-- completion configuration
local cmp = require'cmp'
cmp.setup({
	snippet = {
		expand = function(args)
			require('luasnip').lsp_expand(args.body)
		end,
	},
	window = {
		completion = cmp.config.window.bordered(),
		documentation = cmp.config.window.bordered(),
	},
	mapping = cmp.mapping.preset.insert({
		['<C-b>'] = cmp.mapping.scroll_docs(-4),
		['<C-f>'] = cmp.mapping.scroll_docs(4),
		['<C-Space>'] = cmp.mapping.complete(),
		['<C-e>'] = cmp.mapping.abort(),
		['<CR>'] = cmp.mapping.confirm({ select = true }),
	}),
	sources = cmp.config.sources({
		{ name = 'nvim_lsp' },
		{ name = 'luasnip' },
	}, {
		{ name = 'buffer' },
	})
})

-- Language Server Protocol server configuration
local capabilities = require('cmp_nvim_lsp').default_capabilities()
local lsp = require'lspconfig'
local servers = {
	'clangd',
	'pyright',
	'gopls',
	'zls',
-- more: pack/neovim/start/nvim-lspconfig/lua/lspconfig/server_configurations
}
for _, server in ipairs(servers) do
	lsp[server].setup{capabilities = capabilities}
end

-- snippet loading configuration
require("luasnip.loaders.from_vscode").lazy_load()

-- setup telescope
local telescope_builtin = require('telescope.builtin')

vim.cmd.colorscheme('vim')
vim.cmd.syntax('on')
vim.cmd.filetype({'plugin', 'indent', 'on'})
vim.cmd.highlight('SpellBad', 'ctermbg=Red')
vim.cmd.highlight('SpellBad', 'ctermfg=Black')

vim.opt.mouse         = 'a'
vim.opt.tabstop       = 4
vim.opt.expandtab     = false
vim.opt.number        = true
vim.opt.shiftwidth    = 4
vim.opt.autoindent    = true
vim.opt.spelllang     = {'en', 'de'}
vim.opt.colorcolumn   = {81}
vim.opt.encoding      = 'utf-8'
vim.opt.fileencodings = {'utf-8'}
vim.opt.list          = true
vim.opt.listchars     = {tab = '→ ', nbsp = '␣', trail = '•'}
vim.opt.spell         = true
vim.opt.termguicolors = false
vim.opt.hlsearch      = false

-- telescope related keymaps
vim.g.mapleader = ' '
vim.keymap.set('n', '<leader>ff', telescope_builtin.find_files, {})
vim.keymap.set('n', '<leader>fg', telescope_builtin.live_grep, {})
vim.keymap.set('n', '<leader>fb', telescope_builtin.buffers, {})
vim.keymap.set('n', '<leader>fh', telescope_builtin.help_tags, {})

-- tab management
vim.keymap.set('n', '<C-t>', ':tabe <LF>')
vim.keymap.set('n', '<Tab>', ':tabn <LF>')
vim.keymap.set('n', '<S-Tab>', ':tabp <LF>')

-- convert binary buffer to ASCII and back
vim.keymap.set('n', '<F5>', ':%!xxd -r <LF>')
vim.keymap.set('n', '<F6>', ':%!xxd <LF>')