local cmp = require'cmp'
local lspkind = require('lspkind')
local luasnip = require 'luasnip'

local source_mapping = {
  buffer = "[Buffer]",
  nvim_lsp = "[LSP]",
  nvim_lua = "[Lua]",
  cmp_tabnine = "[TN]",
  path = "[Path]",
  orgmode = "[Org]",
  luasnip = "[Snippet]",
}

local has_words_before = function()
  local line, col = unpack(vim.api.nvim_win_get_cursor(0))
  return col ~= 0 and
    vim.api.nvim_buf_get_lines(0, line - 1, line, true)[1]:sub(
      col, col):match("%s") == nil
end

cmp.setup({
  snippet = {
    expand = function(args)
      luasnip.lsp_expand(args.body)
    end,
  },
  mapping = {
    ['<C-p>'] = cmp.mapping(cmp.mapping.select_prev_item(), { 'i', 'c' }),
    ['<C-n>'] = cmp.mapping(cmp.mapping.select_next_item(), { 'i', 'c' }),
    ['<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 = false, -- only replace if explicitly selected
    },
    ["<Tab>"] = cmp.mapping(function(fallback)
      if cmp.visible() then
        cmp.select_next_item()
      elseif luasnip.expand_or_jumpable() then
        luasnip.expand_or_jump()
      elseif has_words_before() then
        cmp.complete()
      else
        fallback()
      end
    end, { "i", "s" }),

    ["<S-Tab>"] = cmp.mapping(function(fallback)
      if cmp.visible() then
        cmp.select_prev_item()
      elseif luasnip.jumpable(-1) then
        luasnip.jump(-1)
      else
        fallback()
      end
    end, { "i", "s" })
  },
  sources = cmp.config.sources({
    { name = 'cmp_tabnine' },
    { name = 'nvim_lsp' },
    { name = 'luasnip' },
  }),
  formatting = {
    format = function(entry, vim_item)
      vim_item.kind = lspkind.presets.default[vim_item.kind]
      local menu = source_mapping[entry.source.name]
      if entry.source.name == 'cmp_tabnine' then
        if entry.completion_item.data ~= nil and entry.completion_item.data.detail ~= nil then
          menu = entry.completion_item.data.detail .. ' ' .. menu
        end
        vim_item.kind = '?'
      end
      vim_item.menu = menu
      return vim_item
    end
  }
})

-- Set configuration for specific filetype.
cmp.setup.filetype('org', {
  sources = cmp.config.sources({
    { name = 'orgmode' },
    { name = 'cmp_tabnine' },
  }, {
      { name = 'buffer' },
    })
})

-- Use buffer source for `/` (if you enabled `native_menu`, this won't work anymore).
cmp.setup.cmdline('/', {
  sources = {
    { name = 'buffer' }
  }
})

-- Use cmdline & path source for ':' (if you enabled `native_menu`, this won't work anymore).
cmp.setup.cmdline(':', {
  sources = cmp.config.sources({
    { name = 'path' }
  }, {
      { name = 'cmdline' }
    }),
  mappings = cmp.mapping.preset.cmdline(),
})

-- Setup tabnine 
local tabnine = require('cmp_tabnine.config')
tabnine:setup({
  max_lines = 1000;
  max_num_results = 20;
  sort = true;
  run_on_every_keystroke = true;
  snippet_placeholder = '..';
  ignored_file_types = { -- default is not to ignore
    -- uncomment to ignore in lua:
    lua = true
  };
})