polkadot-js/api

// Copyright 2017-2024 @polkadot/types-codec authors & contributors
// SPDX-License-Identifier: Apache-2.0

import type { AnyString } from '../types/index.js';

type Mapper = (value: string) => string;

const BOUNDED = ['BTreeMap', 'BTreeSet', 'HashMap', 'Vec'];
const ALLOWED_BOXES = BOUNDED.concat(['Compact', 'DoNotConstruct', 'Int', 'Linkage', 'Range', 'RangeInclusive', 'Result', 'Opaque', 'Option', 'UInt', 'WrapperKeepOpaque', 'WrapperOpaque']);
const BOX_PRECEDING = ['<', '(', '[', '"', ',', ' ']; // start of vec, tuple, fixed array, part of struct def or in tuple

const mappings: Mapper[] = [
  // alias <T::InherentOfflineReport as InherentOfflineReport>::Inherent -> InherentOfflineReport
  alias('<T::InherentOfflineReport as InherentOfflineReport>::Inherent', 'InherentOfflineReport', false),
  alias('VecDeque<', 'Vec<', false),
  // <T::Balance as HasCompact>
  cleanupCompact(),
  // Change BoundedVec<Type, Size> to Vec<Type>
  removeExtensions('Bounded', true),
  // Change WeakVec<Type> to Vec<Type>
  removeExtensions('Weak', false),
  // Remove all the trait prefixes
  removeTraits(),
  // remove PairOf<T> -> (T, T)
  removePairOf(),
  // remove boxing, `Box<Proposal>` -> `Proposal`
  removeWrap('Box<'),
  // remove generics, `MisbehaviorReport<Hash, BlockNumber>` -> `MisbehaviorReport`
  removeGenerics(),
  // alias String -> Text (compat with jsonrpc methods)
  alias('String', 'Text'),
  // alias Vec<u8> -> Bytes
  alias('Vec<u8>', 'Bytes'),
  alias('&\\[u8\\]', 'Bytes'),
  alias("&'static\\[u8\\]", 'Bytes'),
  // alias RawAddress -> Address
  alias('RawAddress', 'Address'),
  // lookups, mapped to Address/AccountId as appropriate in runtime
  alias('Lookup::Source', 'LookupSource'),
  alias('Lookup::Target', 'LookupTarget'),
  // HACK duplication between contracts & primitives, however contracts prefixed with exec
  alias('exec::StorageKey', 'ContractStorageKey'),
  // flattens tuples with one value, `(AccountId)` -> `AccountId`
  flattenSingleTuple(),
  // converts ::Type to Type, <T as Trait<I>>::Proposal -> Proposal
  removeColons(),
  // remove all trailing spaces - this should always be the last
  trim()
];

// given a string, trim it
export function trim (): Mapper {
  return (value: string): string =>
    value.trim();
}

// given a starting index, find the closing >
export function findClosing (value: string, start: number): number {
  let depth = 0;

  for (let i = start, count = value.length; i < count; i++) {
    if (value[i] === '>') {
      if (!depth) {
        return i;
      }

      depth--;
    } else if (value[i] === '<') {
      depth++;
    }
  }

  throw new Error(`Unable to find closing matching <> on '${value}' (start ${start})`);
}

export function alias (src: string, dest: string, withChecks = true): Mapper {
  const from = new RegExp(`(^${src}|${BOX_PRECEDING.map((box) => `\\${box}${src}`).join('|')})`, 'g');

  const to = (src: string): string => {
    from.lastIndex = 0;

    return withChecks && BOX_PRECEDING.includes(src[0])
      ? `${src[0]}${dest}`
      : dest;
  };

  return (value: string): string =>
    value.replace(from, to);
}

export function cleanupCompact (): Mapper {
  return (value: string): string => {
    if (value.includes(' as HasCompact')) {
      for (let i = 0, count = value.length; i < count; i++) {
        if (value[i] === '<') {
          const end = findClosing(value, i + 1) - 14;

          if (value.substring(end, end + 14) === ' as HasCompact') {
            value = `Compact<${value.substring(i + 1, end)}>`;
          }
        }
      }
    }

    return value;
  };
}

export function flattenSingleTuple (): Mapper {
  const from1 = /,\)/g;
  const from2 = /\(([^,]+)\)/;

  return (value: string) => {
    from1.lastIndex = 0;

    return value
      // tuples may have trailing commas, e.g. (u32, BlockNumber, )
      .replace(from1, ')')
      // change (u32) -> u32
      .replace(from2, '$1');
  };
}

function replaceTagWith (value: string, matcher: string, replacer: (inner: string) => string): string {
  let index = -1;

  while (true) {
    index = value.indexOf(matcher, index + 1);

    if (index === -1) {
      return value;
    }

    const start = index + matcher.length;
    const end = findClosing(value, start);

    value = `${value.substring(0, index)}${replacer(value.substring(start, end))}${value.substring(end + 1)}`;
  }
}

// remove the Bounded* or Weak* wrappers
export function removeExtensions (type: string, isSized: boolean): Mapper {
  return (value: string): string => {
    for (let i = 0, count = BOUNDED.length; i < count; i++) {
      const tag = BOUNDED[i];

      value = replaceTagWith(value, `${type}${tag}<`, (v: string): string => {
        const parts = v
          .split(',')
          .map((s) => s.trim())
          .filter((s) => s);

        if (isSized) {
          parts.pop();
        }

        return `${tag}<${parts.join(',')}>`;
      });
    }

    return value;
  };
}

export function removeColons (): Mapper {
  return (value: string): string => {
    let index = 0;

    while (index !== -1) {
      index = value.indexOf('::');

      if (index === 0) {
        value = value.substring(2);
      } else if (index !== -1) {
        let start = index;

        while (start !== -1 && !BOX_PRECEDING.includes(value[start])) {
          start--;
        }

        value = `${value.substring(0, start + 1)}${value.substring(index + 2)}`;
      }
    }

    return value;
  };
}

export function removeGenerics (): Mapper {
  return (value: string): string => {
    for (let i = 0, count = value.length; i < count; i++) {
      if (value[i] === '<') {
        // check against the allowed wrappers, be it Vec<..>, Option<...> ...
        const box = ALLOWED_BOXES.find((box): boolean => {
          const start = i - box.length;

          return (
            (
              start >= 0 &&
              value.substring(start, i) === box
            ) && (
              // make sure it is stand-alone, i.e. don't catch ElectionResult<...> as Result<...>
              start === 0 ||
              BOX_PRECEDING.includes(value[start - 1])
            )
          );
        });

        // we have not found anything, unwrap generic innards
        if (!box) {
          const end = findClosing(value, i + 1);

          value = `${value.substring(0, i)}${value.substring(end + 1)}`;
        }
      }
    }

    return value;
  };
}

// remove the PairOf wrappers
export function removePairOf (): Mapper {
  const replacer = (v: string) => `(${v},${v})`;

  return (value: string) =>
    replaceTagWith(value, 'PairOf<', replacer);
}

// remove the type traits
export function removeTraits (): Mapper {
  const from1 = /\s/g;
  const from2 = /(T|Self)::/g;
  const from3 = /<(T|Self)asTrait>::/g;
  const from4 = /<Tas[a-z]+::Trait>::/g;
  const from5 = /<LookupasStaticLookup>/g;
  const from6 = /::Type/g;

  return (value: string): string => {
    from1.lastIndex = 0;
    from2.lastIndex = 0;
    from3.lastIndex = 0;
    from4.lastIndex = 0;
    from5.lastIndex = 0;
    from6.lastIndex = 0;

    return value
      // remove all whitespaces
      .replace(from1, '')
      // anything `T::<type>` to end up as `<type>`
      .replace(from2, '')
      // replace `<T as Trait>::` (whitespaces were removed above)
      .replace(from3, '')
      // replace `<T as something::Trait>::` (whitespaces were removed above)
      .replace(from4, '')
      // replace <Lookup as StaticLookup>
      .replace(from5, 'Lookup')
      // replace `<...>::Type`
      .replace(from6, '');
  };
}

// remove wrapping values, i.e. Box<Proposal> -> Proposal
export function removeWrap (check: string): Mapper {
  const replacer = (v: string) => v;

  return (value: string) =>
    replaceTagWith(value, check, replacer);
}

const sanitizeMap = new Map<string, string>();

export function sanitize (value: AnyString): string {
  const startValue = value.toString();
  const memoized = sanitizeMap.get(startValue);

  if (memoized) {
    return memoized;
  }

  let result = startValue;

  for (let i = 0, count = mappings.length; i < count; i++) {
    result = mappings[i](result);
  }

  sanitizeMap.set(startValue, result);

  return result;
}