-- language server setup
return {
    {
        "neovim/nvim-lspconfig",
        event = { "BufReadPre", "BufNewFile" },
        dependencies = {
        },
        config = function()
            -- Go
            vim.lsp.config["gopls"] = {
                cmd = {"gopls", "serve"},
                filetypes = {"go", "gomod"},
                settings = {
                    gopls = {
                        analyses = {
                            unusedparams = true,
                        },
                        staticcheck = true,
                    },
                },
            }
            -- C/C++
            vim.lsp.config["clangd"] = {}

            -- Arduino (C)
            vim.lsp.config["arduino_language_server"] = {}

            -- Lua
            vim.lsp.config["lua_ls"] = {
                cmd = {"lua-language-server" },
                settings = {
                    Lua = {
                        diagnostics = {globals = {'vim', 'opts'}},
                    },
                    telemetry = {
                        enable = false,
                    },
                },
            }

            -- Rust
            vim.lsp.config["rust_analyzer"] = {}

            -- Python
            vim.lsp.config["pylsp"] = {}

            -- TypeScript
            vim.lsp.config["tsls"] = {}

            -- Fix virtual text going off screen
            vim.diagnostic.config({
                virtual_text = false,
                signs = true,
                underline = true,
                update_in_insert = false,
                severity_sort = false,
            })

            -- creating key mappings 
            vim.api.nvim_create_autocmd('LspAttach', {
                callback = function(ev)
                    -- custom colors
                    vim.cmd('hi DiagnosticUnderlineError cterm=undercurl')
                    vim.cmd('hi DiagnosticUnderlineWarn cterm=undercurl')
                    vim.cmd('hi DiagnosticUnderlineInfo cterm=undercurl')
                    vim.cmd('hi DiagnosticUnderlineHint cterm=undercurl')
                    vim.cmd('hi DiagnosticUnderlineOk cterm=undercurl')
                    -- key mappings
                    local opts = { buffer = ev.buf,}
                    -- error viewing
                    vim.keymap.set('n', '<leader>e', vim.diagnostic.open_float, opts)
                    vim.keymap.set('n', '<leader>[d', vim.diagnostic.goto_prev, opts)
                    vim.keymap.set('n', '<leader>]d', vim.diagnostic.goto_next, opts)
                    -- def viewing/rename
                    vim.keymap.set('n', '<leader>gD', vim.lsp.buf.declaration, opts)
                    vim.keymap.set('n', '<leader>gd', vim.lsp.buf.definition, opts)
                    vim.keymap.set('n', '<leader>rn', vim.lsp.buf.rename, opts)
                    vim.keymap.set('n', '<leader>H', vim.lsp.buf.hover, opts)
                    -- auto hover for error viewing
                    vim.api.nvim_create_autocmd("CursorHold", {
                        callback = function()
                            opts = {
                                buffer = ev.buf,
                                focusable = false,
                                border = 'rounded',
                                source = 'always',
                                prefix = ' ',
                                scope = 'cursor',
                                close_events = { "BufLeave","CursorMoved","InsertEnter","FocusLost" },
                            }
                            vim.diagnostic.open_float(nil, opts)
                        end
                    })
                end,
            })
        end
    }
}