// SPDX-License-Identifier: MIT
pragma solidity >=0.7.6 <0.9;

import "../../userInterfaces/IVPToken.sol";
import "../../userInterfaces/IVPContractEvents.sol";
import "./IICleanable.sol";

interface IIVPContract is IICleanable, IVPContractEvents {
    /**
     * Update vote powers when tokens are transfered.
     * Also update delegated vote powers for percentage delegation
     * and check for enough funds for explicit delegations.
     **/
    function updateAtTokenTransfer(
        address _from, 
        address _to, 
        uint256 _fromBalance,
        uint256 _toBalance,
        uint256 _amount
    ) external;

    /**
     * @notice Delegate `_bips` percentage of voting power to `_to` from `_from`
     * @param _from The address of the delegator
     * @param _to The address of the recipient
     * @param _balance The delegator's current balance
     * @param _bips The percentage of voting power to be delegated expressed in basis points (1/100 of one percent).
     *   Not cummulative - every call resets the delegation value (and value of 0 revokes delegation).
     **/
    function delegate(
        address _from, 
        address _to, 
        uint256 _balance, 
        uint256 _bips
    ) external;
    
    /**
     * @notice Explicitly delegate `_amount` of voting power to `_to` from `msg.sender`.
     * @param _from The address of the delegator
     * @param _to The address of the recipient
     * @param _balance The delegator's current balance
     * @param _amount An explicit vote power amount to be delegated.
     *   Not cummulative - every call resets the delegation value (and value of 0 undelegates `to`).
     **/    
    function delegateExplicit(
        address _from, 
        address _to, 
        uint256 _balance, 
        uint _amount
    ) external;    

    /**
     * @notice Revoke all delegation from sender to `_who` at given block. 
     *    Only affects the reads via `votePowerOfAtCached()` in the block `_blockNumber`.
     *    Block `_blockNumber` must be in the past. 
     *    This method should be used only to prevent rogue delegate voting in the current voting block.
     *    To stop delegating use delegate/delegateExplicit with value of 0 or undelegateAll/undelegateAllExplicit.
     * @param _from The address of the delegator
     * @param _who Address of the delegatee
     * @param _balance The delegator's current balance
     * @param _blockNumber The block number at which to revoke delegation.
     **/
    function revokeDelegationAt(
        address _from, 
        address _who, 
        uint256 _balance,
        uint _blockNumber
    ) external;
    
        /**
     * @notice Undelegate all voting power for delegates of `msg.sender`
     *    Can only be used with percentage delegation.
     *    Does not reset delegation mode back to NOTSET.
     * @param _from The address of the delegator
     **/
    function undelegateAll(
        address _from,
        uint256 _balance
    ) external;
    
    /**
     * @notice Undelegate all explicit vote power by amount delegates for `msg.sender`.
     *    Can only be used with explicit delegation.
     *    Does not reset delegation mode back to NOTSET.
     * @param _from The address of the delegator
     * @param _delegateAddresses Explicit delegation does not store delegatees' addresses, 
     *   so the caller must supply them.
     * @return The amount still delegated (in case the list of delegates was incomplete).
     */
    function undelegateAllExplicit(
        address _from, 
        address[] memory _delegateAddresses
    ) external returns (uint256);
    
    /**
    * @notice Get the vote power of `_who` at block `_blockNumber`
    *   Reads/updates cache and upholds revocations.
    * @param _who The address to get voting power.
    * @param _blockNumber The block number at which to fetch.
    * @return Vote power of `_who` at `_blockNumber`.
    */
    function votePowerOfAtCached(address _who, uint256 _blockNumber) external returns(uint256);
    
    /**
     * @notice Get the current vote power of `_who`.
     * @param _who The address to get voting power.
     * @return Current vote power of `_who`.
     */
    function votePowerOf(address _who) external view returns(uint256);
    
    /**
    * @notice Get the vote power of `_who` at block `_blockNumber`
    * @param _who The address to get voting power.
    * @param _blockNumber The block number at which to fetch.
    * @return Vote power of `_who` at `_blockNumber`.
    */
    function votePowerOfAt(address _who, uint256 _blockNumber) external view returns(uint256);

    /**
    * @notice Get the vote power of `_who` at block `_blockNumber`, ignoring revocation information (and cache).
    * @param _who The address to get voting power.
    * @param _blockNumber The block number at which to fetch.
    * @return Vote power of `_who` at `_blockNumber`. Result doesn't change if vote power is revoked.
    */
    function votePowerOfAtIgnoringRevocation(address _who, uint256 _blockNumber) external view returns(uint256);

    /**
     * Return vote powers for several addresses in a batch.
     * @param _owners The list of addresses to fetch vote power of.
     * @param _blockNumber The block number at which to fetch.
     * @return A list of vote powers.
     */    
    function batchVotePowerOfAt(
        address[] memory _owners, 
        uint256 _blockNumber
    )
        external view returns(uint256[] memory);

    /**
    * @notice Get current delegated vote power `_from` delegator delegated `_to` delegatee.
    * @param _from Address of delegator
    * @param _to Address of delegatee
    * @param _balance The delegator's current balance
    * @return The delegated vote power.
    */
    function votePowerFromTo(
        address _from, 
        address _to, 
        uint256 _balance
    ) external view returns(uint256);
    
    /**
    * @notice Get delegated the vote power `_from` delegator delegated `_to` delegatee at `_blockNumber`.
    * @param _from Address of delegator
    * @param _to Address of delegatee
    * @param _balance The delegator's current balance
    * @param _blockNumber The block number at which to fetch.
    * @return The delegated vote power.
    */
    function votePowerFromToAt(
        address _from, 
        address _to, 
        uint256 _balance,
        uint _blockNumber
    ) external view returns(uint256);

    /**
     * @notice Compute the current undelegated vote power of `_owner`
     * @param _owner The address to get undelegated voting power.
     * @param _balance Owner's current balance
     * @return The unallocated vote power of `_owner`
     */
    function undelegatedVotePowerOf(
        address _owner,
        uint256 _balance
    ) external view returns(uint256);

    /**
     * @notice Get the undelegated vote power of `_owner` at given block.
     * @param _owner The address to get undelegated voting power.
     * @param _blockNumber The block number at which to fetch.
     * @return The undelegated vote power of `_owner` (= owner's own balance minus all delegations from owner)
     */
    function undelegatedVotePowerOfAt(
        address _owner, 
        uint256 _balance,
        uint256 _blockNumber
    ) external view returns(uint256);

    /**
     * @notice Get the delegation mode for '_who'. This mode determines whether vote power is
     *  allocated by percentage or by explicit value.
     * @param _who The address to get delegation mode.
     * @return Delegation mode (NOTSET=0, PERCENTAGE=1, AMOUNT=2))
     */
    function delegationModeOf(address _who) external view returns (uint256);
    
    /**
    * @notice Get the vote power delegation `_delegateAddresses` 
    *  and `pcts` of an `_owner`. Returned in two separate positional arrays.
    * @param _owner The address to get delegations.
    * @return _delegateAddresses Positional array of delegation addresses.
    * @return _bips Positional array of delegation percents specified in basis points (1/100 or 1 percent)
    * @return _count The number of delegates.
    * @return _delegationMode The mode of the delegation (NOTSET=0, PERCENTAGE=1, AMOUNT=2).
    */
    function delegatesOf(
        address _owner
    )
        external view 
        returns (
            address[] memory _delegateAddresses, 
            uint256[] memory _bips,
            uint256 _count,
            uint256 _delegationMode
        );

    /**
    * @notice Get the vote power delegation `delegationAddresses` 
    *  and `pcts` of an `_owner`. Returned in two separate positional arrays.
    * @param _owner The address to get delegations.
    * @param _blockNumber The block for which we want to know the delegations.
    * @return _delegateAddresses Positional array of delegation addresses.
    * @return _bips Positional array of delegation percents specified in basis points (1/100 or 1 percent)
    * @return _count The number of delegates.
    * @return _delegationMode The mode of the delegation (NOTSET=0, PERCENTAGE=1, AMOUNT=2).
    */
    function delegatesOfAt(
        address _owner,
        uint256 _blockNumber
    )
        external view 
        returns (
            address[] memory _delegateAddresses, 
            uint256[] memory _bips,
            uint256 _count,
            uint256 _delegationMode
        );

    /**
     * The VPToken (or some other contract) that owns this VPContract.
     * All state changing methods may be called only from this address.
     * This is because original msg.sender is sent in `_from` parameter
     * and we must be sure that it cannot be faked by directly calling VPContract.
     * Owner token is also used in case of replacement to recover vote powers from balances.
     */
    function ownerToken() external view returns (IVPToken);
    
    /**
     * Return true if this IIVPContract is configured to be used as a replacement for other contract.
     * It means that vote powers are not necessarily correct at the initialization, therefore
     * every method that reads vote power must check whether it is initialized for that address and block.
     */
    function isReplacement() external view returns (bool);
}