// Copyright 2018 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/android/explore_sites/explore_sites_schema.h"

#include "sql/database.h"
#include "sql/meta_table.h"
#include "sql/transaction.h"

namespace explore_sites {

constexpr int ExploreSitesSchema::kCurrentVersion;
constexpr int ExploreSitesSchema::kCompatibleVersion;

// Schema versions changelog:
// * 1: Initial version.

namespace {
static const char kCategoriesTableCreationSql[] =
    "CREATE TABLE IF NOT EXISTS categories ( "
    "category_id INTEGER PRIMARY KEY AUTOINCREMENT, "  // for local use only,
                                                       // not known by server.
                                                       // ID is *not* retained
                                                       // across catalog
                                                       // updates.
    "version INTEGER NOT NULL, "  // matches an entry in the meta table:
                                  // ‘current_catalog’ or ‘downloading_catalog’.
    "type INTEGER NOT NULL, "
    "usable_on_ntp BOOLEAN NOT NULL, "
    "label TEXT NOT NULL, "
    "image BLOB, "  // can be NULL if no image is available, but must be
                    // populated for use on the NTP.
    "ntp_click_count INTEGER NOT NULL DEFAULT 0, "
    "esp_site_click_count INTEGER NOT NULL DEFAULT 0);";

bool CreateCategoriesTable(sql::Database* db) {
  return db->Execute(kCategoriesTableCreationSql);
}

static const char kSitesTableCreationSql[] =
    "CREATE TABLE IF NOT EXISTS sites ( "
    "site_id INTEGER PRIMARY KEY AUTOINCREMENT, "  // locally generated. Same
                                                   // caveats as |category_id|.
    "url TEXT NOT NULL, "
    "category_id INTEGER NOT NULL, "  // A row from the categories table.
    "title TEXT NOT NULL, "
    // The favicon of the website encoded as a WebP.
    "favicon BLOB, "
    "click_count INTEGER NOT NULL DEFAULT 0, "
    "removed BOOLEAN NOT NULL default FALSE); ";

bool CreateSitesTable(sql::Database* db) {
  return db->Execute(kSitesTableCreationSql);
}

static const char kSiteBlacklistTableCreationSql[] =
    "CREATE TABLE IF NOT EXISTS site_blacklist ( "
    "url TEXT NOT NULL UNIQUE, "
    "date_removed INTEGER NOT NULL);";  // stored as unix timestamp

bool CreateSiteBlacklistTable(sql::Database* db) {
  return db->Execute(kSiteBlacklistTableCreationSql);
}

bool CreateLatestSchema(sql::Database* db) {
  sql::Transaction transaction(db);
  if (!transaction.Begin())
    return false;

  if (!CreateCategoriesTable(db) || !CreateSitesTable(db) ||
      !CreateSiteBlacklistTable(db)) {
    return false;
  }

  return transaction.Commit();
}

}  // namespace

// static
bool ExploreSitesSchema::CreateOrUpgradeIfNeeded(sql::Database* db) {
  DCHECK_GE(kCurrentVersion, kCompatibleVersion);
  if (!db)
    return false;

  sql::MetaTable meta_table;
  if (!meta_table.Init(db, kCurrentVersion, kCompatibleVersion))
    return false;

  const int compatible_version = meta_table.GetCompatibleVersionNumber();
  int current_version = meta_table.GetVersionNumber();
  // sql::MetaTable docs say that an error returns 0 for the version number,
  // and DCHECKs in that class prevent it from being the actual version number
  // stored.
  const int kInvalidVersion = 0;
  if (current_version == kInvalidVersion ||
      compatible_version == kInvalidVersion)
    return false;
  DCHECK_GE(current_version, compatible_version);

  // Stored database version is newer and incompatible with the current running
  // code (Chrome was downgraded). The DB will never work until Chrome is
  // re-upgraded.
  if (compatible_version > kCurrentVersion)
    return false;

  // Database is already at the latest version or has just been created. Create
  // any missing tables and return.
  if (current_version == kCurrentVersion)
    return CreateLatestSchema(db);

  // Versions 0 and below are unexpected.
  if (current_version <= 0)
    return false;

  // NOTE: Insert schema upgrade scripts here when required.

  return current_version == kCurrentVersion;
}

}  // namespace explore_sites