/*
 * Copyright (C) 2012-2013 Andy Spencer <andy753421@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#define _GNU_SOURCE
#define _XOPEN_SOURCE
#define _XOPEN_SOURCE_EXTENDED
#define _POSIX_C_SOURCE 200100

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <time.h>

#include <sys/epoll.h>

#include "view.h"
#include "util.h"

#pragma weak view_exit
#pragma weak view_debug

/* Static data */
static int   epoll    = 0;
static FILE *debug_fd = NULL;
static int   running  = 0;

/* View debugging */
extern void view_debug(const char *fmt, va_list ap);

/* Helper functions */
static void message(FILE *output_fd, const char *prefix, const char *fmt, va_list ap)
{
	va_list tmp;
	struct timespec ts;

	clock_gettime(CLOCK_REALTIME, &ts);
	unsigned int sec = ts.tv_sec;
	unsigned int msec = ts.tv_nsec / 1000000;

	/* Log to standard out */
	if (output_fd) {
		va_copy(tmp, ap);
		fprintf(output_fd, "%u.%03u: ", sec, msec);
		fprintf(output_fd, "%s: ", prefix);
		vfprintf(output_fd, fmt, tmp);
		fprintf(output_fd, "\n");
		fflush(output_fd);
	}

	/* Log to debug file */
	if (debug_fd) {
		va_copy(tmp, ap);
		fprintf(debug_fd, "%u.%03u: ", sec, msec);
		fprintf(debug_fd, "%s: ", prefix);
		vfprintf(debug_fd, fmt, tmp);
		fprintf(debug_fd, "\n");
		fflush(debug_fd);
	}

	/* Log to status bar */
	if (&view_debug) {
		va_copy(tmp, ap);
		view_debug(fmt, tmp);
	}
}

/* Initialize */
void util_init(void)
{
	epoll    = epoll_create(1);
	debug_fd = fopen("/tmp/lamechat.log", "w+");
	running  = 1;
}

/* String functions */
void strsub(char *str, char find, char repl)
{
	for (char *cur = str; *cur; cur++)
		if (*cur == find)
			*cur = repl;
}

char *strcopy(const char *str)
{
	if (str == NULL)
		return NULL;
	return strdup(str);
}

void strset(char **old, const char *str)
{
	if (*old)
		free(*old);
	if (str)
		*old = strdup(str);
	else
		*old = NULL;
}

int match(const char *a, const char *b)
{
	if (a == b)
		return 1;
	if (!a || !b)
		return 0;
	return !strcmp(a, b);
}

int prefix(const char *str, const char *prefix, const char **suffix)
{
	while (*str && *prefix) {
		if (*str != *prefix)
			return 0;
		str++;
		prefix++;
	}
	if (*prefix)
		return 0;
	if (*str && *str != ' ')
		return 0;
	while (*str && *str == ' ')
		str++;
	if (suffix)
		*suffix = *str ? str : NULL;
	return 1;
}

/* Memory functions */
void *alloc0(int size)
{
	void *data = calloc(1, size);
	if (!data)
		error("memory allocation failed");
	return data;
}

void append(buf_t *buf, const char *data, int len)
{
	if (buf->len + len + 1 > buf->max) {
		buf->max += (((buf->len+len)/4096)+1)*4096;
		buf->data = realloc(buf->data, buf->max);
		if (!buf->data)
			error("buffer reallocation allocation failed");
	}
	if (data)
		memcpy(buf->data + buf->len, data, len);
	buf->len += len;
	((char*)buf->data)[buf->len] = '\0';
}

void release(buf_t *buf)
{
	free(buf->data);
	buf->data = 0;
	buf->len  = 0;
	buf->max  = 0;
}

const char *reset(buf_t *buf)
{
	if (!buf->len)
		return NULL;
	buf->len = 0;
	return buf->data;
}

/* Data functions */
int base64(const void *_in, int ilen, void *_out, int olen)
{
	static const char table[] =
		"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
		"abcdefghijklmnopqrstuvwxyz"
		"0123456789+/";

	const unsigned char *in  = _in;
	unsigned char       *out = _out;

	int val = 0;
	int len = ((ilen-1)/3+1)*4;

	if (olen < len)
		return 0;

	for (int i=0; i<ilen/3; i++) {
		val      = *(in++) << 020;
		val     |= *(in++) << 010;
		val     |= *(in++) << 000;
		*(out++) = table[(val>>6*3)&077];
		*(out++) = table[(val>>6*2)&077];
		*(out++) = table[(val>>6*1)&077];
		*(out++) = table[(val>>6*0)&077];
	}

	switch (ilen%3) {
		case 2:
			val    = *(in++)<<020;
			val   |= *(in++)<<010;
			*out++ = table[(val>>6*3)&077];
			*out++ = table[(val>>6*2)&077];
			*out++ = table[(val>>6*1)&077];
			*out++ = '=';
			break;
		case 1:
			val    = *(in++)<<020;
			*out++ = table[(val>>6*3)&077];
			*out++ = table[(val>>6*2)&077];
			*out++ = '=';
			*out++ = '=';
			break;
	}

	return len;
}

/* File functions */
char *read_file(const char *path, int *len)
{
	/* we could use stat, but we'll try to be portable */
	FILE *fd = fopen(path, "rt+");
	if (!fd)
		return NULL;

	int   block = 512; // read size
	int   size  = 512; // buffer size
	int   slen  = 0;   // string length
	char *buf   = malloc(size);
	if (!buf)
		goto err;

	while (!feof(fd)) {
		if (slen + block + 1 > size) {
			size *= 2;
			buf   = realloc(buf, size);
			if (!buf)
				goto err;
		}
		slen += fread(&buf[slen], 1, block, fd);
		buf[slen] = '\0';
	}

err:
	if (len)
		*len = slen;
	fclose(fd);
	return buf;
}

/* Polling functions */
int poll_add(poll_t *poll, int fd, cb_t cb, void *data)
{
	struct epoll_event ctl = {
		.events = EPOLLIN | EPOLLOUT | EPOLLERR,
		.data.ptr = poll,
	};
	poll->fd   = fd;
	poll->cb   = cb;
	poll->data = data;
	return epoll_ctl(epoll, EPOLL_CTL_ADD, fd, &ctl);
}

int poll_ctl(poll_t *poll, int in, int out, int err)
{
	struct epoll_event ctl = {
		.events = (in  ? EPOLLIN  : 0)
		        | (out ? EPOLLOUT : 0)
		        | (err ? EPOLLERR : 0),
		.data.ptr = poll,
	};
	return epoll_ctl(epoll, EPOLL_CTL_MOD, poll->fd, &ctl);
}

int poll_del(poll_t *poll)
{
	return epoll_ctl(epoll, EPOLL_CTL_DEL, poll->fd, NULL);
}

int poll_run(int timeout)
{
	poll_t *poll;
	int count;
	struct epoll_event event;

	while (running) {
		errno = 0;
		count = epoll_wait(epoll, &event, 1, timeout);
		if (errno == EINTR)
			continue;
		if (count < 0)
			continue;
		if (count == 0)
			continue;
		if (!(poll = event.data.ptr))
			continue;
		if (!(poll->cb))
			continue;
		//debug("poll fd=%d count=%d,%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
                //        poll->fd, count,
                //        event.events & EPOLLIN      ? " in"      : "",
                //        event.events & EPOLLPRI     ? " pri"     : "",
                //        event.events & EPOLLOUT     ? " out"     : "",
                //        event.events & EPOLLRDNORM  ? " rdnorm"  : "",
                //        event.events & EPOLLRDBAND  ? " rdband"  : "",
                //        event.events & EPOLLWRNORM  ? " wrnorm"  : "",
                //        event.events & EPOLLWRBAND  ? " wrband"  : "",
                //        event.events & EPOLLMSG     ? " msg"     : "",
                //        event.events & EPOLLERR     ? " err"     : "",
                //        event.events & EPOLLHUP     ? " hup"     : "",
                //        event.events & EPOLLRDHUP   ? " rdhup"   : "",
                //        event.events & EPOLLWAKEUP  ? " wakeup"  : "",
                //        event.events & EPOLLONESHOT ? " oneshot" : "",
                //        event.events & EPOLLET      ? " et"      : "");
		poll->cb(poll->data);
		return running;
	}
	return running;
}

void poll_quit(void)
{
	running = 0;
}

/* Debugging functions */
void debug(char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	message(NULL, "debug", fmt, ap);
	va_end(ap);
}

void error(char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	fflush(stdout);
	fflush(stderr);
	message(stderr, "error", fmt, ap);
	va_end(ap);
	if (view_exit)
		view_exit();
	exit(-1);
}