import { Fetch, IFetchOptions } from 'rpc-request';

export type formatParam = { format?: 'json' | 'hex' | 'bin' };

export type BlockParams = formatParam & { hash: string };

export type BlockHeightParams = formatParam & { height: number };

export type Outpoint = { txid: string; n: number };

export type UtxosParams = formatParam & {
    checkmempool?: boolean;
    outpoints: Outpoint[] | Outpoint;
};

export type HeaderParams = BlockParams & { count?: number };

export type TxParams = formatParam & { txid: string };

export type Auth = { user: string; pass: string };

export type RESTIniOptions = IFetchOptions & { auth?: Auth; port?: number; url: string };

export type AuthHeaders = HeadersInit & { Authorization: string };

export class RESTClient extends Fetch {
    /**
     * @param {RESTIniOptions} [opts]
     */
    constructor(opts: RESTIniOptions) {
        if (!opts.url) {
            throw new Error('URL is required');
        }

        const params: RESTIniOptions = {
            ...opts,
            base_url: opts.base_url || opts.url + ':' + (opts.port || 8332).toString(),
            transform: 'json',
            headers: { 'Content-Type': 'application/json' },
        };

        if (opts.auth) {
            if (!params.headers) {
                params.headers = {};
            }

            (params.headers as AuthHeaders).Authorization =
                'Basic ' +
                Buffer.from(opts.auth.user + ':' + opts.auth.pass, 'utf8').toString('base64');
        }

        super(params);
    }

    /**
     * @description Get a block with a particular header hash
     * @param {object} [params]
     * @param {string} params.hash - The hash of the header of the block to get
     * @param {string} [params.format='json'] - Set to 'json' for decoded block contents in JSON, or 'bin' or 'hex' for a serialized block in binary or hex
     */
    getBlock({ hash, format = 'json' }: BlockParams) {
        return this.get(`/rest/block/${hash}.${format}`);
    }

    /**
     * @description Get a block with a particular header hash (includes TXIDs for transactions within the block rather than the complete transactions)
     * @param {object} [params]
     * @param {string} params.hash - The hash of the header of the block to get
     * @param {string} [params.format='json'] - Set to 'json' for decoded block contents in JSON, or 'bin' or 'hex' for a serialized block in binary or hex
     */
    getBlockNoTxDetails({ hash, format = 'json' }: BlockParams) {
        return this.get(`/rest/block/notxdetails/${hash}.${format}`);
    }

    /**
     * @description Get the hash of the block in the current best blockchain based on its height.
     * @param {object} [params]
     * @param {number} params.height - The height of the block
     * @param {string} [params.format='json'] - Set to `json`, `bin` or `hex`.
     */
    getBlockHashByHeight({ height, format = 'json' }: BlockHeightParams) {
        return this.get(`/rest/blockhashbyheight/${height}.${format}`);
    }

    /**
     * @description Get information about the current state of the block chain.
     */
    getChainInfo() {
        return this.get('rest/chaininfo.json');
    }

    /**
     * @description Get an UTXO set given a set of outpoints.
     * @param {object} [params]
     * @param {boolean} [params.checkmempool=true] - Set to `true` to include transactions that are currently in the memory pool to the calculation
     * @param {Object|Object[]} params.outpoints - The list of outpoints to be queried.
     * @param {string} [params.format='json'] - Set to `json`, `bin` or `hex`.
     */
    getUtxos({ checkmempool = true, outpoints, format = 'json' }: UtxosParams) {
        let uri = `rest/getutxos${checkmempool ? '/checkmempool' : ''}`;
        outpoints = !Array.isArray(outpoints) ? [outpoints] : outpoints;
        for (const { txid, n } of outpoints) {
            uri += `/${txid}-${n}`;
        }
        return this.get(uri + '.' + format);
    }

    /**
     * @description Get a specified amount of block headers in upward direction.
     * @param {object} [params]
     * @param {number} [params.count=1] - The amount of block headers in upward direction to return
     * @param {string} params.hash - The hash of the header of the block to get
     * @param {string} [params.format='json'] - Set to `json`, `bin` or `hex`.
     */
    getHeaders({ count, hash, format = 'json' }: HeaderParams) {
        return this.get(`rest/headers/${count}/${hash}.${format}`);
    }

    /**
     * @description Get all transaction in the memory pool with detailed information.
     */
    getMemPoolContents() {
        return this.get('rest/mempool/contents.json');
    }

    /**
     * @description Get information about the node’s current transaction memory pool.
     */
    getMemPoolInfo() {
        return this.get('rest/mempool/info.json');
    }

    /**
     * @description Gets a hex-encoded serialized transaction or a JSON object describing the transaction.
     * @param {object} [params]
     * @param {string} params.txid - The TXID of the transaction to get.
     * @param {string} [params.format='json'] - Set to `json`, `bin` or `hex`.
     */
    getTx({ txid, format = 'json' }: TxParams) {
        return this.get(`rest/tx/${txid}.${format}`);
    }
}