// 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.

#include "chrome/browser/predictors/autocomplete_action_predictor_table.h"

#include "base/guid.h"
#include "base/logging.h"
#include "base/metrics/histogram.h"
#include "base/stringprintf.h"
#include "base/utf_string_conversions.h"
#include "content/public/browser/browser_thread.h"
#include "sql/statement.h"

namespace {

// TODO(shishir): Rename the table for consistency.
const char kAutocompletePredictorTableName[] = "network_action_predictor";

// The maximum length allowed for strings in the database.
const size_t kMaxDataLength = 2048;

void BindRowToStatement(
    const predictors::AutocompleteActionPredictorTable::Row& row,
    sql::Statement* statement) {
  DCHECK(base::IsValidGUID(row.id));
  statement->BindString(0, row.id);
  statement->BindString16(1, row.user_text.substr(0, kMaxDataLength));
  statement->BindString(2, row.url.spec().substr(0, kMaxDataLength));
  statement->BindInt(3, row.number_of_hits);
  statement->BindInt(4, row.number_of_misses);
}

bool StepAndInitializeRow(
    sql::Statement* statement,
    predictors::AutocompleteActionPredictorTable::Row* row) {
  if (!statement->Step())
    return false;

  row->id = statement->ColumnString(0);
  row->user_text = statement->ColumnString16(1);
  row->url = GURL(statement->ColumnString(2));
  row->number_of_hits = statement->ColumnInt(3);
  row->number_of_misses = statement->ColumnInt(4);
  return true;
}

}  // namespace

namespace predictors {

AutocompleteActionPredictorTable::Row::Row()
    : number_of_hits(0),
      number_of_misses(0) {
}

AutocompleteActionPredictorTable::Row::Row(const Row::Id& id,
                                           const string16& user_text,
                                           const GURL& url,
                                           int number_of_hits,
                                           int number_of_misses)
    : id(id),
      user_text(user_text),
      url(url),
      number_of_hits(number_of_hits),
      number_of_misses(number_of_misses) {
}

AutocompleteActionPredictorTable::Row::Row(const Row& row)
    : id(row.id),
      user_text(row.user_text),
      url(row.url),
      number_of_hits(row.number_of_hits),
      number_of_misses(row.number_of_misses) {
}


void AutocompleteActionPredictorTable::GetRow(const Row::Id& id, Row* row) {
  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::DB));
  if (CantAccessDatabase())
    return;

  sql::Statement statement(DB()->GetCachedStatement(SQL_FROM_HERE,
      base::StringPrintf("SELECT * FROM %s WHERE id=?",
                         kAutocompletePredictorTableName).c_str()));
  statement.BindString(0, id);

  bool success = StepAndInitializeRow(&statement, row);
  DCHECK(success) << "Failed to get row " << id << " from "
                  << kAutocompletePredictorTableName;
}

void AutocompleteActionPredictorTable::GetAllRows(Rows* row_buffer) {
  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::DB));
  if (CantAccessDatabase())
    return;

  row_buffer->clear();

  sql::Statement statement(DB()->GetCachedStatement(SQL_FROM_HERE,
      base::StringPrintf(
          "SELECT * FROM %s", kAutocompletePredictorTableName).c_str()));
  if (!statement.is_valid())
    return;

  Row row;
  while (StepAndInitializeRow(&statement, &row))
    row_buffer->push_back(row);
}

void AutocompleteActionPredictorTable::AddRow(
    const AutocompleteActionPredictorTable::Row& row) {
  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::DB));
  if (CantAccessDatabase())
    return;

  AddAndUpdateRows(Rows(1, row), Rows());
}

void AutocompleteActionPredictorTable::UpdateRow(
    const AutocompleteActionPredictorTable::Row& row) {
  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::DB));
  if (CantAccessDatabase())
    return;

  AddAndUpdateRows(Rows(), Rows(1, row));
}

void AutocompleteActionPredictorTable::AddAndUpdateRows(
    const Rows& rows_to_add,
    const Rows& rows_to_update) {
  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::DB));
  if (CantAccessDatabase())
    return;

  if (!DB()->BeginTransaction())
    return;
  for (Rows::const_iterator it = rows_to_add.begin();
       it != rows_to_add.end(); ++it) {
    sql::Statement statement(DB()->GetCachedStatement(SQL_FROM_HERE,
        base::StringPrintf(
            "INSERT INTO %s "
            "(id, user_text, url, number_of_hits, number_of_misses) "
            "VALUES (?,?,?,?,?)", kAutocompletePredictorTableName).c_str()));
    if (!statement.is_valid()) {
      DB()->RollbackTransaction();
      return;
    }

    BindRowToStatement(*it, &statement);
    if (!statement.Run()) {
      DB()->RollbackTransaction();
      return;
    }
  }
  for (Rows::const_iterator it = rows_to_update.begin();
       it != rows_to_update.end(); ++it) {
    sql::Statement statement(DB()->GetCachedStatement(SQL_FROM_HERE,
        base::StringPrintf(
            "UPDATE %s "
            "SET id=?, user_text=?, url=?, number_of_hits=?, number_of_misses=?"
            " WHERE id=?1", kAutocompletePredictorTableName).c_str()));
    if (!statement.is_valid()) {
      DB()->RollbackTransaction();
      return;
    }

    BindRowToStatement(*it, &statement);
    if (!statement.Run()) {
      DB()->RollbackTransaction();
      return;
    }
    DCHECK_GT(DB()->GetLastChangeCount(), 0);
  }
  DB()->CommitTransaction();
}

void AutocompleteActionPredictorTable::DeleteRows(
    const std::vector<Row::Id>& id_list) {
  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::DB));
  if (CantAccessDatabase())
    return;

  if (!DB()->BeginTransaction())
    return;
  for (std::vector<Row::Id>::const_iterator it = id_list.begin();
       it != id_list.end(); ++it) {
    sql::Statement statement(DB()->GetCachedStatement(SQL_FROM_HERE,
        base::StringPrintf(
            "DELETE FROM %s WHERE id=?",
            kAutocompletePredictorTableName).c_str()));
    if (!statement.is_valid()) {
      DB()->RollbackTransaction();
      return;
    }

    statement.BindString(0, *it);
    if (!statement.Run()) {
      DB()->RollbackTransaction();
      return;
    }
  }
  DB()->CommitTransaction();
}

void AutocompleteActionPredictorTable::DeleteAllRows() {
  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::DB));
  if (CantAccessDatabase())
    return;

  sql::Statement statement(DB()->GetCachedStatement(SQL_FROM_HERE,
      base::StringPrintf("DELETE FROM %s",
                         kAutocompletePredictorTableName).c_str()));
  if (!statement.is_valid())
    return;

  statement.Run();
}

AutocompleteActionPredictorTable::AutocompleteActionPredictorTable()
    : PredictorTableBase() {
}

AutocompleteActionPredictorTable::~AutocompleteActionPredictorTable() {
}

void AutocompleteActionPredictorTable::CreateTableIfNonExistent() {
  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::DB));
  if (CantAccessDatabase())
    return;

  if (DB()->DoesTableExist(kAutocompletePredictorTableName))
    return;

  bool success = DB()->Execute(base::StringPrintf(
      "CREATE TABLE %s ( "
      "id TEXT PRIMARY KEY, "
      "user_text TEXT, "
      "url TEXT, "
      "number_of_hits INTEGER, "
      "number_of_misses INTEGER)", kAutocompletePredictorTableName).c_str());
  if (!success)
    ResetDB();
}

void AutocompleteActionPredictorTable::LogDatabaseStats()  {
  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::DB));
  if (CantAccessDatabase())
    return;

  sql::Statement count_statement(DB()->GetUniqueStatement(
      base::StringPrintf("SELECT count(id) FROM %s",
                         kAutocompletePredictorTableName).c_str()));
  if (!count_statement.is_valid() || !count_statement.Step())
    return;
  UMA_HISTOGRAM_COUNTS("AutocompleteActionPredictor.DatabaseRowCount",
                       count_statement.ColumnInt(0));
}

}  // namespace predictors