local on_attach = function(_, bufnr)
    local function buf_set_keymap(...) vim.api.nvim_buf_set_keymap(bufnr, ...) end
    local function buf_set_option(...) vim.api.nvim_set_option_value(...) end

    -- Enable completion triggered by <c-x><c-o>
    buf_set_option('omnifunc', 'v:lua.vim.lsp.omnifunc', {})

    -- Mappings.
    local opts = { noremap=true, silent=true }

    -- See `:help vim.lsp.*` for documentation on any of the below functions
    buf_set_keymap('n', 'gD', '<cmd>lua vim.lsp.buf.declaration()<CR>', opts)
    buf_set_keymap('n', 'gd', '<cmd>lua vim.lsp.buf.definition()<CR>', opts)
    buf_set_keymap('n', 'gi', '<cmd>lua vim.lsp.buf.implementation()<CR>', opts)
    buf_set_keymap('n', 'gr', '<cmd>lua vim.lsp.buf.references()<CR>', opts)
    buf_set_keymap('n', '<space>k', '<cmd>lua vim.lsp.buf.hover()<CR>', opts)
    buf_set_keymap('n', '<space>K', '<cmd>lua vim.lsp.buf.signature_help()<CR>', opts)
    buf_set_keymap('n', '<space>wa', '<cmd>lua vim.lsp.buf.add_workspace_folder()<CR>', opts)
    buf_set_keymap('n', '<space>wr', '<cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>', opts)
    buf_set_keymap('n', '<space>wl', '<cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>', opts)
    buf_set_keymap('n', '<space>D', '<cmd>lua vim.lsp.buf.type_definition()<CR>', opts)
    buf_set_keymap('n', '<space>rn', '<cmd>lua vim.lsp.buf.rename()<CR>', opts)
    buf_set_keymap('n', '<space>ca', '<cmd>lua vim.lsp.buf.code_action()<CR>', opts)
    buf_set_keymap('n', '<space>e', '<cmd>lua vim.diagnostic.open_float()<CR>', opts)
    buf_set_keymap('n', '<space>p', '<cmd>lua vim.diagnostic.goto_prev()<CR>', opts)
    buf_set_keymap('n', '<space>n', '<cmd>lua vim.diagnostic.goto_next()<CR>', opts)
    buf_set_keymap('n', '<space>q', '<cmd>lua vim.diagnostic.setloclist()<CR>', opts)
    buf_set_keymap('n', '<space>f', '<cmd>lua vim.lsp.buf.format()<CR>', opts)
end

return {
    {
        'williamboman/mason.nvim',
        dependencies = {
            'neovim/nvim-lspconfig',
            "williamboman/mason-lspconfig.nvim",
        },
        config = function()
            require("mason").setup()
            local mason_lspconfig = require("mason-lspconfig")

            mason_lspconfig.setup()

            mason_lspconfig.setup_handlers({
                function (server_name)
                    require("lspconfig")[server_name].setup({
                        on_attach = on_attach,
                        flags = {
                            debounce_text_changes = 150,
                        }
                    })
                end
            })
        end,
    },
}