-- Copyright (C) 2018-2021 by KittenOS NEO contributors
--
-- Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.
--
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
-- THIS SOFTWARE.

-- 'neolithic': Text Editor
-- This was textedit (femto) from KittenOS 'ported' to NEO.
-- It also has fixes for bugs involving wide text, and runs faster due to the chars -> lines change.

local lines = {
 "Neolithic: Text Editor",
 "F3, F4, F1: Load, Save, New",
 "F5, F6, ^←: Copy, Paste, Delete Line",
 -- These two are meant to replace similar functionality in GNU Nano
 --  (which I consider the best console text editor out there - Neolithic is an *imitation* and a poor one at that),
 --  except fixing a UI flaw by instead adding a visible way to reset the append flag,
 --  so the user can more or less arbitrarily mash together lines
 "F7: Reset 'append' flag for Cut Lines",
 "F8: Cut Line(s)",
 "^<arrows>: Resize Win",
 "'^' is Control.",
 "Wide text & clipboard supported.",
 "Ｆｏｒ ｅｘａｍｐｌｅ， ｔｈｉｓ．",
}

-- If replicating Nano's clipboard :
-- Nano starts off in a "replace" mode,
--  and then after an action occurs switches to "append" until *any cursor action is performed*.
-- The way I have things setup is that you perform J then K(repeat) *instead*, which means you have to explicitly say "destroy current clipboard".

local clipsrc = neo.requireAccess("x.neo.pub.globals", "clipboard")
local windows = neo.requireAccess("x.neo.pub.window", "windows")
local files = neo.requireAccess("x.neo.pub.base", "files").showFileDialogAsync

local lineEdit = require("lineedit")

local cursorX = 1
local cursorY = math.ceil(#lines / 2)
local ctrlFlag, appendFlag
local dialogLock = false
local sW, sH = 37, #lines + 2
local window = windows(sW, sH)
local filedialog = nil
local flush

local cbs = {}

local function fileDialog(writing, callback)
 filedialog = function (res)
  local ok, e = pcall(callback, res)
  if not ok then
   e = unicode.safeTextFormat(tostring(e))
   local wnd = windows(unicode.len(e), 1, "ERROR")
   cbs[wnd.id] = {
    wnd.close,
    wnd.span,
    e
   }
  end
 end
 files(writing)
end

-- Save/Load
local function startSave()
 dialogLock = true
 fileDialog(true, function (res)
  dialogLock = false
  local x = ""
  if res then
   for k, v in ipairs(lines) do
    if k ~= 1 then
     x = x .. "\n"
    end
    x = x .. v
    while #x >= neo.readBufSize do
     res.write(x:sub(1, neo.readBufSize))
     x = x:sub(neo.readBufSize + 1)
    end
   end
   res.write(x)
   res.close()
  end
 end)
end

local function startLoad()
 dialogLock = true
 fileDialog(false, function (res)
  dialogLock = false
  if res then
   lines = {}
   local lb = ""
   while true do
    local l = res.read(neo.readBufSize)
    if not l then
     table.insert(lines, lb)
     cursorX = 1
     cursorY = 1
     res.close()
     flush()
     return
    end
    local lp = l:find("\n")
    while lp do
     lb = lb .. l:sub(1, lp - 1)
     table.insert(lines, lb)
     lb = ""
     l = l:sub(lp + 1)
     lp = l:find("\n")
    end
    lb = lb .. l
   end
  end
 end)
end

local function getline(y)
 -- do rY first since unw
 -- only requires that
 -- horizontal stuff be
 -- messed with...
 -- ...thankfully
 local rY = (y + cursorY) - math.ceil(sH / 2)

 -- rX is difficult!
 local rX = 1
 local Xthold = math.max(1, math.floor(sW / 2) - 1)
 local cLine, cursorXP = unicode.safeTextFormat(lines[cursorY], cursorX)
 rX = (math.max(0, math.floor(cursorXP / Xthold) - 1) * Xthold) + 1
 local line = lines[rY]
 if not line then
  return ("¬"):rep(sW)
 end
 line = unicode.safeTextFormat(line)
 return lineEdit.draw(sW, line, rY == cursorY and cursorXP, rX)
end
local function delLine()
 local contents = lines[cursorY]
 if cursorY == #lines then
  if cursorY == 1 then
   lines[1] = ""
  else
   cursorY = cursorY - 1
   lines[#lines] = nil
  end
 else
  table.remove(lines, cursorY)
 end
 return contents
end
local function key(ks, kc, down)
 if dialogLock then
  return false
 end
 if kc == 29 then
  ctrlFlag = down
  return false
 end
 -- Action keys
 if not down then return false end
 if ctrlFlag then
  -- Control Action Keys
  if kc == 200 then -- Up
   sH = sH - 1
   if sH == 0 then
    sH = 1
   end
   sW, sH = window.setSize(sW, sH)
   return false
  elseif kc == 208 then -- Down
   sH = sH + 1
   sW, sH = window.setSize(sW, sH)
   return false
  elseif kc == 203 then -- Left
   sW = sW - 1
   if sW == 0 then
    sW = 1
   end
   sW, sH = window.setSize(sW, sH)
   return false
  elseif kc == 205 then -- Right
   sW = sW + 1
   sW, sH = window.setSize(sW, sH)
   return false
  elseif kc == 14 then -- ^Backspace
   delLine()
   return true
  end
 else
  -- Non-Control Action Keys
  -- Basic Action Keys
  if kc == 200 or kc == 201 then -- Go up one - go up page
   local moveAmount = 1
   if kc == 201 then
    moveAmount = math.floor(sH / 2)
   end
   cursorY = cursorY - moveAmount
   if cursorY < 1 then
    cursorY = 1
   end
   cursorX = lineEdit.clamp(lines[cursorY], cursorX)
   return true
  elseif kc == 208 or kc == 209 then -- Go down one - go down page
   local moveAmount = 1
   if kc == 209 then
    moveAmount = math.floor(sH / 2)
   end
   cursorY = cursorY + moveAmount
   if cursorY > #lines then
    cursorY = #lines
   end
   cursorX = lineEdit.clamp(lines[cursorY], cursorX)
   return true
  end
  -- Major Actions
  if kc == 59 then -- F1
   lines = {""}
   cursorX = 1
   cursorY = 1
   return true
  elseif kc == 61 then -- F3
   startLoad()
   return false
  elseif kc == 62 then -- F4
   startSave()
   return false
  elseif kc == 63 then -- F5
   clipsrc.setSetting("clipboard", lines[cursorY])
   return false
  elseif kc == 64 then -- F6
   local tx = clipsrc.getSetting("clipboard") or ""
   local txi = tx:find("\n")
   local nt = {}
   while txi do
    table.insert(nt, 1, tx:sub(1, txi - 1))
    tx = tx:sub(txi + 1)
    txi = tx:find("\n")
   end
   table.insert(lines, cursorY, tx)
   for _, v in ipairs(nt) do
    table.insert(lines, cursorY, v)
   end
   return true
  elseif kc == 65 then -- F7
   appendFlag = false
   return false
  elseif kc == 66 then -- F8
   if appendFlag then
    local base = clipsrc.getSetting("clipboard")
    clipsrc.setSetting("clipboard", base .. "\n" .. delLine())
   else
    clipsrc.setSetting("clipboard", delLine())
   end
   appendFlag = true
   return true
  end
 end
 -- LEL Keys
 local lT, lC, lX = lineEdit.key(ks, kc, lines[cursorY], cursorX)
 if lT then
  lines[cursorY] = lT
 end
 if lC then
  cursorX = lC
 end
 if lX == "l<" and cursorY > 1 then
  cursorY = cursorY - 1
  cursorX = unicode.len(lines[cursorY]) + 1
 elseif lX == "l>" and cursorY < #lines then
  cursorY = cursorY + 1
  cursorX = 1
 elseif lX == "w<" and cursorY ~= 1 then
  local l = table.remove(lines, cursorY)
  cursorY = cursorY - 1
  cursorX = unicode.len(lines[cursorY]) + 1
  lines[cursorY] = lines[cursorY] .. l
 elseif lX == "w>" and cursorY ~= #lines then
  local l = table.remove(lines, cursorY)
  cursorX = unicode.len(l) + 1
  lines[cursorY] = l .. lines[cursorY]
 elseif lX == "nl" then
  local line = lines[cursorY]
  lines[cursorY] = unicode.sub(line, 1, cursorX - 1)
  table.insert(lines, cursorY + 1, unicode.sub(line, cursorX))
  cursorX = 1
  cursorY = cursorY + 1
 end
 return true
end

flush = function ()
 for i = 1, sH do
  window.span(1, i, getline(i), 0xFFFFFF, 0)
 end
end

while true do
 local e = {coroutine.yield()}
 if e[1] == "x.neo.pub.window" then
  if e[2] == window.id then
   if e[3] == "line" then
    window.span(1, e[4], getline(e[4]), 0xFFFFFF, 0)
   elseif filedialog then
   elseif e[3] == "touch" then
    -- reverse:
    --local rY = (y + cursorY) - math.ceil(sH / 2)
    local csY = math.ceil(sH / 2)
    local nY = math.max(1, math.min(#lines, (math.floor(e[5]) - csY) + cursorY))
    cursorY = nY
    cursorX = lineEdit.clamp(lines[cursorY], cursorX)
    flush()
   elseif e[3] == "key" then
    if key(e[4] ~= 0 and unicode.char(e[4]), e[5], e[6]) then
     flush()
    end
   elseif e[3] == "focus" then
    ctrlFlag = false
   elseif e[3] == "close" then
    return
   elseif e[3] == "clipboard" then
    local t = e[4]
    for i = 1, unicode.len(t) do
     local c = unicode.sub(t, i, i)
     if c ~= "\r" then
      if c == "\n" then
       c = "\r"
      end
      key(c, 0, true)
     end
    end
    flush()
   end
  elseif cbs[e[2]] then
   if e[3] == "line" then
    cbs[e[2]][2](1, 1, cbs[e[2]][3], 0, 0xFFFFFF)
   elseif e[3] == "close" then
    cbs[e[2]][1]()
    cbs[e[2]] = nil
   end
  end
 elseif e[1] == "x.neo.pub.base" and e[2] == "filedialog" and filedialog then
  filedialog(e[4])
  filedialog = nil
 end
end