// Copyright 2014 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 "components/search_provider_logos/google_logo_api.h"

#include <stdint.h>

#include <algorithm>

#include "base/base64.h"
#include "base/json/json_reader.h"
#include "base/memory/ref_counted_memory.h"
#include "base/strings/string_util.h"
#include "base/values.h"

namespace search_provider_logos {

namespace {
const char kResponsePreamble[] = ")]}'";
}

GURL GoogleAppendQueryparamsToLogoURL(const GURL& logo_url,
                                      const std::string& fingerprint,
                                      bool wants_cta) {
  // Note: we can't just use net::AppendQueryParameter() because it escapes
  // ":" to "%3A", but the server requires the colon not to be escaped.
  // See: http://crbug.com/413845

  // TODO(newt): Switch to using net::AppendQueryParameter once it no longer
  // escapes ":"
  if (!fingerprint.empty() || wants_cta) {
    std::string query(logo_url.query());
    if (!query.empty())
      query += "&";

    query += "async=";
    if (!fingerprint.empty()) {
      query += "es_dfp:" + fingerprint;
      if (wants_cta)
        query += ",";
    }
    if (wants_cta) {
      query += "cta:1";
    }
    GURL::Replacements replacements;
    replacements.SetQueryStr(query);
    return logo_url.ReplaceComponents(replacements);
  }

  return logo_url;
}

scoped_ptr<EncodedLogo> GoogleParseLogoResponse(
    const scoped_ptr<std::string>& response,
    base::Time response_time,
    bool* parsing_failed) {
  // Google doodles are sent as JSON with a prefix. Example:
  //   )]}' {"update":{"logo":{
  //     "data": "/9j/4QAYRXhpZgAASUkqAAgAAAAAAAAAAAAAAP/...",
  //     "mime_type": "image/png",
  //     "fingerprint": "db063e32",
  //     "target": "http://www.google.com.au/search?q=Wilbur+Christiansen",
  //     "url": "http://www.google.com/logos/doodle.png",
  //     "alt": "Wilbur Christiansen's Birthday"
  //     "time_to_live": 1389304799
  //   }}}

  // The response may start with )]}'. Ignore this.
  base::StringPiece response_sp(*response);
  if (response_sp.starts_with(kResponsePreamble))
    response_sp.remove_prefix(strlen(kResponsePreamble));

  // Default parsing failure to be true.
  *parsing_failed = true;
  scoped_ptr<base::Value> value = base::JSONReader::Read(response_sp);
  if (!value.get())
    return scoped_ptr<EncodedLogo>();
  // The important data lives inside several nested dictionaries:
  // {"update": {"logo": { "mime_type": ..., etc } } }
  const base::DictionaryValue* outer_dict;
  if (!value->GetAsDictionary(&outer_dict))
    return scoped_ptr<EncodedLogo>();
  const base::DictionaryValue* update_dict;
  if (!outer_dict->GetDictionary("update", &update_dict))
    return scoped_ptr<EncodedLogo>();

  // If there is no logo today, the "update" dictionary will be empty.
  if (update_dict->empty()) {
    *parsing_failed = false;
    return scoped_ptr<EncodedLogo>();
  }

  const base::DictionaryValue* logo_dict;
  if (!update_dict->GetDictionary("logo", &logo_dict))
    return scoped_ptr<EncodedLogo>();

  scoped_ptr<EncodedLogo> logo(new EncodedLogo());

  std::string encoded_image_base64;
  if (logo_dict->GetString("data", &encoded_image_base64)) {
    // Data is optional, since we may be revalidating a cached logo.
    base::RefCountedString* encoded_image_string = new base::RefCountedString();
    if (!base::Base64Decode(encoded_image_base64,
                            &encoded_image_string->data()))
      return scoped_ptr<EncodedLogo>();
    logo->encoded_image = encoded_image_string;
    if (!logo_dict->GetString("mime_type", &logo->metadata.mime_type))
      return scoped_ptr<EncodedLogo>();
  }

  // Don't check return values since these fields are optional.
  logo_dict->GetString("target", &logo->metadata.on_click_url);
  logo_dict->GetString("fingerprint", &logo->metadata.fingerprint);
  logo_dict->GetString("alt", &logo->metadata.alt_text);

  // Existance of url indicates |data| is a call to action image for an
  // animated doodle. |url| points to that animated doodle.
  logo_dict->GetString("url", &logo->metadata.animated_url);

  base::TimeDelta time_to_live;
  int time_to_live_ms;
  if (logo_dict->GetInteger("time_to_live", &time_to_live_ms)) {
    time_to_live = base::TimeDelta::FromMilliseconds(
        std::min(static_cast<int64_t>(time_to_live_ms), kMaxTimeToLiveMS));
    logo->metadata.can_show_after_expiration = false;
  } else {
    time_to_live = base::TimeDelta::FromMilliseconds(kMaxTimeToLiveMS);
    logo->metadata.can_show_after_expiration = true;
  }
  logo->metadata.expiration_time = response_time + time_to_live;

  // If this point is reached, parsing has succeeded.
  *parsing_failed = false;
  return logo;
}

}  // namespace search_provider_logos