/* vi: set sw=4 ts=4: */
/*
 * Progress bar code.
 */
/* Original copyright notice which applies to the CONFIG_FEATURE_WGET_STATUSBAR stuff,
 * much of which was blatantly stolen from openssh.
 */
/*-
 * Copyright (c) 1992, 1993
 * The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. BSD Advertising Clause omitted per the July 22, 1999 licensing change
 *    ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change
 *
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <libubox/utils.h>
#include "progress.h"

enum {
	/* Seconds when xfer considered "stalled" */
	STALLTIME = 5
};

static int
wh_helper(int value, int def_val, const char *env_name)
{
	if (value == 0) {
		char *s = getenv(env_name);
		if (s)
			value = atoi(s);
	}
	if (value <= 1 || value >= 30000)
		value = def_val;
	return value;
}

static unsigned int
get_tty2_width(void)
{
#ifndef TIOCGWINSZ
	return wh_helper(0, 80, "COLUMNS");
#else
	struct winsize win = {0};
	ioctl(2, TIOCGWINSZ, &win);
	return wh_helper(win.ws_col, 80, "COLUMNS");
#endif
}

static unsigned int
monotonic_sec(void)
{
	struct timespec tv;
	clock_gettime(CLOCK_MONOTONIC, &tv);
	return tv.tv_sec;
}

void
progress_init(struct progress *p, const char *curfile)
{
	p->curfile = strdup(curfile);
	p->start_sec = monotonic_sec();
	p->last_update_sec = p->start_sec;
	p->last_change_sec = p->start_sec;
	p->last_size = 0;
}

/* File already had beg_size bytes.
 * Then we started downloading.
 * We downloaded "transferred" bytes so far.
 * Download is expected to stop when total size (beg_size + transferred)
 * will be "totalsize" bytes.
 * If totalsize == 0, then it is unknown.
 */
void
progress_update(struct progress *p, off_t beg_size,
		off_t transferred, off_t totalsize)
{
	off_t beg_and_transferred;
	unsigned since_last_update, elapsed;
	int barlength;
	int kiloscale;

	//transferred = 1234; /* use for stall detection testing */
	//totalsize = 0; /* use for unknown size download testing */

	elapsed = monotonic_sec();
	since_last_update = elapsed - p->last_update_sec;
	p->last_update_sec = elapsed;

	if (totalsize != 0 && transferred >= totalsize - beg_size) {
		/* Last call. Do not skip this update */
		transferred = totalsize - beg_size; /* sanitize just in case */
	}
	else if (since_last_update == 0) {
		/*
		 * Do not update on every call
		 * (we can be called on every network read!)
		 */
		return;
	}

	kiloscale = 0;
	/*
	 * Scale sizes down if they are close to overflowing.
	 * This allows calculations like (100 * transferred / totalsize)
	 * without risking overflow: we guarantee 10 highest bits to be 0.
	 * Introduced error is less than 1 / 2^12 ~= 0.025%
	 */
	if (ULONG_MAX > 0xffffffff || sizeof(off_t) == 4 || sizeof(off_t) != 8) {
		/*
		 * 64-bit CPU || small off_t: in either case,
		 * >> is cheap, single-word operation.
		 * ... || strange off_t: also use this code
		 * (it is safe, just suboptimal wrt code size),
		 * because 32/64 optimized one works only for 64-bit off_t.
		 */
		if (totalsize >= (1 << 22)) {
			totalsize >>= 10;
			beg_size >>= 10;
			transferred >>= 10;
			kiloscale = 1;
		}
	} else {
		/* 32-bit CPU and 64-bit off_t.
		 * Use a 40-bit shift, it is easier to do on 32-bit CPU.
		 */
/* ONE suppresses "warning: shift count >= width of type" */
#define ONE (sizeof(off_t) > 4)
		if (totalsize >= (off_t)(1ULL << 54*ONE)) {
			totalsize = (uint32_t)(totalsize >> 32*ONE) >> 8;
			beg_size = (uint32_t)(beg_size >> 32*ONE) >> 8;
			transferred = (uint32_t)(transferred >> 32*ONE) >> 8;
			kiloscale = 4;
		}
	}

	fprintf(stderr, "\r%-20.20s", p->curfile);

	beg_and_transferred = beg_size + transferred;

	if (totalsize != 0) {
		unsigned ratio = 100 * beg_and_transferred / totalsize;
		fprintf(stderr, "%4u%%", ratio);

		barlength = get_tty2_width() - 49;
		if (barlength > 0) {
			/* god bless gcc for variable arrays :) */
			char buf[barlength + 1];
			unsigned stars = (unsigned)barlength * beg_and_transferred / totalsize;
			memset(buf, ' ', barlength);
			buf[barlength] = '\0';
			memset(buf, '*', stars);
			fprintf(stderr, " |%s|", buf);
		}
	}

	while (beg_and_transferred >= 100000) {
		beg_and_transferred >>= 10;
		kiloscale++;
	}
	/* see http://en.wikipedia.org/wiki/Tera */
	fprintf(stderr, "%6u%c", (unsigned)beg_and_transferred, " kMGTPEZY"[kiloscale]);

	since_last_update = elapsed - p->last_change_sec;
	if ((unsigned)transferred != p->last_size) {
		p->last_change_sec = elapsed;
		p->last_size = (unsigned)transferred;
		if (since_last_update >= STALLTIME) {
			/* We "cut out" these seconds from elapsed time
			 * by adjusting start time */
			p->start_sec += since_last_update;
		}
		since_last_update = 0; /* we are un-stalled now */
	}

	elapsed -= p->start_sec; /* now it's "elapsed since start" */

	if (since_last_update >= STALLTIME) {
		fprintf(stderr, "  - stalled -");
	} else if (!totalsize || !transferred || (int)elapsed < 0) {
		fprintf(stderr, " --:--:-- ETA");
	} else {
		unsigned eta, secs, hours;

		totalsize -= beg_size; /* now it's "total to upload" */

		/* Estimated remaining time =
		 * estimated_sec_to_dl_totalsize_bytes - elapsed_sec =
		 * totalsize / average_bytes_sec_so_far - elapsed =
		 * totalsize / (transferred/elapsed) - elapsed =
		 * totalsize * elapsed / transferred - elapsed
		 */
		eta = totalsize * elapsed / transferred - elapsed;
		if (eta >= 1000*60*60)
			eta = 1000*60*60 - 1;
		secs = eta % 3600;
		hours = eta / 3600;
		fprintf(stderr, "%3u:%02u:%02u ETA", hours, secs / 60, secs % 60);
	}
}
