-- ============================================================================
-- Completion - nvim-cmp Configuration
-- ============================================================================

return {
  {
    'hrsh7th/nvim-cmp',
    event = 'InsertEnter',
    dependencies = {
      -- Snippet Engine
      {
        'L3MON4D3/LuaSnip',
        build = (function()
          return 'make install_jsregexp'
        end)(),
        dependencies = {
          'rafamadriz/friendly-snippets',
        },
      },
      'saadparwaiz1/cmp_luasnip',

      -- Completion Sources
      'hrsh7th/cmp-nvim-lsp',
      'hrsh7th/cmp-buffer',
      'hrsh7th/cmp-path',
    },
    config = function()
      local cmp = require('cmp')
      local luasnip = require('luasnip')

      -- Friendly snippets laden
      require('luasnip.loaders.from_vscode').lazy_load()

      -- Custom Snippets für Go
      luasnip.add_snippets('go', {
        luasnip.snippet('iferr', {
          luasnip.text_node('if err != nil {'),
          luasnip.text_node({ '', '\treturn err' }),
          luasnip.text_node({ '', '}' }),
        }),
      })

      cmp.setup({
        snippet = {
          expand = function(args)
            luasnip.lsp_expand(args.body)
          end,
        },
        completion = { completeopt = 'menu,menuone,noinsert' },

        -- Keymaps
        mapping = cmp.mapping.preset.insert({
          -- Select next/prev item
          ['<C-n>'] = cmp.mapping.select_next_item(),
          ['<C-p>'] = cmp.mapping.select_prev_item(),

          -- Scroll docs
          ['<C-b>'] = cmp.mapping.scroll_docs(-4),
          ['<C-f>'] = cmp.mapping.scroll_docs(4),

          -- Confirm completion
          ['<CR>'] = cmp.mapping.confirm({ select = true }),

          -- Manual trigger
          ['<C-Space>'] = cmp.mapping.complete({}),

          -- Tab für Snippet forward/backward + completion
          ['<Tab>'] = cmp.mapping(function(fallback)
            if cmp.visible() then
              cmp.select_next_item()
            elseif luasnip.expand_or_locally_jumpable() then
              luasnip.expand_or_jump()
            else
              fallback()
            end
          end, { 'i', 's' }),

          ['<S-Tab>'] = cmp.mapping(function(fallback)
            if cmp.visible() then
              cmp.select_prev_item()
            elseif luasnip.locally_jumpable(-1) then
              luasnip.jump(-1)
            else
              fallback()
            end
          end, { 'i', 's' }),
        }),

        -- Sources (Priorität von oben nach unten)
        sources = {
          { name = 'nvim_lsp' },
          { name = 'luasnip' },
          { name = 'buffer' },
          { name = 'path' },
        },

        -- Window styling
        window = {
          completion = cmp.config.window.bordered(),
          documentation = cmp.config.window.bordered(),
        },

        -- Formatting
        formatting = {
          fields = { 'kind', 'abbr', 'menu' },
          format = function(entry, item)
            local icons = {
              Text = '',
              Method = '󰆧',
              Function = '󰊕',
              Constructor = '',
              Field = '󰇽',
              Variable = '󰂡',
              Class = '󰠱',
              Interface = '',
              Module = '',
              Property = '󰜢',
              Unit = '',
              Value = '󰎠',
              Enum = '',
              Keyword = '󰌋',
              Snippet = '',
              Color = '󰏘',
              File = '󰈙',
              Reference = '',
              Folder = '󰉋',
              EnumMember = '',
              Constant = '󰏿',
              Struct = '',
              Event = '',
              Operator = '󰆕',
              TypeParameter = '󰅲',
            }
            item.kind = string.format('%s %s', icons[item.kind] or '', item.kind)
            item.menu = ({
              nvim_lsp = '[LSP]',
              luasnip = '[Snippet]',
              buffer = '[Buffer]',
              path = '[Path]',
            })[entry.source.name]
            return item
          end,
        },
      })
    end,
  },
}