#include "console.h"

const char digits[] = "0123456789abcdef";

console::console(const font &f, const screen &s, void *scratch, size_t len) :
	m_font(f),
	m_screen(s),
	m_size(s.width() / f.width(), s.height() / f.height()),
	m_fg(0xffffff),
	m_bg(0),
	m_first(0),
	m_length(len),
	m_data(nullptr),
	m_attrs(nullptr),
	m_palette(nullptr)
{
	const unsigned count = m_size.size();
	const size_t palette_size = sizeof(screen::pixel_t) * 256;
	const size_t attrs_size = 2 * count;

	if (len >= count) {
		// We have enough scratch space to keep the contents of the screen
		m_data = static_cast<char *>(scratch);
		for (unsigned i = 0; i < count; ++i)
			m_data[i] = 0;
	}

	if (len >= count + palette_size + attrs_size) {
		// We have enough scratch space to also keep the colors of the text
		m_palette = reinterpret_cast<screen::pixel_t *>(m_data + count);

		unsigned index = 0;

		// Manually add the 16 basic ANSI colors
		m_palette[index++] = m_screen.color(0x00, 0x00, 0x00);
		m_palette[index++] = m_screen.color(0xcd, 0x00, 0x00);
		m_palette[index++] = m_screen.color(0x00, 0xcd, 0x00);
		m_palette[index++] = m_screen.color(0xcd, 0xcd, 0x00);
		m_palette[index++] = m_screen.color(0x00, 0x00, 0xee);
		m_palette[index++] = m_screen.color(0xcd, 0x00, 0xcd);
		m_palette[index++] = m_screen.color(0x00, 0xcd, 0xcd);
		m_palette[index++] = m_screen.color(0xe5, 0xe5, 0xe5);
		m_palette[index++] = m_screen.color(0x7f, 0x7f, 0x7f);
		m_palette[index++] = m_screen.color(0xff, 0x00, 0x00);
		m_palette[index++] = m_screen.color(0x00, 0xff, 0x00);
		m_palette[index++] = m_screen.color(0xff, 0xff, 0x00);
		m_palette[index++] = m_screen.color(0x00, 0x50, 0xff);
		m_palette[index++] = m_screen.color(0xff, 0x00, 0xff);
		m_palette[index++] = m_screen.color(0x00, 0xff, 0xff);
		m_palette[index++] = m_screen.color(0xff, 0xff, 0xff);

		// Build the high-color portion of the table
		const uint32_t intensity[] = {0, 0x5f, 0x87, 0xaf, 0xd7, 0xff};
		const uint32_t intensities = sizeof(intensity) / sizeof(uint32_t);

		for (uint32_t r = 0; r < intensities; ++r) {
			for (uint32_t g = 0; g < intensities; ++g) {
				for (uint32_t b = 0; b < intensities; ++b) {
					m_palette[index++] = m_screen.color(
							intensity[r], intensity[g], intensity[b]);
				}
			}
		}

		// Build the greyscale portion of the table
		for (uint8_t i = 0x08; i <= 0xee; i += 10)
			m_palette[index++] = m_screen.color(i, i, i);

		set_color(7, 0); // Grey on black default
		m_attrs = reinterpret_cast<uint16_t *>(m_data + count + palette_size);
		for (unsigned i = 0; i < count; ++i)
			m_attrs[i] = m_attr;
	}

	repaint();
}

char *
console::line_pointer(unsigned line)
{
	if (!m_data) return nullptr;
	return m_data + ((m_first + line) % m_size.y) * m_size.x;
}

uint16_t *
console::attr_pointer(unsigned line)
{
	if (!m_attrs) return nullptr;
	return m_attrs + ((m_first + line) % m_size.y) * m_size.x;
}

void
console::repaint()
{
	m_screen.fill(m_bg);
	if (!m_data) return;

	for (unsigned y = 0; y < m_size.y; ++y) {
		const char *line = line_pointer(y);
		const uint16_t *attrs = attr_pointer(y);
		for (unsigned x = 0; x < m_size.x; ++x) {
			const uint16_t attr = attrs[x];

			set_color(static_cast<uint8_t>(attr),
					static_cast<uint8_t>(attr >> 8));

			m_font.draw_glyph(
				m_screen,
				line[x] ? line[x] : ' ',
				m_fg,
				m_bg,
				x * m_font.width(),
				y * m_font.height());
		}
	}
}

void
console::set_color(uint8_t fg, uint8_t bg)
{
	if (!m_palette) return;

	m_bg = m_palette[bg];
	m_fg = m_palette[fg];
	m_attr = (bg << 8) | fg;
}

void
console::scroll(unsigned lines)
{
	if (!m_data) {
		m_pos.x = 0;
		m_pos.y = 0;
	} else {
		unsigned bytes = lines * m_size.x;
		char *line = line_pointer(0);
		for (unsigned i = 0; i < bytes; ++i)
			*line++ = 0;

		m_first = (m_first + lines) % m_size.y;
		m_pos.y -= lines;
	}
	repaint();
}

size_t
console::puts(const char *message)
{
	char *line = line_pointer(m_pos.y);
	uint16_t *attrs = attr_pointer(m_pos.y);
	size_t count = 0;

	while (message && *message) {
		const unsigned x = m_pos.x * m_font.width();
		const unsigned y = m_pos.y * m_font.height();
		const char c = *message++;
		++count;

		switch (c) {
		case '\t':
			m_pos.x = (m_pos.x + 4) / 4 * 4;
			break;

		case '\r':
			m_pos.x = 0;
			break;

		case '\n':
			m_pos.x = 0;
			m_pos.y++;
			break;

		default:
			if (line) line[m_pos.x] = c;
			if (attrs) attrs[m_pos.x] = m_attr;
			m_font.draw_glyph(m_screen, c, m_fg, m_bg, x, y);
			m_pos.x++;
		}

		if (m_pos.x >= m_size.x) {
			m_pos.x = m_pos.x % m_size.x;
			m_pos.y++;
		}

		if (m_pos.y >= m_size.y) {
			scroll(1);
			line = line_pointer(m_pos.y);
		}
	}

	return count;
}