// 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.

#ifndef COMPONENTS_AUTOFILL_BROWSER_AUTOFILL_XML_PARSER_H_
#define COMPONENTS_AUTOFILL_BROWSER_AUTOFILL_XML_PARSER_H_

#include <string>
#include <vector>

#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "base/memory/scoped_ptr.h"
#include "components/autofill/browser/autofill_server_field_info.h"
#include "components/autofill/browser/field_types.h"
#include "components/autofill/browser/form_structure.h"
#include "components/autofill/common/web_element_descriptor.h"
#include "third_party/libjingle/source/talk/xmllite/xmlparser.h"

// The base class that contains common functionality between
// AutofillQueryXmlParser and AutofillUploadXmlParser.
class AutofillXmlParser : public buzz::XmlParseHandler {
 public:
  AutofillXmlParser();
  virtual ~AutofillXmlParser();

  // Returns true if no parsing errors were encountered.
  bool succeeded() const { return succeeded_; }

 private:
  // A callback for the end of an </element>, called by Expat.
  // |context| is a parsing context used to resolve element/attribute names.
  // |name| is the name of the element.
  virtual void EndElement(buzz::XmlParseContext* context,
                          const char* name) OVERRIDE;

  // The callback for character data between tags (<element>text...</element>).
  // |context| is a parsing context used to resolve element/attribute names.
  // |text| is a pointer to the beginning of character data (not null
  // terminated).
  // |len| is the length of the string pointed to by text.
  virtual void CharacterData(buzz::XmlParseContext* context,
                             const char* text,
                             int len) OVERRIDE;

  // The callback for parsing errors.
  // |context| is a parsing context used to resolve names.
  // |error_code| is a code representing the parsing error.
  virtual void Error(buzz::XmlParseContext* context,
                     XML_Error error_code) OVERRIDE;

  // True if parsing succeeded.
  bool succeeded_;

  DISALLOW_COPY_AND_ASSIGN(AutofillXmlParser);
};

// The XML parse handler for parsing Autofill query responses.  A typical
// response looks like:
//
// <autofillqueryresponse experimentid="1">
//   <field autofilltype="0" />
//   <field autofilltype="1" />
//   <field autofilltype="3" />
//   <field autofilltype="2" />
// </autofillqueryresponse>
//
// Fields are returned in the same order they were sent to the server.
// autofilltype: The server's guess at what type of field this is.  0
// is unknown, other types are documented in
// components/autofill/browser/field_types.h.
class AutofillQueryXmlParser : public AutofillXmlParser {
 public:
  AutofillQueryXmlParser(std::vector<AutofillServerFieldInfo>* field_infos,
                         UploadRequired* upload_required,
                         std::string* experiment_id);
  virtual ~AutofillQueryXmlParser();

  int current_page_number() const { return current_page_number_; }

  int total_pages() const { return total_pages_; }

  // Returns the proceed element for multipage Autofill flows if the current
  // page is part of such a flow or NULL otherwise.
  const autofill::WebElementDescriptor* proceed_element_descriptor() const {
    return proceed_element_descriptor_.get();
  }

 private:
  // A callback for the beginning of a new <element>, called by Expat.
  // |context| is a parsing context used to resolve element/attribute names.
  // |name| is the name of the element.
  // |attrs| is the list of attributes (names and values) for the element.
  virtual void StartElement(buzz::XmlParseContext* context,
                            const char* name,
                            const char** attrs) OVERRIDE;

  // A helper function to retrieve integer values from strings.  Raises an
  // XML parse error if it fails.
  // |context| is the current parsing context.
  // |value| is the string to convert.
  int GetIntValue(buzz::XmlParseContext* context, const char* attribute);

  // The parsed <field type, default value> pairs.
  std::vector<AutofillServerFieldInfo>* field_infos_;

  // A flag indicating whether the client should upload Autofill data when this
  // form is submitted.
  UploadRequired* upload_required_;

  // Page number of present page in multipage autofill flow.
  int current_page_number_;

  // Total number of pages in multipage autofill flow.
  int total_pages_;

  // Proceed element for multipage Autofill flow.
  scoped_ptr<autofill::WebElementDescriptor> proceed_element_descriptor_;

  // The server experiment to which this query response belongs.
  // For the default server implementation, this is empty.
  std::string* experiment_id_;

  DISALLOW_COPY_AND_ASSIGN(AutofillQueryXmlParser);
};

// The XML parser for handling Autofill upload responses.  Typical upload
// responses look like:
//
// <autofilluploadresponse negativeuploadrate="0.00125" positiveuploadrate="1"/>
//
// The positive upload rate is the percentage of uploads to send to the server
// when something in the users profile matches what they have entered in a form.
// The negative upload rate is the percentage of uploads to send when nothing in
// the form matches what's in the users profile.
// The negative upload rate is typically much lower than the positive upload
// rate.
class AutofillUploadXmlParser : public AutofillXmlParser {
 public:
  AutofillUploadXmlParser(double* positive_upload_rate,
                          double* negative_upload_rate);

 private:
  // A callback for the beginning of a new <element>, called by Expat.
  // |context| is a parsing context used to resolve element/attribute names.
  // |name| is the name of the element.
  // |attrs| is the list of attributes (names and values) for the element.
  virtual void StartElement(buzz::XmlParseContext* context,
                            const char* name,
                            const char** attrs) OVERRIDE;

  // A helper function to retrieve double values from strings.  Raises an XML
  // parse error if it fails.
  // |context| is the current parsing context.
  // |value| is the string to convert.
  double GetDoubleValue(buzz::XmlParseContext* context, const char* attribute);

  // True if parsing succeeded.
  bool succeeded_;

  double* positive_upload_rate_;
  double* negative_upload_rate_;

  DISALLOW_COPY_AND_ASSIGN(AutofillUploadXmlParser);
};

#endif  // COMPONENTS_AUTOFILL_BROWSER_AUTOFILL_XML_PARSER_H_