/* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
 *     Copyright 2014 Couchbase, Inc.
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 */

#include "settings.h"
#include "logging.h"
#include "internal.h" /* for lcb_getenv* */
#include <stdio.h>
#include <stdarg.h>

#ifdef _WIN32
#define flockfile(x) (void) 0
#define funlockfile(x) (void) 0
#endif


#if defined(unix) || defined(__unix__) || defined(__unix) || defined(_POSIX_VERSION)
    #include <unistd.h>
    #include <pthread.h>
    #include <sys/types.h>

    /** XXX: If any of these blocks give problems for your platform, just
     * erase it and have it use the fallback implementation. This isn't core
     * functionality of the library, but is a rather helpful feature in order
     * to get the thread/process identifier
     */

    #if defined(__linux__)
        #include <sys/syscall.h>
        #define GET_THREAD_ID() (long)syscall(SYS_gettid)
        #define THREAD_ID_FMT "ld"
    #elif defined(__APPLE__)
        #define GET_THREAD_ID() pthread_mach_thread_np(pthread_self())
        #define THREAD_ID_FMT "x"
    #elif defined(__sun) && defined(__SVR4)
        #include <thread.h>
        /* Thread IDs are not global in solaris, so it's nice to print the PID alongside it */
        #define GET_THREAD_ID() getpid(), thr_self()
        #define THREAD_ID_FMT "ld/%u"
    #elif defined(__FreeBSD__)
        /* Like solaris, but thr_self is a bit different here */
        #include <sys/thr.h>
        static long ret_thr_self(void) { long tmp; thr_self(&tmp); return tmp; }
        #define GET_THREAD_ID() getpid(), ret_thr_self()
        #define THREAD_ID_FMT "d/%ld"
    #else
        /* other unix? */
        #define GET_THREAD_ID() 0
        #define THREAD_ID_FMT "d"
    #endif
#elif defined(_WIN32)
    #define GET_THREAD_ID() GetCurrentThreadId()
    #define THREAD_ID_FMT "d"
#else
    #define GET_THREAD_ID() 0
    #define THREAD_ID_FMT "d"
#endif

static hrtime_t start_time = 0;

static void console_log(struct lcb_logprocs_st *procs,
                        unsigned int iid,
                        const char *subsys,
                        int severity,
                        const char *srcfile,
                        int srcline,
                        const char *fmt,
                        va_list ap);

static struct lcb_CONSOLELOGGER console_logprocs = {
        {0 /* version */, {{console_log} /* v1 */} /*v*/},
        NULL,
        /** Minimum severity */
        LCB_LOG_INFO
};

struct lcb_logprocs_st *lcb_console_logprocs = &console_logprocs.base;


/**
 * Return a string representation of the severity level
 */
static const char * level_to_string(int severity)
{
    switch (severity) {
    case LCB_LOG_TRACE:
        return "TRACE";
    case LCB_LOG_DEBUG:
        return "DEBUG";
    case LCB_LOG_INFO:
        return "INFO";
    case LCB_LOG_WARN:
        return "WARN";
    case LCB_LOG_ERROR:
        return "ERROR";
    case LCB_LOG_FATAL:
        return "FATAL";
    default:
        return "";
    }
}

/**
 * Default logging callback for the verbose logger.
 */
static void console_log(struct lcb_logprocs_st *procs,
                        unsigned int iid,
                        const char *subsys,
                        int severity,
                        const char *srcfile,
                        int srcline,
                        const char *fmt,
                        va_list ap)
{
    FILE *fp;
    hrtime_t now;
    struct lcb_CONSOLELOGGER *vprocs = (struct lcb_CONSOLELOGGER *)procs;

    if (severity < vprocs->minlevel) {
        return;
    }

    if (!start_time) {
        start_time = gethrtime();
    }

    now = gethrtime();
    if (now == start_time) {
        now++;
    }

    fp = vprocs->fp ? vprocs->fp : stderr;

    flockfile(fp);
    fprintf(fp, "%lums ", (unsigned long)(now - start_time) / 1000000);

    fprintf(fp, "[I%d] {%"THREAD_ID_FMT"} [%s] (%s - L:%d) ",
            iid,
            GET_THREAD_ID(),
            level_to_string(severity),
            subsys,
            srcline);
    vfprintf(fp, fmt, ap);
    fprintf(fp, "\n");
    funlockfile(fp);

    (void)procs;
    (void)srcfile;
}


LCB_INTERNAL_API
void lcb_log(const struct lcb_settings_st *settings,
             const char *subsys,
             int severity,
             const char *srcfile,
             int srcline,
             const char *fmt,
             ...)
{
    va_list ap;
    lcb_logging_callback callback;

    if (!settings->logger) {
        return;
    }

    if (settings->logger->version != 0) {
        return;
    }

    callback = settings->logger->v.v0.callback;

    va_start(ap, fmt);
    callback(settings->logger, settings->iid, subsys, severity, srcfile, srcline, fmt, ap);
    va_end(ap);
}

LCB_INTERNAL_API
void lcb_log_badconfig(const struct lcb_settings_st *settings,
    const char *subsys, int severity, const char *srcfile, int srcline,
    const lcbvb_CONFIG *vbc, const char *origin_txt)
{
    const char *errstr = lcbvb_get_error(vbc);
    if (!errstr) {
        errstr = "<FIXME: No error string provided for parse failure>";
    }

    lcb_log(settings, subsys, severity, srcfile, srcline,
        "vBucket config parsing failed: %s. Raw text in DEBUG level", errstr);
    if (!origin_txt) {
        errstr = "<FIXME: No origin text available>";
    }
    lcb_log(settings, subsys, LCB_LOG_DEBUG, srcfile, srcline, "%s", origin_txt);
}

lcb_logprocs * lcb_init_console_logger(void)
{
    char vbuf[1024];
    char namebuf[PATH_MAX] = { 0 };
    int lvl = 0;
    int has_file = 0;

    has_file = lcb_getenv_nonempty("LCB_LOGFILE", namebuf, sizeof(namebuf));
    if (has_file && console_logprocs.fp == NULL) {
        FILE *fp = fopen(namebuf, "a");
        if (!fp) {
            fprintf(stderr, "libcouchbase: could not open file '%s' for logging output. (%s)\n",
                namebuf, strerror(errno));
        }
        console_logprocs.fp = fp;
    }

    if (!lcb_getenv_nonempty("LCB_LOGLEVEL", vbuf, sizeof(vbuf))) {
        return NULL;
    }

    if (sscanf(vbuf, "%d", &lvl) != 1) {
        return NULL;
    }

    if (!lvl) {
        /** "0" */
        return NULL;
    }

    /** The "lowest" level we can expose is WARN, e.g. ERROR-1 */
    lvl = LCB_LOG_ERROR - lvl;
    console_logprocs.minlevel = lvl;
    return lcb_console_logprocs;
}
