main.lua
local M = {}

function M:peek(job)
  local child
  local l = job.file.cha.len
  if l == 0 then
    child = Command("hexyl")
        :args({
          tostring(job.file.url),
        })
        :stdout(Command.PIPED)
        :stderr(Command.PIPED)
        :spawn()
  else
    child = Command("hexyl")
        :args({
          "--border", "none",
          "--terminal-width", tostring(job.area.w),
          tostring(job.file.url),
        })
        :stdout(Command.PIPED)
        :stderr(Command.PIPED)
        :spawn()
  end

  if not child then
    return require("code").peek(job)
  end

  local limit = job.area.h
  local i, lines = 0, ""
  repeat
    local line, event = child:read_line()
    if event == 1 then
      ya.err(tostring(event))
      break
    elseif event ~= 0 then
      break
    end

    i = i + 1
    if i > job.skip then
      lines = lines .. line
    end
  until i >= job.skip + limit

  child:start_kill()
  if job.skip > 0 and i < job.skip + limit then
    ya.mgr_emit("peek", {
      math.max(0, i - limit),
      only_if = job.file.url,
      upper_bound = true,
    })
  else
    lines = lines:gsub("\t", string.rep(" ", rt.preview.tab_size))
    ya.preview_widgets(job, { ui.Text.parse(lines):area(job.area) })
  end
end

function M:seek(job)
  -- Get the currently hovered file from your UI context.
  local h = cx.active.current.hovered
  if not h or h.url ~= job.file.url then
    return
  end

  local scroll_offset = job.units

  -- Emit a new peek event with the updated skip value.
  ya.mgr_emit("peek", {
    math.max(0, cx.active.preview.skip + scroll_offset),
    only_if = job.file.url,
  })
end

return M
