/**
 * Copyright (c) 2007-2012, Timothy Stack
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 * * 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.
 * * Neither the name of Timothy Stack 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.
 *
 * @file log_format_impls.cc
 */

#include <stdio.h>

#include "log_format.hh"
#include "log_vtab_impl.hh"

using namespace std;

static pcrepp RDNS_PATTERN("^(?:com|net|org|edu|[a-z][a-z])"
                           "(\\.\\w+)+(.+)");

/**
 * Attempt to scrub a reverse-DNS string.
 *
 * @param  str The string to scrub.  If the string looks like a reverse-DNS
 *   string, the leading components of the name will be reduced to a single
 *   letter.  For example, "com.example.foo" will be reduced to "c.e.foo".
 * @return     The scrubbed version of the input string or the original string
 *   if it is not a reverse-DNS string.
 */
static string scrub_rdns(const string &str)
{
    pcre_context_static<30> context;
    pcre_input input(str);
    string     retval;

    if (RDNS_PATTERN.match(context, input)) {
        pcre_context::capture_t *cap;

        cap = context.begin();
        for (int index = 0; index < cap->c_begin; index++) {
            if (index == 0 || str[index - 1] == '.') {
                if (index > 0) {
                    retval.append(1, '.');
                }
                retval.append(1, str[index]);
            }
        }
        retval += input.get_substr(cap);
        retval += input.get_substr(cap + 1);
    }
    else {
        retval = str;
    }
    return retval;
}

class access_log_format : public log_format {
    static pcrepp &value_pattern(void)
    {
        static pcrepp VALUE_PATTERN(
            "^([\\w\\.-]+) [\\w\\.-]+ ([\\w\\.-]+) "
            "\\[([^\\]]+)\\] \"(?:\\-|(\\w+) ([^ \\?]+)(\\?[^ ]+)? "
            "([\\w/\\.]+))\" (\\d+) "
            "(\\d+|-)(?: \"([^\"]+)\" \"([^\"]+)\")?.*");

        return VALUE_PATTERN;
    };

    string get_name() { return "access_log"; };

    bool scan(vector<logline> &dst,
              off_t offset,
              char *prefix,
              int len)
    {
        static const char *log_fmt[] = {
            "%*s %*s %*s [%63[^]]] \"%*[^\"]\" %d",
            NULL
        };

        bool      retval = false;
        struct tm log_time;
        int       http_code = 0;
        char      timestr[64];
        time_t    line_time;

        if (this->log_scanf(prefix,
                            log_fmt,
                            2,
                            NULL,
                            timestr,
                            &log_time,
                            line_time,

                            timestr,
                            &http_code)) {
            logline::level_t ll = logline::LEVEL_UNKNOWN;

            if (http_code < 400) {
                ll = logline::LEVEL_INFO;
            }
            else {
                ll = logline::LEVEL_ERROR;
            }
            dst.push_back(logline(offset,
                                  line_time,
                                  0,
                                  ll));
            retval = true;
        }

        return retval;
    };

    auto_ptr<log_format> specialized()
    {
        auto_ptr<log_format> retval((log_format *)new access_log_format(*this));

        return retval;
    };

    void annotate(const std::string &line,
                  string_attrs_t &sa,
                  std::vector<logline_value> &values) const
    {
        pcre_context_static<30> pc;
        pcre_input pi(line);

        if (value_pattern().match(pc, pi)) {
            static struct {
                const char *          name;
                logline_value::kind_t kind;
            } columns[] = {
                { "c_ip",
                  logline_value::VALUE_TEXT },
                { "cs_username",
                  logline_value::VALUE_TEXT },
                { "",   },
                { "cs_method",
                  logline_value::VALUE_TEXT },
                { "cs_uri_stem",
                  logline_value::VALUE_TEXT },
                { "cs_uri_query",
                  logline_value::VALUE_TEXT },
                { "cs_version",
                  logline_value::VALUE_TEXT },
                { "sc_status",
                  logline_value::VALUE_INTEGER },
                { "sc_bytes",
                  logline_value::VALUE_INTEGER },
                { "cs_referer",
                  logline_value::VALUE_TEXT },
                { "cs_user_agent",
                  logline_value::VALUE_TEXT },

                { NULL },
            };

            pcre_context::iterator iter;
            struct line_range      lr;

            iter        = pc.begin() + 3;
            lr.lr_start = iter->c_begin;
            lr.lr_end   = iter->c_end;
            sa[lr].insert(make_string_attr("timestamp", 0));

            lr.lr_start = 0;
            lr.lr_end   = line.length();
            sa[lr].insert(make_string_attr("prefix", 0));

            lr.lr_start = line.length();
            lr.lr_end   = line.length();
            sa[lr].insert(make_string_attr("body", 0));

            for (int lpc = 0; columns[lpc].name; lpc++) {
                if (columns[lpc].name[0] == '\0') {
                    continue;
                }
                values.push_back(logline_value(columns[lpc].name,
                                               columns[lpc].kind,
                                               pi.get_substr(pc.begin() +
                                                             lpc)));
            }
        }
        else {
            fprintf(stderr, "bad match! %s\n", line.c_str());
        }
    };
};

log_format::register_root_format<access_log_format> access_log_instance;

class syslog_log_format : public log_format {
    static const int TIMESTAMP_LENGTH = 16;

    static pcrepp &repeated_pattern(void)
    {
        static pcrepp REPEATED_PATTERN("last message repeated \\d+ times");

        return REPEATED_PATTERN;
    }

    static pcrepp &scrub_pattern(void)
    {
        static pcrepp SCRUB_PATTERN(
            "(\\w+\\s[\\s\\d]\\d \\d+:\\d+:\\d+) [\\.\\-\\w]+( .*)");

        return SCRUB_PATTERN;
    }

    static pcrepp &error_pattern(void)
    {
        static pcrepp ERROR_PATTERN("(?:failed|failure|error)", PCRE_CASELESS);

        return ERROR_PATTERN;
    }

    static pcrepp &warning_pattern(void)
    {
        static pcrepp WARNING_PATTERN(
            "(?:warn|not responding|init: cannot execute)", PCRE_CASELESS);

        return WARNING_PATTERN;
    }

    string get_name() { return "syslog_log"; };

    void scrub(string &line)
    {
        pcre_context_static<30> context;
        pcre_input pi(line);
        string     new_line = "";

        if (scrub_pattern().match(context, pi)) {
            pcre_context::capture_t *cap;

            for (cap = context.begin(); cap != context.end(); cap++) {
                new_line += pi.get_substr(cap);
            }

            line = new_line;
        }
    };

    void annotate(const string &line,
                  string_attrs_t &sa,
                  std::vector<logline_value> &values) const
    {
        bool found_hostname = false, found_procname = false, found_prefix =
            false;
        struct line_range lr, hostname_range = { 0, 0 };
        struct line_range procname_range = { 0, 0 };
        int log_pid = -1;

        lr.lr_start = 0;
        lr.lr_end   = TIMESTAMP_LENGTH;
        sa[lr].insert(make_string_attr("timestamp", 0));

        for (size_t lpc = TIMESTAMP_LENGTH; lpc < line.size(); lpc++) {
            if (line[lpc] == ' ' && !found_hostname) {
                hostname_range.lr_start = TIMESTAMP_LENGTH;
                hostname_range.lr_end   = lpc;
                sa[hostname_range].insert(make_string_attr("log_hostname", 0));

                found_hostname = true;
            }

            if (line[lpc] == ' ' && found_hostname && !found_procname) {
                bool done = false;

                procname_range.lr_start = procname_range.lr_end = lpc + 1;
                while (!done) {
                    switch (line[lpc]) {
                    case '\0':
                        done = true;
                        break;

                    case ':':
                    case '[':
                        procname_range.lr_end = lpc;
                        done = true;
                        break;

                    default:
                        lpc += 1;
                        break;
                    }
                }

                sa[procname_range].insert(make_string_attr("log_procname", 0));

                found_procname = true;
            }

            if (line[lpc] == '[' && log_pid == -1) {
                const char *line_c_str = line.c_str();

                sscanf(&line_c_str[lpc + 1], "%d", &log_pid);
            }

            if (line[lpc] == ':') {
                lr.lr_start = 0;
                lr.lr_end   = lpc + 1;
                sa[lr].insert(make_string_attr("prefix", 0));

                lr.lr_start = lpc + 1;
                lr.lr_end   = line.length();
                sa[lr].insert(make_string_attr("body", 0));

                found_prefix = true;
                break;
            }
        }

        if (!found_prefix) {
            lr.lr_start = 0;
            lr.lr_end   = line.length();
            sa[lr].insert(make_string_attr("prefix", 0));

            lr.lr_start = line.length();
            lr.lr_end   = line.length();
            sa[lr].insert(make_string_attr("body", 0));

            hostname_range.lr_start = 0;
            hostname_range.lr_end   = 0;
        }

        values.push_back(logline_value("log_hostname",
                                       line.substr(hostname_range.lr_start,
                                                   hostname_range.length())));
        values.push_back(logline_value("log_procname",
                                       line.substr(procname_range.lr_start,
                                                   procname_range.length())));
        values.push_back(logline_value("log_pid", (int64_t)log_pid));
    };

    bool scan(vector<logline> &dst,
              off_t offset,
              char *prefix,
              int len)
    {
        bool      retval = false;
        struct tm log_time;
        short     millis = 0;
        time_t    now;
        char *    rest;

        now = time(NULL);
        localtime_r(&now, &log_time);

        log_time.tm_isdst = 0;

        if ((rest = strptime(prefix,
                             "%b %d %H:%M:%S",
                             &log_time)) != NULL) {
            pcre_context_static<20> context;
            pcre_input       pi(prefix, 0, len);
            logline::level_t ll = logline::LEVEL_UNKNOWN;
            time_t           log_gmt;

            if (repeated_pattern().match(context, pi)) {
                ll = logline::LEVEL_CONTINUED;
            }
            else if (error_pattern().match(context, pi)) {
                ll = logline::LEVEL_ERROR;
            }
            else if (warning_pattern().match(context, pi)) {
                ll = logline::LEVEL_WARNING;
            }
            log_gmt = tm2sec(&log_time);
            if (!dst.empty() &&
                ((dst.back().get_time() - log_gmt) > (24 * 60 * 60))) {
                vector<logline>::iterator iter;

                for (iter = dst.begin(); iter != dst.end(); iter++) {
                    time_t     ot = iter->get_time();
                    struct tm *otm;

                    otm           = gmtime(&ot);
                    otm->tm_year -= 1;
                    iter->set_time(tm2sec(otm));
                }
            }
            dst.push_back(logline(offset, log_gmt, millis, ll));

            retval = true;
        }

        return retval;
    };

    auto_ptr<log_format> specialized()
    {
        auto_ptr<log_format> retval((log_format *)new syslog_log_format(*this));

        return retval;
    };
};

log_format::register_root_format<syslog_log_format> syslog_instance;

class tcsh_history_format : public log_format {
    string get_name() { return "tcsh_history"; };

    bool scan(vector<logline> &dst,
              off_t offset,
              char *prefix,
              int len)
    {
        bool   retval = false;
        time_t log_time;
        int    log_time_int;

        if (sscanf(prefix, "#+%d", &log_time_int) == 1) {
            struct tm log_tm;

            log_time = log_time_int;

            /*
             * NB: We convert any displayed dates to gm time, so we need to
             * convert this time to local and then back to gmt.
             */
            memset(&log_tm, 0, sizeof(log_tm));
            log_tm          = *localtime(&log_time);
            log_tm.tm_zone  = NULL;
            log_tm.tm_isdst = 0;

            dst.push_back(logline(offset,
                                  tm2sec(&log_tm),
                                  0,
                                  logline::LEVEL_UNKNOWN));

            retval = true;
        }

        return retval;
    };

    auto_ptr<log_format> specialized()
    {
        auto_ptr<log_format> retval((log_format *)
                                    new tcsh_history_format(*this));

        return retval;
    };
};

log_format::register_root_format<tcsh_history_format> tcsh_instance;

class generic_log_format : public log_format {
    static pcrepp &scrub_pattern(void)
    {
        static pcrepp SCRUB_PATTERN(
            "\\d+-(\\d+-\\d+ \\d+:\\d+:\\d+(?:,\\d+)?:)\\w+:(.*)");

        return SCRUB_PATTERN;
    }

    static const char **get_log_formats()
    {
        static const char *log_fmt[] = {
            "%63[0-9TZ: ,.-]%63[^:]%n",
            "%63[a-zA-Z0-9:-+/.] [%*x %63[^\n]%n",
            "%63[a-zA-Z0-9:.,-] %63[^\n]%n",
            "%63[a-zA-Z0-9: .,-] [%*[^]]]%63[^:]%n",
            "%63[a-zA-Z0-9: .,-] %63[^\n]%n",
            "[%63[0-9: .-] %*s %63[^\n]%n",
            "[%63[a-zA-Z0-9: -+/]] %63[^\n]%n",
            "[%63[a-zA-Z0-9: -+/]] [%63[a-zA-Z]]%n",
            "[%63[a-zA-Z0-9: .-+/] %*s %63[^\n]%n",
            "[%63[a-zA-Z0-9: -+/]] (%*d) %63[^\n]%n",
            NULL
        };

        return log_fmt;
    };

    string get_name() { return "generic_log"; };

    void scrub(string &line)
    {
        pcre_context_static<30> context;
        pcre_input pi(line);
        string     new_line = "";

        if (scrub_pattern().match(context, pi)) {
            pcre_context::capture_t *cap;

            for (cap = context.begin(); cap != context.end(); cap++) {
                new_line += scrub_rdns(pi.get_substr(cap));
            }

            line = new_line;
        }
    };

    bool scan(vector<logline> &dst,
              off_t offset,
              char *prefix,
              int len)
    {
        bool      retval = false;
        struct tm log_time;
        char      timestr[64 + 32];
        time_t    line_time;
        char      level[64];
        char *    last_pos;
        int       prefix_len;

        if ((last_pos = this->log_scanf(prefix,
                                        get_log_formats(),
                                        2,
                                        NULL,
                                        timestr,
                                        &log_time,
                                        line_time,

                                        timestr,
                                        level,
                                        &prefix_len)) != NULL) {
            uint16_t millis = 0;

            /* Try to pull out the milliseconds value. */
            if (last_pos[0] == ',' || last_pos[0] == '.') {
                sscanf(last_pos + 1, "%hd", &millis);
                if (millis >= 1000) {
                    millis = 0;
                }
            }
            dst.push_back(logline(offset,
                                  line_time,
                                  millis,
                                  logline::string2level(level)));
            retval = true;
        }

        return retval;
    };

    void annotate(const string &line,
                  string_attrs_t &sa,
                  std::vector<logline_value> &values) const
    {
        const char *      fmt = get_log_formats()[this->lf_fmt_lock];
        char              timestr[64 + 32] = "";
        char              level[64]        = "";
        struct line_range lr;
        int prefix_len = 0;

        sscanf(line.c_str(), fmt, timestr, level, &prefix_len);

        lr.lr_start = fmt[0] == '%' ? 0 : 1;
        lr.lr_end   = lr.lr_start + strlen(timestr);
        sa[lr].insert(make_string_attr("timestamp", 0));

        for (int lpc = 0; level[lpc]; lpc++) {
            if (!isalpha(level[lpc])) {
                level[lpc] = '\0';
                prefix_len = strlen(timestr) + lpc;
                break;
            }
        }

        if (logline::string2level(level, true) == logline::LEVEL_UNKNOWN) {
            prefix_len = strlen(timestr);
        }

        lr.lr_start = 0;
        lr.lr_end   = prefix_len;
        sa[lr].insert(make_string_attr("prefix", 0));

        lr.lr_start = prefix_len;
        lr.lr_end   = line.length();
        sa[lr].insert(make_string_attr("body", 0));
    };

    auto_ptr<log_format> specialized()
    {
        auto_ptr<log_format> retval((log_format *)
                                    new generic_log_format(*this));

        return retval;
    };
};

log_format::register_root_format<generic_log_format> generic_log_instance;

class glog_log_format : public log_format {
    static pcrepp &value_pattern(void)
    {
        static pcrepp VALUE_PATTERN(
            "\\s*(?:[IWECF])\\d+ \\d+:\\d+:\\d+\\.(\\d+)" /* level, date */
            "\\s*([0-9]*)"                                /* thread */
            "\\s*(.*):(\\d*)\\]"                          /* filename:number */
            "\\s*(.*)");

        return VALUE_PATTERN;
    };

    string get_name() { return "glog_log"; };

    bool scan(vector<logline> &dst,
              off_t offset,
              char *prefix,
              int len)
    {
        bool      retval = false;
        struct tm log_time;
        short     millis = 0;
        time_t    now;
        char *    rest;

        now = time(NULL);
        localtime_r(&now, &log_time);

        log_time.tm_isdst = 0;

        if ((rest = strptime(prefix + 1,
                             "%m%d %H:%M:%S.",
                             &log_time)) != NULL) {
            logline::level_t ll = logline::LEVEL_UNKNOWN;
            time_t           log_gmt;

            millis = atoi(rest) / 1000;

            switch (*prefix) {
            case 'I':     /* info */
                ll = logline::LEVEL_INFO;
                break;

            case 'W':     /* warning */
                ll = logline::LEVEL_WARNING;
                break;

            case 'E':     /* error */
                ll = logline::LEVEL_ERROR;
                break;

            case 'C':     /* critical */
                ll = logline::LEVEL_CRITICAL;
                break;

            case 'F':     /* fatal */
                ll = logline::LEVEL_FATAL;
                break;
            }
            log_gmt = tm2sec(&log_time);
            dst.push_back(logline(offset, log_gmt, millis, ll));

            retval = true;
        }

        return retval;
    };

    auto_ptr<log_format> specialized()
    {
        auto_ptr<log_format> retval((log_format *)new glog_log_format(*this));

        return retval;
    };
    void annotate(const std::string &line,
                  string_attrs_t &sa,
                  std::vector<logline_value> &values) const
    {
        pcre_context_static<30> pc;
        pcre_input pi(line);

        if (value_pattern().match(pc, pi)) {
            static struct {
                const char *          name;
                logline_value::kind_t kind;
            } columns[] = {
                { "micros",   logline_value::VALUE_INTEGER },
                { "thread",   logline_value::VALUE_TEXT    },
                { "src_file", logline_value::VALUE_TEXT    },
                { "src_line", logline_value::VALUE_TEXT    },
                { "message",  logline_value::VALUE_TEXT    },

                { NULL }
            };

            pcre_context::iterator iter;
            struct line_range      lr;

            lr.lr_start = 1;
            lr.lr_end   = 21;
            sa[lr].insert(make_string_attr("timestamp", 0));

            iter        = pc.begin() + 4;
            lr.lr_start = 0;
            lr.lr_end   = iter->c_begin;
            sa[lr].insert(make_string_attr("prefix", 0));

            lr.lr_start = iter->c_begin;
            lr.lr_end   = line.length();
            sa[lr].insert(make_string_attr("body", 0));

            for (int lpc = 0; columns[lpc].name; lpc++) {
                if (columns[lpc].name[0] == '\0') {
                    continue;
                }
                values.push_back(logline_value(columns[lpc].name,
                                               columns[lpc].kind,
                                               pi.get_substr(pc.begin() +
                                                             lpc)));
            }
        }
        else {
            fprintf(stderr, "bad match! %s\n", line.c_str());
        }
    };
};

log_format::register_root_format<glog_log_format> glog_instance;

class strace_log_format : public log_format {
    static pcrepp &value_pattern(void)
    {
        static pcrepp VALUE_PATTERN(
            "[0-9:.]* ([a-zA-Z_][a-zA-Z_0-9]*)\\("
            "(.*)\\)"
            "\\s+= ([-xa-fA-F\\d\\?]+).*(?:<(\\d+\\.\\d+)>)?");

        return VALUE_PATTERN;
    };

    string get_name() { return "strace_log"; };

    bool scan(vector<logline> &dst,
              off_t offset,
              char *prefix,
              int len)
    {
        static const char *log_fmt[] = {
            "%63[0-9:].%d",
            NULL
        };

        static const char *time_fmt[] = {
            "%H:%M:%S",
            NULL
        };

        bool      retval = false;
        struct tm log_time;
        char      timestr[64];
        time_t    line_time;
        int       usecs;

        if (this->log_scanf(prefix,
                            log_fmt,
                            2,
                            time_fmt,
                            timestr,
                            &log_time,
                            line_time,

                            timestr,
                            &usecs)) {
            logline::level_t level = logline::LEVEL_UNKNOWN;
            const char *     eq;

            if ((eq = strrchr(prefix, '=')) != NULL) {
                int rc;

                if (sscanf(eq, "= %d", &rc) == 1 && rc < 0) {
                    level = logline::LEVEL_ERROR;
                }
            }

            if (!dst.empty() && (line_time < dst.back().get_time())) {
                line_time += (24 * 60 * 60);
            }
            dst.push_back(logline(offset,
                                  line_time,
                                  usecs / 1000,
                                  level));
            retval = true;
        }

        return retval;
    };

    auto_ptr<log_format> specialized()
    {
        auto_ptr<log_format> retval((log_format *)
                                    new strace_log_format(*this));

        return retval;
    };

    void annotate(const std::string &line,
                  string_attrs_t &sa,
                  std::vector<logline_value> &values) const
    {
        pcre_context_static<30> pc;
        pcre_input pi(line);

        if (value_pattern().match(pc, pi)) {
            static struct {
                const char *          name;
                logline_value::kind_t kind;
            } columns[] = {
                { "funcname", logline_value::VALUE_TEXT },
                { "args",     logline_value::VALUE_TEXT },
                { "result",   logline_value::VALUE_TEXT },
                { "duration", logline_value::VALUE_TEXT },

                { NULL },
            };

            pcre_context::iterator iter;
            struct line_range      lr;

            iter        = pc.begin() + 3;
            lr.lr_start = iter->c_begin;
            lr.lr_end   = iter->c_end;
            sa[lr].insert(make_string_attr("timestamp", 0));

            lr.lr_start = 0;
            lr.lr_end   = line.length();
            sa[lr].insert(make_string_attr("prefix", 0));

            lr.lr_start = line.length();
            lr.lr_end   = line.length();
            sa[lr].insert(make_string_attr("body", 0));

            for (int lpc = 0; columns[lpc].name; lpc++) {
                if (columns[lpc].name[0] == '\0') {
                    continue;
                }
                values.push_back(logline_value(columns[lpc].name,
                                               columns[lpc].kind,
                                               pi.get_substr(pc.begin() +
                                                             lpc)));
            }
        }
        else {
            fprintf(stderr, "bad match! %s\n", line.c_str());
        }
    };
};

log_format::register_root_format<strace_log_format> strace_log_instance;