// 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 CHROME_BROWSER_AUTOCOMPLETE_AUTOCOMPLETE_INPUT_H_
#define CHROME_BROWSER_AUTOCOMPLETE_AUTOCOMPLETE_INPUT_H_

#include <string>

#include "base/basictypes.h"
#include "base/string16.h"
#include "googleurl/src/gurl.h"
#include "googleurl/src/url_parse.h"

// The user input for an autocomplete query.  Allows copying.
class AutocompleteInput {
 public:
  // Note that the type below may be misleading.  For example, "http:/" alone
  // cannot be opened as a URL, so it is marked as a QUERY; yet the user
  // probably intends to type more and have it eventually become a URL, so we
  // need to make sure we still run it through inline autocomplete.
  enum Type {
    INVALID,        // Empty input
    UNKNOWN,        // Valid input whose type cannot be determined
    REQUESTED_URL,  // Input autodetected as UNKNOWN, which the user wants to
                    // treat as an URL by specifying a desired_tld
    URL,            // Input autodetected as a URL
    QUERY,          // Input autodetected as a query
    FORCED_QUERY,   // Input forced to be a query by an initial '?'
  };

  // Enumeration of the possible match query types. Callers who only need some
  // of the matches for a particular input can get answers more quickly by
  // specifying that upfront.
  enum MatchesRequested {
    // Only the best match in the whole result set matters.  Providers should at
    // most return synchronously-available matches, and if possible do even less
    // work, so that it's safe to ask for these repeatedly in the course of one
    // higher-level "synchronous" query.
    BEST_MATCH,

    // Only synchronous matches should be returned.
    SYNCHRONOUS_MATCHES,

    // All matches should be fetched.
    ALL_MATCHES,
  };

  AutocompleteInput();
  // |text| and |cursor_position| represent the input query and location of
  // the cursor with the query respectively.  |cursor_position| may be set to
  // string16::npos if the input |text| doesn't come directly from the user's
  // typing.
  //
  // See AutocompleteInput::desired_tld() for meaning of |desired_tld|.
  //
  // |prevent_inline_autocomplete| is true if the generated result set should
  // not require inline autocomplete for the default match.  This is difficult
  // to explain in the abstract; the practical use case is that after the user
  // deletes text in the edit, the HistoryURLProvider should make sure not to
  // promote a match requiring inline autocomplete too highly.
  //
  // |prefer_keyword| should be true when the keyword UI is onscreen; this will
  // bias the autocomplete result set toward the keyword provider when the input
  // string is a bare keyword.
  //
  // |allow_exact_keyword_match| should be false when triggering keyword mode on
  // the input string would be surprising or wrong, e.g. when highlighting text
  // in a page and telling the browser to search for it or navigate to it. This
  // parameter only applies to substituting keywords.

  // If |matches_requested| is BEST_MATCH or SYNCHRONOUS_MATCHES the controller
  // asks the providers to only return matches which are synchronously
  // available, which should mean that all providers will be done immediately.
  AutocompleteInput(const string16& text,
                    size_t cursor_position,
                    const string16& desired_tld,
                    bool prevent_inline_autocomplete,
                    bool prefer_keyword,
                    bool allow_exact_keyword_match,
                    MatchesRequested matches_requested);
  ~AutocompleteInput();

  // If type is |FORCED_QUERY| and |text| starts with '?', it is removed.
  // Returns number of leading characters removed.
  static size_t RemoveForcedQueryStringIfNecessary(Type type, string16* text);

  // Converts |type| to a string representation.  Used in logging.
  static std::string TypeToString(Type type);

  // Parses |text| and returns the type of input this will be interpreted as.
  // The components of the input are stored in the output parameter |parts|, if
  // it is non-NULL. The scheme is stored in |scheme| if it is non-NULL. The
  // canonicalized URL is stored in |canonicalized_url|; however, this URL is
  // not guaranteed to be valid, especially if the parsed type is, e.g., QUERY.
  static Type Parse(const string16& text,
                    const string16& desired_tld,
                    url_parse::Parsed* parts,
                    string16* scheme,
                    GURL* canonicalized_url);

  // Parses |text| and fill |scheme| and |host| by the positions of them.
  // The results are almost as same as the result of Parse(), but if the scheme
  // is view-source, this function returns the positions of scheme and host
  // in the URL qualified by "view-source:" prefix.
  static void ParseForEmphasizeComponents(const string16& text,
                                          const string16& desired_tld,
                                          url_parse::Component* scheme,
                                          url_parse::Component* host);

  // Code that wants to format URLs with a format flag including
  // net::kFormatUrlOmitTrailingSlashOnBareHostname risk changing the meaning if
  // the result is then parsed as AutocompleteInput.  Such code can call this
  // function with the URL and its formatted string, and it will return a
  // formatted string with the same meaning as the original URL (i.e. it will
  // re-append a slash if necessary).
  static string16 FormattedStringWithEquivalentMeaning(
      const GURL& url,
      const string16& formatted_url);

  // Returns the number of non-empty components in |parts| besides the host.
  static int NumNonHostComponents(const url_parse::Parsed& parts);

  // User-provided text to be completed.
  const string16& text() const { return text_; }

  // Returns 0-based cursor position within |text_| or string16::npos if not
  // used.
  size_t cursor_position() const { return cursor_position_; }

  // Use of this setter is risky, since no other internal state is updated
  // besides |text_|, |cursor_position_| and |parts_|.  Only callers who know
  // that they're not changing the type/scheme/etc. should use this.
  void UpdateText(const string16& text,
                  size_t cursor_position,
                  const url_parse::Parsed& parts);

  // User's desired TLD, if one is not already present in the text to
  // autocomplete.  When this is non-empty, it also implies that "www." should
  // be prepended to the domain where possible.  This should not have a leading
  // '.' (use "com" instead of ".com").
  const string16& desired_tld() const { return desired_tld_; }

  // The type of input supplied.
  Type type() const { return type_; }

  // Returns parsed URL components.
  const url_parse::Parsed& parts() const { return parts_; }

  // The scheme parsed from the provided text; only meaningful when type_ is
  // URL.
  const string16& scheme() const { return scheme_; }

  // The input as an URL to navigate to, if possible.
  const GURL& canonicalized_url() const { return canonicalized_url_; }

  // Returns whether inline autocompletion should be prevented.
  bool prevent_inline_autocomplete() const {
    return prevent_inline_autocomplete_;
  }

  // Returns whether, given an input string consisting solely of a substituting
  // keyword, we should score it like a non-substituting keyword.
  bool prefer_keyword() const { return prefer_keyword_; }

  // Returns whether this input is allowed to be treated as an exact
  // keyword match.  If not, the default result is guaranteed not to be a
  // keyword search, even if the input is "<keyword> <search string>".
  bool allow_exact_keyword_match() const { return allow_exact_keyword_match_; }

  // See description of enum for details.
  MatchesRequested matches_requested() const { return matches_requested_; }

  // Resets all internal variables to the null-constructed state.
  void Clear();

 private:
  // NOTE: Whenever adding a new field here, please make sure to update Clear()
  // method.
  string16 text_;
  size_t cursor_position_;
  string16 desired_tld_;
  Type type_;
  url_parse::Parsed parts_;
  string16 scheme_;
  GURL canonicalized_url_;
  bool prevent_inline_autocomplete_;
  bool prefer_keyword_;
  bool allow_exact_keyword_match_;
  MatchesRequested matches_requested_;
};

#endif  // CHROME_BROWSER_AUTOCOMPLETE_AUTOCOMPLETE_INPUT_H_