local ls = require("luasnip")
local fmt = require('luasnip.extras.fmt').fmt

local ls_namespace = vim.api.nvim_create_namespace('luasnip')
local group = vim.api.nvim_create_augroup('LuaSnip', { clear = true })

vim.api.nvim_create_autocmd('ModeChanged', {
  callback = function(opts)
    if ls.session.current_nodes[opts.buf]
        and ((vim.v.event.old_mode == 's' and vim.v.event.new_mode == 'n') or vim.v.event.old_mode == 'i')
    then
      ls.unlink_current()
      ls.cleanup()
    end
  end,
})
vim.api.nvim_create_autocmd({'CursorHold', 'CursorHoldI'}, {
  callback = function(opts)
    vim.api.nvim_buf_clear_namespace(opts.buf, ls_namespace, 0, -1)

    if ls.session.current_nodes[opts.buf]
        and ls.choice_active()
    then
      vim.notify('current nodes: ' .. #ls.session.current_nodes[opts.buf])
      local pos = vim.api.nvim_win_get_cursor(0)
      vim.api.nvim_buf_set_extmark(opts.buf, ls_namespace, pos[1] - 1, pos[2], {
        virt_text = {{'<-- choice node', 'Comment'}},
        virt_text_pos = 'eol',
        hl_mode = 'combine',
      })
    end
  end,
  group = group
})
vim.api.nvim_create_autocmd('User', {
  pattern = 'LuasnipCleanup',
  callback = function(opts)
    vim.api.nvim_buf_clear_namespace(opts.buf, ls_namespace, 0, -1)
  end,
  group = group
})

local s = ls.s
local sn = ls.sn
local t = ls.text_node
local f = ls.function_node
local i = ls.insert_node
local c = ls.choice_node
local d = ls.dynamic_node

local exec = function(command)
  return f(function(_, _, command_arg)
    local results, code = require('plenary.job'):new({
      command = vim.env.SHELL,
      args = {'-c', command_arg},
      enable_recording = true,
    }):sync()
    if not code == 0 or #results == 0 then
      error(string.format('exec "%s" failed', command_arg))
    end
    return results
  end, {}, {user_args = {command}})
end

local user_email = {
  exec([[git config --get user.name]]),
  t(' <'),
  c(1, {
    exec([[git config --get user.email]]),
    t([[robert.gunzler@postman.com]]),
    t([[robert@gnzler.io]]),
  }),
  t('>'),
}

-- snipmate snippets
require('luasnip.loaders.from_snipmate').load({ paths = {'~/.config/nvim/after/snippets'} })

ls.add_snippets('all', {
  s('me'   , user_email),
  s('today', f(function() return os.date('%Y-%m-%d') end, {})),
  s('now'  , f(function() return os.date('%Y-%m-%dT%H:%M:%SZ') end, {}))
}, { type = 'snippets', key = 'generic_helpers'})

local autowrap = function(top, bot, inner)
  local autoinsert = function(args, _, _, wrap_with)
    local nodes = {}
    if vim.trim(table.concat(args[1] or {})) ~= "" then
      table.insert(nodes, wrap_with)
    end
    return sn(nil, nodes)
  end

  local argnodes = {}
  local maxpos = -1
  for _, e in ipairs(inner) do
    if e.pos ~= nil then
      table.insert(argnodes, e.pos)
      if e.pos > maxpos then
        maxpos = e.pos
      end
    end
  end

  local nodes = {}
  table.insert(nodes, d(maxpos+1, autoinsert, argnodes, {user_args = {top}}))
  for _, e in ipairs(inner) do table.insert(nodes, e) end
  table.insert(nodes, d(maxpos+2, autoinsert, argnodes, {user_args = {bot}}))
  return nodes
end

local comment = function(wrapped, blockcomment)
  local get_cstring = function()
    local cs = require('Comment.ft').calculate {
      ctype = blockcomment and 2 or 1,
      range = require('Comment.utils').get_region()
    }
    local tbl = vim.split(cs or '', '%s', {plain = true, trimempty = true})
    return (#tbl == 0) and {'', ''}
      or ((#tbl == 1) and {tbl[1] .. ' ', ''}
        or {tbl[1], tbl[2]})
  end

  if type(wrapped) ~= "table" then
    wrapped = {wrapped}
  end

  local nodes = {}
  table.insert(nodes, f(function() return get_cstring()[1] end))
  for _, n in ipairs(wrapped) do table.insert(nodes, n) end
  table.insert(nodes, f(function() return get_cstring()[2] end))
  return nodes
end

local todo_comment = function(key)
  local nodes = {}
  if type(key) == 'string' then
    table.insert(nodes, t(key))
  elseif type(key) == 'table' then
    table.insert(nodes, c(1, vim.tbl_map(function(e) return t(e) end, key)))
  end
  local wrapped = autowrap(t('('), t(')'), {
    c(#nodes, {
      t(''), -- bare
      exec([[git config --get user.name]]), -- name
      f(function() return os.date('%Y-%m-%d') end, {}), -- time
    }),
  })
  for _, n in ipairs(wrapped) do table.insert(nodes, n) end
  table.insert(nodes, t(': '))
  return comment(nodes)
end

ls.add_snippets('all', {
  s('todo', todo_comment('TODO')),
  s('note', todo_comment('NOTE')),
  s('hack', todo_comment('HACK')),
  s('warn', todo_comment({'WARN', 'XXX'})),
  s('fix' , todo_comment({'FIX', 'FIXME', 'ISSUE', 'BUG'})),
}, { type = 'snippets', key = 'todo_comments'})

ls.add_snippets('gitcommit', {
  s('sign'  , fmt('Signed-off-by: {}', {sn(1, user_email)})),
  s('change', fmt('Change-type: {}', {c(1, {t('patch'), t('minor'), t('major')}) }))
}, { type = 'snippets', key = 'signature_helpers'})

ls.add_snippets('go', {
  s('pack:main', fmt([[
    package main

    func main() {{
	{}
    }}
    ]], {i(1, 'println("hello world!")')}))
}, { type = 'snippets', key = 'golang'})