/**
 * Copyright (c) 2013, 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_loader.cc
 */

#include "config.h"

#include <errno.h>
#include <fcntl.h>
#include <glob.h>

#include <map>
#include <string>

#include "yajlpp.hh"
#include "lnav_config.hh"
#include "log_format.hh"
#include "auto_fd.hh"
#include "format-text-files.hh"
#include "default-log-formats-json.hh"

#ifndef SYSCONFDIR
#define SYSCONFDIR "/usr/etc"
#endif

using namespace std;

static map<string, external_log_format *> LOG_FORMATS;

static external_log_format *ensure_format(yajlpp_parse_context *ypc)
{
    const string &name = ypc->get_path_fragment(0);
    external_log_format *retval;

    retval = LOG_FORMATS[name];
    if (retval == NULL) {
        LOG_FORMATS[name] = retval = new external_log_format(name);
    }
    retval->elf_source_path.insert(ypc->ypc_source.substr(0, ypc->ypc_source.rfind('/')));

    return retval;
}

static int read_format_regex(yajlpp_parse_context *ypc, const unsigned char *str, size_t len)
{
    external_log_format *elf = ensure_format(ypc);
    string regex_name = ypc->get_path_fragment(2);
    string value = string((const char *)str, len);

    log_debug("regex: %s", value.c_str());
    elf->elf_patterns[regex_name].p_string = value;

    return 1;
}

static int read_format_bool(yajlpp_parse_context *ypc, int val)
{
    external_log_format *elf = ensure_format(ypc);
    string field_name = ypc->get_path_fragment(1);

    if (field_name == "convert-to-local-time")
        elf->lf_date_time.dts_local_time = val;
    else if (field_name == "json")
        elf->jlf_json = val;

    return 1;
}

static int read_format_double(yajlpp_parse_context *ypc, double val)
{
    external_log_format *elf = ensure_format(ypc);
    string field_name = ypc->get_path_fragment(1);

    if (field_name == "timestamp-divisor") {
        if (val <= 0) {
            fprintf(stderr, "error:%s: timestamp-divisor cannot be less "
                "than or equal to zero\n",
                ypc->get_path_fragment(0).c_str());
            return 0;
        }
        elf->elf_timestamp_divisor = val;
    }

    return 1;
}

static int read_format_int(yajlpp_parse_context *ypc, long long val)
{
    external_log_format *elf = ensure_format(ypc);
    string field_name = ypc->get_path_fragment(1);

    if (field_name == "timestamp-divisor") {
        if (val <= 0) {
            fprintf(stderr, "error:%s: timestamp-divisor cannot be less "
                "than or equal to zero\n",
                ypc->get_path_fragment(0).c_str());
            return 0;
        }
        elf->elf_timestamp_divisor = val;
    }

    return 1;
}

static int read_format_field(yajlpp_parse_context *ypc, const unsigned char *str, size_t len)
{
    external_log_format *elf = ensure_format(ypc);
    string value = string((const char *)str, len);
    string field_name = ypc->get_path_fragment(1);

    if (field_name == "file-pattern")
        elf->elf_file_pattern = value;
    else if (field_name == "level-field")
        elf->elf_level_field = value;
    else if (field_name == "timestamp-field")
        elf->lf_timestamp_field = value;
    else if (field_name == "body-field")
        elf->elf_body_field = value;

    return 1;
}

static int read_levels(yajlpp_parse_context *ypc, const unsigned char *str, size_t len)
{
    external_log_format *elf = ensure_format(ypc);
    string regex = string((const char *)str, len);
    logline::level_t level = logline::string2level(ypc->get_path_fragment(2).c_str());

    elf->elf_level_patterns[level].lp_regex = regex;

    return 1;
}

static int read_value_def(yajlpp_parse_context *ypc, const unsigned char *str, size_t len)
{
    external_log_format *elf = ensure_format(ypc);
    string value_name = ypc->get_path_fragment(2);
    string field_name = ypc->get_path_fragment(3);
    string val = string((const char *)str, len);

    elf->elf_value_defs[value_name].vd_name = value_name;
    if (field_name == "kind") {
        logline_value::kind_t kind;

        if ((kind = logline_value::string2kind(val.c_str())) ==
            logline_value::VALUE_UNKNOWN) {
            fprintf(stderr, "error: unknown value kind %s\n", val.c_str());
            return 0;
        }
        elf->elf_value_defs[value_name].vd_kind = kind;
    }
    else if (field_name == "unit" && ypc->get_path_fragment(4) == "field") {
        elf->elf_value_defs[value_name].vd_unit_field = val;
    }
    else if (field_name == "collate") {
        elf->elf_value_defs[value_name].vd_collate = val;
    }

    return 1;
}

static int read_value_action(yajlpp_parse_context *ypc, const unsigned char *str, size_t len)
{
    external_log_format *elf = ensure_format(ypc);
    string value_name = ypc->get_path_fragment(2);
    string field_name = ypc->get_path_fragment(3);
    string val = string((const char *)str, len);

    elf->elf_value_defs[value_name].vd_action_list.push_back(val);

    return 1;
}

static int read_value_bool(yajlpp_parse_context *ypc, int val)
{
    external_log_format *elf = ensure_format(ypc);
    string value_name = ypc->get_path_fragment(2);
    string key_name = ypc->get_path_fragment(3);

    if (key_name == "identifier")
        elf->elf_value_defs[value_name].vd_identifier = val;
    else if (key_name == "foreign-key")
        elf->elf_value_defs[value_name].vd_foreign_key = val;
    else if (key_name == "hidden")
        elf->elf_value_defs[value_name].vd_hidden = val;

    return 1;
}

static int read_action_def(yajlpp_parse_context *ypc, const unsigned char *str, size_t len)
{
    external_log_format *elf = ensure_format(ypc);
    string action_name = ypc->get_path_fragment(2);
    string field_name = ypc->get_path_fragment(3);
    string val = string((const char *)str, len);

    elf->lf_action_defs[action_name].ad_name = action_name;
    if (field_name == "label")
        elf->lf_action_defs[action_name].ad_label = val;

    return 1;
}

static int read_action_bool(yajlpp_parse_context *ypc, int val)
{
    external_log_format *elf = ensure_format(ypc);
    string action_name = ypc->get_path_fragment(2);
    string field_name = ypc->get_path_fragment(3);

    elf->lf_action_defs[action_name].ad_capture_output = val;

    return 1;
}

static int read_action_cmd(yajlpp_parse_context *ypc, const unsigned char *str, size_t len)
{
    external_log_format *elf = ensure_format(ypc);
    string action_name = ypc->get_path_fragment(2);
    string field_name = ypc->get_path_fragment(3);
    string val = string((const char *)str, len);

    elf->lf_action_defs[action_name].ad_name = action_name;
    elf->lf_action_defs[action_name].ad_cmdline.push_back(val);

    return 1;
}

static external_log_format::sample &ensure_sample(external_log_format *elf,
                                                  int index)
{
    elf->elf_samples.resize(index + 1);

    return elf->elf_samples[index];
}

static int read_scaling(yajlpp_parse_context *ypc, double val)
{
    external_log_format *elf = ensure_format(ypc);
    string value_name = ypc->get_path_fragment(2);
    string scale_name = ypc->get_path_fragment(5);

    if (scale_name.empty()) {
        fprintf(stderr,
                "error:%s:%s: scaling factor field cannot be empty\n",
                ypc->get_path_fragment(0).c_str(),
                value_name.c_str());
        return 0;
    }

    struct scaling_factor &sf = elf->elf_value_defs[value_name].vd_unit_scaling[scale_name.substr(1)];

    if (scale_name[0] == '/') {
        sf.sf_op = SO_DIVIDE;
    }
    else if (scale_name[0] == '*') {
        sf.sf_op = SO_MULTIPLY;
    }
    else {
        fprintf(stderr,
                "error:%s:%s: scaling factor field must start with '/' or '*'\n",
                ypc->get_path_fragment(0).c_str(),
                value_name.c_str());
        return 0;
    }

    sf.sf_value = val;

    return 1;
}

static int read_sample_line(yajlpp_parse_context *ypc, const unsigned char *str, size_t len)
{
    external_log_format *elf = ensure_format(ypc);
    string val = string((const char *)str, len);
    int index = ypc->ypc_array_index.back();
    external_log_format::sample &sample = ensure_sample(elf, index);

    sample.s_line = val;

    return 1;
}

static external_log_format::json_format_element &
    ensure_json_format_element(external_log_format *elf, int index)
{
    elf->jlf_line_format.resize(index + 1);

    return elf->jlf_line_format[index];
}

static int read_json_constant(yajlpp_parse_context *ypc, const unsigned char *str, size_t len)
{
    external_log_format *elf = ensure_format(ypc);
    string val = string((const char *)str, len);

    ypc->ypc_array_index.back() += 1;

    int index = ypc->ypc_array_index.back();
    external_log_format::json_format_element &jfe = ensure_json_format_element(elf, index);

    jfe.jfe_type = external_log_format::JLF_CONSTANT;
    jfe.jfe_default_value = val;

    return 1;
}

static int read_json_variable(yajlpp_parse_context *ypc, const unsigned char *str, size_t len)
{
    external_log_format *elf = ensure_format(ypc);
    string val = string((const char *)str, len);
    int index = ypc->ypc_array_index.back();
    external_log_format::json_format_element &jfe = ensure_json_format_element(elf, index);
    string field_name = ypc->get_path_fragment(3);

    jfe.jfe_type = external_log_format::JLF_VARIABLE;
    if (field_name == "field")
        jfe.jfe_value = val;
    else if (field_name == "default-value")
        jfe.jfe_default_value = val;

    return 1;
}

static int read_json_variable_num(yajlpp_parse_context *ypc, long long val)
{
    external_log_format *elf = ensure_format(ypc);
    int index = ypc->ypc_array_index.back();
    external_log_format::json_format_element &jfe = ensure_json_format_element(elf, index);
    string field_name = ypc->get_path_fragment(2);

    jfe.jfe_type = external_log_format::JLF_VARIABLE;
    jfe.jfe_min_width = val;

    return 1;
}

static struct json_path_handler format_handlers[] = {
    json_path_handler("^/\\w+/regex/[^/]+/pattern$", read_format_regex),
    json_path_handler("^/\\w+/(json|convert-to-local-time)$", read_format_bool),
    json_path_handler("^/\\w+/timestamp-divisor$", read_format_double)
        .add_cb(read_format_int),
    json_path_handler("^/\\w+/(file-pattern|level-field|timestamp-field|body-field|url|url#|title|description)$",
                      read_format_field),
    json_path_handler("^/\\w+/level/"
                      "(trace|debug|info|warning|error|critical|fatal)$",
                      read_levels),
    json_path_handler("^/\\w+/value/\\w+/(kind|collate|unit/field)$", read_value_def),
    json_path_handler("^/\\w+/value/\\w+/(identifier|foreign-key|hidden)$", read_value_bool),
    json_path_handler("^/\\w+/value/\\w+/unit/scaling-factor/.*$",
        read_scaling),
    json_path_handler("^/\\w+/value/\\w+/action-list#", read_value_action),
    json_path_handler("^/\\w+/action/\\w+/label", read_action_def),
    json_path_handler("^/\\w+/action/\\w+/capture-output", read_action_bool),
    json_path_handler("^/\\w+/action/\\w+/cmd#", read_action_cmd),
    json_path_handler("^/\\w+/sample#/line$", read_sample_line),
    json_path_handler("^/\\w+/line-format#/(field|default-value)$", read_json_variable),
    json_path_handler("^/\\w+/line-format#/min-width$", read_json_variable_num),
    json_path_handler("^/\\w+/line-format#$", read_json_constant),

    json_path_handler()
};

static void write_sample_file(void)
{
    string sample_path = dotlnav_path("formats/default/default-formats.json.sample");
    auto_fd sample_fd;

    if ((sample_fd = open(sample_path.c_str(),
                          O_WRONLY|O_TRUNC|O_CREAT,
                          0644)) == -1) {
        perror("error: unable to write default format file");
    }
    else {
        write(sample_fd.get(),
              default_log_formats_json,
              strlen(default_log_formats_json));
    }

    string sh_path = dotlnav_path("formats/default/dump-pid.sh");
    auto_fd sh_fd;

    if ((sh_fd = open(sh_path.c_str(), O_WRONLY|O_TRUNC|O_CREAT, 0755)) == -1) {
        perror("error: unable to write default text file");
    }
    else {
        write(sh_fd.get(), dump_pid_sh, strlen(dump_pid_sh));
    }
}

static void load_from_path(const string &path, std::vector<string> &errors)
{
    string format_path = path + "/formats/*/*.json";
    static_root_mem<glob_t, globfree> gl;
    yajl_handle handle;

    log_info("loading formats from path: %s", format_path.c_str());
    if (glob(format_path.c_str(), 0, NULL, gl.inout()) == 0) {
        for (int lpc = 0; lpc < (int)gl->gl_pathc; lpc++) {
            string filename(gl->gl_pathv[lpc]);
            auto_fd fd;

            log_info("loading formats from file: %s", filename.c_str());
            yajlpp_parse_context ypc(filename, format_handlers);
            if ((fd = open(gl->gl_pathv[lpc], O_RDONLY)) == -1) {
                char errmsg[1024];

                snprintf(errmsg, sizeof(errmsg),
                         "error: unable to open format file -- %s",
                         gl->gl_pathv[lpc]);
                perror(errmsg);
            }
            else {
                char buffer[2048];
                int rc = -1;

                handle = yajl_alloc(&ypc.ypc_callbacks, NULL, &ypc);
                while (true) {
                    rc = read(fd, buffer, sizeof(buffer));
                    if (rc == 0) {
                        break;
                    }
                    else if (rc == -1) {
                        errors.push_back(filename +
                                         ":unable to read file -- " +
                                         string(strerror(errno)));
                        break;
                    }
                    if (yajl_parse(handle, (const unsigned char *)buffer, rc) != yajl_status_ok) {
                        errors.push_back(filename +
                            ": invalid json -- " +
                            string((char *)yajl_get_error(handle, 1, (unsigned char *)buffer, rc)));
                        break;
                    }
                }
                if (rc == 0) {
                    if (yajl_complete_parse(handle) != yajl_status_ok) {
                        errors.push_back(filename +
                            ": invalid json -- " +
                            string((char *)yajl_get_error(handle, 0, NULL, 0)));
                    }
                }
                yajl_free(handle);
            }
        }
    }
}

void load_formats(const std::vector<std::string> &extra_paths,
                  std::vector<std::string> &errors)
{
    string default_source = string(dotlnav_path("formats") + "/default/");
    yajlpp_parse_context ypc_builtin(default_source, format_handlers);
    std::vector<std::string> retval;
    yajl_handle handle;

    write_sample_file();

    handle = yajl_alloc(&ypc_builtin.ypc_callbacks, NULL, &ypc_builtin);
    if (yajl_parse(handle,
                   (const unsigned char *)default_log_formats_json,
                   strlen(default_log_formats_json)) != yajl_status_ok) {
        errors.push_back("builtin: invalid json -- " +
            string((char *)yajl_get_error(handle, 1, (unsigned char *)default_log_formats_json, strlen(default_log_formats_json))));
    }
    yajl_complete_parse(handle);
    yajl_free(handle);

    load_from_path("/etc/lnav", errors);
    load_from_path(SYSCONFDIR "/lnav", errors);
    load_from_path(dotlnav_path(""), errors);

    for (vector<string>::const_iterator path_iter = extra_paths.begin();
         path_iter != extra_paths.end();
         ++path_iter) {
        load_from_path(*path_iter, errors);
    }

    for (map<string, external_log_format *>::iterator iter = LOG_FORMATS.begin();
         iter != LOG_FORMATS.end();
         ++iter) {
        iter->second->build(errors);

        if (errors.empty()) {
            log_format::get_root_formats().insert(log_format::get_root_formats().begin(), iter->second);
        }
    }
}