add buyout extend

contracts/GeneralizedFragment/impl/BuyoutModel.sol

@@ -0,0 +1,87 @@
+/*
+
+    Copyright 2021 DODO ZOO.
+    SPDX-License-Identifier: Apache-2.0
+
+*/
+
+pragma solidity 0.6.9;
+pragma experimental ABIEncoderV2;
+
+import {InitializableOwnable} from "../../lib/InitializableOwnable.sol";
+import {IERC20} from "../../intf/IERC20.sol";
+import {SafeMath} from "../../lib/SafeMath.sol";
+
+interface IBuyout {
+    function getBuyoutQualification(address user) external view returns (bool);
+}
+
+contract BuyoutModel is InitializableOwnable {
+    using SafeMath for uint256;
+
+    uint256 public _MIN_FRAG_ = 100; //0.1
+    uint256 public _MAX_FRAG_ = 1000; //1
+    int public _BUYOUT_FEE_ = 0;
+
+    struct FragInfo {
+        uint256 minFrag;
+        uint256 maxFrag;
+        address buyoutAddr;
+        bool isSet;
+    }
+
+    mapping(address => FragInfo) frags;
+
+    function addFragInfo(address fragAddr, uint256 minFrag, uint256 maxFrag, address buyoutAddr) external onlyOwner {
+        FragInfo memory fragInfo =  FragInfo({
+            minFrag: minFrag,
+            maxFrag: maxFrag,
+            buyoutAddr: buyoutAddr,
+            isSet: true
+        });
+        frags[fragAddr] = fragInfo;
+    }
+
+    function setFragInfo(address fragAddr, uint256 minFrag, uint256 maxFrag, address buyoutAddr) external onlyOwner {
+        frags[fragAddr].minFrag = minFrag;
+        frags[fragAddr].maxFrag = maxFrag;
+        frags[fragAddr].buyoutAddr = buyoutAddr;
+    }
+
+    function setGlobalParam(uint256 minFrag, uint256 maxFrag, uint256 buyoutFee) external onlyOwner {
+        require(minFrag <= 1000 && maxFrag <= 1000, "PARAM_INVALID");
+        _MIN_FRAG_ = minFrag;
+        _MAX_FRAG_ = maxFrag;
+        _BUYOUT_FEE_ = int(buyoutFee);
+    }
+
+    function getBuyoutStatus(address fragAddr, address user) external view returns (int) {
+        FragInfo memory fragInfo = frags[fragAddr];
+        
+        uint256 userBalance = IERC20(fragAddr).balanceOf(user);
+        uint256 totalSupply = IERC20(fragAddr).totalSupply();
+        uint256 minFrag = _MIN_FRAG_;
+        uint256 maxFrag = _MAX_FRAG_;
+
+        if(fragInfo.isSet) {
+            address buyoutAddr = fragInfo.buyoutAddr;
+            if(buyoutAddr != address(0)) {
+                bool isQualified = IBuyout(buyoutAddr).getBuyoutQualification(user);
+                if(isQualified) {
+                    return _BUYOUT_FEE_;
+                }else {
+                    return -1;
+                }
+            }
+
+            minFrag = fragInfo.minFrag;
+            maxFrag = fragInfo.maxFrag;
+        }
+
+        if(userBalance >= totalSupply.mul(minFrag).div(1000) && userBalance <= totalSupply.mul(maxFrag).div(1000)) {
+            return _BUYOUT_FEE_;
+        }else {
+            return -1;
+        }
+    }
+}