/*
This file is part of web3.js.

web3.js is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

web3.js is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 *
 *  @module ABI
 */

import { HexString, AbiParameter, DecodedParams } from 'web3-types';
import { decodeParameter, decodeParametersWith } from './parameters_api.js';

const STATIC_TYPES = ['bool', 'string', 'int', 'uint', 'address', 'fixed', 'ufixed'];

const _decodeParameter = (inputType: string, clonedTopic: string) =>
	inputType === 'string' ? clonedTopic : decodeParameter(inputType, clonedTopic);

/**
 * Decodes ABI-encoded log data and indexed topic data.
 * @param inputs - A {@link AbiParameter} input array. See the [Solidity documentation](https://docs.soliditylang.org/en/develop/types.html) for a list of types.
 * @param data - The ABI byte code in the `data` field of a log.
 * @param topics - An array with the index parameter topics of the log, without the topic[0] if its a non-anonymous event, otherwise with topic[0]
 * @returns - The result object containing the decoded parameters.
 *
 * @example
 * ```ts
 * let res = web3.eth.abi.decodeLog(
 *    [
 *      {
 *        type: "string",
 *        name: "myString",
 *      },
 *      {
 *        type: "uint256",
 *        name: "myNumber",
 *        indexed: true,
 *      },
 *      {
 *        type: "uint8",
 *        name: "mySmallNumber",
 *        indexed: true,
 *      },
 *    ],
 *    "0x0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000748656c6c6f252100000000000000000000000000000000000000000000000000",
 *    [
 *      "0x000000000000000000000000000000000000000000000000000000000000f310",
 *      "0x0000000000000000000000000000000000000000000000000000000000000010",
 *    ]
 *  );
 * > {
 *  '0': 'Hello%!',
 *  '1': 62224n,
 *  '2': 16n,
 *  __length__: 3,
 *  myString: 'Hello%!',
 *  myNumber: 62224n,
 *  mySmallNumber: 16n
 * }
 * ```
 */
export const decodeLog = <ReturnType extends DecodedParams>(
	inputs: Array<AbiParameter> | ReadonlyArray<AbiParameter>,
	data: HexString,
	topics: string | string[],
) => {
	const clonedTopics = Array.isArray(topics) ? topics : [topics];

	const indexedInputs: Record<number, AbiParameter> = {};
	const nonIndexedInputs: Record<number, AbiParameter> = {};

	for (const [i, input] of inputs.entries()) {
		if (input.indexed) {
			indexedInputs[i] = input;
		} else {
			nonIndexedInputs[i] = input;
		}
	}

	const decodedNonIndexedInputs: DecodedParams = data
		? decodeParametersWith(Object.values(nonIndexedInputs), data, true)
		: { __length__: 0 };

	// If topics are more than indexed inputs, that means first topic is the event signature
	const offset = clonedTopics.length - Object.keys(indexedInputs).length;

	const decodedIndexedInputs = Object.values(indexedInputs).map((input, index) =>
		STATIC_TYPES.some(s => input.type.startsWith(s))
			? _decodeParameter(input.type, clonedTopics[index + offset])
			: clonedTopics[index + offset],
	);

	const returnValues: DecodedParams = { __length__: 0 };

	let indexedCounter = 0;
	let nonIndexedCounter = 0;

	for (const [i, res] of inputs.entries()) {
		returnValues[i] = res.type === 'string' ? '' : undefined;

		if (indexedInputs[i]) {
			returnValues[i] = decodedIndexedInputs[indexedCounter];
			indexedCounter += 1;
		}

		if (nonIndexedInputs[i]) {
			returnValues[i] = decodedNonIndexedInputs[String(nonIndexedCounter)];
			nonIndexedCounter += 1;
		}

		if (res.name) {
			returnValues[res.name] = returnValues[i];
		}

		returnValues.__length__ += 1;
	}

	return returnValues as ReturnType;
};