCursor(abs_x, abs_y);
	} else {
		pos_x = abs_x;
		pos_y = abs_y;
	}
}

void TextWindow::reset(char character, CGA::Attribute attrib) {
	for (unsigned abs_y = from_row; abs_y < to_row; ++abs_y) {
		for (unsigned abs_x = from_col; abs_x < to_col; ++abs_x) {
			show(abs_x, abs_y, character, attrib);
		}
	}
	setPos(0, 0);
}

void TextWindow::scrollUp() const {
	for (unsigned y = from_row + 1; y < to_row; ++y) {
		for (unsigned x = from_col; x < to_col; ++x) {
			unsigned pos = (y * CGA::COLUMNS) + x;
			show(x, y - 1, CGA::TEXT_BUFFER_BASE[pos].character,
				 CGA::TEXT_BUFFER_BASE[pos].attribute);
		}
	}
	for (unsigned x = from_col; x < to_col; ++x) {
		CGA::show(x, to_row - 1, ' ');
	}
}