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/tailwindlabs/tailwindcss-intellisense
---
--- Tailwind CSS Language Server can be installed via npm:
---
--- npm install -g @tailwindcss/language-server

return {
    cmd = { 'tailwindcss-language-server', '--stdio' },
    -- filetypes copied and adjusted from tailwindcss-intellisense
    filetypes = {
        -- html
        'aspnetcorerazor',
        'astro',
        'astro-markdown',
        'blade',
        'clojure',
        'django-html',
        'htmldjango',
        'edge',
        'eelixir', -- vim ft
        'elixir',
        'ejs',
        'erb',
        'eruby', -- vim ft
        'gohtml',
        'gohtmltmpl',
        'haml',
        'handlebars',
        'hbs',
        'html',
        'htmlangular',
        'html-eex',
        'heex',
        'jade',
        'leaf',
        'liquid',
        'markdown',
        'mdx',
        'mustache',
        'njk',
        'nunjucks',
        'php',
        'razor',
        'slim',
        'twig',
        -- css
        'css',
        'less',
        'postcss',
        'sass',
        'scss',
        'stylus',
        'sugarss',
        -- js
        'javascript',
        'javascriptreact',
        'reason',
        'rescript',
        'typescript',
        'typescriptreact',
        -- mixed
        'vue',
        'svelte',
        'templ',
    },
    settings = {
        tailwindCSS = {
            validate = true,
            lint = {
                cssConflict = 'warning',
                invalidApply = 'error',
                invalidScreen = 'error',
                invalidVariant = 'error',
                invalidConfigPath = 'error',
                invalidTailwindDirective = 'error',
                recommendedVariantOrder = 'warning',
            },
            classAttributes = {
                'class',
                'className',
                'class:list',
                'classList',
                'ngClass',
            },
            includeLanguages = {
                eelixir = 'html-eex',
                eruby = 'erb',
                templ = 'html',
                htmlangular = 'html',
            },
        },
    },
    before_init = function(_, config)
        if not config.settings then
            config.settings = {}
        end
        if not config.settings.editor then
            config.settings.editor = {}
        end
        if not config.settings.editor.tabSize then
            config.settings.editor.tabSize = vim.lsp.util.get_effective_tabstop()
        end
    end,
    workspace_required = true,
    root_dir = function(bufnr, on_dir)
        local root_files = {
            'tailwind.config.js',
            'tailwind.config.cjs',
            'tailwind.config.mjs',
            'tailwind.config.ts',
            'postcss.config.js',
            'postcss.config.cjs',
            'postcss.config.mjs',
            'postcss.config.ts',
            'package.json',
        }
        local fname = vim.api.nvim_buf_get_name(bufnr)
        on_dir(vim.fs.dirname(vim.fs.find(root_files, { path = fname, upward = true })[1]))
    end,

    capabilities = capabilities,

    on_attach = function(client, bufnr)
        lsp_keymaps(bufnr)
        lsp_highlight_document(client)
    end,
}