contract CrowdSale is Ownable {

    // ERC20 Token
    ERC20 public token;

    // address where receives funds
    address public beneficiary;
    // address where provides tokens
    address public tokenHolder;

    // how many token units per wei
    uint public rate;

    // amount of goal in wei
    uint public amountGoal;

    // amount of current raised money in wei
    uint public amountRaised;

    // amount of tokens issued
    uint public amountTokenIssued;

    // Important Time
    uint public startTime;
    uint public endTime;

    // Stages Info
    struct Stage {
        uint duration;      // Duration in second of current stage
        uint rate;          // 100 = 100%
    }
    Stage[] public icoStages;
    Stage[] public lockStages;


    // Purchaser Info
    struct PurchaserInfo {
        uint amountEtherSpent;
        uint amountTokenTaken;
        uint[] lockedToken;
    }
    mapping(address => PurchaserInfo) public purchasers;

    address[] public purchaserList;


    // ----- Events -----
    event TokenPurchase(address purchaser, uint value, uint buyTokens, uint bonusTokens);
    event GoalReached(uint totalAmountRaised, uint totalTokenIssued);
    event FundingWithdrawn(address beneficiaryAddress, uint value);
    event UnlockToken(address purchaser, uint amountUnlockedTokens);


    // ----- Modifiers -----
    modifier afterEnded {
        require(isEnded());
        _;
    }

    modifier onlyOpenTime {
        require(isStarted());
        require(!isEnded());
        _;
    }


    // ----- Functions -----
    function CrowdSale(address beneficiaryAddr, address tokenHolderAddr, address tokenAddr, uint tokenRate) public {
        require(beneficiaryAddr != address(0));
        require(tokenHolderAddr != address(0));
        require(tokenAddr != address(0));
        require(tokenRate > 0);

        beneficiary = beneficiaryAddr;
        tokenHolder = tokenHolderAddr;
        token = ERC20(tokenAddr);
        rate = tokenRate;

        _initStages();
    }

    function _initStages() internal;   //Need override

    function getTokenAddress() public view returns(address) {
        return token;
    }

    function getLockedToken(address _purchaser, uint stageIdx) public view returns(uint) {
        if(stageIdx >= purchasers[_purchaser].lockedToken.length) {
            return 0;
        }
        return purchasers[_purchaser].lockedToken[stageIdx];
    }

    function canTokenUnlocked(uint stageIndex) public view returns(bool) {
        if(0 <= stageIndex && stageIndex < lockStages.length){
            uint stageEndTime = endTime;
            for(uint i = 0; i <= stageIndex; i++) {
                stageEndTime += lockStages[i].duration;
            }//for
            return now > stageEndTime;
        }
        return false;
    }

    function isStarted() public view returns(bool) {
        return 0 < startTime && startTime <= now;
    }

    function isReachedGoal() public view returns(bool) {
        return amountRaised >= amountGoal;
    }

    function isEnded() public view returns(bool) {
        return now > endTime || isReachedGoal();
    }

    function getCurrentStage() public view returns(int) {
        int stageIdx = -1;
        uint stageEndTime = startTime;
        for(uint i = 0; i < icoStages.length; i++) {
            stageEndTime += icoStages[i].duration;
            if (now <= stageEndTime) {
                stageIdx = int(i);
                break;
            }
        }
        return stageIdx;
    }

    function getRemainingTimeInSecond() public view returns(uint) {
        if(endTime == 0)
            return 0;
        return endTime - now;
    }

    function _addPurchaser(address purchaser) internal {
        require(purchaser != address(0));

//        for (uint i = 0; i < purchaserList.length; i++) {
//            if (purchaser == purchaserList[i]){
//                return;
//            }
//        }
        purchaserList.push(purchaser);
    }

    function start(uint fundingGoalInEther) public onlyOwner {
        require(!isStarted());
        require(fundingGoalInEther > 0);
        amountGoal = fundingGoalInEther * 1 ether;

        startTime = now;

        uint duration = 0;
        for(uint i = 0; i < icoStages.length; i++){
            duration += icoStages[i].duration;
        }

        endTime = startTime + duration;
    }

    function stop() public onlyOwner {
        require(isStarted());
        endTime = now;
    }

    function () payable public onlyOpenTime {
        require(msg.value > 0);

        uint amount = msg.value;
        var (buyTokenCount, bonusTokenCount) = _getTokenCount(amount);

        PurchaserInfo storage pi = purchasers[msg.sender];
        pi.amountEtherSpent += amount;
        pi.amountTokenTaken += buyTokenCount;

        if (pi.lockedToken.length == 0) {
            pi.lockedToken = new uint[](lockStages.length);
        }

        for(uint i = 0; i < lockStages.length; i++) {
            Stage storage stage = lockStages[i];
            pi.lockedToken[i] += stage.rate * bonusTokenCount / 100;
        }


        amountRaised += amount;
        amountTokenIssued += buyTokenCount;

        token.transferFrom(tokenHolder, msg.sender, buyTokenCount);
        TokenPurchase(msg.sender, amount, buyTokenCount, bonusTokenCount);

        _addPurchaser(msg.sender);

        if(isReachedGoal()){
            endTime = now;
        }
    }

    function _getTokenCount(uint amountInWei) internal view returns(uint buyTokenCount, uint bonusTokenCount) {
        buyTokenCount = amountInWei * rate;

        int stageIdx = getCurrentStage();
        assert(stageIdx >= 0 && uint(stageIdx) < icoStages.length);
        bonusTokenCount = buyTokenCount * icoStages[uint(stageIdx)].rate / 100;
    }


    function safeWithdrawal() public onlyOwner {
        require(beneficiary != address(0));
        beneficiary.transfer(amountRaised);
        FundingWithdrawn(beneficiary, amountRaised);
    }

    function unlockBonusTokens(uint stageIndex, uint purchaserStartIdx, uint purchaserEndIdx) public afterEnded onlyOwner {
        require(0 <= purchaserStartIdx && purchaserStartIdx < purchaserEndIdx && purchaserEndIdx <= purchaserList.length);
        require(canTokenUnlocked(stageIndex));

        for (uint j = purchaserStartIdx; j < purchaserEndIdx; j++) {
            address purchaser = purchaserList[j];
            if(purchaser != address(0)){
                PurchaserInfo storage pi = purchasers[purchaser];
                uint unlockedToken = pi.lockedToken[stageIndex];
                if (unlockedToken > 0) {
                    pi.lockedToken[stageIndex] = 0;
                    pi.amountTokenTaken += unlockedToken;

                    amountTokenIssued += unlockedToken;

                    token.transferFrom(tokenHolder, purchaser, unlockedToken);
                    UnlockToken(purchaser, unlockedToken);
                }
            }
        }//for

    }

}
function getTokenAddress() public view returns(address) {
    return token;
}

//Need override