// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you 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/http_channel.h"

#include <absl/strings/str_split.h>

#include <event2/buffer.h>

#include <event2/bufferevent.h>

#include <event2/http.h>

#include <event2/http_struct.h>

#include <sstream>

#include <string>

#include <vector>

#include "common/logging.h"

#include "common/status.h"

#include "http/http_headers.h"

#include "http/http_request.h"

#include "http/http_status.h"

#include "util/slice.h"

#include "util/zlib.h"

namespace doris {

// Send Unauthorized status with basic challenge

void HttpChannel::send_basic_challenge(HttpRequest* req, const std::string& realm) {

    static std::string s_prompt_str = "Please provide your userid and password\n";

    std::stringstream ss;

    ss << "Basic realm=\"" << realm << "\"";

    req->add_output_header(HttpHeaders::WWW_AUTHENTICATE, ss.str().c_str());

    send_reply(req, HttpStatus::UNAUTHORIZED, s_prompt_str);

}

void HttpChannel::send_error(HttpRequest* request, HttpStatus status) {

    evhttp_send_error(request->get_evhttp_request(), status, default_reason(status).c_str());

}

void HttpChannel::send_reply(HttpRequest* request, HttpStatus status) {

    evhttp_send_reply(request->get_evhttp_request(), status, default_reason(status).c_str(),

                      nullptr);

}

void HttpChannel::send_reply(HttpRequest* request, HttpStatus status, const std::string& content) {

    auto* evb = evbuffer_new();

    std::string compressed_content;

    if (compress_content(request->header(HttpHeaders::ACCEPT_ENCODING), content,

                         &compressed_content)) {

        request->add_output_header(HttpHeaders::CONTENT_ENCODING, "gzip");

        evbuffer_add(evb, compressed_content.c_str(), compressed_content.size());

    } else {

        evbuffer_add(evb, content.c_str(), content.size());

    }

    evhttp_send_reply(request->get_evhttp_request(), status, default_reason(status).c_str(), evb);

    evbuffer_free(evb);

}

void HttpChannel::send_file(HttpRequest* request, int fd, size_t off, size_t size,

                            bufferevent_rate_limit_group* rate_limit_group) {

    auto* evb = evbuffer_new();

    evbuffer_add_file(evb, fd, off, size);

    auto* evhttp_request = request->get_evhttp_request();

    if (rate_limit_group) {

        auto* evhttp_connection = evhttp_request_get_connection(evhttp_request);

        auto* buffer_event = evhttp_connection_get_bufferevent(evhttp_connection);

        bufferevent_add_to_rate_limit_group(buffer_event, rate_limit_group);

    }

    evhttp_send_reply(evhttp_request, HttpStatus::OK, default_reason(HttpStatus::OK).c_str(), evb);

    evbuffer_free(evb);

}

void HttpChannel::send_files(HttpRequest* request, const std::string& root_dir,

                             std::vector<std::string> local_files,

                             bufferevent_rate_limit_group* rate_limit_group) {

    if (rate_limit_group) {

        auto* evhttp_request = request->get_evhttp_request();

        auto* evhttp_connection = evhttp_request_get_connection(evhttp_request);

        auto* buffer_event = evhttp_connection_get_bufferevent(evhttp_connection);

        bufferevent_add_to_rate_limit_group(buffer_event, rate_limit_group);

    }

    send_files(request, root_dir, std::move(local_files));

}

void HttpChannel::send_files(HttpRequest* request, const std::string& root_dir,

                             std::vector<std::string> local_files) {

    std::unique_ptr<evbuffer, decltype(&evbuffer_free)> evb(evbuffer_new(), &evbuffer_free);

    for (const std::string& file : local_files) {

        std::string file_path = fmt::format("{}/{}", root_dir, file);

        int fd = open(file_path.c_str(), O_RDONLY);

        if (fd < 0) {

            std::string error_msg = "Failed to open file: " + file_path;

            LOG(WARNING) << "http channel send files: " << error_msg;

            HttpChannel::send_reply(request, HttpStatus::NOT_FOUND, error_msg);

            return;

        }

        struct stat st;

        auto res = fstat(fd, &st);

        if (res < 0) {

            close(fd);

            std::string error_msg = "Failed to open file: " + file_path;

            LOG(WARNING) << "http channel send files: " << error_msg;

            HttpChannel::send_reply(request, HttpStatus::NOT_FOUND, error_msg);

            return;

        }

        int64_t file_size = st.st_size;

        VLOG_DEBUG << "http channel send file " << file_path << ", size: " << file_size;

        evbuffer_add_printf(evb.get(), "File-Name: %s\r\n", file.c_str());

        evbuffer_add_printf(evb.get(), "Content-Length: %" PRIi64 "\r\n", file_size);

        evbuffer_add_printf(evb.get(), "\r\n");

        if (file_size > 0) {

            evbuffer_add_file(evb.get(), fd, 0, file_size);

        }

    }

    evhttp_send_reply(request->get_evhttp_request(), HttpStatus::OK,

                      default_reason(HttpStatus::OK).c_str(), evb.get());

}

bool HttpChannel::compress_content(const std::string& accept_encoding, const std::string& input,

                                   std::string* output) {

    // Don't bother compressing empty content.

    if (input.empty()) {

        return false;

    }

    // Check if gzip compression is accepted by the caller. If so, compress the

    // content and replace the prerendered output.

    bool is_compressed = false;

    std::vector<std::string> encodings = absl::StrSplit(accept_encoding, ",");

    for (auto& encoding : encodings) {

        absl::StripAsciiWhitespace(&encoding);

        if (encoding == "gzip") {

            std::ostringstream oss;

            Status s = zlib::CompressLevel(Slice(input), 1, &oss);

            if (s.ok()) {

                *output = oss.str();

                is_compressed = true;

            } else {

                LOG(WARNING) << "Could not compress output: " << s.to_string();

            }

            break;

        }

    }

    return is_compressed;

}

} // namespace doris