mtcute/packages/tl-utils/src/parse.ts

import { computeConstructorIdFromString } from './ctor-id'
import { TL_PRIMITIVES, TlArgument, TlEntry } from './types'
import { parseArgumentType, parseTdlibStyleComment } from './utils'

const SINGLE_REGEX =
    /^(.+?)(?:#([0-9a-f]{1,8}))?(?: \?)?(?: {(.+?:.+?)})? ((?:.+? )*)= (.+);$/

/**
 * Parse TL schema into a list of entries.
 *
 * @param tl  TL schema
 * @param params  Additional parameters
 */
export function parseTlToEntries(
    tl: string,
    params?: {
        /**
         * Whether to throw an error if a line failed to parse
         */
        panicOnError?: boolean

        /**
         * Function to be called if there was an error while parsing a line
         *
         * @param err  Error
         * @param line  Line that failed to parse
         * @param num  Line number
         */
        onError?: (err: Error, line: string, num: number) => void

        /**
         * Function to be called a comment is found not belonging to any entry
         *
         * @param comment  Comment text
         */
        onOrphanComment?: (comment: string) => void

        /**
         * Prefix to be applied to all types
         */
        prefix?: string

        /**
         * Whether this invocation is for computing constructor ids.
         * If true, the `id` field will be set to 0 for all entries.
         */
        forIdComputation?: boolean
    },
): TlEntry[] {
    const ret: TlEntry[] = []

    const entries: Record<string, TlEntry> = {}
    const unions: Record<string, TlEntry[]> = {}

    const lines = tl.split('\n')

    let currentKind: TlEntry['kind'] = 'class'
    let currentComment = ''
    const prefix = params?.prefix ?? ''

    lines.forEach((line, idx) => {
        line = line.trim()

        if (line === '') {
            if (params?.onOrphanComment) {
                params.onOrphanComment(currentComment)
            }

            currentComment = ''

            return
        }

        if (line.match(/^\/\//)) {
            if (currentComment) {
                if (line[2] === '-') {
                    currentComment += '\n' + line.substring(3).trim()
                } else {
                    currentComment += ' ' + line.substring(2).trim()
                }
            } else {
                currentComment = line.substring(2).trim()
            }

            return
        }

        if (line === '---functions---') {
            currentKind = 'method'

            return
        }

        if (line === '---types---') {
            currentKind = 'class'

            return
        }

        const match = SINGLE_REGEX.exec(line)

        if (!match) {
            const err = new Error(`Failed to parse line ${idx + 1}: ${line}`)

            if (params?.panicOnError) {
                throw err
            } else if (params?.onError) {
                params.onError(err, line, idx + 1)
            } else {
                console.warn(err)
            }

            return
        }

        const [, typeName, typeId, generics, args, type] = match

        if (typeName in TL_PRIMITIVES) {
            return
        }

        let typeIdNum = typeId ? parseInt(typeId, 16) : 0

        if (typeIdNum === 0 && !params?.forIdComputation) {
            typeIdNum = computeConstructorIdFromString(line)
        }

        const argsParsed =
            args && !args.match(/\[ [a-z]+ ]/i) ?
                args
                    .trim()
                    .split(' ')
                    .map((j) => j.split(':')) :
                []

        const entry: TlEntry = {
            kind: currentKind,
            name: typeName,
            id: typeIdNum,
            type,
            arguments: [],
        }

        if (generics) {
            entry.generics = generics.split(',').map((it) => {
                const [name, type] = it.split(':')

                return { name, type }
            })
        }

        if (argsParsed.length) {
            argsParsed.forEach(([name, type_]) => {
                const [type, modifiers] = parseArgumentType(type_)
                const item: TlArgument = {
                    name,
                    type,
                }

                if (Object.keys(modifiers).length) {
                    item.typeModifiers = modifiers
                }

                entry.arguments.push(item)
            })
        }

        if (currentComment) {
            if (currentComment.match(/^@description /)) {
                // tdlib-style comment
                const obj = parseTdlibStyleComment(currentComment)

                if (obj.description) entry.comment = obj.description

                entry.arguments.forEach((arg) => {
                    if (arg.name in obj) {
                        arg.comment = obj[arg.name]
                    }
                })
            } else {
                entry.comment = currentComment
            }

            currentComment = ''
        }

        ret.push(entry)
        entries[entry.name] = entry

        if (entry.kind === 'class') {
            if (!unions[entry.type]) unions[entry.type] = []
            unions[entry.type].push(entry)
        }
    })

    if (currentComment && params?.onOrphanComment) {
        params.onOrphanComment(currentComment)
    }

    // post-process:
    // - find arguments where type is not a union and put corresponding modifiers
    // - apply prefix
    ret.forEach((entry, entryIdx) => {
        entry.arguments.forEach((arg) => {
            const type = arg.type

            if (type in TL_PRIMITIVES) {
                return
            }

            if (type in unions && arg.typeModifiers?.isBareUnion) {
                if (unions[type].length !== 1) {
                    const err = new Error(
                        `Union ${type} has more than one entry, cannot use it like %${type} (found in ${entry.name}#${arg.name})`,
                    )

                    if (params?.panicOnError) {
                        throw err
                    } else if (params?.onError) {
                        params.onError(err, '', entryIdx)
                    } else {
                        console.warn(err)
                    }
                }
                arg.typeModifiers.constructorId = unions[type][0].id
            } else if (type in entries) {
                if (!arg.typeModifiers) arg.typeModifiers = {}
                arg.typeModifiers.isBareType = true
                arg.typeModifiers.constructorId = entries[type].id

                if (prefix) {
                    arg.type = prefix + arg.type
                }
            }
        })

        if (prefix) {
            entry.name = prefix + entry.name
        }
    })

    return ret
}