// SPDX-License-Identifier: MIT
pragma solidity ^0.8.23;

import { IERC7579Account } from "../erc-7579/IMSA.sol";

/**
 * @title Example7710Manager
 * @notice Not for production use.A minimal reference implementation for ERC-7710 focusing on delegation redemption.
 * @dev This is an intentionally simplified implementation to demonstrate core concepts.
 * For a complete production implementation with features like conditional permission enforcement and revocation, see MetaMask's Delegation Framework:
 * https://github.com/MetaMask/delegation-framework/blob/main/src/DelegationManager.sol
 */
contract Example7710Manager {
    ////////////////////////////// Types //////////////////////////////

    struct Delegation {
        address delegator;    // The address delegating authority
        address delegate;     // The address receiving authority
        bytes32 authority;    // The authority being delegated (or ROOT_AUTHORITY)
        bytes signature;      // The delegator's signature authorizing this delegation
    }

    ////////////////////////////// Errors //////////////////////////////

    error TupleDataLengthMismatch();
    error InvalidDelegate();
    error InvalidAuthority();
    error InvalidSignature();

    ////////////////////////////// Constants //////////////////////////////

    /// @dev Special authority value indicating the delegator is the root authority
    bytes32 public constant ROOT_AUTHORITY = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff;

    ////////////////////////////// External Methods //////////////////////////////

    /**
     * @notice Validates and executes delegated actions through a chain of authority.
     * @param _permissionContexts Array of delegation chains, each ordered from leaf to root.
     * Each chain demonstrates authority where:
     * - Index 0 is the leaf delegation (msg.sender's authority)
     * - Each delegation points to its authority via the previous delegation's hash
     * - The last delegation must have ROOT_AUTHORITY
     * @param _modes Execution modes for each action (see ERC-7579)
     * @param _executionCallDatas Encoded actions to execute
     */
    function redeemDelegations(
        bytes[] calldata _permissionContexts,
        bytes32[] calldata _modes,
        bytes[] calldata _executionCallDatas
    ) external {
        uint256 batchSize_ = _permissionContexts.length;
        if (batchSize_ != _executionCallDatas.length || batchSize_ != _modes.length) {
            revert TupleDataLengthMismatch();
        }

        Delegation[][] memory batchDelegations_ = new Delegation[][](batchSize_);

        // Process each batch
        for (uint256 batchIndex_; batchIndex_ < batchSize_; ++batchIndex_) {
            Delegation[] memory delegations_ = abi.decode(_permissionContexts[batchIndex_], (Delegation[]));

            batchDelegations_[batchIndex_] = delegations_;

            // Validate caller is the delegate
            if (delegations_[0].delegate != msg.sender) {
                revert InvalidDelegate();
            }

            // Validate each delegation in chain
            for (uint256 i = 0; i < delegations_.length; i++) {
                Delegation memory delegation_ = delegations_[i];
                bytes32 delegationHash_ = _getDelegationHash(delegation_);

                // Note: In a production implementation, you would want to use EIP-712 for typed data signing
                // and proper signature validation for both EOA and contract signatures.
                // This is simplified for demonstration purposes.
                if (!_isValidSignature(delegationHash_, delegation_.signature, delegation_.delegator)) {
                    revert InvalidSignature();
                }

                // Validate authority chain
                if (i != delegations_.length - 1) {
                    if (delegation_.authority != _getDelegationHash(delegations_[i + 1])) {
                        revert InvalidAuthority();
                    }
                    // Validate delegate chain
                    address nextDelegate_ = delegations_[i + 1].delegate;
                    if (delegation_.delegator != nextDelegate_) {
                        revert InvalidDelegate();
                    }
                } else if (delegation_.authority != ROOT_AUTHORITY) {
                    revert InvalidAuthority();
                }
            }

            // Execute the delegated action on the root delegator
            IERC7579Account(delegations_[delegations_.length - 1].delegator).executeFromExecutor(
                _modes[batchIndex_],
                _executionCallDatas[batchIndex_]
            );
        }
    }

    ////////////////////////////// Internal Methods //////////////////////////////

    /**
     * @notice Creates a simple hash of a Delegation struct
     * @dev In production, use EIP-712 for typed data hashing
     */
    function _getDelegationHash(Delegation memory delegation) internal pure returns (bytes32) {
        return keccak256(abi.encode(
            delegation.delegator,
            delegation.delegate,
            delegation.authority
        ));
    }

    /**
     * @notice Basic signature validation (simplified for example purposes)
     * @dev In production, use EIP-712 and proper signature validation
     */
    function _isValidSignature(
        bytes32 hash,
        bytes memory signature,
        address signer
    ) internal pure returns (bool) {
        // ECDSA recover
        // or ERC1271 isValidSignature
        // Logic would go here
        return true; // Simplified for example
    }
}