/** Full-screen TUI for /bin/edit (TEA via ctx.tui; pre-SDK loop in Legacy). */

/**
 * @param {Record<string, unknown>} ctx
 */
function bareEditTuiRunOpts(ctx) {
  const env =
    ctx.env && typeof ctx.env === 'object'
      ? /** @type {Record<string, string>} */ (ctx.env)
      : {}
  /** @type {{ altScreen?: boolean, bracketedPaste?: boolean, buffer: 'cell' }} */
  const opts = { buffer: 'cell' }
  if (
    (env.BARE_EDIT_NO_ALTSCREEN != null &&
      String(env.BARE_EDIT_NO_ALTSCREEN) !== '') ||
    (env.BARE_OS_TUI_NO_ALTSCREEN != null &&
      String(env.BARE_OS_TUI_NO_ALTSCREEN) !== '')
  ) {
    opts.altScreen = false
  }
  if (
    env.BARE_EDIT_NO_BRACKETED_PASTE != null &&
    String(env.BARE_EDIT_NO_BRACKETED_PASTE) !== ''
  ) {
    opts.bracketedPaste = false
  }
  return opts
}

/**
 * @param {Record<string, unknown>} ctx
 */
function bareEditMaxPromptLen(ctx) {
  const env =
    ctx.env && typeof ctx.env === 'object'
      ? /** @type {Record<string, string>} */ (ctx.env)
      : {}
  let maxPromptLen = 4096
  const maxPromptRaw = env.BARE_EDIT_MAX_PROMPT
  if (maxPromptRaw != null && String(maxPromptRaw) !== '') {
    const n = parseInt(String(maxPromptRaw), 10)
    if (Number.isFinite(n) && n > 0) maxPromptLen = Math.min(n, 65536)
  }
  return maxPromptLen
}

/**
 * @param {string} text
 * @param {'saveas'|'search'|'goto'} kind
 * @param {number} maxPromptLen
 */
function bareEditPromptLineFromPaste(text, kind, maxPromptLen) {
  let line = String(text).split(/\r?\n/)[0] ?? ''
  line = line.replace(/[\x00-\x08\x0b\x0c\x0e-\x1f]/g, '')
  if (line.length > maxPromptLen) line = line.slice(0, maxPromptLen)
  if (kind === 'goto') {
    const m = /^(\s*\d+)/.exec(line)
    return m ? m[1].trim() : ''
  }
  return line
}

/**
 * Ctrl+_ (ASCII US, 0x1f) — Go to line. Decoder names it as ctrl+\x7f.
 * @param {unknown} msg
 */
function bareEditIsGotoChord(msg) {
  if (!msg || /** @type {{ type?: string }} */ (msg).type !== 'key')
    return false
  const m =
    /** @type {{ ctrl?: boolean, sequence?: string, name?: string }} */ (msg)
  if (!m.ctrl) return false
  return m.sequence === '\x1f' || m.name === '\x7f'
}

/**
 * TEA model for /bin/edit. Cell buffer so help / prompts overlay without reflow.
 * @param {Record<string, unknown>} ctx
 * @param {{ path: string, initialText: string, argv0?: string }} opts
 */
function bareEditCreateTuiApp(ctx, opts) {
  const tui = ctx.tui
  const vfs = ctx.vfs
  const b4a = ctx.b4a
  const size0 = tui && typeof tui.size === 'function' ? tui.size() : {}
  const useColor =
    typeof bareEditUseColor === 'function' ? bareEditUseColor(ctx) : true
  return {
    path: opts.path || 'Untitled',
    display: opts.argv0 || 'edit',
    lang: bareEditDetectLang(opts.path || ''),
    buf: bareEditCreateBuffer(opts.initialText),
    scrollRow: 0,
    scrollCol: 0,
    savePath: opts.path || 'Untitled',
    mode: /** @type {'edit'|'quit_confirm'|'help'|'prompt_search'|'prompt_goto'|'prompt_saveas'} */ (
      'edit'
    ),
    promptBuf: '',
    promptTitle: '',
    lastSearch: '',
    maxPromptLen: bareEditMaxPromptLen(ctx),
    pendingQuit: false,
    statusMsg: '',
    width: size0.width || 80,
    height: size0.height || 24,
    init: function () {
      return null
    },
    _contentH: function () {
      return Math.max(1, (this.height || 24) - 2)
    },
    _ensureScroll: function () {
      const cols = Math.max(40, this.width || 80)
      const contentH = this._contentH()
      const buf = this.buf
      if (buf.row < this.scrollRow) this.scrollRow = buf.row
      if (buf.row >= this.scrollRow + contentH)
        this.scrollRow = buf.row - contentH + 1
      if (this.scrollRow < 0) this.scrollRow = 0
      if (this.scrollCol > buf.col) this.scrollCol = buf.col
      if (buf.col - this.scrollCol >= cols) this.scrollCol = buf.col - cols + 1
      if (this.scrollCol < 0) this.scrollCol = 0
    },
    _save: function (targetPath) {
      const self = this
      return function () {
        return Promise.resolve()
          .then(function () {
            const text = bareEditJoinAll(self.buf)
            return vfs.writeFile(targetPath, b4a.from(text))
          })
          .then(function () {
            return { type: 'edit.saved', ok: true, path: targetPath }
          })
          .catch(function (error) {
            return { type: 'edit.saved', ok: false, error: error }
          })
      }
    },
    _applySearch: function () {
      this.lastSearch = this.promptBuf
      if (!this.lastSearch) return
      const hit = bareEditFindNext(
        this.buf,
        this.lastSearch,
        this.buf.row,
        this.buf.col + 1
      )
      if (!hit) {
        const hit2 = bareEditFindNext(this.buf, this.lastSearch, 0, 0)
        if (hit2) {
          this.buf.row = hit2.row
          this.buf.col = hit2.col
        }
      } else {
        this.buf.row = hit.row
        this.buf.col = hit.col
      }
    },
    _promptKind: function () {
      if (this.mode === 'prompt_search') return 'search'
      if (this.mode === 'prompt_goto') return 'goto'
      if (this.mode === 'prompt_saveas') return 'saveas'
      return ''
    },
    update: function (msg) {
      if (msg && msg.type === 'resize') {
        this.width = msg.width || this.width
        this.height = msg.height || this.height
        this._ensureScroll()
        return [this, null]
      }
      if (msg && msg.type === 'edit.saved') {
        if (msg.ok) {
          this.buf.dirty = false
          this.savePath = String(msg.path || this.savePath)
          this.statusMsg = ''
          if (this.pendingQuit) return [this, tui.quit]
        } else {
          const err = msg.error
          this.statusMsg =
            'edit: ' +
            (err && err.message ? err.message : String(err || 'save failed'))
          this.pendingQuit = false
        }
        return [this, null]
      }
      if (this.mode === 'help') {
        if (msg && msg.type === 'key') this.mode = 'edit'
        return [this, null]
      }
      if (this.mode === 'quit_confirm') {
        if (tui.key.matches(msg, 'ctrl+c')) {
          this.mode = 'edit'
          return [this, null]
        }
        if (tui.key.matches(msg, 'y', 'Y')) {
          this.pendingQuit = true
          this.mode = 'edit'
          return [this, this._save(this.savePath)]
        }
        if (tui.key.matches(msg, 'n', 'N')) return [this, tui.quit]
        return [this, null]
      }
      if (this._promptKind()) {
        if (tui.key.matches(msg, 'ctrl+c')) {
          this.mode = 'edit'
          return [this, null]
        }
        if (msg && msg.type === 'paste') {
          this.promptBuf = bareEditPromptLineFromPaste(
            String(msg.text || ''),
            /** @type {'saveas'|'search'|'goto'} */ (this._promptKind()),
            this.maxPromptLen
          )
          return [this, null]
        }
        if (tui.key.matches(msg, 'enter')) {
          if (this.mode === 'prompt_search') this._applySearch()
          else if (this.mode === 'prompt_goto') {
            const n = parseInt(this.promptBuf.trim(), 10)
            if (Number.isFinite(n)) bareEditGotoLine(this.buf, n)
          } else if (this.mode === 'prompt_saveas') {
            const p = this.promptBuf.trim()
            this.mode = 'edit'
            if (p) {
              this.savePath = p
              return [this, this._save(this.savePath)]
            }
          }
          this.mode = 'edit'
          return [this, null]
        }
        if (tui.key.matches(msg, 'backspace')) {
          this.promptBuf = this.promptBuf.slice(0, -1)
          return [this, null]
        }
        if (
          msg &&
          msg.type === 'key' &&
          !msg.ctrl &&
          !msg.meta &&
          typeof msg.sequence === 'string' &&
          msg.sequence.length === 1 &&
          msg.sequence >= ' ' &&
          msg.sequence !== '\x7f'
        ) {
          if (this.promptBuf.length < this.maxPromptLen)
            this.promptBuf += msg.sequence
        }
        return [this, null]
      }
      if (msg && msg.type === 'paste') {
        bareEditInsertPasteText(this.buf, msg.text || '')
        this._ensureScroll()
        return [this, null]
      }
      if (tui.key.matches(msg, 'ctrl+x')) {
        if (this.buf.dirty) {
          this.mode = 'quit_confirm'
          return [this, null]
        }
        return [this, tui.quit]
      }
      if (tui.key.matches(msg, 'ctrl+s')) {
        return [this, this._save(this.savePath)]
      }
      if (tui.key.matches(msg, 'ctrl+o')) {
        this.mode = 'prompt_saveas'
        this.promptTitle = 'File: '
        this.promptBuf = this.savePath
        return [this, null]
      }
      if (tui.key.matches(msg, 'ctrl+w')) {
        this.mode = 'prompt_search'
        this.promptTitle = 'Search: '
        this.promptBuf = this.lastSearch
        return [this, null]
      }
      if (tui.key.matches(msg, 'ctrl+g')) {
        this.mode = 'help'
        return [this, null]
      }
      if (bareEditIsGotoChord(msg)) {
        this.mode = 'prompt_goto'
        this.promptTitle = 'Go to line: '
        this.promptBuf = ''
        return [this, null]
      }
      if (tui.key.matches(msg, 'ctrl+z')) {
        bareEditUndo(this.buf)
        this._ensureScroll()
        return [this, null]
      }
      if (tui.key.matches(msg, 'ctrl+y')) {
        bareEditRedo(this.buf)
        this._ensureScroll()
        return [this, null]
      }
      if (tui.key.matches(msg, 'pageup')) {
        const step = Math.max(1, (this.height || 24) - 4)
        this.buf.row = Math.max(0, this.buf.row - step)
        bareEditClampCursor(this.buf)
        this._ensureScroll()
        return [this, null]
      }
      if (tui.key.matches(msg, 'pagedown')) {
        const step = Math.max(1, (this.height || 24) - 4)
        this.buf.row = Math.min(this.buf.lines.length - 1, this.buf.row + step)
        bareEditClampCursor(this.buf)
        this._ensureScroll()
        return [this, null]
      }
      if (tui.key.matches(msg, 'up', 'down', 'left', 'right', 'home', 'end')) {
        const name = msg && msg.name
        if (
          name === 'up' ||
          name === 'down' ||
          name === 'left' ||
          name === 'right' ||
          name === 'home' ||
          name === 'end'
        ) {
          bareEditMoveKey(this.buf, name)
        }
        this._ensureScroll()
        return [this, null]
      }
      if (tui.key.matches(msg, 'backspace')) {
        bareEditBackspace(this.buf)
        this._ensureScroll()
        return [this, null]
      }
      if (tui.key.matches(msg, 'delete')) {
        bareEditDelete(this.buf)
        this._ensureScroll()
        return [this, null]
      }
      if (tui.key.matches(msg, 'enter')) {
        bareEditNewline(this.buf)
        this._ensureScroll()
        return [this, null]
      }
      if (tui.key.matches(msg, 'tab')) {
        bareEditInsertChar(this.buf, '  ')
        this._ensureScroll()
        return [this, null]
      }
      if (tui.key.matches(msg, 'ctrl+c')) {
        return [this, null]
      }
      if (
        msg &&
        msg.type === 'key' &&
        !msg.ctrl &&
        !msg.meta &&
        typeof msg.sequence === 'string' &&
        msg.sequence.length === 1 &&
        msg.sequence >= ' '
      ) {
        bareEditInsertChar(this.buf, msg.sequence)
        this._ensureScroll()
      }
      return [this, null]
    },
    view: function () {
      const cols = Math.max(40, this.width || 80)
      const contentH = this._contentH()
      this._ensureScroll()
      const lines = []
      for (let r = 0; r < contentH; r++) {
        const lineIndex = this.scrollRow + r
        const line = this.buf.lines[lineIndex] || ''
        const spans = bareEditHighlightLine(line, this.lang)
        lines.push(
          bareEditPaintLineWindow(line, spans, this.scrollCol, cols, useColor)
        )
      }
      const dirtyMark = this.buf.dirty ? ' [Modified]' : ''
      const statusRaw =
        this.statusMsg ||
        this.display +
          '  ' +
          this.savePath +
          dirtyMark +
          '  ' +
          (this.buf.row + 1) +
          ',' +
          (this.buf.col + 1)
      const helpRaw =
        '^G Help  ^O/^S Save  ^X Exit  ^W Find  ^_ Line  ^Z Undo  ^Y Redo'
      const st = tui.style
      const status = st
        ? st()
            .foreground('brightwhite')
            .background('blue')
            .width(cols)
            .render(statusRaw)
        : statusRaw
      const help = st ? st().dim().width(cols).render(helpRaw) : helpRaw
      return lines.join('\n') + '\n' + status + '\n' + help
    },
    overlays: function (size) {
      const cols = (size && size.width) || this.width || 80
      const rows = (size && size.height) || this.height || 24
      const st = tui.style
      /** @type {{ row: number, col: number, text: string }[]} */
      const list = []
      if (this.mode === 'help') {
        const body =
          'Bare OS edit — help\n\n' +
          '^O ^S  Save      ^X  Exit\n' +
          '^W     Search    ^_  Go to line\n' +
          '^Z     Undo      ^Y  Redo\n' +
          'Arrows move cursor; Home/End; Backspace/Del\n\n' +
          'Press any key to return.'
        const boxed = st
          ? st()
              .border(st.borders.rounded)
              .padding(1, 2)
              .background('black')
              .render(body)
          : body
        const h = st ? st.height(boxed) : boxed.split('\n').length
        const w = st ? st.width(boxed) : 40
        list.push({
          row: Math.max(0, Math.floor((rows - h) / 2)),
          col: Math.max(0, Math.floor((cols - w) / 2)),
          text: boxed
        })
        return list
      }
      if (this.mode === 'quit_confirm') {
        const msg = 'Save modified buffer?  Y Yes  N No  ^C Cancel'
        list.push({
          row: Math.max(0, rows - 2),
          col: 0,
          text: st
            ? st()
                .foreground('brightwhite')
                .background('blue')
                .width(cols)
                .render(msg)
            : msg
        })
        return list
      }
      if (this._promptKind()) {
        const bar = this.promptTitle + this.promptBuf
        list.push({
          row: Math.max(0, rows - 2),
          col: 0,
          text: st
            ? st()
                .foreground('brightwhite')
                .background('blue')
                .width(cols)
                .render(bar)
            : bar
        })
        return list
      }
      this._ensureScroll()
      const cr = this.buf.row - this.scrollRow
      const cc = this.buf.col - this.scrollCol
      if (cr >= 0 && cr < rows - 2 && cc >= 0 && cc < cols) {
        const line = this.buf.lines[this.buf.row] || ''
        const ch = line.charAt(this.buf.col) || ' '
        list.push({
          row: cr,
          col: cc,
          text: st ? st().reverse().render(ch) : ch
        })
      }
      return list
    }
  }
}

/**
 * @param {Record<string, unknown>} ctx
 * @param {{ path: string, initialText: string, argv0?: string }} opts
 */
async function bareOsRunEditTui(ctx, opts) {
  if (ctx.tui && typeof ctx.tui.run === 'function') {
    await ctx.tui.run(bareEditCreateTuiApp(ctx, opts), bareEditTuiRunOpts(ctx))
    return
  }
  await bareOsRunEditTuiLegacy(ctx, opts)
}

/**
 * Pre-SDK key loop (BARE_OS_TUI=0).
 * @param {Record<string, unknown>} ctx
 * @param {{ path: string, initialText: string, argv0?: string }} opts
 */
async function bareOsRunEditTuiLegacy(ctx, opts) {
  const vfs = ctx.vfs
  const b4a = ctx.b4a
  const path = opts.path || 'Untitled'
  const display = opts.argv0 || 'edit'
  const lang = bareEditDetectLang(path)
  const buf = bareEditCreateBuffer(opts.initialText)
  const useColor = bareEditUseColor(ctx)
  const stdin = /** @type {import('stream').Readable | undefined} */ (
    ctx.replStdin
  )
  const stdout = bareEditResolveStdout(ctx)
  if (!stdin || !stdout) {
    ctx.console.error('edit: missing stdin/stdout')
    ctx.exitCode = 1
    return
  }

  let scrollRow = 0
  let scrollCol = 0
  let savePath = path

  /** @type {'edit'|'quit_confirm'|'help'|'prompt_search'|'prompt_goto'|'prompt_saveas'} */
  let mode = 'edit'
  let promptBuf = ''
  let promptTitle = ''
  let lastSearch = ''

  const envEditEarly =
    ctx.env && typeof ctx.env === 'object'
      ? /** @type {Record<string, string>} */ (ctx.env)
      : {}
  let maxPromptLen = 4096
  const maxPromptRaw = envEditEarly.BARE_EDIT_MAX_PROMPT
  if (maxPromptRaw != null && String(maxPromptRaw) !== '') {
    const n = parseInt(String(maxPromptRaw), 10)
    if (Number.isFinite(n) && n > 0) maxPromptLen = Math.min(n, 65536)
  }

  /**
   * @param {string} text
   * @param {'saveas'|'search'|'goto'} kind
   */
  function promptLineFromPaste(text, kind) {
    let line = String(text).split(/\r?\n/)[0] ?? ''
    line = line.replace(/[\x00-\x08\x0b\x0c\x0e-\x1f]/g, '')
    if (line.length > maxPromptLen) line = line.slice(0, maxPromptLen)
    if (kind === 'goto') {
      const m = /^(\s*\d+)/.exec(line)
      return m ? m[1].trim() : ''
    }
    return line
  }

  function termDims() {
    const env =
      ctx.env && typeof ctx.env === 'object'
        ? /** @type {Record<string, string>} */ (ctx.env)
        : {}
    const cols =
      /** @type {{ columns?: number }} */ (stdout).columns ||
      parseInt(env.COLUMNS || '80', 10) ||
      80
    const rows =
      /** @type {{ rows?: number }} */ (stdout).rows ||
      parseInt(env.LINES || '24', 10) ||
      24
    return { cols: Math.max(40, cols), rows: Math.max(8, rows) }
  }

  function ensureScroll() {
    const { cols, rows } = termDims()
    const contentH = rows - 2
    if (buf.row < scrollRow) scrollRow = buf.row
    if (buf.row >= scrollRow + contentH) scrollRow = buf.row - contentH + 1
    if (scrollRow < 0) scrollRow = 0
    if (scrollCol > buf.col) scrollCol = buf.col
    if (buf.col - scrollCol >= cols) scrollCol = buf.col - cols + 1
    if (scrollCol < 0) scrollCol = 0
  }

  function draw() {
    const { cols, rows } = termDims()
    const contentH = Math.max(1, rows - 2)
    ensureScroll()

    let out = ''
    out += '\x1b[?25l\x1b[2J\x1b[H'

    if (mode === 'help') {
      out +=
        'Bare OS edit — help\r\n\r\n' +
        '^O ^S  Save      ^X  Exit\r\n' +
        '^W     Search    ^_  Go to line\r\n' +
        '^Z     Undo      ^Y  Redo\r\n' +
        'Arrows move cursor; Home/End; Backspace/Del\r\n\r\n' +
        'Press any key to return.\r\n'
      out += bareEditCup(8, 1) + '\x1b[?25h'
      bareEditWrite(ctx, stdout, out)
      return
    }

    if (mode === 'quit_confirm') {
      for (let row = 1; row <= contentH; row++) {
        out += bareEditCup(row, 1) + '\x1b[K'
      }
      const msg = 'Save modified buffer?  Y Yes  N No  ^C Cancel'
      const st = bareEditSgr('status', useColor) + msg + EDIT_ANSI_RESET
      out += bareEditCup(contentH + 1, 1) + '\x1b[K' + st
      out += bareEditCup(contentH + 1, 1) + '\x1b[?25h'
      bareEditWrite(ctx, stdout, out)
      return
    }

    if (
      mode === 'prompt_search' ||
      mode === 'prompt_goto' ||
      mode === 'prompt_saveas'
    ) {
      const editorLines = Math.max(0, contentH - 1)
      for (let r = 0; r < editorLines; r++) {
        const lineIndex = scrollRow + r
        const line = buf.lines[lineIndex] || ''
        const spans = bareEditHighlightLine(line, lang)
        const vis = bareEditPaintLineWindow(
          line,
          spans,
          scrollCol,
          cols,
          useColor
        )
        out += bareEditCup(1 + r, 1) + '\x1b[K' + vis
      }
      const barBody =
        bareEditSgr('status', useColor) +
        promptTitle +
        promptBuf +
        (useColor ? '\x1b[0m' : '')
      const promptRow = editorLines + 1
      out += bareEditCup(promptRow, 1) + '\x1b[K' + barBody
      const promptCol = 1 + promptTitle.length + promptBuf.length
      out += bareEditCup(promptRow, promptCol) + '\x1b[?25h'
      bareEditWrite(ctx, stdout, out)
      return
    }

    for (let r = 0; r < contentH; r++) {
      const lineIndex = scrollRow + r
      const line = buf.lines[lineIndex] || ''
      const spans = bareEditHighlightLine(line, lang)
      const vis = bareEditPaintLineWindow(
        line,
        spans,
        scrollCol,
        cols,
        useColor
      )
      out += bareEditCup(1 + r, 1) + '\x1b[K' + vis
    }

    const dirtyMark = buf.dirty ? ' [Modified]' : ''
    const statusLine =
      (useColor ? bareEditSgr('status', true) : '') +
      display +
      '  ' +
      savePath +
      dirtyMark +
      '  ' +
      (buf.row + 1) +
      ',' +
      (buf.col + 1) +
      (useColor ? EDIT_ANSI_RESET : '')
    const helpLine =
      (useColor ? bareEditSgr('dim', true) : '') +
      '^G Help  ^O/^S Save  ^X Exit  ^W Find  ^_ Line  ^Z Undo  ^Y Redo' +
      (useColor ? EDIT_ANSI_RESET : '')
    out += bareEditCup(contentH + 1, 1) + '\x1b[K' + statusLine
    out += bareEditCup(contentH + 2, 1) + '\x1b[K' + helpLine
    const curRow = 1 + (buf.row - scrollRow)
    const curCol = 1 + (buf.col - scrollCol)
    const tr = Math.min(Math.max(1, curRow), contentH)
    const tc = Math.min(Math.max(1, curCol), cols)
    out += bareEditCup(tr, tc) + '\x1b[?25h'
    bareEditWrite(ctx, stdout, out)
  }

  async function doSave(targetPath) {
    const text = bareEditJoinAll(buf)
    try {
      await vfs.writeFile(targetPath, b4a.from(text))
      buf.dirty = false
      savePath = targetPath
      return true
    } catch (e) {
      ctx.console.error('edit: ' + ((e && e.message) || String(e)))
      return false
    }
  }

  const reader = bareEditCreateStdinReader(stdin)
  let suspended = false
  /** When true, alternate-screen mode was entered (?1049h); {@link bareEditWrite} must send ?1049l on exit. */
  let useAltScreen = false
  /** When true, bracketed paste mode was enabled (?2004h); must send ?2004l on exit. */
  let useBracketPaste = false
  try {
    if (typeof ctx.suspendReplForSubprocess === 'function') {
      ctx.suspendReplForSubprocess()
      suspended = true
    }
    if (typeof stdin.setRawMode === 'function') stdin.setRawMode(true)
    if (typeof stdin.resume === 'function') stdin.resume()

    const bareEditNoAltScreen =
      envEditEarly.BARE_EDIT_NO_ALTSCREEN != null &&
      String(envEditEarly.BARE_EDIT_NO_ALTSCREEN) !== ''
    if (!bareEditNoAltScreen) {
      bareEditWrite(ctx, stdout, '\x1b[?1049h')
      useAltScreen = true
    }

    const bareEditNoBracketPaste =
      envEditEarly.BARE_EDIT_NO_BRACKETED_PASTE != null &&
      String(envEditEarly.BARE_EDIT_NO_BRACKETED_PASTE) !== ''
    if (!bareEditNoBracketPaste) {
      bareEditWrite(ctx, stdout, '\x1b[?2004h')
      useBracketPaste = true
    }

    draw()

    for (;;) {
      const ev = await bareEditReadKey(reader)
      if (ev.type === 'eof') break

      if (mode === 'help') {
        mode = 'edit'
        draw()
        continue
      }

      if (mode === 'quit_confirm') {
        if (ev.type === 'ctrl' && ev.code === 'interrupt') {
          mode = 'edit'
          draw()
          continue
        }
        if (ev.type === 'key' && ev.ch) {
          const u = ev.ch.toUpperCase()
          if (u === 'Y') {
            await doSave(savePath)
            break
          }
          if (u === 'N') break
        }
        continue
      }

      if (
        mode === 'prompt_search' ||
        mode === 'prompt_goto' ||
        mode === 'prompt_saveas'
      ) {
        if (ev.type === 'ctrl' && ev.code === 'interrupt') {
          mode = 'edit'
          draw()
          continue
        }
        if (ev.type === 'paste') {
          if (mode === 'prompt_saveas') {
            promptBuf = promptLineFromPaste(ev.text || '', 'saveas')
          } else if (mode === 'prompt_search') {
            promptBuf = promptLineFromPaste(ev.text || '', 'search')
          } else if (mode === 'prompt_goto') {
            promptBuf = promptLineFromPaste(ev.text || '', 'goto')
          }
          draw()
          continue
        }
        if (ev.type === 'key' && ev.ch === '\n') {
          if (mode === 'prompt_search') {
            lastSearch = promptBuf
            if (lastSearch) {
              const hit = bareEditFindNext(
                buf,
                lastSearch,
                buf.row,
                buf.col + 1
              )
              if (!hit) {
                const hit2 = bareEditFindNext(buf, lastSearch, 0, 0)
                if (hit2) {
                  buf.row = hit2.row
                  buf.col = hit2.col
                }
              } else {
                buf.row = hit.row
                buf.col = hit.col
              }
            }
          } else if (mode === 'prompt_goto') {
            const n = parseInt(promptBuf.trim(), 10)
            if (Number.isFinite(n)) bareEditGotoLine(buf, n)
          } else if (mode === 'prompt_saveas') {
            const p = promptBuf.trim()
            if (p) {
              savePath = p
              await doSave(savePath)
            }
          }
          mode = 'edit'
          draw()
          continue
        }
        if (ev.type === 'ctrl' && ev.code === 'backspace') {
          promptBuf = promptBuf.slice(0, -1)
          draw()
          continue
        }
        if (ev.type === 'key' && ev.ch && ev.ch !== '\n' && ev.ch !== '\t') {
          if (ev.ch >= ' ' && promptBuf.length < maxPromptLen)
            promptBuf += ev.ch
          draw()
          continue
        }
        continue
      }

      if (ev.type === 'paste') {
        bareEditInsertPasteText(buf, ev.text || '')
        draw()
        continue
      }

      if (ev.type === 'nav') {
        if (ev.key === 'pageup') {
          const { rows } = termDims()
          const step = Math.max(1, rows - 4)
          buf.row = Math.max(0, buf.row - step)
          bareEditClampCursor(buf)
        } else if (ev.key === 'pagedown') {
          const { rows } = termDims()
          const step = Math.max(1, rows - 4)
          buf.row = Math.min(buf.lines.length - 1, buf.row + step)
          bareEditClampCursor(buf)
        } else bareEditMoveKey(buf, ev.key)
        draw()
        continue
      }

      if (ev.type === 'ctrl') {
        if (ev.code === 'backspace') {
          bareEditBackspace(buf)
          draw()
          continue
        }
        if (ev.code === 'delete') {
          bareEditDelete(buf)
          draw()
          continue
        }
        if (ev.code === 'interrupt') {
          /* ignore in edit */
          continue
        }
        const code = typeof ev.code === 'number' ? ev.code : 0
        if (code === 27) {
          /* lone ESC fragment; do not insert */
          continue
        }
        if (code === 24) {
          if (buf.dirty) {
            mode = 'quit_confirm'
            draw()
          } else break
          continue
        }
        if (code === 19) {
          await doSave(savePath)
          draw()
          continue
        }
        if (code === 15) {
          mode = 'prompt_saveas'
          promptTitle = 'File: '
          promptBuf = savePath
          draw()
          continue
        }
        if (code === 23) {
          mode = 'prompt_search'
          promptTitle = 'Search: '
          promptBuf = lastSearch
          draw()
          continue
        }
        if (code === 7) {
          mode = 'help'
          draw()
          continue
        }
        if (code === 31) {
          mode = 'prompt_goto'
          promptTitle = 'Go to line: '
          promptBuf = ''
          draw()
          continue
        }
        if (code === 26) {
          bareEditUndo(buf)
          draw()
          continue
        }
        if (code === 25) {
          bareEditRedo(buf)
          draw()
          continue
        }
        continue
      }

      if (ev.type === 'key' && ev.ch) {
        if (ev.ch === '\n') bareEditNewline(buf)
        else if (ev.ch === '\t') bareEditInsertChar(buf, '  ')
        else bareEditInsertChar(buf, ev.ch)
        draw()
      }
    }
  } finally {
    try {
      if (useBracketPaste) {
        bareEditWrite(ctx, stdout, '\x1b[?2004l')
      }
      if (useAltScreen) {
        bareEditWrite(ctx, stdout, '\x1b[?1049l')
      } else {
        bareEditWrite(ctx, stdout, '\x1b[2J\x1b[H')
      }
      bareEditWrite(ctx, stdout, '\x1b[?25h\x1b[0m')
    } catch {
      /* ignore */
    }
    reader.dispose()
    try {
      if (typeof stdin.setRawMode === 'function') stdin.setRawMode(false)
    } catch {
      /* ignore */
    }
    if (suspended && typeof ctx.resumeReplAfterSubprocess === 'function') {
      ctx.resumeReplAfterSubprocess()
    }
  }
}