// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.0;

// Contract name is VirtualPowerPlant
contract VirtualPowerPlant {
    struct Order {
	    ???
    }

    mapping(address => uint) price_bought;
    mapping(address => uint) quantity_bought;

    function priceBought(address addr) public view returns (uint) {
        ???
    }

    function quantityBought(address addr) public view returns (uint) {
        ???
    }

    Order[] sellOrders; // Creating an empty list of selling orders
    Order[] buyOrders; // Creating an empty list of buying orders

    function newSellOrder(???) public {
        Order memory newOrder =  Order({
            ???
        })
        sellOrders.push(newOrder); // .push takes one item and adds it to the end of the list
    }

    function newBuyOrder(???) public {
        Order memory newOrder = ???

        buyOrders.push(newOrder); // .push takes one item and adds it to the end of the list
    }

    function nbSellOrders() public view returns (uint) {
        // Return the number of item sellOrders
    }

    function allSellOrders() public view returns (Order[] memory) {
        // Return all sellOrders price and quantity
    } 

    function nbBuyOrders() public view returns (uint) {
        // Return the number of items in buyOrders
    }
   
    function allBuyOrders() public view returns (Order[] memory) {
        // Return the number of items in buyOrders
    }

    function matchOrders() public {
	// match all buying and selling orders, fullfilling them if possible
    }
}