#include <kernel/console.h>
#include <mutex.h>
#include <ringbuffer.h>
#include <logging.h>
#include <kernel/term.h>
#include <kernel/devfs.h>
#include <errno.h>
#include <kernel/keyboard.h>
#include <termios.h>

#define BUFFER_SIZE 4096
static mutex_t writemutex;
static mutex_t readmutex;
static semaphore_t readsemaphore;
static ringbuffer_t readbuffer;
static thread_t *thread;
static termios_t termios;

void console_write(char *str, size_t count) {
	MUTEX_ACQUIRE(&writemutex, false);

	term_write(str, count);

	MUTEX_RELEASE(&writemutex);
}

void console_putc(char c) {
	console_write(&c, 1);
}

#define THREAD_BUFFER_SIZE 128

static void consolethread() {
	char buffer[THREAD_BUFFER_SIZE + 1];
	uintmax_t buffpos = 0;

	for (;;) {
		kbpacket_t packet;
		keyboard_wait(keyboard_console, &packet);
		if (packet.flags & KBPACKET_FLAGS_RELEASED)
			continue;

		char asciibuffer[2] = {0, 0};
		char *target = asciibuffer;

		if (packet.ascii) {
			if (packet.ascii == '\r' && (termios.c_iflag & IGNCR))
				continue;

			if (packet.ascii == '\r' && (termios.c_iflag & ICRNL))
				packet.ascii = '\n';

			if (packet.ascii == '\n' && (termios.c_iflag & INLCR))
				packet.ascii = '\r';

			// TODO TRANSLATE TO CTRL CODE IF APPLICABLE
		} else {
			// TODO SWITCH OF SPECIAL KEYS
		}

		asciibuffer[0] = packet.ascii;
		size_t targetlen = strlen(target);
		if (targetlen == 0)
			continue;

		if (termios.c_lflag & ICANON) {
			bool flush = false;
			if (packet.ascii == '\b') {
				if (buffpos == 0)
					continue;
				--buffpos;
				buffer[buffpos] = '\0';
				if (termios.c_lflag & ECHO)
					console_write("\b \b", 3);
				continue;
			} else if (packet.ascii == '\n') {
				flush = true;
			}

			if (termios.c_lflag & ECHO)
				console_write(target, targetlen);

			for (size_t i = 0; i < targetlen; ++i) {
				buffer[buffpos++] = target[i];
				if (buffpos == THREAD_BUFFER_SIZE) {
					flush = true;
					break;
				}
			}

			if (flush) {
				MUTEX_ACQUIRE(&readmutex, false);
				bool hasdata = readbuffer.write - readbuffer.read > 0;
				ringbuffer_write(&readbuffer, buffer, buffpos);
				buffpos = 0;
				if (hasdata == false)
					semaphore_signal(&readsemaphore);
				MUTEX_RELEASE(&readmutex);
			}
		} else {
			if (termios.c_lflag & ECHO)
				console_write(target, targetlen);

			MUTEX_ACQUIRE(&readmutex, false);
			bool hasdata = readbuffer.write - readbuffer.read > 0;
			ringbuffer_write(&readbuffer, target, targetlen);
			if (hasdata == false)
				semaphore_signal(&readsemaphore);
			MUTEX_RELEASE(&readmutex);
		}
	}
}

static int read(int minor, void *buffer, size_t size, uintmax_t offset, int flags, size_t *readc) {
	size_t total = 0;
	for (;;) {
		if (semaphore_test(&readsemaphore) == false) {
			*readc = 0;
			if (termios.c_cc[VMIN] == 0)
				return 0;

			if (flags & V_FFLAGS_NONBLOCKING)
				return EAGAIN;

			int i = semaphore_wait(&readsemaphore, true);
			if (i)
				return i;
		}

		MUTEX_ACQUIRE(&readmutex, false);

		size_t read = ringbuffer_read(&readbuffer, buffer, size);
		size_t left = readbuffer.write - readbuffer.read;

		MUTEX_RELEASE(&readmutex);

		size -= read;
		buffer = (void *)((uintptr_t)buffer + read);
		total += read;

		if (size == 0 || total >= termios.c_cc[VMIN]) {
			if (left > 0)
				semaphore_signal(&readsemaphore);
			*readc = total;
			return 0;
		}
	}
}

static int write(int minor, void *buffer, size_t size, uintmax_t offset, int flags, size_t *writec) {
	*writec = size;
	console_write(buffer, size);
	return 0;
}

static int isatty(int minor) {
	return 0;
}

static devops_t devops = {
	.write = write,
	.read = read,
	.isatty = isatty
};

void console_init() {
	SEMAPHORE_INIT(&readsemaphore, 0);
	MUTEX_INIT(&writemutex);
	MUTEX_INIT(&readmutex);
	__assert(ringbuffer_init(&readbuffer, BUFFER_SIZE) == 0);
	__assert(devfs_register(&devops, "console", V_TYPE_CHDEV, DEV_MAJOR_CONSOLE, 0, 0644) == 0);
	thread = sched_newthread(consolethread, PAGE_SIZE * 16, 0, NULL, NULL);
	__assert(thread);
	sched_queue(thread);

	termios.c_iflag = ICRNL;
	termios.c_lflag = ECHO | ICANON | ISIG;
	termios.c_cc[VINTR] = 0x03;
    	termios.ibaud = 38400;
    	termios.obaud = 38400;
	termios.c_cc[VMIN] = 1;
}