local str = require('cmp.utils.str')
local misc = require('cmp.utils.misc')
local compare = require('cmp.config.compare')
local types = require('cmp.types')

local WIDE_HEIGHT = 40

---@return cmp.ConfigSchema
return function()
  return {
    completion = {
      autocomplete = {
        types.cmp.TriggerEvent.InsertEnter,
        types.cmp.TriggerEvent.TextChanged,
      },
      completeopt = 'menu,menuone,noselect',
      keyword_pattern = [[\%(-\?\d\+\%(\.\d\+\)\?\|\h\w*\%(-\w*\)*\)]],
      keyword_length = 1,
    },

    snippet = {
      expand = function()
        error('snippet engine does not configured.')
      end,
    },

    documentation = {
      border = { '', '', '', ' ', '', '', '', ' ' },
      winhighlight = 'NormalFloat:CmpDocumentation,FloatBorder:CmpDocumentationBorder',
      maxwidth = math.floor((WIDE_HEIGHT * 2) * (vim.o.columns / (WIDE_HEIGHT * 2 * 16 / 9))),
      maxheight = math.floor(WIDE_HEIGHT * (WIDE_HEIGHT / vim.o.lines)),
    },

    confirmation = {
      default_behavior = types.cmp.ConfirmBehavior.Replace,
    },

    sorting = {
      priority_weight = 2,
      comparators = {
        compare.offset,
        compare.exact,
        compare.score,
        compare.kind,
        compare.sort_text,
        compare.length,
        compare.order,
      }
    },

    mapping = {},

    formatting = {
      format = function(e, suggest_offset)
        local item = e:get_completion_item()
        local word = e:get_word()
        local abbr = str.trim(item.label)

        -- ~ indicator
        if #(misc.safe(item.additionalTextEdits) or {}) > 0 then
          abbr = abbr .. '~'
        elseif item.insertTextFormat == types.lsp.InsertTextFormat.Snippet then
          local insert_text = e:get_insert_text()
          if word ~= insert_text then
            abbr = abbr .. '~'
          end
        end

        -- deprecated
        if item.deprecated or vim.tbl_contains(item.tags or {}, types.lsp.CompletionItemTag.Deprecated) then
          abbr = str.strikethrough(abbr)
        end

        -- append delta text
        if suggest_offset < e:get_offset() then
          word = string.sub(e.context.cursor_before_line, suggest_offset, e:get_offset() - 1) .. word
        end

        -- labelDetails.
        local menu = nil
        if misc.safe(item.labelDetails) then
          menu = ''
          if misc.safe(item.labelDetails.parameters) then
            menu = menu .. item.labelDetails.parameters
          end
          if misc.safe(item.labelDetails.type) then
            menu = menu .. item.labelDetails.type
          end
          if misc.safe(item.labelDetails.qualifier) then
            menu = menu .. item.labelDetails.qualifier
          end
        end

        return {
          word = word,
          abbr = abbr,
          kind = types.lsp.CompletionItemKind[e:get_kind()] or types.lsp.CompletionItemKind[1],
          menu = menu,
        }
      end
    },

    sources = {},
  }
end