local function lsp_highlight_document(client)
    if client.server_capabilities.document_highlight then
        vim.api.nvim_create_augroup("lsp_document_highlight", { clear = true })

        vim.api.nvim_create_autocmd("CursorHold", {
            group = "lsp_document_highlight",
            buffer = 0,
            callback = function()
                vim.lsp.buf.document_highlight()
            end,
        })

        vim.api.nvim_create_autocmd("CursorMoved", {
            group = "lsp_document_highlight",
            buffer = 0,
            callback = function()
                vim.lsp.buf.clear_references()
            end,
        })
    end
end

local function lsp_keymaps(bufnr)
    local opts = { noremap = true, silent = true }

    vim.api.nvim_buf_set_keymap(bufnr, "n", "gd", "<cmd>lua vim.lsp.buf.definition()<CR>", opts)
    vim.api.nvim_buf_set_keymap(bufnr, "n", "gD", "<cmd>lua vim.lsp.buf.declaration()<CR>", opts)
    vim.api.nvim_buf_set_keymap(bufnr, "n", "gi", "<cmd>lua vim.lsp.buf.implementation()<CR>", opts)
    vim.api.nvim_buf_set_keymap(bufnr, "n", "K", "<cmd>lua vim.lsp.buf.hover()<CR>", opts)
    vim.api.nvim_buf_set_keymap(bufnr, "n", "<C-k>", "<cmd>lua vim.lsp.buf.signature_help()<CR>", opts)
    vim.api.nvim_buf_set_keymap(bufnr, "n", "gr", "<cmd>lua vim.lsp.buf.references()<CR>", opts)
    vim.api.nvim_buf_set_keymap(bufnr, "n", "[d", '<cmd>lua vim.diagnostic.goto_prev({border="rounded"})<CR>', opts)
    vim.api.nvim_buf_set_keymap(bufnr, "n", "]d", '<cmd>lua vim.diagnostic.goto_next({border="rounded"})<CR>', opts)

    vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>lr", "<cmd>lua vim.lsp.buf.rename()<cr>", opts)

    vim.api.nvim_buf_set_keymap(bufnr, "n", "<leader>q", "<cmd>lua vim.diagnostic.setloclist()<CR>", opts)

    vim.api.nvim_buf_set_keymap(
        bufnr,
        "n",
        "<leader>td",
        "<cmd>lua require 'telescope.builtin'.diagnostics()<cr>",
        opts
    )
    vim.api.nvim_buf_set_keymap(
        bufnr,
        "n",
        "<leader>tr",
        "<cmd>lua require 'telescope.builtin'.lsp_references()<CR>",
        opts
    )
end

local status_ok, cmp_nvim_lsp = pcall(require, "cmp_nvim_lsp")
if not status_ok then
    print("Failed to require cmp_nvim_lsp")
    return
end

local client_capabilities = vim.lsp.protocol.make_client_capabilities()
local capabilities = cmp_nvim_lsp.default_capabilities(client_capabilities)
capabilities.offsetEncoding = { "utf-8", "utf-16" }

---@brief
---
--- https://github.com/hrsh7th/vscode-langservers-extracted
---
--- `css-languageserver` can be installed via `npm`:
---
--- ```sh
--- npm i -g vscode-langservers-extracted
--- ```
---
--- Neovim does not currently include built-in snippets. `vscode-css-language-server` only provides completions when snippet support is enabled. To enable completion, install a snippet plugin and add the following override to your language client capabilities during setup.
---
--- ```lua
--- --Enable (broadcasting) snippet capability for completion
--- local capabilities = vim.lsp.protocol.make_client_capabilities()
--- capabilities.textDocument.completion.completionItem.snippetSupport = true
---
--- vim.lsp.config('cssls', {
---   capabilities = capabilities,
--- })
--- ```
return {
    cmd = { 'vscode-css-language-server', '--stdio' },
    filetypes = { 'css', 'scss', 'less' },
    init_options = { provideFormatter = true }, -- needed to enable formatting capabilities
    root_markers = { 'package.json', '.git' },
    settings = {
        css = { validate = true },
        scss = { validate = true },
        less = { validate = true },
    },
    capabilities = capabilities,
    on_attach = function(client, bufnr)
        lsp_keymaps(bufnr)
        lsp_highlight_document(client)

        if client.supports_method("textDocument/formatting") then
            vim.api.nvim_clear_autocmds({ group = augroup, buffer = bufnr })
            vim.api.nvim_create_autocmd("BufWritePre", {
                group = augroup,
                buffer = bufnr,
                callback = function()
                    vim.lsp.buf.format()
                end,
            })
        end
    end,
}