local vim, api = vim, vim.api
local utils = require('go.utils')
local log = utils.log
local diagnostic_map = function(bufnr)
  local opts = { noremap = true, silent = true }
  api.nvim_buf_set_keymap(bufnr, 'n', ']O', ':lua vim.lsp.diagnostic.set_loclist()<CR>', opts)
end

if vim.lsp.buf.format == nil then
  -- neovim < 0.8 only
  vim.lsp.buf.format = function(options)
    if options.async then
      vim.lsp.buf.formatting()
    else
      vim.lsp.buf.formatting_sync()
    end
  end
end

local codelens_enabled = false

local on_attach = function(client, bufnr)
  log(client, bufnr)
  local function buf_set_keymap(...)
    vim.api.nvim_buf_set_keymap(bufnr, ...)
  end
  local uri = vim.uri_from_bufnr(bufnr)
  if uri == 'file://' or uri == 'file:///' or #uri < 11 then
    return { error = 'invalid file', result = nil }
  end
  diagnostic_map(bufnr)
  -- add highlight for Lspxxx

  api.nvim_buf_set_option(bufnr, 'omnifunc', 'v:lua.vim.lsp.omnifunc')

  local opts = { noremap = true, silent = true }
  if _GO_NVIM_CFG.lsp_document_formatting == false then
    -- client.resolved_capabilities.document_formatting = false
    client.server_capabilities.documentFormattingProvider = false
  end

  if _GO_NVIM_CFG.lsp_codelens then
    codelens_enabled = (client.server_capabilities.codeLensProvider ~= false)
    if not codelens_enabled then
      vim.notify('codelens not support by your gopls', vim.lsp.log_levels.WARN)
    end
    vim.lsp.codelens.refresh()
  end

  if _GO_NVIM_CFG.lsp_keymaps == true then
    buf_set_keymap('n', 'gD', '<Cmd>lua vim.lsp.buf.format({async = true}))<CR>', opts)
    buf_set_keymap('n', 'gD', '<Cmd>lua vim.lsp.buf.declaration()<CR>', opts)
    buf_set_keymap('n', 'gd', '<Cmd>lua vim.lsp.buf.definition()<CR>', opts)
    buf_set_keymap('n', 'K', '<Cmd>lua vim.lsp.buf.hover()<CR>', opts)
    buf_set_keymap('n', 'gi', '<cmd>lua vim.lsp.buf.implementation()<CR>', opts)
    buf_set_keymap('n', '<C-k>', '<cmd>lua vim.lsp.buf.signature_help()<CR>', opts)
    buf_set_keymap('n', '<space>wa', '<cmd>lua vim.lsp.buf.add_workspace_folder()<CR>', opts)
    buf_set_keymap('n', '<space>wr', '<cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>', opts)
    buf_set_keymap('n', '<space>wl', '<cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>', opts)
    buf_set_keymap('n', '<space>D', '<cmd>lua vim.lsp.buf.type_definition()<CR>', opts)
    buf_set_keymap('n', '<space>rn', "<cmd>lua require('go.rename').run()<CR>", opts)
    buf_set_keymap('n', '<space>ca', "<cmd>lua require('go.codeaction').run_action()<CR>", opts)
    buf_set_keymap('v', '<space>ca', "<cmd>lua require('go.codeaction').run_action()<CR>", opts)
    buf_set_keymap('n', 'gr', '<cmd>lua vim.lsp.buf.references()<CR>', opts)
    buf_set_keymap('n', '<space>e', '<cmd>lua vim.lsp.diagnostic.show_line_diagnostics()<CR>', opts)
    buf_set_keymap('n', '[d', '<cmd>lua vim.lsp.diagnostic.goto_prev()<CR>', opts)
    buf_set_keymap('n', ']d', '<cmd>lua vim.lsp.diagnostic.goto_next()<CR>', opts)
    buf_set_keymap('n', '<space>q', '<cmd>lua vim.lsp.diagnostic.set_loclist()<CR>', opts)

    if client.server_capabilities.documentFormattingProvider then
      buf_set_keymap('n', '<space>ff', '<cmd>lua vim.lsp.buf.format({async = true})<CR>', opts)
    end

    -- local vim_version = vim.version().major * 100 + vim.version().minor * 10 + vim.version().patch
  elseif type(_GO_NVIM_CFG.lsp_keymaps) == 'function' then
    _GO_NVIM_CFG.lsp_keymaps(bufnr)
  end
end

local extend_config = function(gopls, opts)
  if next(opts) == nil or gopls == nil then
    return gopls
  end
  for key, value in pairs(opts) do
    if type(gopls[key]) == 'table' and type(value) == 'table' then
      gopls[key] = vim.tbl_deep_extend('force', gopls[key], value)
    else
      if type(gopls[key]) ~= type(value) and key ~= 'handlers' then
        vim.notify('gopls setup for ' .. key .. ' is not ' .. type(value))
      end
      gopls[key] = value
    end
  end
  return gopls
end

local M = {}

function M.client()
  local clients = vim.lsp.get_active_clients()
  for _, cl in pairs(clients) do
    if cl.name == 'gopls' then
      return cl
    end
  end
end

function M.config()
  local gopls = require('go.gopls').setups()
  if gopls == nil then
    return
  end
  if _GO_NVIM_CFG == nil then
    vim.notify('please setup go.nvim', vim.lsp.log_levels.WARN)
    require('go').setup({})
  end
  gopls.on_attach = on_attach
  if type(_GO_NVIM_CFG.lsp_on_attach) == 'function' then
    gopls.on_attach = _GO_NVIM_CFG.lsp_on_attach
  end
  if _GO_NVIM_CFG.lsp_on_client_start and type(_GO_NVIM_CFG.lsp_on_client_start) == 'function' then
    gopls.on_attach = function(client, bufnr)
      on_attach(client, bufnr)
      _GO_NVIM_CFG.lsp_on_client_start(client, bufnr)
    end
  end

  if _GO_NVIM_CFG.gopls_cmd then
    gopls.cmd = _GO_NVIM_CFG.gopls_cmd
  else
    gopls.cmd = { 'gopls' }
    require('go.install').install('gopls')
  end

  if _GO_NVIM_CFG.lsp_gofumpt then
    gopls.settings.gopls.gofumpt = true
  end

  if _GO_NVIM_CFG.gopls_remote_auto then
    table.insert(gopls.cmd, '-remote=auto')
  end

  if type(_GO_NVIM_CFG.lsp_cfg) == 'table' then
    return extend_config(gopls, _GO_NVIM_CFG.lsp_cfg)
  end
  return gopls
end

function M.setup()
  local goplscfg = M.config()
  local lspconfig = utils.load_plugin('nvim-lspconfig', 'lspconfig')
  if lspconfig == nil then
    vim.notify('failed to load lspconfig', vim.lsp.log_levels.WARN)
    return
  end

  local vim_version = vim.version().major * 100 + vim.version().minor * 10 + vim.version().patch

  if vim_version < 61 then
    vim.notify('LSP: go.nvim requires neovim 0.6.1 or later', vim.log.levels.WARN)
  end
  log(goplscfg)
  lspconfig.gopls.setup(goplscfg)
end

--[[
	FillStruct      = "fill_struct"
	UndeclaredName  = "undeclared_name"
	ExtractVariable = "extract_variable"
	ExtractFunction = "extract_function"
	ExtractMethod   = "extract_method"
valueSet = { "", "Empty", "QuickFix", "Refactor", "RefactorExtract", "RefactorInline", "RefactorRewrite", "Source", "SourceOrganizeImports", "quickfix", "refactor", "refactor.extract", "refactor.inline", "refactor.re
write", "source", "source.organizeImports" }
]]

-- action / fix to take
-- only this action   'refactor.rewrite' source.organizeImports
M.codeaction = function(action, only, wait_ms)
  wait_ms = wait_ms or 1000
  local params = vim.lsp.util.make_range_params()
  log(action, only)
  if only then
    params.context = { only = { only } }
  end
  local result = vim.lsp.buf_request_sync(0, 'textDocument/codeAction', params, wait_ms)
  if not result or next(result) == nil then
    log('nil result')
    return
  end
  log('code action result', result)
  local c = M.client()
  for _, res in pairs(result) do
    for _, r in pairs(res.result or {}) do
      if r.edit and not vim.tbl_isempty(r.edit) then
        local re = vim.lsp.util.apply_workspace_edit(r.edit, c.offset_encoding)
        log('workspace edit', r, re)
      end
      if type(r.command) == 'table' then
        if type(r.command) == 'table' and r.command.arguments then
          for _, arg in pairs(r.command.arguments) do
            if action == nil or arg['Fix'] == action then
              vim.lsp.buf.execute_command(r.command)
              return
            end
          end
        end
      end
    end
  end
end

M.gopls_on_attach = on_attach
M.codelens_enabled = function()
  return codelens_enabled
end

return M