/*
 * Copyright (c) 2008, 2009 Apple Computer, Inc.  All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <inttypes.h>
#include <string.h>
#include <curses.h>
#include <unistd.h>
#include <signal.h>
#include <sys/select.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <termios.h>

#include "libtop.h"
#include "top.h"
#include "log.h"
#include "userinput.h"
#include "preferences.h"
#include "options.h"
#include "logging.h"
#include "sig.h"

const libtop_tsamp_t *tsamp;

static volatile sig_atomic_t resized = 1;

static int cached_lines = 0, cached_columns = 0;

static void init(void);

enum {
    MICROSECONDS = 1000000
};

static void event_loop(void *tinst) {
    sigset_t sset, oldsset;
    int samples;
    struct timeval before, now, tlimit;
 
    if(sigemptyset(&sset)) {
	perror("sigemptyset");
	exit(EXIT_FAILURE);
    }
    
    if(sigaddset(&sset, SIGWINCH)) {
	perror("sigaddset");
	exit(EXIT_FAILURE);
    }

    if(-1 == gettimeofday(&before, NULL))
	perror("gettimeofday");

    while(1) {
	bool sleep_expired = false;
	fd_set fset;
	int ready;

	FD_ZERO(&fset);
	FD_SET(STDIN_FILENO, &fset);
	
	tlimit.tv_sec = top_prefs_get_sleep();
	tlimit.tv_usec = 0;

	ready = select(STDIN_FILENO + 1, &fset, NULL, NULL, &tlimit);

	if(-1 == gettimeofday(&now, NULL))
	    perror("gettimeofday");

	if(now.tv_sec >= (before.tv_sec + tlimit.tv_sec)) {
	    /*
	     * The sleep has expired, so we should insert new
	     * data for all stats.  This is different than just
	     * the case where we handle user input and the rest
	     * of the data is awaiting a sleep interval update.
	     */
	    sleep_expired = true;
	    before = now;
	}

	if(sleep_expired) {
	    samples = top_prefs_get_samples();
	    
	    if(samples > -1) {
		/* Samples was set in the preferences. */
		if(0 == samples) {
		    /* We had N samples and now it's time to exit. */
		    endwin();
		    exit(EXIT_SUCCESS);
		}
	  
		top_prefs_set_samples(samples - 1);
	    }
	}

	if(top_signal_is_exit_set()) {
	    exit(EXIT_SUCCESS);
	}
	
	if(ready && FD_ISSET(STDIN_FILENO, &fset))
	    (void)user_input_process(tinst);
	
	if(sleep_expired)
	    top_insert(tinst);
	
	/* Block SIGWINCH signals while we are in a relayout. */
	if(-1 == sigprocmask(SIG_BLOCK, &sset, &oldsset)) {
	    perror("sigprocmask");
	    exit(EXIT_FAILURE);
	}
	
	if(top_need_relayout() 
	   || resized || LINES != cached_lines || COLS != cached_columns) {
	    cached_lines = LINES;
	    cached_columns = COLS;
	    
	    if(top_layout(tinst)) {
		resized = 1;
	    } else { 
		resized = 0;
	    }	
	}
	
	if(-1 == sigprocmask(SIG_SETMASK, &oldsset, NULL)) {
	    perror("sigprocmask");
		exit(EXIT_FAILURE);
	}
	
	top_draw(tinst);
    }
}

void exit_handler(void) {
    endwin();
}

void init(void) {
    if(NULL == initscr()) {
	fprintf(stderr, "error: unable to initscr!\n");
	exit(EXIT_FAILURE);
    }

    atexit(exit_handler);    

    if(ERR == cbreak() /* disable line buffering */
       || ERR == noecho() /* disable echoing what the user types */
       || ERR == nonl() /* no newline */
       || ERR == intrflush(stdscr, FALSE)
       || ERR == meta(stdscr, TRUE)
       || ERR == keypad(stdscr, TRUE)) {
	fprintf(stderr, "error: initializing curses\n");
	exit(EXIT_FAILURE);
    }

    timeout(0);
}

int main(int argc, char *argv[]) {
    void *tinst;
 
    top_prefs_init();
    top_options_init();

    if(top_options_parse(argc, argv)) {
	top_options_usage(stderr, argv[0]);
	return EXIT_FAILURE;
    }

    if(top_prefs_get_samples() > -1)
	top_prefs_set_logging_mode(true);
    
    if(!top_prefs_get_logging_mode())
	init();

    top_signal_init();
  
    if(libtop_init(NULL, NULL)) {
	endwin();
	fprintf(stderr, "libtop_init failed!\n");
	return EXIT_FAILURE;
    }

    if(top_prefs_get_frameworks()
       && libtop_set_interval(top_prefs_get_frameworks_interval())) {
	endwin();
	fprintf(stderr, "error: setting framework update interval.\n");
	exit(EXIT_FAILURE);
    }

    tinst = top_create(stdscr);    

    if(!top_prefs_get_logging_mode()) {
	top_insert(tinst);
	top_layout(tinst);
	top_draw(tinst);
	event_loop(tinst);
    } else {
	top_logging_loop(tinst);
    }

    return EXIT_SUCCESS;    
}