#include "../../include/odhtdb/sql/SqlQuery.hpp"
#include <sqlite3.h>

namespace odhtdb
{
    int SqlArg::bind(sqlite3_stmt *stmt, int paramIndex) const
    {
        switch(type)
        {
            case Type::DATA_VIEW:
                return sqlite3_bind_blob(stmt, paramIndex, dataView.data, dataView.size, SQLITE_STATIC);
            case Type::INT:
                return sqlite3_bind_int(stmt, paramIndex, integer);
            case Type::INT64:
                return sqlite3_bind_int64(stmt, paramIndex, integer64);
        }
        return SQLITE_OK;
    }
    
    SqlQuery::SqlQuery(sqlite3 *_db, const char *sql, std::initializer_list<SqlArg> args) : 
        db(_db),
        stmt(nullptr),
        numColumns(0)
    {
        int rc = sqlite3_prepare_v2(db, sql, -1, &stmt, nullptr);
        if(rc != SQLITE_OK)
        {
            std::string errMsg = "Failed to prepare sqlite statement, error: ";
            errMsg += sqlite3_errmsg(db);
            sqlite3_exec(db, "ROLLBACK", 0, 0, 0);
            throw SqlQueryException(errMsg);
        }
        
        int numParams = sqlite3_bind_parameter_count(stmt);
        if(args.size() != numParams)
        {
            std::string errMsg = "Failed to prepare sqlite statement, error: Sql has ";
            errMsg += std::to_string(numParams);
            errMsg += " parameters, got ";
            errMsg += std::to_string(args.size());
            errMsg += " arguments";
            sqlite3_finalize(stmt);
            stmt = nullptr;
            sqlite3_exec(db, "ROLLBACK", 0, 0, 0);
            throw SqlQueryException(errMsg);
        }
        
        int paramIndex = 1;
        for(const SqlArg &arg : args)
        {
            rc = arg.bind(stmt, paramIndex);
            if(rc != SQLITE_OK)
            {
                std::string errMsg = "Failed to bind param, error code: ";
                errMsg += std::to_string(rc);
                sqlite3_finalize(stmt);
                stmt = nullptr;
                sqlite3_exec(db, "ROLLBACK", 0, 0, 0);
                throw SqlQueryException(errMsg);
            }
            ++paramIndex;
        }
    }
    
    SqlQuery::~SqlQuery()
    {
        sqlite3_finalize(stmt);
    }
    
    bool SqlQuery::next()
    {
        int rc = sqlite3_step(stmt);
        if(rc == SQLITE_DONE)
            return false;
        else if(rc != SQLITE_ROW)
        {
            std::string errMsg = "Failed to perform sql select, error: ";
            errMsg += sqlite3_errmsg(db);
            sqlite3_exec(db, "ROLLBACK", 0, 0, 0);
            throw SqlQueryException(errMsg);
        }
        
        numColumns = sqlite3_data_count(stmt);
        return true;
    }
    
    void SqlQuery::checkColumnIndex(int index)
    {
        if(index < 0 || index >= numColumns)
        {
            std::string errMsg;
            if(numColumns == 0)
            {
                errMsg += "Attempt to get column ";
                errMsg += std::to_string(index);
                errMsg += " but result does not have any columns";
            }
            else
            {
                errMsg += "Column index ";
                errMsg += std::to_string(index);
                errMsg += " has to be between 0 and ";
                errMsg += std::to_string(numColumns - 1);
            }
            sqlite3_exec(db, "ROLLBACK", 0, 0, 0);
            throw SqlQueryException(errMsg);
        }
    }
    
    int SqlQuery::getInt(int index)
    {
        checkColumnIndex(index);
        return sqlite3_column_int(stmt, index);
    }
    
    i64 SqlQuery::getInt64(int index)
    {
        checkColumnIndex(index);
        return sqlite3_column_int64(stmt, index);
    }
    
    const DataView SqlQuery::getBlob(int index)
    {
        checkColumnIndex(index);
        const void *data = sqlite3_column_blob(stmt, index);
        int size = sqlite3_column_bytes(stmt, index);
        return { (void*)data, (usize)size };
    }
}