// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/tools/quic/quic_in_memory_cache.h"

#include "base/files/file_enumerator.h"
#include "base/files/file_util.h"
#include "base/stl_util.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "net/http/http_response_headers.h"
#include "net/http/http_util.h"
#include "net/spdy/spdy_http_utils.h"

using base::FilePath;
using base::IntToString;
using base::StringPiece;
using std::string;

namespace net {
namespace tools {

QuicInMemoryCache::Response::Response() : response_type_(REGULAR_RESPONSE) {}

QuicInMemoryCache::Response::~Response() {}

// static
QuicInMemoryCache* QuicInMemoryCache::GetInstance() {
  return Singleton<QuicInMemoryCache>::get();
}

const QuicInMemoryCache::Response* QuicInMemoryCache::GetResponse(
    StringPiece host,
    StringPiece path) const {
  ResponseMap::const_iterator it = responses_.find(GetKey(host, path));
  if (it == responses_.end()) {
    return nullptr;
  }
  return it->second;
}

void QuicInMemoryCache::AddSimpleResponse(StringPiece host,
                                          StringPiece path,
                                          int response_code,
                                          StringPiece response_detail,
                                          StringPiece body) {
  SpdyHeaderBlock response_headers;
  response_headers[":version"] = "HTTP/1.1";
  string status = IntToString(response_code) + " ";
  response_detail.AppendToString(&status);
  response_headers[":status"] = status;
  response_headers["content-length"] =
      IntToString(static_cast<int>(body.length()));
  AddResponse(host, path, response_headers, body);
}

void QuicInMemoryCache::AddResponse(StringPiece host,
                                    StringPiece path,
                                    const SpdyHeaderBlock& response_headers,
                                    StringPiece response_body) {
  AddResponseImpl(host, path, REGULAR_RESPONSE, response_headers,
                  response_body);
}

void QuicInMemoryCache::AddSpecialResponse(StringPiece host,
                                           StringPiece path,
                                           SpecialResponseType response_type) {
  AddResponseImpl(host, path, response_type, SpdyHeaderBlock(), "");
}

QuicInMemoryCache::QuicInMemoryCache() {}

void QuicInMemoryCache::ResetForTests() {
  STLDeleteValues(&responses_);
}

void QuicInMemoryCache::InitializeFromDirectory(const string& cache_directory) {
  if (cache_directory.empty()) {
    LOG(DFATAL) << "cache_directory must not be empty.";
    return;
  }
  VLOG(1) << "Attempting to initialize QuicInMemoryCache from directory: "
          << cache_directory;
  FilePath directory(FilePath::FromUTF8Unsafe(cache_directory));
  base::FileEnumerator file_list(directory,
                                 true,
                                 base::FileEnumerator::FILES);

  for (FilePath file_iter = file_list.Next(); !file_iter.empty();
       file_iter = file_list.Next()) {
    // Need to skip files in .svn directories
    if (file_iter.value().find(FILE_PATH_LITERAL("/.svn/")) != string::npos) {
      continue;
    }

    // Tease apart filename into host and path.
    string file = file_iter.AsUTF8Unsafe();
    file.erase(0, cache_directory.length());
    if (file[0] == '/') {
      file.erase(0, 1);
    }

    string file_contents;
    base::ReadFileToString(file_iter, &file_contents);
    int file_len = static_cast<int>(file_contents.length());
    int headers_end = HttpUtil::LocateEndOfHeaders(file_contents.data(),
                                                   file_len);
    if (headers_end < 1) {
      LOG(DFATAL) << "Headers invalid or empty, ignoring: " << file;
      continue;
    }

    string raw_headers =
        HttpUtil::AssembleRawHeaders(file_contents.data(), headers_end);

    scoped_refptr<HttpResponseHeaders> response_headers =
        new HttpResponseHeaders(raw_headers);

    string base;
    if (response_headers->GetNormalizedHeader("X-Original-Url", &base)) {
      response_headers->RemoveHeader("X-Original-Url");
      // Remove the protocol so we can add it below.
      if (StartsWithASCII(base, "https://", false)) {
        base = base.substr(8);
      } else if (StartsWithASCII(base, "http://", false)) {
        base = base.substr(7);
      }
    } else {
      base = file;
    }

    size_t path_start = base.find_first_of('/');
    StringPiece host(StringPiece(base).substr(0, path_start));
    StringPiece path(StringPiece(base).substr(path_start));
    if (path[path.length() - 1] == ',') {
      path.remove_suffix(1);
    }

    StringPiece body(file_contents.data() + headers_end,
                     file_contents.size() - headers_end);
    // QUIC_VERSION_24 and below use SPDY/3 headers, which includes the
    // status reason in :status, and "HTTP/1.1" in :version. Since this
    // format is a strict superset of SPDY/4 headers, the cache uses this
    // format to store response. Once SPDY/3 responses are no longer
    // required, the cache can store SPDY/4 headers.
    SpdyHeaderBlock header_block;
    CreateSpdyHeadersFromHttpResponse(*response_headers, SPDY3, &header_block);
    AddResponse(host, path, header_block, body);
  }
}

QuicInMemoryCache::~QuicInMemoryCache() {
  STLDeleteValues(&responses_);
}

void QuicInMemoryCache::AddResponseImpl(
    StringPiece host,
    StringPiece path,
    SpecialResponseType response_type,
    const SpdyHeaderBlock& response_headers,
    StringPiece response_body) {
  string key = GetKey(host, path);
  VLOG(1) << "Adding response for: " << key;
  if (ContainsKey(responses_, key)) {
    LOG(DFATAL) << "Response for '" << key << "' already exists!";
    return;
  }
  Response* new_response = new Response();
  new_response->set_response_type(response_type);
  new_response->set_headers(response_headers);
  new_response->set_body(response_body);
  responses_[key] = new_response;
}

string QuicInMemoryCache::GetKey(StringPiece host, StringPiece path) const {
  return host.as_string() + path.as_string();
}

}  // namespace tools
}  // namespace net