// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.6.0;

import {IWriterRegistry} from './interface/IWriterRegistry.sol';
import {Bitcoin} from './types/Bitcoin.sol';

contract WriterRegistry is IWriterRegistry {
    string internal constant ERR_NO_BTC_HASH = 'Cannot set empty BTC address';

    // for external enumeration
    address[] internal _writers;

    mapping(address => Bitcoin.Address) internal _btcAddresses;

    function _setBtcAddress(
        address account,
        bytes20 btcHash,
        Bitcoin.Script format
    ) internal {
        require(btcHash != 0, ERR_NO_BTC_HASH);
        _btcAddresses[account].btcHash = btcHash;
        _btcAddresses[account].format = format;
    }

    /**
     * @notice Sets the payout address for the caller.
     *
     * The script format is defined by the `Bitcoin.Script` enum which describes
     * the expected output format (P2SH, P2PKH, P2WPKH).
     *
     * @param btcHash Address hash
     * @param format Payment format
     **/
    function setBtcAddress(bytes20 btcHash, Bitcoin.Script format)
        external
        virtual
        override
    {
        _setBtcAddress(msg.sender, btcHash, format);
    }

    function _getBtcAddress(address account)
        internal
        view
        returns (bytes20 btcHash, Bitcoin.Script format)
    {
        return (_btcAddresses[account].btcHash, _btcAddresses[account].format);
    }

    /**
     * @notice Get the configured BTC address for an account.
     * @param account Minter address
     * @return btcHash Address hash
     * @return format Expected payment format
     **/
    function getBtcAddress(address account)
        external
        override
        view
        returns (bytes20 btcHash, Bitcoin.Script format)
    {
        return _getBtcAddress(account);
    }

    /**
     * @notice Return all option sellers (may contain null entries if obligations are sold).
     * @dev The caller should check that each account's obligation balance is sufficient.
     * @return Array of all obligation writers / buyers.
     **/
    function allWriters() external override view returns (address[] memory) {
        return _writers;
    }
}