// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract Murabaha {
  address public buyer;
  uint256 public cost;
  uint256 public profitMargin;
  uint256 public totalPrice;
  uint8 public installments;
  uint8 public paid;

  event InstallmentPaid(address indexed buyer, uint256 amount, uint8 paid);

  constructor(address _buyer, uint256 _cost, uint256 _margin, uint8 _installments) {
    buyer = _buyer;
    cost = _cost;
    profitMargin = _margin;
    totalPrice = cost + (cost * margin / 100);
    installments = _installments;
  }

  function payInstallment() external payable {
    require(msg.sender == buyer, "Only buyer");
    require(paid < installments, "Already paid");
    uint256 perInstallment = totalPrice / installments;
    require(msg.value == perInstallment, "Incorrect amount");
    paid++;
    emit InstallmentPaid(buyer, msg.value, paid);
  }

  function getRemaining() external view returns (uint256) {
    return (installments - paid) * (totalPrice / installments);
  }
}