local reftool = {}

local utils = require('go.utils')
local log = utils.log
local fn, api = vim.fn, vim.api

local function insert_result(result)
  local curpos = fn.getcurpos()
  local goto_l = string.format('goto %d', result['start'] + 1)
  vim.cmd(goto_l)
  local inserts = result.code
  inserts = vim.split(inserts, '\n')
  local change = string.format('normal! %ds%s', result['end'] - result.start, inserts[1])
  vim.cmd(change)
  vim.cmd('startinsert!')
  log(change)
  local curline = curpos[2]
  for i = 2, #inserts do
    log("append ", curline, inserts[i])
    vim.fn.append(curline, inserts[i])
    curline = curline + 1
  end

  vim.cmd('stopinsert!')
  vim.cmd('write')
  -- format(#inserts, curpos)
  fn.setpos('.', curpos)
  vim.lsp.buf.formatting()
end

-- can only be fillstruct and fillswitch
local function fill(cmd)
  if cmd ~= 'fillstruct' and cmd ~= 'fillswitch' then
    log(cmd, "not found")
    error('cmd not supported by go.nvim', cmd)
  end
  require("go.install").install(cmd)

  log(cmd)
  local file = fn.expand("%:p")
  local line = fn.line(".")
  local run = string.format("%s -file=%s -line=%d 2>/dev/null", cmd, file, line)
  local farg = string.format('-file=%s', file)
  local larg = string.format('-line=%d', line)
  local args = {cmd, farg, larg, '2>/dev/null'}
  log(args)
  vim.fn.jobstart(args, {
    on_stdout = function(jobid, str, event)
      log(str)
      if #str < 2 then
        log('reftools', cmd, 'finished with no result')
        return
      end
      local json = fn.json_decode(str)
      if #json == 0 then
        print('reftools', cmd, 'finished with no result')
      end

      local result = json[1]
      insert_result(result)
    end
  })
end

local function gopls_fillstruct(timeout_ms)
  log('fill struct with gopls')
  local codeaction = require'go.lsp'.codeaction
  codeaction('fill_struct', 'refactor.rewrite', timeout_ms)
end

function reftool.fillstruct()
  if _GO_NVIM_CFG.fillstruct == 'gopls' then
    gopls_fillstruct(1000)
  else
    log('fillstruct')
    fill('fillstruct')
  end
end

function reftool.fixplurals()
  local fx = "fixplurals"
  require("go.install").install(fx)
  local curdir = fn.getcwd()
  local filedir = fn.expand("%:p:h")
  local setup = {fx, ","}
  local cdpkg = string.format("exec cd %s", filedir)
  local cdback = string.format("exec cd %s", curdir)
  vim.cmd(cdpkg)
  vim.fn.jobstart(setup, {
    on_stdout = function(jobid, data, event)
      vim.cmd(cdback)
      -- print("fixplurals finished  ")
    end
  })
end

reftool.fillswitch = function()
  fill('fillswitch')
end

return reftool