#include "Database.h"
string Path = "data"; //该程序所有生成文件的文件夹路径

Database::Database(string name) :databaseName(name){}

//获取书库名称
const string& Database::getDatabaseName() const
{
    return databaseName;
}

//获取表名列表
const vector<string>& Database::getTableNames() const
{
    return tableNames;
}

//找到某表的位置
size_t Database::getIndexOfTable(string tableName)
{
    size_t index = -1;
    for (size_t i = 0; i < tables.size(); i++)
    {
        if (tables[i]->getTableName() == tableName)
        {
            index = i;
        }
    }
    return index;
}

//创建表格
void Database::createTable(string tableName)
{
    if (!tableNames.empty())
    {
        if (find(tableNames.begin(), tableNames.end(), tableName) != tableNames.end())
        {
            cout << "已经存在表: " << tableName << endl;
            return;
        }
    }
    tables.push_back(make_shared<Table>(tableName));
    tableNames.push_back(tableName);
}

//删除表格
void Database::dropTable(string tableName)
{
    auto it = find(tableNames.begin(), tableNames.end(), tableName);
    if (it != tableNames.end())
    {
        for (int i = 0; i < tables.size(); i++)
        {
            if (tables[i]->getTableName() == tableName)
            {
                tables.erase(tables.begin() + i);
                tableNames.erase(it);                
                string filePath = Path + "/" + databaseName + "/" + tableName + ".txt";
                // 删除文件
                if (remove(filePath.c_str()) != 0)
                {
                    //删除了定义上的表，但没能成功删除文件夹中的文件，对程序没有影响
                }
                else
                {
                    //cout << "文件已删除: " << filePath << endl;
                }
                break;
            }
        }
    }
}

//查询表格结构
vector<vector<string>> Database::descTable(string tableName)
{
    vector<vector<string>> results;
    size_t i = getIndexOfTable(tableName);
    if (i == -1)
    {
        vector<string>result;
        result.push_back("不存在表: "+tableName);
        results.push_back(result);
    }
    else
    {
        results = tables[i]->desc();
    }
    return results;
}

//更改表名
void Database::alterTableName(string tableName, string newTableName)
{
    size_t i = getIndexOfTable(tableName);
    if (i == -1)
    {
        cout << "不存在表: " <<tableName<<endl;
    }
    else
    {
        tables[i]->rename(newTableName);
        for (size_t j = 0; j<tableNames.size();j++)
        {
            if (tableNames[j] == tableName)
            {
                tableNames[j] = newTableName;
                break;
            }
        }

        string filePath = Path + "/" + databaseName + "/" + tableName + ".txt";
        // 删除文件
        if (remove(filePath.c_str()) != 0)
        {
            //没能成功删除文件夹中的旧文件，对程序没有影响
        }
        else
        {
            //cout << "文件已删除: " << filePath << endl;
        }
    }
}

//增加列
void Database::addColumnToTable(string tableName, string columnName, string dataType)
{
    size_t i = getIndexOfTable(tableName);
    if (i == -1)
    {
        cout << "不存在表: " << tableName << endl;
    }
    else
    {
        tables[i]->addNewColumn(columnName,dataType);
    }
}

//删除列
void Database::dropColumnInTable(string tableName, string columnName)
{
    size_t i = getIndexOfTable(tableName);
    if (i == -1)
    {
        cout << "不存在表: " << tableName << endl;
    }
    else
    {
        tables[i]->dropColumn(columnName);
    }
}

//插入一行数据
void Database::insertIntoTable(string tableName, vector<string> values)
{
    size_t i = getIndexOfTable(tableName);
    if (i == -1)
    {
        cout << "不存在表: " << tableName << endl;
    }
    else
    {
        tables[i]->insertRow(values);
    }
}

//删除一行数据
void Database::deleteFromTable(string tableName, ConditionForColumn condition)
{
    size_t i = getIndexOfTable(tableName);
    if (i == -1)
    {
        cout << "不存在表: " << tableName << endl;
    }
    else
    {
        tables[i]->deleteRowsByCondition(condition);
    }
}

//查询数据
vector<vector<string>> Database::selectFromTable(string tableName,
    vector<string> columnNames, ConditionForColumn condition)
{
    vector<vector<string>> results;
    size_t i = getIndexOfTable(tableName);
    if (i == -1)
    {
        cout << "不存在表: " << tableName << endl;
        vector<string>result;
        results.push_back(result);
    }
    else
    {
        results = tables[i]->selectRowsInColumnsByCondition(columnNames, condition);
    }
    return results;
}

//更改数据
void Database::updateValueInTable(string tableName, string columnName,
    string newVal, ConditionForColumn condition)
{
    size_t i = getIndexOfTable(tableName);
    if (i == -1)
    {
        cout << "不存在表: " << tableName << endl;
    }
    else
    {
        tables[i]->updateValueInColumnByCondition(columnName, newVal, condition);
    }
    return;
}

//创建索引
void Database::createIndexInTable(string tableName, string ColumnName)
{
    size_t i = getIndexOfTable(tableName);
    if (i == -1)
    {
        cout << "不存在表: " << tableName << endl;
    }
    else
    {
        tables[i]->createIndexOnColumn(ColumnName);
    }
    return;
}

//删除索引
void Database::removeIndexInTable(string tableName, string ColumnName)
{
    size_t i = getIndexOfTable(tableName);
    if (i == -1)
    {
        cout << "不存在表: " << tableName << endl;
    }
    else
    {
        tables[i]->removeIndexOnColumn(ColumnName);
    }
    return;
}

//保存数据库
void Database::saveDatabase(string dataPath)
{
    string path = dataPath + "/" + databaseName;
    ofstream out;
    out.open((path + "/" + "tableNames.txt").c_str());
    if (out.is_open())
    {
        //cout << "创建成功:" << (path + "/" + "tableNames.txt").c_str() << endl;

        for (string tableName : tableNames)
        {
            //cout << "保存表名：" << tableName << '\n';
            out << tableName << '\n';
        }
        out.close();
    }
    else
    {
        //cout << "创建失败:" << (path + "/" + "tableNames.txt").c_str() << endl;
        return;
    }
    for (shared_ptr<Table>table : tables)
    {
        string tablePath = path + "/" + table->getTableName() + ".txt";
        table->saveTable(tablePath);
    }
}

//加载数据库
void Database::loadDatabase(string dataPath)
{
    string path = dataPath + "/" + databaseName;
    ifstream in;
    in.open((path + "/" + "tableNames.txt").c_str());
    if (in.is_open())
    {
        //cout << "读取成功:" << (path + "/" + "tableNames.txt").c_str() << endl;
        string tableName;
        while (in >> tableName)
        {
            createTable(tableName);
        }
        in.close();
    }
    else
    {
        //cout << "读取失败:" << (path + "/" + "tableNames.txt").c_str() << endl;
        return;
    }
    for (shared_ptr<Table>table : tables)
    {
        string tablePath = path + "/" + table->getTableName() + ".txt";
        table->loadTable(tablePath);
    }
}