Ethereum Smart Contract

Looking for an experienced Solidity developer with at least 1 year experience in smart contract development. The smart contract required is a simple mintable crowdsale contract which should issue tokens immediately after purchase. Token holders should then be able to claim a certain amount of the Ethereum stored in the contract by sending the purchased tokens back to the contract. In other words, the contract should be able to exchange Ethereum for Tokens and Tokens for Ethereum based on a given exchange rate. This rate should be modifiable by the owner only. A small extra ETH fee should included in each exchange, apart from Ethereum's gas fee. This fee will then be sent to an external wallet. Ideally, the fees will be stored in the contract address until claimed by the owner (this will help reduce gas fees). Essentially, smart contract should be able to: 1) Mint tokens if no more tokens are available 2) Exchange ETH for Tokens and viceversa 3) Adjust exchange rate 4) Charge a claimable fee in each exchange