package com.alibaba.druid.mock.handler;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.util.List;

import com.alibaba.druid.mock.MockResultSet;
import com.alibaba.druid.mock.MockStatement;
import com.alibaba.druid.sql.ast.SQLExpr;
import com.alibaba.druid.sql.ast.SQLStatement;
import com.alibaba.druid.sql.ast.expr.SQLMethodInvokeExpr;
import com.alibaba.druid.sql.ast.expr.SQLNullExpr;
import com.alibaba.druid.sql.ast.expr.SQLNumericLiteralExpr;
import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
import com.alibaba.druid.sql.ast.statement.SQLSelect;
import com.alibaba.druid.sql.ast.statement.SQLSelectItem;
import com.alibaba.druid.sql.ast.statement.SQLSelectQuery;
import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
import com.alibaba.druid.sql.ast.statement.SQLTableSource;
import com.alibaba.druid.sql.dialect.mysql.parser.MySqlStatementParser;
import com.alibaba.druid.sql.parser.SQLStatementParser;

public class MySqlMockExecuteHandlerImpl implements MockExecuteHandler {

    @Override
    public ResultSet executeQuery(MockStatement statement, String sql) throws SQLException {
        SQLStatementParser parser = new MySqlStatementParser(sql);
        List<SQLStatement> stmtList = parser.parseStatementList(); //

        if (stmtList.size() > 1) {
            throw new SQLException("not support multi-statment. " + sql);
        }

        if (stmtList.size() == 0) {
            throw new SQLException("executeQueryError : " + sql);
        }

        SQLStatement stmt = stmtList.get(0);

        if (!(stmt instanceof SQLSelectStatement)) {
            throw new SQLException("executeQueryError : " + sql);
        }

        SQLSelect select = ((SQLSelectStatement) stmt).getSelect();
        SQLSelectQuery query = select.getQuery();

        if (query instanceof SQLSelectQueryBlock) {
            return executeQuery(statement, (SQLSelectQueryBlock) query);
        }

        throw new SQLException("TODO");
    }

    public ResultSet executeQuery(MockStatement statement, SQLSelectQueryBlock query) throws SQLException {
        SQLTableSource from = query.getFrom();

        if (from instanceof SQLExprTableSource) {
            throw new SQLException("TODO");
        } else if (from == null) {
            return executeQueryFromDual(statement, query);
        } else {
            throw new SQLException("TODO");
        }

    }

    public ResultSet executeQueryFromDual(MockStatement statement, SQLSelectQueryBlock query) throws SQLException {
        MockResultSet rs = new MockResultSet(statement);
        Object[] row = new Object[query.getSelectList().size()];

        for (int i = 0, size = query.getSelectList().size(); i < size; ++i) {
            SQLSelectItem item = query.getSelectList().get(i);
            SQLExpr expr = item.getExpr();

            if (expr instanceof SQLNumericLiteralExpr) {
                row[i] = ((SQLNumericLiteralExpr) expr).getNumber();
            } else if (expr instanceof SQLNullExpr) {
                row[i] = null;
            } else if (expr instanceof SQLMethodInvokeExpr) {
                SQLMethodInvokeExpr methodInvokeExpr = (SQLMethodInvokeExpr) expr;
                
                if ("NOW".equalsIgnoreCase(methodInvokeExpr.getMethodName())) {
                    row[i] = new Timestamp(System.currentTimeMillis());
                } else {
                    throw new SQLException("TODO");
                }
                
            } else {
                throw new SQLException("TODO");
            }
        }

        rs.getRows().add(row);

        return rs;
    }
}