term_mod.lua

local component = require("component")
local computer = require("computer")
local event = require("event")
local keyboard = require("keyboard")
local text = require("text")
local unicode = require("unicode")
local term=require("term")

--modified version of term.read preventing line shifts and supporting color system of GUI-API
--not perfect, just a temporary solution

local function read_mod(history, dobreak, hint, pwchar, filter,fcol,fcol,bcol_std,bcol_std)
  checkArg(1, history, "table", "nil")
  checkArg(3, hint, "function", "table", "nil")
  checkArg(4, pwchar, "string", "nil")
  checkArg(5, filter, "string", "function", "nil")
  fcol=fcol or 0xFFFFFF
  bcol=bcol or 0x000000
  fcol_std=fcol_std or 0xFFFFFF
  bcol_std=bcol_std or 0x000000
  history = history or {}
  table.insert(history, "")
  local offset = term.getCursor() - 1
  local scrollX, scrollY = 0, #history - 1
  local cursorX = 1

  if type(hint) == "table" then
    local hintTable = hint
    hint = function()
      return hintTable
    end
  end
  local hintCache, hintIndex

  if pwchar and unicode.len(pwchar) > 0 then
    pwchar = unicode.sub(pwchar, 1, 1)
  end

  if type(filter) == "string" then
    local pattern = filter
    filter = function(line)
      return line:match(pattern)
    end
  end

  local function masktext(str)
    return pwchar and pwchar:rep(unicode.len(str)) or str
  end

  local function getCursor()
    return cursorX, 1 + scrollY
  end

  local function line()
    local _, cby = getCursor()
    return history[cby]
  end

  local function clearHint()
    hintCache = nil
  end

  local function setCursor(nbx, nby)
    local w, h = component.gpu.getResolution()
    local cx, cy = term.getCursor()

    scrollY = nby - 1

    nbx = math.max(1, math.min(unicode.len(history[nby]) + 1, nbx))
    local ncx = nbx + offset - scrollX
    if ncx > w then
      local sx = nbx - (w - offset)
      local dx = math.abs(scrollX - sx)
      scrollX = sx
      --component.gpu.copy(1 + offset + dx, cy, w - offset - dx, 1, -dx, 0)
      local str = masktext(unicode.sub(history[nby], nbx - (dx - 1), nbx))
      str = text.padRight(str, dx)
      component.gpu.setBackground(bcol)
      component.gpu.setForeground(fcol)
      component.gpu.set(1 + math.max(offset, w - dx), cy, unicode.sub(str, 1 + math.max(0, dx - (w - offset))))
      component.gpu.setBackground(bcol_std)
      component.gpu.setForeground(fcol_std)
    elseif ncx < 1 + offset then
      local sx = nbx - 1
      local dx = math.abs(scrollX - sx)
      scrollX = sx
      --component.gpu.copy(1 + offset, cy, w - offset - dx, 1, dx, 0)
      local str = masktext(unicode.sub(history[nby], nbx, nbx + dx))
      component.gpu.setBackground(bcol)
      component.gpu.setForeground(fcol)
      component.gpu.set(1 + offset, cy, str)
      component.gpu.setBackground(bcol_std)
      component.gpu.setForeground(fcol_std)
    end

    cursorX = nbx
    term.setCursor(nbx - scrollX + offset, cy)
    clearHint()
  end

  local function copyIfNecessary()
    local cbx, cby = getCursor()
    if cby ~= #history then
      history[#history] = line()
      setCursor(cbx, #history)
    end
  end

  local function redraw()
    local cx, cy = term.getCursor()
    local bx, by = 1 + scrollX, 1 + scrollY
    local w, h = component.gpu.getResolution()
    local l = w - offset
    local str = masktext(unicode.sub(history[by], bx, bx + l))
    str = text.padRight(str, l)
    component.gpu.setBackground(bcol)
    component.gpu.setForeground(fcol)
    component.gpu.set(1 + offset, cy, str)
    component.gpu.setBackground(bcol_std)
    component.gpu.setForeground(fcol_std)
  end

  local function home()
    local cbx, cby = getCursor()
    setCursor(1, cby)
  end

  local function ende()
    local cbx, cby = getCursor()
    setCursor(unicode.len(line()) + 1, cby)
  end

  local function left()
    local cbx, cby = getCursor()
    if cbx > 1 then
      setCursor(cbx - 1, cby)
      return true -- for backspace
    end
  end

  local function right(n)
    n = n or 1
    local cbx, cby = getCursor()
    local be = unicode.len(line()) + 1
    if cbx < be then
      setCursor(math.min(be, cbx + n), cby)
    end
  end

  local function up()
    local cbx, cby = getCursor()
    if cby > 1 then
      setCursor(1, cby - 1)
      redraw()
      ende()
    end
  end

  local function down()
    local cbx, cby = getCursor()
    if cby < #history then
      setCursor(1, cby + 1)
      redraw()
      ende()
    end
  end

  local function delete()
    copyIfNecessary()
    clearHint()
    local cbx, cby = getCursor()
    if cbx <= unicode.len(line()) then
      local cw = unicode.charWidth(unicode.sub(line(), cbx))
      history[cby] = unicode.sub(line(), 1, cbx - 1) ..
                     unicode.sub(line(), cbx + 1)
      local cx, cy = term.getCursor()
      local w, h = component.gpu.getResolution()
      -- component.gpu.copy(cx + cw, cy, w - cx, 1, -cw, 0)
      local br = cbx + (w - cx)
      local char = masktext(unicode.sub(line(), br, br))
      if not char or unicode.wlen(char) == 0 then
        char = " "
      end
      component.gpu.setBackground(bcol)
      component.gpu.setForeground(fcol)
      component.gpu.set(w, cy, char)
      component.gpu.setBackground(bcol_std)
      component.gpu.setForeground(fcol_std)
    end
  end

  local function insert(value)
    copyIfNecessary()
    clearHint()
    local cx, cy = term.getCursor()
    local cbx, cby = getCursor()
    local w, h = component.gpu.getResolution()
    history[cby] = unicode.sub(line(), 1, cbx - 1) ..
                   value ..
                   unicode.sub(line(), cbx)
    local len = unicode.wlen(value)
    local n = w - (cx - 1) - len
    -- if n > 0 then
      -- component.gpu.copy(cx, cy, n, 1, len, 0)
    -- end
    component.gpu.setBackground(bcol)
      component.gpu.setForeground(fcol)
      component.gpu.set(cx, cy, masktext(value))
      component.gpu.setBackground(bcol_std)
      component.gpu.setForeground(fcol_std)
    right(unicode.len(value))
  end

  local function tab(direction)
    local cbx, cby = getCursor()
    if not hintCache then -- hint is never nil, see onKeyDown
      hintCache = hint(line(), cbx)
      hintIndex = 0
      if type(hintCache) == "string" then
        hintCache = {hintCache}
      end
      if type(hintCache) ~= "table" or #hintCache < 1 then
        hintCache = nil -- invalid hint
      end
    end
    if hintCache then
      hintIndex = (hintIndex + direction + #hintCache - 1) % #hintCache + 1
      history[cby] = tostring(hintCache[hintIndex])
      -- because all other cases of the cursor being moved will result
      -- in the hint cache getting invalidated we do that in setCursor,
      -- so we have to back it up here to restore it after moving.
      local savedCache = hintCache
      redraw()
      ende()
      if #savedCache > 1 then -- stop if only one hint exists.
        hintCache = savedCache
      end
    end
  end

  local function onKeyDown(char, code)
    term.setCursorBlink(false)
    if code == keyboard.keys.back then
      if left() then delete() end
    elseif code == keyboard.keys.delete then
      delete()
    elseif code == keyboard.keys.left then
      left()
    elseif code == keyboard.keys.right then
      right()
    elseif code == keyboard.keys.home then
      home()
    elseif code == keyboard.keys["end"] then
      ende()
    elseif code == keyboard.keys.up then
      up()
    elseif code == keyboard.keys.down then
      down()
    elseif code == keyboard.keys.tab and hint then
      tab(keyboard.isShiftDown() and -1 or 1)
    elseif code == keyboard.keys.enter then
      if not filter or filter(line() or "") then
        local cbx, cby = getCursor()
        if cby ~= #history then -- bring entry to front
          history[#history] = line()
          table.remove(history, cby)
        end
        return true, history[#history] .. "\n"
      else
        computer.beep(2000, 0.1)
      end
    elseif keyboard.isControlDown() and code == keyboard.keys.d then
      if line() == "" then
        history[#history] = ""
        return true, nil
      end
    elseif not keyboard.isControl(char) then
      insert(unicode.char(char))
    end
    term.setCursorBlink(true)
    term.setCursorBlink(true) -- force toggle to caret
  end

  local function onClipboard(value)
    copyIfNecessary()
    term.setCursorBlink(false)
    local cbx, cby = getCursor()
    local l = value:find("\n", 1, true)
    if l then
      history[cby] = unicode.sub(line(), 1, cbx - 1)
      redraw()
      insert(unicode.sub(value, 1, l - 1))
      return true, line() .. "\n"
    else
      insert(value)
      term.setCursorBlink(true)
      term.setCursorBlink(true) -- force toggle to caret
    end
  end

  local function cleanup()
    if history[#history] == "" then
      table.remove(history)
    end
    term.setCursorBlink(false)
    if term.getCursor() > 1 and dobreak ~= false then
      term.write("\n")
    end
  end

  term.setCursorBlink(true)
  while term.isAvailable() do
    local ocx, ocy = getCursor()
    local ok, name, address, charOrValue, code = pcall(event.pull)
    if not ok then
      cleanup()
      error("interrupted", 0)
    end
    if name == "interrupted" then
      cleanup()
      return nil
    end
    local ncx, ncy = getCursor()
    if ocx ~= ncx or ocy ~= ncy then
      cleanup()
      return "" -- soft fail the read if someone messes with the term
    end
    if term.isAvailable() and -- may have changed since pull
       type(address) == "string" and
       component.isPrimary(address)
    then
      local done, result
      if name == "key_down" then
        done, result = onKeyDown(charOrValue, code)
      elseif name == "clipboard" then
        done, result = onClipboard(charOrValue)
      end
      if done then
        cleanup()
        return result
      end
    end
  end
  cleanup()
  return nil -- fail the read if term becomes unavailable
end

return read_mod