// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/no_state_prefetch/common/no_state_prefetch_utils.h"

#include "base/metrics/histogram.h"
#include "base/metrics/histogram_functions.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "extensions/buildflags/buildflags.h"
#include "url/gurl.h"
#include "url/url_constants.h"

#if BUILDFLAG(ENABLE_EXTENSIONS_CORE)
// GN doesn't understand conditional includes, so we need nogncheck here.
#include "extensions/common/constants.h"  // nogncheck
#endif

namespace prerender {

namespace {

// Valid HTTP methods for NoStatePrefetch.
const char* const kValidHttpMethods[] = {
    "GET",
    "HEAD",
};

}  // namespace

const char kFollowOnlyWhenPrerenderShown[] = "follow-only-when-prerender-shown";

bool DoesURLHaveValidScheme(const GURL& url) {
  return (url.SchemeIsHTTPOrHTTPS() ||
#if BUILDFLAG(ENABLE_EXTENSIONS_CORE)
          url.SchemeIs(extensions::kExtensionScheme) ||
#endif
          url.SchemeIs(url::kDataScheme));
}

bool DoesSubresourceURLHaveValidScheme(const GURL& url) {
  return DoesURLHaveValidScheme(url) || url == url::kAboutBlankURL;
}

bool IsValidHttpMethod(const std::string& method) {
  // |method| has been canonicalized to upper case at this point so we can just
  // compare them.
  DCHECK_EQ(method, base::ToUpperASCII(method));
  for (auto* valid_method : kValidHttpMethods) {
    if (method == valid_method) {
      return true;
    }
  }
  return false;
}

std::string ComposeHistogramName(const std::string& prefix_type,
                                 const std::string& name) {
  if (prefix_type.empty()) {
    return std::string("Prerender.") + name;
  }
  return std::string("Prerender.") + prefix_type + std::string("_") + name;
}

}  // namespace prerender