interface.ts

/**
 *  The Interface class is a low-level class that accepts an
 *  ABI and provides all the necessary functionality to encode
 *  and decode paramaters to and results from methods, events
 *  and errors.
 *
 *  It also provides several convenience methods to automatically
 *  search and find matching transactions and events to parse them.
 *
 *  @_subsection api/abi:Interfaces  [interfaces]
 */

import { keccak256 } from "../crypto/index.js"
import { id } from "../hash/index.js"
import {
    concat, dataSlice, getBigInt, getBytes, getBytesCopy,
    hexlify, zeroPadBytes, zeroPadValue, isHexString, defineProperties,
    assertArgument, toBeHex, assert
} from "../utils/index.js";

import { AbiCoder } from "./abi-coder.js";
import { checkResultErrors, Result } from "./coders/abstract-coder.js";
import {
    ConstructorFragment, ErrorFragment, EventFragment, FallbackFragment,
    Fragment, FunctionFragment, ParamType
} from "./fragments.js";
import { Typed } from "./typed.js";

import type { BigNumberish, BytesLike, CallExceptionError, CallExceptionTransaction } from "../utils/index.js";

import type { JsonFragment } from "./fragments.js";


export { checkResultErrors, Result };

/**
 *  When using the [[Interface-parseLog]] to automatically match a Log to its event
 *  for parsing, a **LogDescription** is returned.
 */
export class LogDescription {
    /**
     *  The matching fragment for the ``topic0``.
     */
    readonly fragment!: EventFragment;

    /**
     *  The name of the Event.
     */
    readonly name!: string;

    /**
     *  The full Event signature.
     */
    readonly signature!: string;

    /**
     *  The topic hash for the Event.
     */
    readonly topic!: string;

    /**
     *  The arguments passed into the Event with ``emit``.
     */
    readonly args!: Result

    /**
     *  @_ignore:
     */
    constructor(fragment: EventFragment, topic: string, args: Result) {
        const name = fragment.name, signature = fragment.format();
        defineProperties<LogDescription>(this, {
            fragment, name, signature, topic, args
        });
    }
}

/**
 *  When using the [[Interface-parseTransaction]] to automatically match
 *  a transaction data to its function for parsing,
 *  a **TransactionDescription** is returned.
 */
export class TransactionDescription {
    /**
     *  The matching fragment from the transaction ``data``.
     */
    readonly fragment!: FunctionFragment;

    /**
     *  The name of the Function from the transaction ``data``.
     */
    readonly name!: string;

    /**
     *  The arguments passed to the Function from the transaction ``data``.
     */
    readonly args!: Result;

    /**
     *  The full Function signature from the transaction ``data``.
     */
    readonly signature!: string;

    /**
     *  The selector for the Function from the transaction ``data``.
     */
    readonly selector!: string;

    /**
     *  The ``value`` (in wei) from the transaction.
     */
    readonly value!: bigint;

    /**
     *  @_ignore:
     */
    constructor(fragment: FunctionFragment, selector: string, args: Result, value: bigint) {
        const name = fragment.name, signature = fragment.format();
        defineProperties<TransactionDescription>(this, {
            fragment, name, args, signature, selector, value
        });
    }
}

/**
 *  When using the [[Interface-parseError]] to automatically match an
 *  error for a call result for parsing, an **ErrorDescription** is returned.
 */
export class ErrorDescription {
    /**
     *  The matching fragment.
     */
    readonly fragment!: ErrorFragment;

    /**
     *  The name of the Error.
     */
    readonly name!: string;

    /**
     *  The arguments passed to the Error with ``revert``.
     */
    readonly args!: Result;

    /**
     *  The full Error signature.
     */
    readonly signature!: string;

    /**
     *  The selector for the Error.
     */
    readonly selector!: string;

    /**
     *  @_ignore:
     */
    constructor(fragment: ErrorFragment, selector: string, args: Result) {
        const name = fragment.name, signature = fragment.format();
        defineProperties<ErrorDescription>(this, {
            fragment, name, args, signature, selector
        });
    }
}

/**
 *  An **Indexed** is used as a value when a value that does not
 *  fit within a topic (i.e. not a fixed-length, 32-byte type). It
 *  is the ``keccak256`` of the value, and used for types such as
 *  arrays, tuples, bytes and strings.
 */
export class Indexed {
    /**
     *  The ``keccak256`` of the value logged.
     */
    readonly hash!: null | string;

    /**
     *  @_ignore:
     */
    readonly _isIndexed!: boolean;

    /**
     *  Returns ``true`` if %%value%% is an **Indexed**.
     *
     *  This provides a Type Guard for property access.
     */
    static isIndexed(value: any): value is Indexed {
        return !!(value && value._isIndexed);
    }

    /**
     *  @_ignore:
     */
    constructor(hash: null | string) {
        defineProperties<Indexed>(this, { hash, _isIndexed: true })
    }
}

type ErrorInfo = {
    signature: string,
    inputs: Array<string>,
    name: string,
    reason: (...args: Array<any>) => string;
};

// https://docs.soliditylang.org/en/v0.8.13/control-structures.html?highlight=panic#panic-via-assert-and-error-via-require
const PanicReasons: Record<string, string> = {
    "0": "generic panic",
    "1": "assert(false)",
    "17": "arithmetic overflow",
    "18": "division or modulo by zero",
    "33": "enum overflow",
    "34": "invalid encoded storage byte array accessed",
    "49": "out-of-bounds array access; popping on an empty array",
    "50": "out-of-bounds access of an array or bytesN",
    "65": "out of memory",
    "81": "uninitialized function",
}

const BuiltinErrors: Record<string, ErrorInfo> = {
    "0x08c379a0": {
        signature: "Error(string)",
        name: "Error",
        inputs: [ "string" ],
        reason: (message: string) => {
            return `reverted with reason string ${ JSON.stringify(message) }`;
        }
    },
    "0x4e487b71": {
        signature: "Panic(uint256)",
        name: "Panic",
        inputs: [ "uint256" ],
        reason: (code: bigint) => {
            let reason = "unknown panic code";
            if (code >= 0 && code <= 0xff && PanicReasons[code.toString()]) {
                reason = PanicReasons[code.toString()];
            }
            return `reverted with panic code 0x${ code.toString(16) } (${ reason })`;
        }
    }
}

/*
function wrapAccessError(property: string, error: Error): Error {
    const wrap = new Error(`deferred error during ABI decoding triggered accessing ${ property }`);
    (<any>wrap).error = error;
    return wrap;
}
*/
/*
function checkNames(fragment: Fragment, type: "input" | "output", params: Array<ParamType>): void {
    params.reduce((accum, param) => {
        if (param.name) {
            if (accum[param.name]) {
                logger.throwArgumentError(`duplicate ${ type } parameter ${ JSON.stringify(param.name) } in ${ fragment.format("full") }`, "fragment", fragment);
            }
            accum[param.name] = true;
        }
        return accum;
    }, <{ [ name: string ]: boolean }>{ });
}
*/

/**
 *  An **InterfaceAbi** may be any supported ABI format.
 *
 *  A string is expected to be a JSON string, which will be parsed
 *  using ``JSON.parse``. This means that the value **must** be a valid
 *  JSON string, with no stray commas, etc.
 *
 *  An array may contain any combination of:
 *  - Human-Readable fragments
 *  - Parsed JSON fragment
 *  - [[Fragment]] instances
 *
 *  A **Human-Readable Fragment** is a string which resembles a Solidity
 *  signature and is introduced in [this blog entry](link-ricmoo-humanreadableabi).
 *  For example, ``function balanceOf(address) view returns (uint)``.
 *
 *  A **Parsed JSON Fragment** is a JavaScript Object desribed in the
 *  [Solidity documentation](link-solc-jsonabi).
 */
export type InterfaceAbi = string | ReadonlyArray<Fragment | JsonFragment | string>;

/**
 *  An Interface abstracts many of the low-level details for
 *  encoding and decoding the data on the blockchain.
 *
 *  An ABI provides information on how to encode data to send to
 *  a Contract, how to decode the results and events and how to
 *  interpret revert errors.
 *
 *  The ABI can be specified by [any supported format](InterfaceAbi).
 */
export class Interface {

    /**
     *  All the Contract ABI members (i.e. methods, events, errors, etc).
     */
    readonly fragments!: ReadonlyArray<Fragment>;

    /**
     *  The Contract constructor.
     */
    readonly deploy!: ConstructorFragment;

    /**
     *  The Fallback method, if any.
     */
    readonly fallback!: null | FallbackFragment;

    /**
     *  If receiving ether is supported.
     */
    readonly receive!: boolean;

    #errors: Map<string, ErrorFragment>;
    #events: Map<string, EventFragment>;
    #functions: Map<string, FunctionFragment>;
//    #structs: Map<string, StructFragment>;

    #abiCoder: AbiCoder;

    /**
     *  Create a new Interface for the %%fragments%%.
     */
    constructor(fragments: InterfaceAbi) {
        let abi: ReadonlyArray<Fragment | JsonFragment | string> = [ ];
        if (typeof(fragments) === "string") {
            abi = JSON.parse(fragments);
        } else {
            abi = fragments;
        }

        this.#functions = new Map();
        this.#errors = new Map();
        this.#events = new Map();
//        this.#structs = new Map();


        const frags: Array<Fragment> = [ ];
        for (const a of abi) {
            try {
                frags.push(Fragment.from(a));
            } catch (error: any) {
                console.log(`[Warning] Invalid Fragment ${ JSON.stringify(a) }:`, error.message);
            }
        }

        defineProperties<Interface>(this, {
            fragments: Object.freeze(frags)
        });

        let fallback: null | FallbackFragment = null;
        let receive = false;

        this.#abiCoder = this.getAbiCoder();

        // Add all fragments by their signature
        this.fragments.forEach((fragment, index) => {
            let bucket: Map<string, Fragment>;
            switch (fragment.type) {
                case "constructor":
                    if (this.deploy) {
                        console.log("duplicate definition - constructor");
                        return;
                    }
                    //checkNames(fragment, "input", fragment.inputs);
                    defineProperties<Interface>(this, { deploy: <ConstructorFragment>fragment });
                    return;

                case "fallback":
                    if (fragment.inputs.length === 0) {
                        receive = true;
                    } else {
                        assertArgument(!fallback || (<FallbackFragment>fragment).payable !== fallback.payable,
                            "conflicting fallback fragments", `fragments[${ index }]`, fragment);
                        fallback = <FallbackFragment>fragment;
                        receive = fallback.payable;
                    }
                    return;

                case "function":
                    //checkNames(fragment, "input", fragment.inputs);
                    //checkNames(fragment, "output", (<FunctionFragment>fragment).outputs);
                    bucket = this.#functions;
                    break;

                case "event":
                    //checkNames(fragment, "input", fragment.inputs);
                    bucket = this.#events;
                    break;

                case "error":
                    bucket = this.#errors;
                    break;

                default:
                    return;
            }

            // Two identical entries; ignore it
            const signature = fragment.format();
            if (bucket.has(signature)) { return; }

            bucket.set(signature, fragment);
        });

        // If we do not have a constructor add a default
        if (!this.deploy) {
            defineProperties<Interface>(this, {
                deploy: ConstructorFragment.from("constructor()")
            });
        }

        defineProperties<Interface>(this, { fallback, receive });
    }

    /**
     *  Returns the entire Human-Readable ABI, as an array of
     *  signatures, optionally as %%minimal%% strings, which
     *  removes parameter names and unneceesary spaces.
     */
    format(minimal?: boolean): Array<string> {
        const format = (minimal ? "minimal": "full");
        const abi = this.fragments.map((f) => f.format(format));
        return abi;
    }

    /**
     *  Return the JSON-encoded ABI. This is the format Solidiy
     *  returns.
     */
    formatJson(): string {
        const abi = this.fragments.map((f) => f.format("json"));

        // We need to re-bundle the JSON fragments a bit
        return JSON.stringify(abi.map((j) => JSON.parse(j)));
    }

    /**
     *  The ABI coder that will be used to encode and decode binary
     *  data.
     */
    getAbiCoder(): AbiCoder {
        return AbiCoder.defaultAbiCoder();
    }

    // Find a function definition by any means necessary (unless it is ambiguous)
    #getFunction(key: string, values: null | Array<any | Typed>, forceUnique: boolean): null | FunctionFragment {

        // Selector
        if (isHexString(key)) {
            const selector = key.toLowerCase();
            for (const fragment of this.#functions.values()) {
                if (selector === fragment.selector) { return fragment; }
            }
            return null;
        }

        // It is a bare name, look up the function (will return null if ambiguous)
        if (key.indexOf("(") === -1) {
            const matching: Array<FunctionFragment> = [ ];
            for (const [ name, fragment ] of this.#functions) {
                if (name.split("("/* fix:) */)[0] === key) { matching.push(fragment); }
            }

            if (values) {
                const lastValue = (values.length > 0) ? values[values.length - 1]: null;

                let valueLength = values.length;
                let allowOptions = true;
                if (Typed.isTyped(lastValue) && lastValue.type === "overrides") {
                    allowOptions = false;
                    valueLength--;
                }

                // Remove all matches that don't have a compatible length. The args
                // may contain an overrides, so the match may have n or n - 1 parameters
                for (let i = matching.length - 1; i >= 0; i--) {
                    const inputs = matching[i].inputs.length;
                    if (inputs !== valueLength && (!allowOptions || inputs !== valueLength - 1)) {
                        matching.splice(i, 1);
                    }
                }

                // Remove all matches that don't match the Typed signature
                for (let i = matching.length - 1; i >= 0; i--) {
                    const inputs = matching[i].inputs;
                    for (let j = 0; j < values.length; j++) {
                        // Not a typed value
                        if (!Typed.isTyped(values[j])) { continue; }

                        // We are past the inputs
                        if (j >= inputs.length) {
                            if (values[j].type === "overrides") { continue; }
                            matching.splice(i, 1);
                            break;
                        }

                        // Make sure the value type matches the input type
                        if (values[j].type !== inputs[j].baseType) {
                            matching.splice(i, 1);
                            break;
                        }
                    }
                }
            }

            // We found a single matching signature with an overrides, but the
            // last value is something that cannot possibly be an options
            if (matching.length === 1 && values && values.length !== matching[0].inputs.length) {
                const lastArg = values[values.length - 1];
                if (lastArg == null || Array.isArray(lastArg) || typeof(lastArg) !== "object") {
                    matching.splice(0, 1);
                }
            }

            if (matching.length === 0) { return null; }

            if (matching.length > 1 && forceUnique) {
                const matchStr = matching.map((m) => JSON.stringify(m.format())).join(", ");
                assertArgument(false, `ambiguous function description (i.e. matches ${ matchStr })`, "key", key);
            }

            return matching[0];
        }

        // Normalize the signature and lookup the function
        const result = this.#functions.get(FunctionFragment.from(key).format());
        if (result) { return result; }

        return null;
    }

    /**
     *  Get the function name for %%key%%, which may be a function selector,
     *  function name or function signature that belongs to the ABI.
     */
    getFunctionName(key: string): string {
        const fragment = this.#getFunction(key, null, false);
        assertArgument(fragment, "no matching function", "key", key);
        return fragment.name;
    }

    /**
     *  Returns true if %%key%% (a function selector, function name or
     *  function signature) is present in the ABI.
     *
     *  In the case of a function name, the name may be ambiguous, so
     *  accessing the [[FunctionFragment]] may require refinement.
     */
    hasFunction(key: string): boolean {
        return !!this.#getFunction(key, null, false);
    }

    /**
     *  Get the [[FunctionFragment]] for %%key%%, which may be a function
     *  selector, function name or function signature that belongs to the ABI.
     *
     *  If %%values%% is provided, it will use the Typed API to handle
     *  ambiguous cases where multiple functions match by name.
     *
     *  If the %%key%% and %%values%% do not refine to a single function in
     *  the ABI, this will throw.
     */
    getFunction(key: string, values?: Array<any | Typed>): null | FunctionFragment {
        return this.#getFunction(key, values || null, true);
    }

    /**
     *  Iterate over all functions, calling %%callback%%, sorted by their name.
     */
    forEachFunction(callback: (func: FunctionFragment, index: number) => void): void {
        const names = Array.from(this.#functions.keys());
        names.sort((a, b) => a.localeCompare(b));
        for (let i = 0; i < names.length; i++) {
            const name = names[i];
            callback(<FunctionFragment>(this.#functions.get(name)), i);
        }
    }


    // Find an event definition by any means necessary (unless it is ambiguous)
    #getEvent(key: string, values: null | Array<null | any | Typed>, forceUnique: boolean): null | EventFragment {

        // EventTopic
        if (isHexString(key)) {
            const eventTopic = key.toLowerCase();
            for (const fragment of this.#events.values()) {
                if (eventTopic === fragment.topicHash) { return fragment; }
            }
            return null;
        }

        // It is a bare name, look up the function (will return null if ambiguous)
        if (key.indexOf("(") === -1) {
            const matching: Array<EventFragment> = [ ];
            for (const [ name, fragment ] of this.#events) {
                if (name.split("("/* fix:) */)[0] === key) { matching.push(fragment); }
            }

            if (values) {
                // Remove all matches that don't have a compatible length.
                for (let i = matching.length - 1; i >= 0; i--) {
                    if (matching[i].inputs.length < values.length) {
                        matching.splice(i, 1);
                    }
                }

                // Remove all matches that don't match the Typed signature
                for (let i = matching.length - 1; i >= 0; i--) {
                    const inputs = matching[i].inputs;
                    for (let j = 0; j < values.length; j++) {
                        // Not a typed value
                        if (!Typed.isTyped(values[j])) { continue; }

                        // Make sure the value type matches the input type
                        if (values[j].type !== inputs[j].baseType) {
                            matching.splice(i, 1);
                            break;
                        }
                    }
                }
            }

            if (matching.length === 0) { return null; }

            if (matching.length > 1 && forceUnique) {
                const matchStr = matching.map((m) => JSON.stringify(m.format())).join(", ");
                assertArgument(false, `ambiguous event description (i.e. matches ${ matchStr })`, "key", key);
            }

            return matching[0];
        }

        // Normalize the signature and lookup the function
        const result = this.#events.get(EventFragment.from(key).format());
        if (result) { return result; }

        return null;
    }

    /**
     *  Get the event name for %%key%%, which may be a topic hash,
     *  event name or event signature that belongs to the ABI.
     */
    getEventName(key: string): string {
        const fragment = this.#getEvent(key, null, false);
        assertArgument(fragment, "no matching event", "key", key);

        return fragment.name;
    }

    /**
     *  Returns true if %%key%% (an event topic hash, event name or
     *  event signature) is present in the ABI.
     *
     *  In the case of an event name, the name may be ambiguous, so
     *  accessing the [[EventFragment]] may require refinement.
     */
    hasEvent(key: string): boolean {
        return !!this.#getEvent(key, null, false);
    }

    /**
     *  Get the [[EventFragment]] for %%key%%, which may be a topic hash,
     *  event name or event signature that belongs to the ABI.
     *
     *  If %%values%% is provided, it will use the Typed API to handle
     *  ambiguous cases where multiple events match by name.
     *
     *  If the %%key%% and %%values%% do not refine to a single event in
     *  the ABI, this will throw.
     */
    getEvent(key: string, values?: Array<any | Typed>): null | EventFragment {
        return this.#getEvent(key, values || null, true)
    }

    /**
     *  Iterate over all events, calling %%callback%%, sorted by their name.
     */
    forEachEvent(callback: (func: EventFragment, index: number) => void): void {
        const names = Array.from(this.#events.keys());
        names.sort((a, b) => a.localeCompare(b));
        for (let i = 0; i < names.length; i++) {
            const name = names[i];
            callback(<EventFragment>(this.#events.get(name)), i);
        }
    }

    /**
     *  Get the [[ErrorFragment]] for %%key%%, which may be an error
     *  selector, error name or error signature that belongs to the ABI.
     *
     *  If %%values%% is provided, it will use the Typed API to handle
     *  ambiguous cases where multiple errors match by name.
     *
     *  If the %%key%% and %%values%% do not refine to a single error in
     *  the ABI, this will throw.
     */
    getError(key: string, values?: Array<any | Typed>): null | ErrorFragment {
        if (isHexString(key)) {
            const selector = key.toLowerCase();

            if (BuiltinErrors[selector]) {
                return ErrorFragment.from(BuiltinErrors[selector].signature);
            }

            for (const fragment of this.#errors.values()) {
                if (selector === fragment.selector) { return fragment; }
            }

            return null;
        }

        // It is a bare name, look up the function (will return null if ambiguous)
        if (key.indexOf("(") === -1) {
            const matching: Array<ErrorFragment> = [ ];
            for (const [ name, fragment ] of this.#errors) {
                if (name.split("("/* fix:) */)[0] === key) { matching.push(fragment); }
            }

            if (matching.length === 0) {
                if (key === "Error") { return ErrorFragment.from("error Error(string)"); }
                if (key === "Panic") { return ErrorFragment.from("error Panic(uint256)"); }
                return null;
            } else if (matching.length > 1) {
                const matchStr = matching.map((m) => JSON.stringify(m.format())).join(", ");
                assertArgument(false, `ambiguous error description (i.e. ${ matchStr })`, "name", key);
            }

            return matching[0];
        }

        // Normalize the signature and lookup the function
        key = ErrorFragment.from(key).format()
        if (key === "Error(string)") { return ErrorFragment.from("error Error(string)"); }
        if (key === "Panic(uint256)") { return ErrorFragment.from("error Panic(uint256)"); }

        const result = this.#errors.get(key);
        if (result) { return result; }

        return null;
    }

    /**
     *  Iterate over all errors, calling %%callback%%, sorted by their name.
     */
    forEachError(callback: (func: ErrorFragment, index: number) => void): void {
        const names = Array.from(this.#errors.keys());
        names.sort((a, b) => a.localeCompare(b));
        for (let i = 0; i < names.length; i++) {
            const name = names[i];
            callback(<ErrorFragment>(this.#errors.get(name)), i);
        }
    }

    // Get the 4-byte selector used by Solidity to identify a function
        /*
    getSelector(fragment: ErrorFragment | FunctionFragment): string {
        if (typeof(fragment) === "string") {
            const matches: Array<Fragment> = [ ];

            try { matches.push(this.getFunction(fragment)); } catch (error) { }
            try { matches.push(this.getError(<string>fragment)); } catch (_) { }

            if (matches.length === 0) {
                logger.throwArgumentError("unknown fragment", "key", fragment);
            } else if (matches.length > 1) {
                logger.throwArgumentError("ambiguous fragment matches function and error", "key", fragment);
            }

            fragment = matches[0];
        }

        return dataSlice(id(fragment.format()), 0, 4);
    }
        */

    // Get the 32-byte topic hash used by Solidity to identify an event
    /*
    getEventTopic(fragment: EventFragment): string {
        //if (typeof(fragment) === "string") { fragment = this.getEvent(eventFragment); }
        return id(fragment.format());
    }
    */


    _decodeParams(params: ReadonlyArray<ParamType>, data: BytesLike): Result {
        return this.#abiCoder.decode(params, data)
    }

    _encodeParams(params: ReadonlyArray<ParamType>, values: ReadonlyArray<any>): string {
        return this.#abiCoder.encode(params, values)
    }

    /**
     *  Encodes a ``tx.data`` object for deploying the Contract with
     *  the %%values%% as the constructor arguments.
     */
    encodeDeploy(values?: ReadonlyArray<any>): string {
        return this._encodeParams(this.deploy.inputs, values || [ ]);
    }

    /**
     *  Decodes the result %%data%% (e.g. from an ``eth_call``) for the
     *  specified error (see [[getError]] for valid values for
     *  %%key%%).
     *
     *  Most developers should prefer the [[parseCallResult]] method instead,
     *  which will automatically detect a ``CALL_EXCEPTION`` and throw the
     *  corresponding error.
     */
    decodeErrorResult(fragment: ErrorFragment | string, data: BytesLike): Result {
        if (typeof(fragment) === "string") {
            const f = this.getError(fragment);
            assertArgument(f, "unknown error", "fragment", fragment);
            fragment = f;
        }

        assertArgument(dataSlice(data, 0, 4) === fragment.selector,
            `data signature does not match error ${ fragment.name }.`, "data", data);

        return this._decodeParams(fragment.inputs, dataSlice(data, 4));
    }

    /**
     *  Encodes the transaction revert data for a call result that
     *  reverted from the the Contract with the sepcified %%error%%
     *  (see [[getError]] for valid values for %%fragment%%) with the %%values%%.
     *
     *  This is generally not used by most developers, unless trying to mock
     *  a result from a Contract.
     */
    encodeErrorResult(fragment: ErrorFragment | string, values?: ReadonlyArray<any>): string {
        if (typeof(fragment) === "string") {
            const f = this.getError(fragment);
            assertArgument(f, "unknown error", "fragment", fragment);
            fragment = f;
        }

        return concat([
            fragment.selector,
            this._encodeParams(fragment.inputs, values || [ ])
        ]);
    }

    /**
     *  Decodes the %%data%% from a transaction ``tx.data`` for
     *  the function specified (see [[getFunction]] for valid values
     *  for %%fragment%%).
     *
     *  Most developers should prefer the [[parseTransaction]] method
     *  instead, which will automatically detect the fragment.
     */
    decodeFunctionData(fragment: FunctionFragment | string, data: BytesLike): Result {
        if (typeof(fragment) === "string") {
            const f = this.getFunction(fragment);
            assertArgument(f, "unknown function", "fragment", fragment);
            fragment = f;
        }

        assertArgument(dataSlice(data, 0, 4) === fragment.selector,
            `data signature does not match function ${ fragment.name }.`, "data", data);

        return this._decodeParams(fragment.inputs, dataSlice(data, 4));
    }

    /**
     *  Encodes the ``tx.data`` for a transaction that calls the function
     *  specified (see [[getFunction]] for valid values for %%fragment%%) with
     *  the %%values%%.
     */
    encodeFunctionData(fragment: FunctionFragment | string, values?: ReadonlyArray<any>): string {
        if (typeof(fragment) === "string") {
            const f = this.getFunction(fragment);
            assertArgument(f, "unknown function", "fragment", fragment);
            fragment = f;
        }

        return concat([
            fragment.selector,
            this._encodeParams(fragment.inputs, values || [ ])
        ]);
    }

    /**
     *  Decodes the result %%data%% (e.g. from an ``eth_call``) for the
     *  specified function (see [[getFunction]] for valid values for
     *  %%key%%).
     *
     *  Most developers should prefer the [[parseCallResult]] method instead,
     *  which will automatically detect a ``CALL_EXCEPTION`` and throw the
     *  corresponding error.
     */
    decodeFunctionResult(fragment: FunctionFragment | string, data: BytesLike): Result {
        if (typeof(fragment) === "string") {
            const f = this.getFunction(fragment);
            assertArgument(f, "unknown function", "fragment", fragment);
            fragment = f;
        }

        let message = "invalid length for result data";

        const bytes = getBytesCopy(data);
        if ((bytes.length % 32) === 0) {
            try {
                return this.#abiCoder.decode(fragment.outputs, bytes);
            } catch (error) {
                message = "could not decode result data";
            }
        }

        // Call returned data with no error, but the data is junk
        assert(false, message, "BAD_DATA", {
            value: hexlify(bytes),
            info: { method: fragment.name, signature: fragment.format() }
        });
    }

    makeError(_data: BytesLike, tx: CallExceptionTransaction): CallExceptionError {
        const data = getBytes(_data, "data");

        const error = AbiCoder.getBuiltinCallException("call", tx, data);

        // Not a built-in error; try finding a custom error
        const customPrefix = "execution reverted (unknown custom error)";
        if (error.message.startsWith(customPrefix)) {
            const selector = hexlify(data.slice(0, 4));

            const ef = this.getError(selector);
            if (ef) {
                try {
                    const args = this.#abiCoder.decode(ef.inputs, data.slice(4));
                    error.revert = {
                        name: ef.name, signature: ef.format(), args
                    };
                    error.reason = error.revert.signature;
                    error.message = `execution reverted: ${ error.reason }`
                 } catch (e) {
                    error.message = `execution reverted (coult not decode custom error)`
                }
            }
        }

        // Add the invocation, if available
        const parsed = this.parseTransaction(tx);
        if (parsed) {
            error.invocation = {
                method: parsed.name,
                signature: parsed.signature,
                args: parsed.args
            };
        }

        return error;
    }

    /**
     *  Encodes the result data (e.g. from an ``eth_call``) for the
     *  specified function (see [[getFunction]] for valid values
     *  for %%fragment%%) with %%values%%.
     *
     *  This is generally not used by most developers, unless trying to mock
     *  a result from a Contract.
     */
    encodeFunctionResult(fragment: FunctionFragment | string, values?: ReadonlyArray<any>): string {
        if (typeof(fragment) === "string") {
            const f = this.getFunction(fragment);
            assertArgument(f, "unknown function", "fragment", fragment);
            fragment = f;
        }
        return hexlify(this.#abiCoder.encode(fragment.outputs, values || [ ]));
    }
/*
    spelunk(inputs: Array<ParamType>, values: ReadonlyArray<any>, processfunc: (type: string, value: any) => Promise<any>): Promise<Array<any>> {
        const promises: Array<Promise<>> = [ ];
        const process = function(type: ParamType, value: any): any {
            if (type.baseType === "array") {
                return descend(type.child
            }
            if (type. === "address") {
            }
        };

        const descend = function (inputs: Array<ParamType>, values: ReadonlyArray<any>) {
            if (inputs.length !== values.length) { throw new Error("length mismatch"); }
            
        };

        const result: Array<any> = [ ];
        values.forEach((value, index) => {
            if (value == null) {
                topics.push(null);
            } else if (param.baseType === "array" || param.baseType === "tuple") {
                logger.throwArgumentError("filtering with tuples or arrays not supported", ("contract." + param.name), value);
            } else if (Array.isArray(value)) {
                topics.push(value.map((value) => encodeTopic(param, value)));
            } else {
                topics.push(encodeTopic(param, value));
            }
        });
    }
*/
    // Create the filter for the event with search criteria (e.g. for eth_filterLog)
    encodeFilterTopics(fragment: EventFragment | string, values: ReadonlyArray<any>): Array<null | string | Array<string>> {
        if (typeof(fragment) === "string") {
            const f = this.getEvent(fragment);
            assertArgument(f, "unknown event", "eventFragment", fragment);
            fragment = f;
        }

        assert(values.length <= fragment.inputs.length, `too many arguments for ${ fragment.format() }`,
            "UNEXPECTED_ARGUMENT", { count: values.length, expectedCount: fragment.inputs.length })

        const topics: Array<null | string | Array<string>> = [];
        if (!fragment.anonymous) { topics.push(fragment.topicHash); }

        // @TODO: Use the coders for this; to properly support tuples, etc.
        const encodeTopic = (param: ParamType, value: any): string => {
            if (param.type === "string") {
                 return id(value);
            } else if (param.type === "bytes") {
                 return keccak256(hexlify(value));
            }

            if (param.type === "bool" && typeof(value) === "boolean") {
                value = (value ? "0x01": "0x00");
            } else if (param.type.match(/^u?int/)) {
                value = toBeHex(value);  // @TODO: Should this toTwos??
            } else if (param.type.match(/^bytes/)) {
                value = zeroPadBytes(value, 32);
            } else if (param.type === "address") {
                // Check addresses are valid
                this.#abiCoder.encode( [ "address" ], [ value ]);
            }

            return zeroPadValue(hexlify(value), 32);
        };

        values.forEach((value, index) => {

            const param = (<EventFragment>fragment).inputs[index];

            if (!param.indexed) {
                assertArgument(value == null,
                    "cannot filter non-indexed parameters; must be null", ("contract." + param.name), value);
                return;
            }

            if (value == null) {
                topics.push(null);
            } else if (param.baseType === "array" || param.baseType === "tuple") {
                assertArgument(false, "filtering with tuples or arrays not supported", ("contract." + param.name), value);
            } else if (Array.isArray(value)) {
                topics.push(value.map((value) => encodeTopic(param, value)));
            } else {
                topics.push(encodeTopic(param, value));
            }
        });

        // Trim off trailing nulls
        while (topics.length && topics[topics.length - 1] === null) {
            topics.pop();
        }

        return topics;
    }

    encodeEventLog(fragment: EventFragment | string, values: ReadonlyArray<any>): { data: string, topics: Array<string> } {
        if (typeof(fragment) === "string") {
            const f = this.getEvent(fragment);
            assertArgument(f, "unknown event", "eventFragment", fragment);
            fragment = f;
        }

        const topics: Array<string> = [ ];

        const dataTypes: Array<ParamType> = [ ];
        const dataValues: Array<string> = [ ];

        if (!fragment.anonymous) {
            topics.push(fragment.topicHash);
        }

        assertArgument(values.length === fragment.inputs.length,
            "event arguments/values mismatch", "values", values);

        fragment.inputs.forEach((param, index) => {
            const value = values[index];
            if (param.indexed) {
                if (param.type === "string") {
                    topics.push(id(value))
                } else if (param.type === "bytes") {
                    topics.push(keccak256(value))
                } else if (param.baseType === "tuple" || param.baseType === "array") {
                    // @TODO
                    throw new Error("not implemented");
                } else {
                    topics.push(this.#abiCoder.encode([ param.type] , [ value ]));
                }
            } else {
                dataTypes.push(param);
                dataValues.push(value);
            }
        });

        return {
            data: this.#abiCoder.encode(dataTypes , dataValues),
            topics: topics
        };
    }

    // Decode a filter for the event and the search criteria
    decodeEventLog(fragment: EventFragment | string, data: BytesLike, topics?: ReadonlyArray<string>): Result {
        if (typeof(fragment) === "string") {
            const f = this.getEvent(fragment);
            assertArgument(f, "unknown event", "eventFragment", fragment);
            fragment = f;
        }

        if (topics != null && !fragment.anonymous) {
            const eventTopic = fragment.topicHash;
            assertArgument(isHexString(topics[0], 32) && topics[0].toLowerCase() === eventTopic,
                "fragment/topic mismatch", "topics[0]", topics[0]);
            topics = topics.slice(1);
        }

        const indexed: Array<ParamType> = [];
        const nonIndexed: Array<ParamType> = [];
        const dynamic: Array<boolean> = [];

        fragment.inputs.forEach((param, index) => {
            if (param.indexed) {
                if (param.type === "string" || param.type === "bytes" || param.baseType === "tuple" || param.baseType === "array") {
                    indexed.push(ParamType.from({ type: "bytes32", name: param.name }));
                    dynamic.push(true);
                } else {
                    indexed.push(param);
                    dynamic.push(false);
                }
            } else {
                nonIndexed.push(param);
                dynamic.push(false);
            }
        });

        const resultIndexed = (topics != null) ? this.#abiCoder.decode(indexed, concat(topics)): null;
        const resultNonIndexed = this.#abiCoder.decode(nonIndexed, data, true);

        //const result: (Array<any> & { [ key: string ]: any }) = [ ];
        const values: Array<any> = [ ];
        const keys: Array<null | string> = [ ];
        let nonIndexedIndex = 0, indexedIndex = 0;
        fragment.inputs.forEach((param, index) => {
            let value: null | Indexed | Error = null;
            if (param.indexed) {
                if (resultIndexed == null) {
                    value = new Indexed(null);

                } else if (dynamic[index]) {
                    value = new Indexed(resultIndexed[indexedIndex++]);

                } else {
                    try {
                        value = resultIndexed[indexedIndex++];
                    } catch (error: any) {
                        value = error;
                    }
                }
            } else {
                try {
                    value = resultNonIndexed[nonIndexedIndex++];
                } catch (error: any) {
                    value = error;
                }
            }

            values.push(value);
            keys.push(param.name || null);
        });

        return Result.fromItems(values, keys);
    }

    /**
     *  Parses a transaction, finding the matching function and extracts
     *  the parameter values along with other useful function details.
     *
     *  If the matching function cannot be found, return null.
     */
    parseTransaction(tx: { data: string, value?: BigNumberish }): null | TransactionDescription {
        const data = getBytes(tx.data, "tx.data");
        const value = getBigInt((tx.value != null) ? tx.value: 0, "tx.value");

        const fragment = this.getFunction(hexlify(data.slice(0, 4)));

        if (!fragment) { return null; }

        const args = this.#abiCoder.decode(fragment.inputs, data.slice(4));
        return new TransactionDescription(fragment, fragment.selector, args, value);
    }

    parseCallResult(data: BytesLike): Result {
        throw new Error("@TODO");
    }

    /**
     *  Parses a receipt log, finding the matching event and extracts
     *  the parameter values along with other useful event details.
     *
     *  If the matching event cannot be found, returns null.
     */
    parseLog(log: { topics: ReadonlyArray<string>, data: string}): null | LogDescription {
        const fragment = this.getEvent(log.topics[0]);

        if (!fragment || fragment.anonymous) { return null; }

        // @TODO: If anonymous, and the only method, and the input count matches, should we parse?
        //        Probably not, because just because it is the only event in the ABI does
        //        not mean we have the full ABI; maybe just a fragment?


       return new LogDescription(fragment, fragment.topicHash, this.decodeEventLog(fragment, log.data, log.topics));
    }

    /**
     *  Parses a revert data, finding the matching error and extracts
     *  the parameter values along with other useful error details.
     *
     *  If the matching error cannot be found, returns null.
     */
    parseError(data: BytesLike): null | ErrorDescription {
        const hexData = hexlify(data);

        const fragment = this.getError(dataSlice(hexData, 0, 4));

        if (!fragment) { return null; }

        const args = this.#abiCoder.decode(fragment.inputs, dataSlice(hexData, 4));
        return new ErrorDescription(fragment, fragment.selector, args);
    }

    /**
     *  Creates a new [[Interface]] from the ABI %%value%%.
     *
     *  The %%value%% may be provided as an existing [[Interface]] object,
     *  a JSON-encoded ABI or any Human-Readable ABI format.
     */
    static from(value: InterfaceAbi | Interface): Interface {
        // Already an Interface, which is immutable
        if (value instanceof Interface) { return value; }

        // JSON
        if (typeof(value) === "string") { return new Interface(JSON.parse(value)); }

        // An Interface; possibly from another v6 instance
        if (typeof((<any>value).formatJson) === "function") {
            return new Interface((<any>value).formatJson());
        }

        // A legacy Interface; from an older version
        if (typeof((<any>value).format) === "function") {
            return new Interface((<any>value).format("json"));
        }

        // Array of fragments
        return new Interface(value);
    }
}