-- base64 encode and decode from http://lua-users.org/wiki/BaseSixtyFour
local b='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_'
-- encoding
function enc(data)
    return ((data:gsub('.', function(x) 
        local r,b='',x:byte()
        for i=8,1,-1 do r=r..(b%2^i-b%2^(i-1)>0 and '1' or '0') end
        return r;
    end)..'0000'):gsub('%d%d%d?%d?%d?%d?', function(x)
        if (#x < 6) then return '' end
        local c=0
        for i=1,6 do c=c+(x:sub(i,i)=='1' and 2^(6-i) or 0) end
        return b:sub(c+1,c+1)
    end)..({ '', '==', '=' })[#data%3+1])
end

-- decoding
function dec(data)
    data = string.gsub(data, '[^'..b..'=]', '')
    return (data:gsub('.', function(x)
        if (x == '=') then return '' end
        local r,f='',(b:find(x)-1)
        for i=6,1,-1 do r=r..(f%2^i-f%2^(i-1)>0 and '1' or '0') end
        return r;
    end):gsub('%d%d%d?%d?%d?%d?%d?%d?', function(x)
        if (#x ~= 8) then return '' end
        local c=0
        for i=1,8 do c=c+(x:sub(i,i)=='1' and 2^(8-i) or 0) end
            return string.char(c)
    end))
end

return function()
  vim.opt.expandtab = true -- tabs to spaces
  vim.opt.shiftwidth = 2 -- 4 spaces for < and > TODO: change back to 4
  vim.opt.softtabstop = 2 -- 4 spaces in a tab TODO: change back to 4
  vim.opt.number = true -- Show line numbers
  vim.opt.relativenumber = true -- Show other line numbers as relative
  vim.opt.smartindent = true -- Smart indent
  vim.g.airline_powerline_fonts = 1 -- nice icons for airline
  vim.g.wrap = false -- don't wrap lines
  vim.g.termguicolors = true -- better colors
  vim.g.gruvbox_italic = 1 -- gruvbox can use italic font
  vim.g.material_style = 'oceanic' -- material theme
  vim.g.bf_array_mode = 2 -- cyclic brainfuck memory
  vim.g.bf_value_mode = 2 -- cyclic brainfuck values

  -- load colorscheme
  local file = io.open(vim.fn.stdpath('config') .. "/colorscheme", "r")
  local cs = file:read("l")
  file:close()
  vim.cmd("colorscheme " .. cs)

  -- ufo
  vim.o.foldcolumn = '1'
  vim.o.foldlevel = 99
  vim.o.foldlevelstart = 99
  vim.o.foldenable = true
  require('ufo').setup()

  -- vimtex
  vim.g.vimtex_view_general_viewer = 'evince'

  -- -- autoclose
  -- require('autoclose').setup({})

  -- uiua pad
  vim.api.nvim_create_user_command('UiuaPad', function(opts)
    math.randomseed(os.time())

    -- pad file
    if vim.g.pad_file == nil then
      vim.g.pad_file = vim.fn.stdpath('cache') .. '/pad_' .. math.random(100, 999) .. '.ua'
      io.open(vim.g.pad_file, 'w'):close()
    end
    local pad_file = vim.g.pad_file

    -- open relevant buffers
    vim.cmd.edit(pad_file)
    vim.cmd.vsplit()
    local pad_buf = vim.fn.bufnr('%')
    local pad_win = vim.fn.win_getid();
    vim.cmd.wincmd('l')
    vim.cmd.term('cd ' .. vim.fn.stdpath('cache') .. '; uiua watch --clear ' .. pad_file)
    local term_buf = vim.fn.bufnr('%')
    local term_win = vim.fn.win_getid();
    vim.cmd.wincmd('h')

    -- close either one when the other closes
    vim.api.nvim_create_augroup("uiuapad", {clear = true})
    vim.api.nvim_create_autocmd("WinClosed", {
        group = "uiuapad",
        pattern = {tostring(pad_win), tostring(term_win)}, --pad_file, --{"*" .. pad_file, pad_file},
        callback = function(ev)
          -- print(pad_buf)
          -- print(term_buf)
          -- print(vim.fn.bufexists( pad_buf ))
          -- print(vim.fn.bufexists( term_buf ))
          -- if vim.fn.bufexists(pad_buf) then vim.cmd("bdelete! " .. pad_buf) end
          if vim.fn.bufexists(pad_buf) then vim.cmd("bdelete! " .. pad_buf) end
          if vim.fn.bufexists(term_buf) then vim.cmd("bdelete! " .. term_buf) end
        end,
    })

  end, {})

  -- generate uiua pad link
  vim.api.nvim_create_user_command('UiuaLink', function(opts)
    local uiua_version_raw = vim.fn.system({"uiua", "--version"})
    print(uiua_version_raw)
    local uiua_version = uiua_version_raw:sub(6, -2):gsub('%p', '_')
    local buf_text = vim.fn.join(vim.fn.getline(0, '$'), '\n')
    local url = "https://uiua.org/pad?src=" .. uiua_version .. "__" .. enc(buf_text)
    print(url)
    vim.fn.setreg('+', url)
  end, {})
end