kima2/src/core/database.cpp

#include "database.h"

#include <iostream>
#include <stdexcept>
#include <vector>

Database::Database(const std::string& dbname) : db_(nullptr)
{
    dbname_ = dbname;
    const int errCode = sqlite3_open(dbname_.c_str(), &db_);
    if (errCode) {
        throw std::runtime_error("Could not open database file.");
    }
    sqlite3_db_config(db_, SQLITE_DBCONFIG_ENABLE_FKEY);
}

Database::~Database() { sqlite3_close(db_); }

void Database::exec(const std::string& sql)
{
    char* errMsg;
    const int errCode = sqlite3_exec(db_, sql.c_str(), nullptr, nullptr, &errMsg);
    if (errCode) {
        std::string errMsgString(errMsg); // Make a C++ string of the errMsg, so that we can call
                                          // sqlite3_free() before throwing the exception
        sqlite3_free(errMsg);
        throw std::runtime_error("Error in SQL execution: " + errMsgString);
    }
}

void Database::createNew()
{
    std::vector<std::string> sqlStrings{};

    std::string sqlCreateKima2{"CREATE TABLE IF NOT EXISTS kima2 ("
                               "version INTEGER NOT NULL);"
                               "INSERT INTO kima2 (version) VALUES (1);"};
    sqlStrings.push_back(sqlCreateKima2);
    std::string sqlCreateSellers{"CREATE TABLE IF NOT EXISTS sellers ("
                                 "id TEXT PRIMARY KEY NOT NULL, "
                                 "seller_no INTEGER, "
                                 "first_name TEXT, "
                                 "last_name TEXT, "
                                 "num_offered_articles INTEGER, "
                                 "UNIQUE (seller_no)"
                                 ");"};
    sqlStrings.push_back(sqlCreateSellers);
    std::string sqlCreateArticles{
        "CREATE TABLE IF NOT EXISTS articles ("
        "id TEXT PRIMARY KEY NOT NULL, "
        "seller_id TEXT NOT NULL, "
        "source_no INTEGER NOT NULL, "
        "article_no INTEGER NOT NULL, "
        "description TEXT, "
        "price INTEGER NOT NULL, "
        "UNIQUE (source_no, article_no), "
        "FOREIGN KEY (seller_id) REFERENCES sellers(id) ON DELETE CASCADE, "
        "CHECK (article_no BETWEEN 0 AND 99999)"
        ");"};
    sqlStrings.push_back(sqlCreateArticles);
    std::string sqlCreateSales{"CREATE TABLE IF NOT EXISTS sales ("
                               " id TEXT PRIMARY KEY NOT NULL,"
                               " source_no INTEGER NOT NULL,"
                               " sold_at TEXT"
                               ");"};
    sqlStrings.push_back(sqlCreateSales);
    std::string sqlCreateSalesItems{
        "CREATE TABLE IF NOT EXISTS sales_items("
        " sale_id TEXT NOT NULL,"
        " article_id TEXT NOT NULL,"
        " FOREIGN KEY (sale_id) REFERENCES sales(id) ON DELETE CASCADE,"
        " FOREIGN KEY (article_id) REFERENCES articles(id) ON DELETE CASCADE"
        ");"};
    sqlStrings.push_back(sqlCreateSalesItems);

    beginTransaction();
    for (const auto& sql : sqlStrings) {
        exec(sql);
    }
    endTransaction();
}

void Database::init()
{
    int version = getVersion();

    switch (version) {
    case 0:
        createNew();
        break;
        // perhaps handle upgrades for db schema here...
    default:
        // Do nothing because we are up-to-date.
        break;
    }
}

int Database::getVersion()
{
    int retCode{};
    sqlite3_stmt* stmt;

    // Check if there's already a kima2 table available.
    // If not, return version == 0.
    retCode = sqlite3_prepare_v2(
        db_, "SELECT count(*) FROM sqlite_master WHERE type='table' AND name='kima2';", -1, &stmt,
        nullptr);
    if (retCode != SQLITE_OK)
        throw std::string(sqlite3_errmsg(db_));
    retCode = sqlite3_step(stmt);
    if (retCode != SQLITE_ROW && retCode != SQLITE_DONE) {
        std::string errMsg(sqlite3_errmsg(db_));
        sqlite3_finalize(stmt);
        throw errMsg;
    } else if (retCode != SQLITE_DONE) {
        int count = sqlite3_column_int(stmt, 0);
        sqlite3_finalize(stmt);
        if (count == 0)
            return 0; // no kima2 table, so version is 0
    }

    // Now that we know that the kima2 table is present, read and return the schema version.
    retCode = sqlite3_prepare_v2(db_, "SELECT version FROM kima2", -1, &stmt, nullptr);
    if (retCode != SQLITE_OK)
        throw std::string(sqlite3_errmsg(db_));

    retCode = sqlite3_step(stmt);

    if (retCode != SQLITE_ROW && retCode != SQLITE_DONE) {
        std::string errMsg(sqlite3_errmsg(db_));
        sqlite3_finalize(stmt);
        throw errMsg;
    } else if (retCode == SQLITE_DONE) {
        sqlite3_finalize(stmt);
        return 0; // no version entry, so version is 0
    }

    int version = sqlite3_column_int(stmt, 0);
    sqlite3_finalize(stmt);

    return version;
}

void Database::beginTransaction() { exec("BEGIN TRANSACTION"); }

void Database::endTransaction() { exec("END TRANSACTION"); }

unsigned int Database::storeSellers(std::vector<Seller>& sellers)
{
    int retCode{};
    int count{};
    sqlite3_stmt* stmt;

    beginTransaction();

    for (auto& seller : sellers) {
        if (seller.getState() == Entity::State::NEW) {
            retCode = sqlite3_prepare_v2(
                db_,
                "INSERT INTO sellers"
                " (id, seller_no, first_name, last_name, num_offered_articles)"
                " VALUES (:uuid, :seller_no, :first_name, :last_name, :num_offered_articles)",
                -1, &stmt, nullptr);

            if (retCode != SQLITE_OK)
                throw std::runtime_error(sqlite3_errmsg(db_));

            sqlite3_bind_text(stmt, sqlite3_bind_parameter_index(stmt, ":uuid"),
                              boost::uuids::to_string(seller.getUuid()).c_str(), -1, nullptr);
            sqlite3_bind_int(stmt, sqlite3_bind_parameter_index(stmt, ":seller_no"),
                             seller.getSellerNo());
            sqlite3_bind_text(stmt, sqlite3_bind_parameter_index(stmt, ":first_name"),
                              seller.getFirstName().c_str(), -1, nullptr);
            sqlite3_bind_text(stmt, sqlite3_bind_parameter_index(stmt, ":last_name"),
                              seller.getLastName().c_str(), -1, nullptr);
            sqlite3_bind_int(stmt, sqlite3_bind_parameter_index(stmt, ":num_offered_articles"),
                             seller.numArticlesOffered());

            retCode = sqlite3_step(stmt);

            if (retCode != SQLITE_DONE) {

                std::string errMsg(sqlite3_errmsg(db_));
                sqlite3_finalize(stmt);
                throw std::runtime_error(errMsg);
            }
            seller.setState(Seller::State::OK);
            ++count;
            sqlite3_finalize(stmt);
        }
    }

    endTransaction();
    return count;
}