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

/**
 * @title PercentageMath library
 * @author Aave
 * @notice Provides functions to perform percentage calculations
 * @dev Percentages are defined by default with 2 decimals of precision (100.00). The precision is indicated by PERCENTAGE_FACTOR
 * @dev Operations are rounded half up
 **/

library PercentageMath {
    uint256 constant PERCENTAGE_FACTOR = 1e4; //percentage plus two decimals
    uint256 constant HALF_PERCENT = PERCENTAGE_FACTOR / 2;

    /**
     * @dev Executes a percentage multiplication
     * @param value The value of which the percentage needs to be calculated
     * @param percentage The percentage of the value to be calculated
     * @return The percentage of value
     **/
    function percentMul(uint256 value, uint256 percentage)
        internal
        pure
        returns (uint256)
    {
        if (value == 0 || percentage == 0) {
            return 0;
        }

        require(
            value <= (type(uint256).max) / percentage,
            "MATH_MULTIPLICATION_OVERFLOW"
        );

        return (value * percentage) / PERCENTAGE_FACTOR;
    }

    /**
     * @dev Executes a percentage division
     * @param value The value of which the percentage needs to be calculated
     * @param percentage The percentage of the value to be calculated
     * @return The value divided the percentage
     **/
    function percentDiv(uint256 value, uint256 percentage)
        internal
        pure
        returns (uint256)
    {
        require(percentage != 0, "MATH_DIVISION_BY_ZERO");

        require(
            value <= type(uint256).max / PERCENTAGE_FACTOR,
            "MATH_MULTIPLICATION_OVERFLOW"
        );

        return (value * PERCENTAGE_FACTOR) / percentage;
    }
}