// Source: contracts/utils/InterchainAddressTracker.sol

pragma solidity ^0.8.0;

// SPDX-License-Identifier: MIT

// File contracts/interfaces/IInterchainAddressTracker.sol

/**
 * @title IInterchainAddressTracker
 * @dev Manages trusted addresses by chain, keeps track of addresses supported by the Axelar gateway contract
 */
interface IInterchainAddressTracker {
    error ZeroAddress();
    error LengthMismatch();
    error ZeroStringLength();
    error UntrustedChain();

    event TrustedAddressSet(string chain, string address_);
    event TrustedAddressRemoved(string chain);

    /**
     * @dev Gets the name of the chain this is deployed at
     */
    function chainName() external view returns (string memory);

    /**
     * @dev Gets the trusted address at a remote chain
     * @param chain Chain name of the remote chain
     * @return trustedAddress_ The trusted address for the chain. Returns '' if the chain is untrusted
     */
    function trustedAddress(string memory chain) external view returns (string memory trustedAddress_);

    /**
     * @dev Gets the trusted address hash for a chain
     * @param chain Chain name
     * @return trustedAddressHash_ the hash of the trusted address for that chain
     */
    function trustedAddressHash(string memory chain) external view returns (bytes32 trustedAddressHash_);

    /**
     * @dev Checks whether the interchain sender is a trusted address
     * @param chain Chain name of the sender
     * @param address_ Address of the sender
     * @return bool true if the sender chain/address are trusted, false otherwise
     */
    function isTrustedAddress(string calldata chain, string calldata address_) external view returns (bool);
}

// File contracts/libs/StringStorage.sol

library StringStorage {
    struct Wrapper {
        string value;
    }

    function set(bytes32 slot, string memory value) internal {
        _getStorageStruct(slot).value = value;
    }

    function get(bytes32 slot) internal view returns (string memory value) {
        value = _getStorageStruct(slot).value;
    }

    function clear(bytes32 slot) internal {
        delete _getStorageStruct(slot).value;
    }

    function _getStorageStruct(bytes32 slot) internal pure returns (Wrapper storage wrapper) {
        assembly {
            wrapper.slot := slot
        }
    }
}

// File contracts/utils/InterchainAddressTracker.sol

/**
 * @title InterchainAddressTracker
 * @dev Manages and validates trusted interchain addresses of an application.
 */
contract InterchainAddressTracker is IInterchainAddressTracker {
    bytes32 internal constant PREFIX_ADDRESS_MAPPING = keccak256('interchain-address-tracker-address-mapping');
    bytes32 internal constant PREFIX_ADDRESS_HASH_MAPPING =
        keccak256('interchain-address-tracker-address-hash-mapping');
    // bytes32(uint256(keccak256('interchain-address-tracker-chain-name')) - 1)
    bytes32 internal constant _CHAIN_NAME_SLOT = 0x0e2c162a1f4b5cff9fdbd6b34678a9bcb9898a0b9fbca695b112d61688d8b2ac;

    function _setChainName(string memory chainName_) internal {
        StringStorage.set(_CHAIN_NAME_SLOT, chainName_);
    }

    /**
     * @dev Gets the name of the chain this is deployed at
     */
    function chainName() public view returns (string memory chainName_) {
        chainName_ = StringStorage.get(_CHAIN_NAME_SLOT);
    }

    /**
     * @dev Gets the trusted address at a remote chain
     * @param chain Chain name of the remote chain
     * @return trustedAddress_ The trusted address for the chain. Returns '' if the chain is untrusted
     */
    function trustedAddress(string memory chain) public view returns (string memory trustedAddress_) {
        trustedAddress_ = StringStorage.get(_getTrustedAddressSlot(chain));
    }

    /**
     * @dev Gets the trusted address hash for a chain
     * @param chain Chain name
     * @return trustedAddressHash_ the hash of the trusted address for that chain
     */
    function trustedAddressHash(string memory chain) public view returns (bytes32 trustedAddressHash_) {
        bytes32 slot = _getTrustedAddressHashSlot(chain);
        assembly {
            trustedAddressHash_ := sload(slot)
        }
    }

    /**
     * @dev Checks whether the interchain sender is a trusted address
     * @param chain Chain name of the sender
     * @param address_ Address of the sender
     * @return bool true if the sender chain/address are trusted, false otherwise
     */
    function isTrustedAddress(string calldata chain, string calldata address_) public view returns (bool) {
        bytes32 addressHash = keccak256(bytes(address_));

        return addressHash == trustedAddressHash(chain);
    }

    /**
     * @dev Gets the key for the trusted address at a remote chain
     * @param chain Chain name of the remote chain
     * @return slot the slot to store the trusted address in
     */
    function _getTrustedAddressSlot(string memory chain) internal pure returns (bytes32 slot) {
        slot = keccak256(abi.encode(PREFIX_ADDRESS_MAPPING, chain));
    }

    /**
     * @dev Gets the key for the trusted address at a remote chain
     * @param chain Chain name of the remote chain
     * @return slot the slot to store the trusted address hash in
     */
    function _getTrustedAddressHashSlot(string memory chain) internal pure returns (bytes32 slot) {
        slot = keccak256(abi.encode(PREFIX_ADDRESS_HASH_MAPPING, chain));
    }

    /**
     * @dev Sets the trusted address and its hash for a remote chain
     * @param chain Chain name of the remote chain
     * @param address_ the string representation of the trusted address
     */
    function _setTrustedAddress(string memory chain, string memory address_) internal {
        if (bytes(chain).length == 0) revert ZeroStringLength();
        if (bytes(address_).length == 0) revert ZeroStringLength();

        StringStorage.set(_getTrustedAddressSlot(chain), address_);

        bytes32 slot = _getTrustedAddressHashSlot(chain);
        bytes32 addressHash = keccak256(bytes(address_));
        assembly {
            sstore(slot, addressHash)
        }

        emit TrustedAddressSet(chain, address_);
    }

    /**
     * @dev Remove the trusted address of the chain.
     * @param chain Chain name that should be made untrusted
     */
    function _removeTrustedAddress(string memory chain) internal {
        if (bytes(chain).length == 0) revert ZeroStringLength();

        StringStorage.clear(_getTrustedAddressSlot(chain));

        bytes32 slot = _getTrustedAddressHashSlot(chain);
        assembly {
            sstore(slot, 0)
        }

        emit TrustedAddressRemoved(chain);
    }
}