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Deal.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.4.18;

contract Trade
{
    address owner_address;
    address buyer_address;
    
    // constructor to set the owner of the contract
    constructor (address buyer_add) public {
        owner_address = msg.sender;
        buyer_address = buyer_add;
    }
    
    // structure of the buyer
    struct Buyer
    {
        address addr;
        string name;
        bool init;
    }
    
    // structure of the current shipment
    struct Shipment
    {
        address courier;
        uint price;
        uint payment;
        address payer;
        uint date;
        uint delivery_date;
        bool init;
    }
    
    // structure of a particular order
    struct Order
    {
        string product;
        uint quantity;
        string location;
        uint seq_no;
        uint phone;
        uint price;
        uint payment;
        
        Shipment shipment;
        bool init;
    }
    
    // structure of the invoice
    struct Invoice
    {
        uint order_no;
        uint phone;
        bool init;
    }
    
    // store orders mapping
    mapping (uint => Order) orders;
    
    // store invoices mapping
    mapping (uint => Invoice) invoices;
    
    // Events that depicts the flow in a smart contract
    uint order_seq;
    uint invoice_seq;
    
    event OrderSent (address buyer, string product, uint quantity, string location, uint order_no);
    event PriceSent (address buyer, uint order_no, uint product_price, uint delivery_charge, uint delivery_date);
    event Payment (address buyer, uint order_no, uint amount, uint phone, uint time_stamp);
    event InvoiceSent (address buyer, uint invoice_no, uint order_no, uint delivery_date, address courier);
    event OrderDelivered (address buyer, uint invoice_no, uint order_no, uint date, address courier);

    // Buyer request order
    function sendOrder(string product, uint quantity, string location) public {
        require(msg.sender == buyer_address);
        order_seq++;
        
        orders[order_seq] = Order(product, quantity, location, order_seq, 0, 0, 0, Shipment(0, 0, 0, 0, 0, 0, false), true);

        emit OrderSent(msg.sender, product, quantity, location, order_seq);
    }

    // line up orders
    function query(uint seq_no) constant public returns (address, string, uint, string, uint, uint, uint)
    {
        require(orders[seq_no].init);
        
        Order memory orderStruct;
        orderStruct = orders[seq_no];
        
        return (buyer_address, orderStruct.product, orderStruct.quantity, orderStruct.location, orderStruct.price, orderStruct.shipment.price, orderStruct.payment);
    }
    
    // seller sends the price and delivery_charge for the product
    function sendPrice(uint order_no, uint price, uint delivery_charge, uint delivery_date) public
    {
        
    }
    
    
    
    
}