/** Stdin chunk queue + async key reader for edit/chat TUIs (requires edit-key-parse.js first). */

/**
 * @param {unknown} chunk
 * @returns {number[]}
 */
function bareEditChunkBytes(chunk) {
  if (chunk == null) return []
  if (typeof chunk === 'string') {
    const out = []
    for (let i = 0; i < chunk.length; i++) out.push(chunk.charCodeAt(i) & 0xff)
    return out
  }
  const len = /** @type {{ length: number, [k: number]: number }} */ (chunk).length
  const out = []
  for (let i = 0; i < len; i++) out.push(Number(chunk[i]) & 0xff)
  return out
}

/**
 * @param {{ nextByte: () => Promise<number|undefined>, dispose?: () => void, _keyq?: number[] }} reader
 */
async function bareEditReadKey(reader) {
  reader._keyq = reader._keyq || []
  const q = reader._keyq
  for (;;) {
    const pasteText = bareEditTryConsumeBracketedPaste(q)
    if (pasteText !== undefined && pasteText !== null) {
      return { type: 'paste', text: pasteText }
    }
    if (pasteText === null) {
      const b = await reader.nextByte()
      if (b === undefined) {
        const eofPaste = bareEditFinalizeBracketedPasteOnEof(q)
        if (eofPaste !== undefined) {
          return { type: 'paste', text: eofPaste }
        }
        if (!q.length) return { type: 'eof' }
        if (q.length === 1 && q[0] === 27) {
          q.length = 0
          return { type: 'key', ch: '\x1b' }
        }
        const lone = q.shift()
        if (lone !== undefined && lone < 0x20) {
          return { type: 'ctrl', code: lone }
        }
        if (lone !== undefined) {
          return { type: 'key', ch: String.fromCharCode(lone) }
        }
        return { type: 'eof' }
      }
      q.push(b)
      continue
    }
    const ev = bareEditTryConsumeKey(q)
    if (ev) return ev
    const b = await reader.nextByte()
    if (b === undefined) {
      const eofPaste = bareEditFinalizeBracketedPasteOnEof(q)
      if (eofPaste !== undefined) {
        return { type: 'paste', text: eofPaste }
      }
      if (!q.length) return { type: 'eof' }
      if (q.length === 1 && q[0] === 27) {
        q.length = 0
        return { type: 'key', ch: '\x1b' }
      }
      const lone = q.shift()
      if (lone !== undefined && lone < 0x20) {
        return { type: 'ctrl', code: lone }
      }
      if (lone !== undefined) {
        return { type: 'key', ch: String.fromCharCode(lone) }
      }
      return { type: 'eof' }
    }
    q.push(b)
  }
}

/**
 * @param {import('stream').Readable} stdin
 */
function bareEditCreateStdinReader(stdin) {
  /** @type {number[]} */
  const bytes = []
  /** @type {(() => void)[]} */
  const waiters = []
  function drain() {
    while (waiters.length && bytes.length) {
      const w = waiters.shift()
      if (w) w()
    }
  }
  /** @param {unknown} chunk */
  function onData(chunk) {
    bytes.push(...bareEditChunkBytes(chunk))
    drain()
  }
  stdin.on('data', onData)
  return {
    nextByte() {
      if (bytes.length) return Promise.resolve(bytes.shift())
      return new Promise((resolve) => {
        waiters.push(() => resolve(bytes.shift()))
      })
    },
    dispose() {
      stdin.removeListener('data', onData)
    }
  }
}