----------- LSP
require'lspconfig'.solargraph.setup{}
local nvim_lsp = require('lspconfig')

-- Use an on_attach function to only map the following keys
-- after the language server attaches to the current buffer
local on_attach = function(client, bufnr)
  local function buf_set_keymap(...) vim.api.nvim_buf_set_keymap(bufnr, ...) end
  local function buf_set_option(...) vim.api.nvim_buf_set_option(bufnr, ...) end

  -- Enable completion triggered by <c-x><c-o>
  buf_set_option('omnifunc', 'v:lua.vim.lsp.omnifunc')

  -- Mappings.
  local opts = { noremap=true, silent=true }

  -- See `:help vim.lsp.*` for documentation on any of the below functions
  buf_set_keymap('n', 'gd', '<cmd>lua vim.lsp.buf.definition()<CR>', opts)
  buf_set_keymap('n', 'gr', '<cmd>lua vim.lsp.buf.references()<CR>', opts)
  buf_set_keymap('n', 'K', '<cmd>lua vim.lsp.buf.hover()<CR>', opts)
  buf_set_keymap('n', '<space>=', '<cmd>lua vim.lsp.buf.formatting()<CR>', opts)
end

-- Use a loop to conveniently call 'setup' on multiple servers and
-- map buffer local keybindings when the language server attaches
local servers = { 'solargraph' }
for _, lsp in ipairs(servers) do
  nvim_lsp[lsp].setup {
    on_attach = on_attach,
    flags = {
      debounce_text_changes = 150,
    }
  }
end

local cmp = require 'cmp'
cmp.setup {
  snippet = {
    expand = function(args)
      require('luasnip').lsp_expand(args.body)
    end,
  },
  mapping = {
    ['<C-p>'] = cmp.mapping.select_prev_item(),
    ['<C-n>'] = cmp.mapping.select_next_item(),
    ['<C-d>'] = cmp.mapping.scroll_docs(-4),
    ['<C-f>'] = cmp.mapping.scroll_docs(4),
    ['<C-Space>'] = cmp.mapping.complete(),
    ['<C-e>'] = cmp.mapping.close(),
    ['<CR>'] = cmp.mapping.confirm {
      behavior = cmp.ConfirmBehavior.Replace,
      select = true,
    },
    ['<Tab>'] = function(fallback)
      if cmp.visible() then
        cmp.select_next_item()
      elseif luasnip.expand_or_jumpable() then
        vim.fn.feedkeys(vim.api.nvim_replace_termcodes('<Plug>luasnip-expand-or-jump', true, true, true), '')
      else
        fallback()
      end
    end,
    ['<S-Tab>'] = function(fallback)
      if cmp.visible() then
        cmp.select_prev_item()
      elseif luasnip.jumpable(-1) then
        vim.fn.feedkeys(vim.api.nvim_replace_termcodes('<Plug>luasnip-jump-prev', true, true, true), '')
      else
        fallback()
      end
    end,
  },
  sources = {
    { name = 'nvim_lsp' },
    { name = 'luasnip' },
  },
}