/*
    The following is an extremely basic example of a solidity contract.
    It takes a string upon creation and then repeats it when greet() is called.
*/

contract Greeter         // The contract definition. A constructor of the same name will be automatically called on contract creation.
{
    address creator;     // At first, an empty "address"-type variable of the name "creator". Will be set in the constructor.
    string greeting;     // At first, an empty "string"-type variable of the name "greeting". Will be set in constructor and can be changed.
    bytes32 hashMessage;

    event offChainStuff (bytes32 hash, string greeting);
    event onChainStuff (bytes32 hashMessage);

    function Greeter(string _greeting) public   // The constructor. It accepts a string input and saves it to the contract's "greeting" variable.
    {
        creator = msg.sender;
        greeting = _greeting;
    }

    function mortal() {
        creator = msg.sender;
    }

    function getCreator() constant public returns (address) {
        return creator;
    }

    // Hey, go provide me the value of the message from the db with this contract's greeting hash.
    function fireOnChainEvent() public {
        onChainStuff(hashMessage);
    }

    // get the value back from the DB, and returns it to the user.
    function greet(string message) constant public returns (string)
    {
        // run intergrity check here.
        if(keccak256(message) == hashMessage) {
             return message;
        } else {
            return "ALERT! DATA HAS BEEN CORRUPTED";
        }

    }


    function getBlockNumber() constant public returns (uint) // this doesn't have anything to do with the act of greeting
    {                                                   // just demonstrating return of some global variable
        return block.number;
    }

    function setGreeting(string _newgreeting) public
    {
        greeting = _newgreeting;
    }

    function startOffChain(string _newgreeting) public {
        hashMessage = keccak256(_newgreeting);
        offChainStuff(hashMessage, _newgreeting);
    }

     /**********
     Standard kill() function to recover funds
     **********/

    function kill() public
    {
        if (msg.sender == creator)  // only allow this action if the account sending the signal is the creator
            suicide(creator);       // kills this contract and sends remaining funds back to creator
    }

}