/*
 * Copyright 2008, Axel Dörfler, axeld@pinc-software.de.
 * Distributed under the terms of the MIT License.
 */


#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <system_info.h>


static struct option const kLongOptions[] = {
        {"periodic", no_argument, 0, 'p'},
        {"rate", required_argument, 0, 'r'},
        {"help", no_argument, 0, 'h'},
        {NULL}
};

extern const char *__progname;
static const char *kProgramName = __progname;


void
usage(int status)
{
        fprintf(stderr, "usage: %s [-p] [-r <time>]\n"
                " -p,--periodic\tDumps changes periodically every second.\n"
                " -r,--rate\tDumps changes periodically every <time> milli seconds.\n",
                kProgramName);

        exit(status);
}


int
main(int argc, char** argv)
{
        bool periodically = false;
        bigtime_t rate = 1000000LL;

        int c;
        while ((c = getopt_long(argc, argv, "pr:h", kLongOptions, NULL)) != -1) {
                switch (c) {
                        case 0:
                                break;
                        case 'p':
                                periodically = true;
                                break;
                        case 'r':
                                rate = atoi(optarg) * 1000LL;
                                if (rate <= 0) {
                                        fprintf(stderr, "%s: Invalid rate: %s\n",
                                                kProgramName, optarg);
                                        return 1;
                                }
                                periodically = true;
                                break;
                        case 'h':
                                usage(0);
                                break;
                        default:
                                usage(1);
                                break;
                }
        }
        system_info info;
        status_t status = get_system_info(&info);
        if (status != B_OK) {
                fprintf(stderr, "%s: cannot get system info: %s\n", kProgramName,
                        strerror(status));
                return 1;
        }

        printf("max memory:\t\t%" B_PRIu64 "\n", info.max_pages * B_PAGE_SIZE);
        printf("free memory:\t\t%" B_PRIu64 "\n", info.free_memory);
        printf("needed memory:\t\t%" B_PRIu64 "\n", info.needed_memory);
        printf("block cache memory:\t%" B_PRIu64 "\n",
                info.block_cache_pages * B_PAGE_SIZE);
        printf("max swap space:\t\t%" B_PRIu64 "\n",
                info.max_swap_pages * B_PAGE_SIZE);
        printf("free swap space:\t%" B_PRIu64 "\n",
                info.free_swap_pages * B_PAGE_SIZE);
        printf("page faults:\t\t%" B_PRIu32 "\n", info.page_faults);

        if (periodically) {
                puts("\npage faults  used memory    used swap  block cache");
                system_info lastInfo = info;

                while (true) {
                        snooze(rate);

                        get_system_info(&info);

                        int32 pageFaults = info.page_faults - lastInfo.page_faults;
                        int64 usedMemory
                                = (info.max_pages * B_PAGE_SIZE - info.free_memory)
                                        - (lastInfo.max_pages * B_PAGE_SIZE - lastInfo.free_memory);
                        int64 usedSwap
                                = ((info.max_swap_pages - info.free_swap_pages)
                                                - (lastInfo.max_swap_pages - lastInfo.free_swap_pages))
                                        * B_PAGE_SIZE;
                        int64 blockCache
                                = (info.block_cache_pages - lastInfo.block_cache_pages)
                                        * B_PAGE_SIZE;
                        printf("%11" B_PRId32 "  %11" B_PRId64 "  %11" B_PRId64 "  %11"
                                B_PRId64 "\n", pageFaults, usedMemory, usedSwap, blockCache);

                        lastInfo = info;
                }
        }

        return 0;
}