toon/packages/cli/src/conversion.ts

import type { DecodeOptions, Delimiter, EncodeOptions } from '../../toon/src'
import type { InputSource } from './types'
import * as fsp from 'node:fs/promises'
import * as path from 'node:path'
import process from 'node:process'
import { consola } from 'consola'
import { estimateTokenCount } from 'tokenx'
import { decode, encode } from '../../toon/src'
import { formatInputLabel, readInput } from './utils'

export async function encodeToToon(config: {
  input: InputSource
  output?: string
  delimiter: Delimiter
  indent: number
  lengthMarker: NonNullable<EncodeOptions['lengthMarker']>
  printStats: boolean
}): Promise<void> {
  const jsonContent = await readInput(config.input)

  let data: unknown
  try {
    data = JSON.parse(jsonContent)
  }
  catch (error) {
    throw new Error(`Failed to parse JSON: ${error instanceof Error ? error.message : String(error)}`)
  }

  const encodeOptions: EncodeOptions = {
    delimiter: config.delimiter,
    indent: config.indent,
    lengthMarker: config.lengthMarker,
  }

  const toonOutput = encode(data, encodeOptions)

  if (config.output) {
    await fsp.writeFile(config.output, toonOutput, 'utf-8')
    const relativeInputPath = formatInputLabel(config.input)
    const relativeOutputPath = path.relative(process.cwd(), config.output)
    consola.success(`Encoded \`${relativeInputPath}\` → \`${relativeOutputPath}\``)
  }
  else {
    console.log(toonOutput)
  }

  if (config.printStats) {
    const jsonTokens = estimateTokenCount(jsonContent)
    const toonTokens = estimateTokenCount(toonOutput)
    const diff = jsonTokens - toonTokens
    const percent = ((diff / jsonTokens) * 100).toFixed(1)

    console.log()
    consola.info(`Token estimates: ~${jsonTokens} (JSON) → ~${toonTokens} (TOON)`)
    consola.success(`Saved ~${diff} tokens (-${percent}%)`)
  }
}

export async function decodeToJson(config: {
  input: InputSource
  output?: string
  indent: number
  strict: boolean
}): Promise<void> {
  const toonContent = await readInput(config.input)

  let data: unknown
  try {
    const decodeOptions: DecodeOptions = {
      indent: config.indent,
      strict: config.strict,
    }
    data = decode(toonContent, decodeOptions)
  }
  catch (error) {
    throw new Error(`Failed to decode TOON: ${error instanceof Error ? error.message : String(error)}`)
  }

  const jsonOutput = JSON.stringify(data, undefined, config.indent)

  if (config.output) {
    await fsp.writeFile(config.output, jsonOutput, 'utf-8')
    const relativeInputPath = formatInputLabel(config.input)
    const relativeOutputPath = path.relative(process.cwd(), config.output)
    consola.success(`Decoded \`${relativeInputPath}\` → \`${relativeOutputPath}\``)
  }
  else {
    console.log(jsonOutput)
  }
}