// Copyright (c) 2017, Baidu.com, Inc. All Rights Reserved

// 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 "http/default_path_handlers.h"

#include <sstream>
#include <fstream>
#include <sys/stat.h>
#include <boost/algorithm/string.hpp>
#include <boost/bind.hpp>
#include <gperftools/malloc_extension.h>

#include "common/logging.h"
#include "runtime/mem_tracker.h"
#include "util/debug_util.h"
#include "util/logging.h"
#include "http/web_page_handler.h"

namespace palo {

// Writes the last config::web_log_bytes of the INFO logfile to a webpage
// Note to get best performance, set GLOG_logbuflevel=-1 to prevent log buffering
void logs_handler(const WebPageHandler::ArgumentMap& args, std::stringstream* output) {
    /*std::string logfile;
    get_full_log_filename(google::INFO, &logfile);
    (*output) << "<h2>INFO logs</h2>" << std::endl;
    (*output) << "Log path is: " << logfile << std::endl;

    struct stat file_stat;

    if (stat(logfile.c_str(), &file_stat) == 0) {
        long size = file_stat.st_size;
        long seekpos = size < config::web_log_bytes ? 0L : size - config::web_log_bytes;
        std::ifstream log(logfile.c_str(), std::ios::in);
        // Note if the file rolls between stat and seek, this could fail
        // (and we could wind up reading the whole file). But because the
        // file is likely to be small, this is unlikely to be an issue in
        // practice.
        log.seekg(seekpos);
        (*output) << "<br/>Showing last " << config::web_log_bytes << " bytes of log" << std::endl;
        (*output) << "<br/><pre>" << log.rdbuf() << "</pre>";

    } else {
        (*output) << "<br/>Couldn't open INFO log file: " << logfile;
    }*/

    (*output) << "<br/>Couldn't open INFO log file: ";


}

// Registered to handle "/flags", and prints out all command-line flags and their values
void config_handler(const WebPageHandler::ArgumentMap& args, std::stringstream* output) {
    (*output) << "<h2>Command-line Flags</h2>";
    // (*output) << "<pre>" << google::CommandlineFlagsIntoString() << "</pre>";
}

// Registered to handle "/memz", and prints out memory allocation statistics.
void mem_usage_handler(MemTracker* mem_tracker, const WebPageHandler::ArgumentMap& args,
                     std::stringstream* output) {
    if (mem_tracker != NULL) {
        (*output) << "<pre>"
                  << "Mem Limit: "
                  << PrettyPrinter::print(mem_tracker->limit(), TUnit::BYTES)
                  << std::endl
                  << "Mem Consumption: "
                  << PrettyPrinter::print(mem_tracker->consumption(), TUnit::BYTES)
                  << std::endl
                  << "</pre>";
    } else {
        (*output) << "<pre>"
                  << "No process memory limit set."
                  << "</pre>";
    }

    (*output) << "<pre>";
#ifdef ADDRESS_SANITIZER
    (*output) << "Memory tracking is not available with address sanitizer builds.";
#else
    char buf[2048];
    MallocExtension::instance()->GetStats(buf, 2048);
    // Replace new lines with <br> for html
    std::string tmp(buf);
    boost::replace_all(tmp, "\n", "<br>");
    (*output) << tmp << "</pre>";
#endif
}

void add_default_path_handlers(WebPageHandler* web_page_handler, MemTracker* process_mem_tracker) {
    web_page_handler->register_page("/logs", logs_handler);
    web_page_handler->register_page("/varz", config_handler);
    web_page_handler->register_page(
            "/memz",
            boost::bind<void>(&mem_usage_handler, process_mem_tracker, _1, _2));
}

}