pragma solidity ^0.4.13;


/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
  address public owner;


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable() {
    owner = msg.sender;
  }


  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }


  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) onlyOwner {
    if (newOwner != address(0)) {
      owner = newOwner;
    }
  }

}

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/179
 */
contract ERC20Basic {
  uint256 public totalSupply;
  function balanceOf(address who) constant returns (uint256);
  function transfer(address to, uint256 value) returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}


/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender) constant returns (uint256);
  function transferFrom(address from, address to, uint256 value) returns (bool);
  function approve(address spender, uint256 value) returns (bool);
  event Approval(address indexed owner, address indexed spender, uint256 value);
}

/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
  function mul(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal constant returns (uint256) {
    // assert(b > 0); // Solidity automatically throws when dividing by 0
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
    return c;
  }

  function sub(uint256 a, uint256 b) internal constant returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}


/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances. 
 */
contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) balances;

  /**
  * @dev transfer token for a specified address
  * @param _to The address to transfer to.
  * @param _value The amount to be transferred.
  */
  function transfer(address _to, uint256 _value) returns (bool) {
    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    Transfer(msg.sender, _to, _value);
    return true;
  }

  /**
  * @dev Gets the balance of the specified address.
  * @param _owner The address to query the the balance of. 
  * @return An uint256 representing the amount owned by the passed address.
  */
  function balanceOf(address _owner) constant returns (uint256 balance) {
    return balances[_owner];
  }

}


/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is ERC20, BasicToken {

  mapping (address => mapping (address => uint256)) allowed;


  /**
   * @dev Transfer tokens from one address to another
   * @param _from address The address which you want to send tokens from
   * @param _to address The address which you want to transfer to
   * @param _value uint256 the amout of tokens to be transfered
   */
  function transferFrom(address _from, address _to, uint256 _value) returns (bool) {
    var _allowance = allowed[_from][msg.sender];

    // Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
    // require (_value <= _allowance);

    balances[_to] = balances[_to].add(_value);
    balances[_from] = balances[_from].sub(_value);
    allowed[_from][msg.sender] = _allowance.sub(_value);
    Transfer(_from, _to, _value);
    return true;
  }

  /**
   * @dev Aprove the passed address to spend the specified amount of tokens on behalf of msg.sender.
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
  function approve(address _spender, uint256 _value) returns (bool) {

    // To change the approve amount you first have to reduce the addresses`
    //  allowance to zero by calling `approve(_spender, 0)` if it is not
    //  already 0 to mitigate the race condition described here:
    //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    require((_value == 0) || (allowed[msg.sender][_spender] == 0));

    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
    return true;
  }

  /**
   * @dev Function to check the amount of tokens that an owner allowed to a spender.
   * @param _owner address The address which owns the funds.
   * @param _spender address The address which will spend the funds.
   * @return A uint256 specifing the amount of tokens still avaible for the spender.
   */
  function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
    return allowed[_owner][_spender];
  }

}


contract PGDToken is StandardToken,Ownable{

	//the base info of the token
	string public constant name="pagoda coin";
	string public constant symbol="PGD";
	string public constant version = "1.0";
	uint256 public constant decimals = 18;

	uint256 public constant MAX_SUPPLY=200000000*10**decimals;
	uint256 public constant MAX_FUNDING_SUPPLY=100000000*10**decimals;
	//teamKeeping
	uint256 public constant TEAM_KEEPING=100000000*10**decimals;

	uint256 public constant rate=17000;
	
	uint256 public totalFundingSupply;
	uint256 public totalTeamWithdrawSupply;

	uint256 public startBlock;
	uint256 public endBlock;
	address[] public allFundingUsers;

	mapping(address=>uint256) public fundBalance;
	

	function PGDToken(){
		totalSupply = 0 ;
		totalFundingSupply = 0;
		totalTeamWithdrawSupply=0;

		startBlock = 4000000;
		endBlock = 6000000;
	}

	modifier beforeBlock(uint256 _blockNum){
		assert(getCurrentBlockNum()<_blockNum);
		_;
	}

	modifier afterBlock(uint256 _blockNum){
		assert(getCurrentBlockNum()>=_blockNum);
		_;
	}

	modifier notReachTotalSupply(uint256 _value,uint256 _rate){
		assert(MAX_SUPPLY>=totalSupply.add(_value.mul(_rate)));
		_;
	}

	modifier notReachFundingSupply(uint256 _value,uint256 _rate){
		assert(MAX_FUNDING_SUPPLY>=totalFundingSupply.add(_value.mul(_rate)));
		_;
	}

	modifier notReachTeamWithdrawSupply(uint256 _value,uint256 _rate){
		assert(TEAM_KEEPING>=totalTeamWithdrawSupply.add(_value.mul(_rate)));
		_;
	}

	//owner有权限提取账户中的eth
	function etherProceeds() external
		onlyOwner

	{
		if(!msg.sender.send(this.balance)) revert();
	}


	//众筹，不超过最大众筹份额,要在众筹时间内
	function () payable external
		afterBlock(startBlock)
		beforeBlock(endBlock)
		notReachFundingSupply(msg.value,rate)
	{
			processFunding(msg.sender,msg.value,rate);
			//增加已众筹份额
			uint256 amount=msg.value.mul(rate);
			totalFundingSupply = totalFundingSupply.add(amount);
			
			//另外记录众筹数据，以避免受转账影响
			allFundingUsers.push(msg.sender);
			fundBalance[msg.sender]=fundBalance[msg.sender].add(amount);


	}

	//众筹完成后，owner可以按比例给用户分发剩余代币
	function airdrop(address receiver,uint256 _value) external
	    onlyOwner
		afterBlock(endBlock)
		notReachFundingSupply(_value,1)
	{
		processFunding(receiver,_value,1);
		//增加已众筹份额
		totalFundingSupply=totalFundingSupply.add(_value);
	}

	//owner有权限提取币
	function patformWithdraw(uint256 _value) external
		onlyOwner
		notReachTeamWithdrawSupply(_value,1)

	{
		processFunding(msg.sender,_value,1);
		//增加团队已提现份额
		totalTeamWithdrawSupply=totalTeamWithdrawSupply.add(_value);

	}
	//不能超过最大分发限额
	function processFunding(address receiver,uint256 _value,uint256 _rate) internal
		notReachTotalSupply(_value,_rate)
	{
		uint256 amount=_value.mul(_rate);
		totalSupply=totalSupply.add(amount);
		balances[receiver] +=amount;
		Transfer(0x0, receiver, amount);
	}


	function getCurrentBlockNum() internal returns (uint256){
		return block.number;
	}



    function setupFundingInfo(uint256 _startBlock,uint256 _endBlock) external
        onlyOwner
    {
		startBlock=_startBlock;
		endBlock=_endBlock;
    }
}