// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/ui/webui/new_tab_page/untrusted_source.h"

#include <numeric>
#include <optional>
#include <string>
#include <string_view>
#include <utility>

#include "base/base64.h"
#include "base/files/file_util.h"
#include "base/i18n/rtl.h"
#include "base/memory/ref_counted_memory.h"
#include "base/memory/scoped_refptr.h"
#include "base/strings/string_util.h"
#include "base/strings/string_view_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/to_string.h"
#include "base/strings/utf_string_conversions.h"
#include "base/task/task_traits.h"
#include "base/task/thread_pool.h"
#include "base/time/time.h"
#include "base/token.h"
#include "chrome/browser/new_tab_page/one_google_bar/one_google_bar_data.h"
#include "chrome/browser/new_tab_page/one_google_bar/one_google_bar_service_factory.h"
#include "chrome/browser/policy/chrome_policy_blocklist_service_factory.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/search/background/ntp_custom_background_service.h"
#include "chrome/browser/search/background/ntp_custom_background_service_factory.h"
#include "chrome/browser/ui/search/ntp_user_data_logger.h"
#include "chrome/common/url_constants.h"
#include "chrome/grit/new_tab_page_untrusted_resources.h"
#include "components/policy/core/browser/url_list/policy_blocklist_service.h"
#include "components/search/ntp_features.h"
#include "content/public/common/url_constants.h"
#include "net/base/url_util.h"
#include "services/network/public/mojom/content_security_policy.mojom.h"
#include "third_party/re2/src/re2/re2.h"
#include "third_party/skia/include/core/SkColor.h"
#include "ui/base/resource/resource_bundle.h"
#include "ui/base/template_expressions.h"
#include "url/url_util.h"

using URLBlocklistState = policy::URLBlocklist::URLBlocklistState;

namespace {

constexpr int kMaxUriDecodeLen = 2048;

std::string FormatTemplate(int resource_id,
                           const ui::TemplateReplacements& replacements) {
  ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
  scoped_refptr<base::RefCountedMemory> bytes =
      bundle.LoadDataResourceBytes(resource_id);
  return ui::ReplaceTemplateExpressions(
      base::as_string_view(*bytes), replacements,
      /* skip_unexpected_placeholder_check= */ true);
}

std::string ReadBackgroundImageData(const base::FilePath& path) {
  std::string data_string;
  base::ReadFileToString(path, &data_string);
  return data_string;
}

void ServeBackgroundImageData(content::URLDataSource::GotDataCallback callback,
                              std::string data_string) {
  std::move(callback).Run(
      base::MakeRefCounted<base::RefCountedString>(std::move(data_string)));
}

std::string AsyncParamDataAsCSV(
    const std::map<std::string, std::string>& param_data) {
  if (param_data.empty()) {
    return "";
  }

  std::string csv = std::accumulate(
      param_data.cbegin(), param_data.cend(), std::string(),
      [&](std::string acc, const std::pair<std::string, std::string>& param) {
        return acc + "," + param.first + ":" + param.second;
      });

  // Strip preceding comma and return value.
  return csv.substr(1);
}

// Validates that the background image path is either exactly "background.jpg"
// or a 32-character hex token followed by "background.jpg". This prevents
// directory traversal (crbug.com/497241148). The analogous serialization
// logic can be found in
// `NtpCustomBackgroundService::SetBackgroundToLocalResourceWithId()` and
// `WallpaperSearchBackgroundManager::SelectLocalBackgroundImage()`.
bool IsValidBackgroundImagePath(std::string_view path) {
  std::optional<std::string_view> prefix =
      base::RemoveSuffix(path, "background.jpg");
  if (!prefix) {
    return false;
  }
  return prefix->empty() || base::Token::FromString(*prefix).has_value();
}

std::map<std::string, std::string> ExtractQueryParams(
    std::string_view query_params) {
  std::map<std::string, std::string> params;
  url::Component query(query_params);
  url::Component key, value;
  while (url::ExtractQueryKeyValue(query_params, &query, &key, &value)) {
    url::UrlEscapeDecoder<kMaxUriDecodeLen> output(
        value.AsViewOn(query_params), url::DecodeUrlMode::kUtf8OrIsomorphic);
    params.insert({std::string(key.AsViewOn(query_params)),
                   base::UTF16ToUTF8(output.view())});
  }

  return params;
}

}  // namespace

UntrustedSource::UntrustedSource(Profile* profile)
    : one_google_bar_service_(
          OneGoogleBarServiceFactory::GetForProfile(profile)),
      profile_(profile) {
  // |one_google_bar_service_| is null in incognito, or when the feature is
  // disabled.
  if (one_google_bar_service_) {
    one_google_bar_service_observation_.Observe(one_google_bar_service_.get());
  }
}

UntrustedSource::~UntrustedSource() = default;

std::string UntrustedSource::GetContentSecurityPolicy(
    network::mojom::CSPDirectiveName directive) {
  switch (directive) {
    case network::mojom::CSPDirectiveName::ScriptSrc:
      return "script-src 'self' 'unsafe-inline' https:;";
    case network::mojom::CSPDirectiveName::ChildSrc:
      return "child-src https:;";
    case network::mojom::CSPDirectiveName::DefaultSrc:
      // TODO(crbug.com/40693567): Audit and tighten CSP.
      return std::string();
    case network::mojom::CSPDirectiveName::FrameAncestors:
      return base::StringPrintf("frame-ancestors %s",
                                chrome::kChromeUINewTabPageURL);
    case network::mojom::CSPDirectiveName::RequireTrustedTypesFor:
      return std::string();
    case network::mojom::CSPDirectiveName::TrustedTypes:
      return std::string();
    case network::mojom::CSPDirectiveName::FormAction:
      return "form-action https://ogs.google.com https://*.corp.google.com;";
    default:
      return content::URLDataSource::GetContentSecurityPolicy(directive);
  }
}

std::string UntrustedSource::GetSource() {
  return chrome::kChromeUIUntrustedNewTabPageUrl;
}

void UntrustedSource::StartDataRequest(
    const GURL& url,
    const content::WebContents::Getter& wc_getter,
    content::URLDataSource::GotDataCallback callback) {
  GURL url_param = GURL(url.GetQuery());
  if (url_param.is_valid() && IsURLBlockedByPolicy(url_param)) {
    std::move(callback).Run(base::MakeRefCounted<base::RefCountedString>());
    return;
  }
  const std::string path = url.has_path() ? url.GetPath().substr(1) : "";
  if (path == "one-google-bar" && one_google_bar_service_) {
    std::map<std::string, std::string> params;

    std::string query_params;
    if (net::GetValueForKeyInQuery(url, "paramsencoded", &query_params)) {
      base::Base64Decode(query_params, &query_params);
      if (!query_params.empty() && query_params.starts_with("&")) {
        params = ExtractQueryParams(query_params.substr(1));
      }
    }

    if (params.find("async") == params.end()) {
      std::map<std::string, std::string> async_param_data;
      async_param_data["fixed"] = "0";

      bool async_bar_parts = base::FeatureList::IsEnabled(
          ntp_features::kNtpOneGoogleBarAsyncBarParts);
      if (async_bar_parts) {
        async_param_data["abp"] = "1";

        NtpCustomBackgroundService* ntp_custom_background_service =
            NtpCustomBackgroundServiceFactory::GetForProfile(profile_);
        if (ntp_custom_background_service &&
            ntp_custom_background_service->GetCustomBackground()) {
          async_param_data["dark"] = "1";
        } else {
          content::WebContents* web_contents = wc_getter.Run();
          if (web_contents && web_contents->GetColorMode() ==
                                  ui::ColorProviderKey::ColorMode::kDark) {
            async_param_data["dark"] = "1";
          }
        }
      }

      params.insert({"async", AsyncParamDataAsCSV(async_param_data)});
    }

    one_google_bar_service_->SetAdditionalQueryParams(params);
    one_google_bar_callbacks_.push_back(std::move(callback));
    if (one_google_bar_callbacks_.size() == 1) {
      one_google_bar_load_start_time_ = base::TimeTicks::Now();
      one_google_bar_service_->Refresh();
    }
    return;
  }
  if (path == "one_google_bar.js") {
    ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
    std::move(callback).Run(bundle.LoadDataResourceBytes(
        IDR_NEW_TAB_PAGE_UNTRUSTED_ONE_GOOGLE_BAR_JS));
    return;
  }
  if (path == "one_google_bar_api.js") {
    ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
    std::move(callback).Run(bundle.LoadDataResourceBytes(
        IDR_NEW_TAB_PAGE_UNTRUSTED_ONE_GOOGLE_BAR_API_JS));
    return;
  }
  // TODO(romanarora): add support for one_google_bar_api.js?
  if (path == "image" && url_param.is_valid() &&
      (url_param.SchemeIs(url::kHttpsScheme) ||
       url_param.SchemeIs(content::kChromeUIUntrustedScheme))) {
    ui::TemplateReplacements replacements;
    replacements["url"] = url_param.spec();
    std::move(callback).Run(base::MakeRefCounted<base::RefCountedString>(
        FormatTemplate(IDR_NEW_TAB_PAGE_UNTRUSTED_IMAGE_HTML, replacements)));
    return;
  }
  if (path == "background_image") {
    ServeBackgroundImage(url_param, GURL(), "cover", "no-repeat", "no-repeat",
                         "center", "center", "inherit", std::move(callback));
    return;
  }
  if (path == "custom_background_image") {
    // Parse all query parameters to hash map and decode values.
    std::map<std::string, std::string> params = ExtractQueryParams(url.query());

    auto lookup_or_default = [&params](const std::string& key,
                                       absl::string_view default_value) {
      if (auto it = params.find(key); it != params.end()) {
        return std::string_view(it->second);
      }
      return default_value;
    };

    // Extract desired values.
    ServeBackgroundImage(GURL(lookup_or_default("url", "")),
                         GURL(lookup_or_default("url2x", "")),
                         lookup_or_default("size", "cover"),
                         lookup_or_default("repeatX", "no-repeat"),
                         lookup_or_default("repeatY", "no-repeat"),
                         lookup_or_default("positionX", "center"),
                         lookup_or_default("positionY", "center"),
                         lookup_or_default("scrimDisplay", "none"),
                         std::move(callback));
    return;
  }
  if (path == "background_image.js") {
    ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
    std::move(callback).Run(bundle.LoadDataResourceBytes(
        IDR_NEW_TAB_PAGE_UNTRUSTED_BACKGROUND_IMAGE_JS));
    return;
  }
  if (IsValidBackgroundImagePath(path)) {
    base::ThreadPool::PostTaskAndReplyWithResult(
        FROM_HERE, {base::TaskPriority::USER_VISIBLE, base::MayBlock()},
        base::BindOnce(&ReadBackgroundImageData,
                       profile_->GetPath().AppendASCII(path)),
        base::BindOnce(&ServeBackgroundImageData, std::move(callback)));
    return;
  }
  std::move(callback).Run(base::MakeRefCounted<base::RefCountedString>());
}

std::string UntrustedSource::GetMimeType(const GURL& url) {
  const std::string_view stripped_path = url.path();
  if (base::EndsWith(stripped_path, ".js",
                     base::CompareCase::INSENSITIVE_ASCII)) {
    return "application/javascript";
  }
  if (base::EndsWith(stripped_path, ".jpg",
                     base::CompareCase::INSENSITIVE_ASCII)) {
    return "image/jpg";
  }

  return "text/html";
}

bool UntrustedSource::AllowCaching() {
  return false;
}

bool UntrustedSource::ShouldReplaceExistingSource() {
  return false;
}

bool UntrustedSource::ShouldServeMimeTypeAsContentTypeHeader() {
  return true;
}

bool UntrustedSource::ShouldServiceRequest(
    const GURL& url,
    content::BrowserContext* browser_context,
    int render_process_id) {
  if (!url.SchemeIs(content::kChromeUIUntrustedScheme) || !url.has_path()) {
    return false;
  }
  const std::string path = url.GetPath().substr(1);
  return path == "one-google-bar" || path == "one_google_bar.js" ||
         path == "one_google_bar_api.js" || path == "image" ||
         path == "background_image" || path == "custom_background_image" ||
         path == "background_image.js" || IsValidBackgroundImagePath(path);
}

void UntrustedSource::OnOneGoogleBarDataUpdated() {
  std::optional<OneGoogleBarData> data =
      one_google_bar_service_->one_google_bar_data();

  if (one_google_bar_load_start_time_.has_value()) {
    NTPUserDataLogger::LogOneGoogleBarFetchDuration(
        /*success=*/data.has_value(),
        /*duration=*/base::TimeTicks::Now() - *one_google_bar_load_start_time_);
    one_google_bar_load_start_time_ = std::nullopt;
  }

  std::string html;
  if (data.has_value()) {
    ui::TemplateReplacements replacements;
    replacements["textdirection"] = base::i18n::IsRTL() ? "rtl" : "ltr";
    replacements["barHtml"] = data->bar_html;
    replacements["varsHeadScript"] = base::StringPrintf(
        "let abp = %s;", base::ToString(base::FeatureList::IsEnabled(
                             ntp_features::kNtpOneGoogleBarAsyncBarParts)));
    replacements["inHeadScript"] = data->in_head_script;
    replacements["inHeadStyle"] = data->in_head_style;
    replacements["afterBarScript"] = data->after_bar_script;
    replacements["endOfBodyHtml"] = data->end_of_body_html;
    replacements["endOfBodyScript"] = data->end_of_body_script;

    html = FormatTemplate(IDR_NEW_TAB_PAGE_UNTRUSTED_ONE_GOOGLE_BAR_HTML,
                          replacements);
  }

  auto html_ref_counted =
      base::MakeRefCounted<base::RefCountedString>(std::move(html));
  for (auto& callback : one_google_bar_callbacks_) {
    std::move(callback).Run(html_ref_counted);
  }
  one_google_bar_callbacks_.clear();
}

void UntrustedSource::OnOneGoogleBarServiceShuttingDown() {
  one_google_bar_service_observation_.Reset();
  one_google_bar_service_ = nullptr;
}

void UntrustedSource::ServeBackgroundImage(
    const GURL& url,
    const GURL& url_2x,
    std::string_view size,
    std::string_view repeat_x,
    std::string_view repeat_y,
    std::string_view position_x,
    std::string_view position_y,
    std::string_view scrim_display,
    content::URLDataSource::GotDataCallback callback) {
  if (!IsURLAllowed(url)) {
    std::move(callback).Run(base::MakeRefCounted<base::RefCountedString>());
    return;
  }
  ui::TemplateReplacements replacements;
  replacements["url"] = url.spec();
  if (IsURLAllowed(url_2x)) {
    replacements["backgroundUrl"] =
        base::StringPrintf("image-set(url(%s) 1x, url(%s) 2x)",
                           url.spec().c_str(), url_2x.spec().c_str());
  } else {
    replacements["backgroundUrl"] =
        base::StringPrintf("url(%s)", url.spec().c_str());
  }
  replacements["size"] = size;
  replacements["repeatX"] = repeat_x;
  replacements["repeatY"] = repeat_y;
  replacements["positionX"] = position_x;
  replacements["positionY"] = position_y;
  replacements["scrimDisplay"] = scrim_display;
  std::move(callback).Run(
      base::MakeRefCounted<base::RefCountedString>(FormatTemplate(
          IDR_NEW_TAB_PAGE_UNTRUSTED_BACKGROUND_IMAGE_HTML, replacements)));
}

bool UntrustedSource::IsURLAllowed(const GURL& url) {
  if (!url.is_valid() ||
      !(url.SchemeIs(url::kHttpsScheme) ||
        url.SchemeIs(content::kChromeUIUntrustedScheme)) ||
      IsURLBlockedByPolicy(url)) {
    LOG(WARNING) << "URL is not allowed.";
    return false;
  }
  return true;
}

bool UntrustedSource::IsURLBlockedByPolicy(const GURL& url) {
  PolicyBlocklistService* service =
      ChromePolicyBlocklistServiceFactory::GetForProfile(profile_);
  URLBlocklistState blocklist_state = service->GetURLBlocklistState(url);
  if (blocklist_state == URLBlocklistState::URL_IN_BLOCKLIST) {
    LOG(WARNING) << "URL is blocked by a policy.";
    return true;
  }
  return false;
}