// 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.

#ifndef CONTENT_RENDERER_MANIFEST_MANIFEST_PARSER_H_
#define CONTENT_RENDERER_MANIFEST_MANIFEST_PARSER_H_

#include "base/strings/nullable_string16.h"
#include "base/strings/string_piece.h"
#include "content/common/content_export.h"
#include "content/public/common/manifest.h"

class GURL;

namespace base {
class DictionaryValue;
}

namespace content {

// ManifestParser handles the logic of parsing the Web Manifest from a string.
// It implements:
// http://w3c.github.io/manifest/#dfn-steps-for-processing-a-manifest
class CONTENT_EXPORT ManifestParser {
 public:
  ManifestParser(const base::StringPiece& data,
                 const GURL& manifest_url,
                 const GURL& document_url);
  ~ManifestParser();

  // Parse the Manifest from a string using following:
  // http://w3c.github.io/manifest/#dfn-steps-for-processing-a-manifest
  void Parse();

  const Manifest& manifest() const;
  const std::vector<std::string>& errors() const;
  bool failed() const;

 private:
  // Used to indicate whether to strip whitespace when parsing a string.
  enum TrimType {
    Trim,
    NoTrim
  };

  // Helper function to parse booleans present on a given |dictionary| in a
  // given field identified by its |key|.
  // Returns the parsed boolean if any, or |default_value| if parsing failed.
  bool ParseBoolean(const base::DictionaryValue& dictionary,
                    const std::string& key,
                    bool default_value);

  // Helper function to parse strings present on a given |dictionary| in a given
  // field identified by its |key|.
  // Returns the parsed string if any, a null string if the parsing failed.
  base::NullableString16 ParseString(const base::DictionaryValue& dictionary,
                                     const std::string& key,
                                     TrimType trim);

  // Helper function to parse URLs present on a given |dictionary| in a given
  // field identified by its |key|. The URL is first parsed as a string then
  // resolved using |base_url|.
  // Returns a GURL. If the parsing failed, the GURL will not be valid.
  GURL ParseURL(const base::DictionaryValue& dictionary,
                const std::string& key,
                const GURL& base_url);

  // Parses the 'name' field of the manifest, as defined in:
  // http://w3c.github.io/manifest/#dfn-steps-for-processing-the-name-member
  // Returns the parsed string if any, a null string if the parsing failed.
  base::NullableString16 ParseName(const base::DictionaryValue& dictionary);

  // Parses the 'short_name' field of the manifest, as defined in:
  // http://w3c.github.io/manifest/#dfn-steps-for-processing-the-short-name-member
  // Returns the parsed string if any, a null string if the parsing failed.
  base::NullableString16 ParseShortName(
      const base::DictionaryValue& dictionary);

  // Parses the 'start_url' field of the manifest, as defined in:
  // http://w3c.github.io/manifest/#dfn-steps-for-processing-the-start_url-member
  // Returns the parsed GURL if any, an empty GURL if the parsing failed.
  GURL ParseStartURL(const base::DictionaryValue& dictionary);

  // Parses the 'display' field of the manifest, as defined in:
  // http://w3c.github.io/manifest/#dfn-steps-for-processing-the-display-member
  // Returns the parsed DisplayMode if any, DISPLAY_MODE_UNSPECIFIED if the
  // parsing failed.
  Manifest::DisplayMode ParseDisplay(const base::DictionaryValue& dictionary);

  // Parses the 'orientation' field of the manifest, as defined in:
  // http://w3c.github.io/manifest/#dfn-steps-for-processing-the-orientation-member
  // Returns the parsed WebScreenOrientationLockType if any,
  // WebScreenOrientationLockDefault if the parsing failed.
  blink::WebScreenOrientationLockType ParseOrientation(
      const base::DictionaryValue& dictionary);

  // Parses the 'src' field of an icon, as defined in:
  // http://w3c.github.io/manifest/#dfn-steps-for-processing-the-src-member-of-an-icon
  // Returns the parsed GURL if any, an empty GURL if the parsing failed.
  GURL ParseIconSrc(const base::DictionaryValue& icon);

  // Parses the 'type' field of an icon, as defined in:
  // http://w3c.github.io/manifest/#dfn-steps-for-processing-the-type-member-of-an-icon
  // Returns the parsed string if any, a null string if the parsing failed.
  base::NullableString16 ParseIconType(const base::DictionaryValue& icon);

  // Parses the 'density' field of an icon, as defined in:
  // http://w3c.github.io/manifest/#dfn-steps-for-processing-a-density-member-of-an-icon
  // Returns the parsed double if any, Manifest::Icon::kDefaultDensity if the
  // parsing failed.
  double ParseIconDensity(const base::DictionaryValue& icon);

  // Parses the 'sizes' field of an icon, as defined in:
  // http://w3c.github.io/manifest/#dfn-steps-for-processing-a-sizes-member-of-an-icon
  // Returns a vector of gfx::Size with the successfully parsed sizes, if any.
  // An empty vector if the field was not present or empty. "Any" is represented
  // by gfx::Size(0, 0).
  std::vector<gfx::Size> ParseIconSizes(const base::DictionaryValue& icon);

  // Parses the 'icons' field of a Manifest, as defined in:
  // http://w3c.github.io/manifest/#dfn-steps-for-processing-the-icons-member
  // Returns a vector of Manifest::Icon with the successfully parsed icons, if
  // any. An empty vector if the field was not present or empty.
  std::vector<Manifest::Icon> ParseIcons(
      const base::DictionaryValue& dictionary);

  // Parses the 'gcm_sender_id' field of the manifest.
  // This is a proprietary extension of the Web Manifest specification.
  // Returns the parsed string if any, a null string if the parsing failed.
  base::NullableString16 ParseGCMSenderID(
      const base::DictionaryValue& dictionary);

  // Parses the 'gcm_user_visible_only' field of the manifest.
  // This is a proprietary extension of the Web Manifest specification.
  // Returns true iff the string could be parsed as the boolean true.
  bool ParseGCMUserVisibleOnly(const base::DictionaryValue& dictionary);

  const base::StringPiece& data_;
  const GURL& manifest_url_;
  const GURL& document_url_;

  bool failed_;
  Manifest manifest_;
  std::vector<std::string> errors_;

  DISALLOW_COPY_AND_ASSIGN(ManifestParser);
};

} // namespace content

#endif // CONTENT_RENDERER_MANIFEST_MANIFEST_PARSER_H_