/*
 * Copyright (c) 2019 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * This code uses concepts and configuration based on 'synth', by
 * John R. Marino <draco@marino.st>, which was written in ada.
 *
 * 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. Neither the name of The DragonFly Project 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 COPYRIGHT HOLDERS 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
 * COPYRIGHT HOLDERS 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 "dsynth.h"
#include <sys/mman.h>

typedef struct MonitorFile {
        char    version[32];
        int32_t maxworkers;
        int32_t maxjobs;
        topinfo_t info;

        char    packagespath[128];
        char    repositorypath[128];
        char    optionspath[128];
        char    distfilespath[128];
        char    buildbase[128];
        char    logspath[128];
        char    systempath[128];
        char    profile[64];

        struct {
                worker_t work;
                char portdir[128];
        } slots[MAXWORKERS];
} monitor_file_t;

#define SNPRINTF(buf, ctl, ...)         \
        snprintf((buf), sizeof(buf), ctl, ## __VA_ARGS__)

static int StatsFd = -1;
static int LockFd = -1;
static monitor_file_t *RStats;

static void
MonitorInit(void)
{
        struct stat st;

        mkdir(StatsBase, 0755);
        if (stat(StatsBase, &st) < 0)
                dfatal_errno("Cannot create %s");
        if (st.st_uid && st.st_uid != getuid())
                dfatal("%s not owned by current uid", StatsBase);
        StatsFd = open(StatsFilePath, O_RDWR|O_CREAT|O_CLOEXEC, 0644);
        if (StatsFd < 0)
                dfatal_errno("Cannot create %s", StatsFilePath);
        ftruncate(StatsFd, sizeof(monitor_file_t));

        LockFd = open(StatsLockPath, O_RDWR|O_CREAT|O_NOFOLLOW|O_CLOEXEC,
                      0666);
        if (LockFd < 0)
                dfatal_errno("Cannot create %s", StatsLockPath);

        RStats = mmap(NULL, sizeof(monitor_file_t),
                      PROT_READ|PROT_WRITE, MAP_SHARED,
                      StatsFd, 0);
        dassert_errno(RStats != MAP_FAILED, "Unable to mmap %s", StatsFilePath);
}

static void
MonitorDone(void)
{
        if (RStats) {
                if (RStats != MAP_FAILED)
                        munmap(RStats, sizeof(monitor_file_t));
                RStats = NULL;
        }
        if (StatsFd >= 0) {
                close(StatsFd);
                StatsFd = -1;
        }
        if (LockFd >= 0) {
                flock(LockFd, LOCK_UN);
                close(LockFd);
                LockFd = -1;
        }
}

static void
MonitorReset(void)
{
        monitor_file_t *rs;

        rs = RStats;
        flock(LockFd, LOCK_UN);                 /* may fail */

        bzero(rs, sizeof(*rs));

        SNPRINTF(rs->version, "%s", DSYNTH_VERSION);
        rs->maxworkers = MaxWorkers;
        rs->maxjobs = MaxJobs;

        SNPRINTF(rs->packagespath, "%s", PackagesPath);
        SNPRINTF(rs->repositorypath, "%s", RepositoryPath);
        SNPRINTF(rs->optionspath, "%s", OptionsPath);
        SNPRINTF(rs->distfilespath, "%s", DistFilesPath);
        SNPRINTF(rs->buildbase, "%s", BuildBase);
        SNPRINTF(rs->logspath, "%s", LogsPath);
        SNPRINTF(rs->systempath, "%s", SystemPath);
        SNPRINTF(rs->profile, "%s", Profile);

        flock(LockFd, LOCK_EX);                 /* ready */
}

static void
MonitorUpdate(worker_t *work, const char *dummy __unused)
{
        monitor_file_t *rs;
        worker_t copy;
        int i = work->index;

        rs = RStats;

        copy = *work;
        copy.pkg = NULL;                /* safety */
        if (work->pkg)
                SNPRINTF(rs->slots[i].portdir, "%s", work->pkg->portdir);
        else
                SNPRINTF(rs->slots[i].portdir, "%s", "");
        rs->slots[i].work = copy;
}

static void
MonitorUpdateTop(topinfo_t *info)
{
        monitor_file_t *rs;

        rs = RStats;

        rs->info = *info;
}

static void
MonitorUpdateLogs(void)
{
}

static void
MonitorSync(void)
{
}

runstats_t MonitorRunStats = {
        .init = MonitorInit,
        .done = MonitorDone,
        .reset = MonitorReset,
        .update = MonitorUpdate,
        .updateTop = MonitorUpdateTop,
        .updateLogs = MonitorUpdateLogs,
        .sync = MonitorSync
};

/****************************************************************************
 *                      MONITOR DIRECTIVE FRONTEND                          *
 *                  (independently executed dsynth app)
 ****************************************************************************
 *
 * Access the monitor file and display available information
 *
 * lkfile may be NULL
 */
void
MonitorDirective(const char *datfile, const char *lkfile)
{
        monitor_file_t *rs;
        monitor_file_t copy;
        int i;
        int running;

        bzero(&copy, sizeof(copy));

        StatsFd = open(datfile, O_RDONLY);
        if (StatsFd < 0) {
                printf("dsynth is not running\n");
                exit(1);
        }
        if (lkfile) {
                LockFd = open(lkfile, O_RDWR);
                if (LockFd < 0) {
                        printf("dsynth is not running\n");
                        exit(1);
                }
        }

        rs = mmap(NULL, sizeof(monitor_file_t),
                  PROT_READ, MAP_SHARED,
                  StatsFd, 0);
        dassert_errno(rs != MAP_FAILED, "Cannot mmap \"%s\"", datfile);

        /*
         * Expect flock() to fail, if it doesn't then dsynth i
         * not running.
         */
        if (flock(LockFd, LOCK_SH|LOCK_NB) == 0) {
                flock(LockFd, LOCK_UN);
                printf("dsynth is not running\n");
                exit(1);
        }

        /*
         * Display setup
         */
        NCursesRunStats.init();
        NCursesRunStats.reset();

        /*
         * Run until done.  When we detect completion we still give the
         * body one more chance at the logs so the final log lines are
         * properly displayed before exiting.
         */
        running = 1;
        while (running) {
                /*
                 * Expect flock() to fail, if it doesn't then dsynth i
                 * not running.
                 */
                if (LockFd >= 0 && flock(LockFd, LOCK_SH|LOCK_NB) == 0) {
                        flock(LockFd, LOCK_UN);
                        running = 0;
                }
                if (rs->version[0])
                        NCursesRunStats.updateTop(&rs->info);
                for (i = 0; rs->version[0] && i < rs->maxworkers; ++i) {
                        /*
                        if (bcmp(&copy.slots[i].work,
                                 &rs->slots[i].work,
                                 sizeof(copy.slots[i].work)) != 0) {
                        */
                        {
                                /*
                                 * A slot changed
                                 */
                                copy.slots[i].work = rs->slots[i].work;
                                NCursesRunStats.update(&copy.slots[i].work,
                                                       rs->slots[i].portdir);
                        }
                }
                if (LockFd >= 0)
                        NCursesRunStats.updateLogs();
                NCursesRunStats.sync();
                usleep(500000);
        }
        NCursesRunStats.done();
        printf("dsynth exited\n");
}