local on_attach = function(client, bufnr)
    -- Mappings.
    -- See `:help vim.lsp.*` for documentation on any of the below functions
    local bufopts = { noremap = true, silent = true, buffer = bufnr }
    vim.keymap.set("n", "gd", vim.lsp.buf.definition, bufopts)
    vim.keymap.set("n", "gr", vim.lsp.buf.references, bufopts)
    vim.keymap.set("n", "gi", vim.lsp.buf.implementation, bufopts)
    vim.keymap.set("n", "K", vim.lsp.buf.hover, bufopts)
    vim.keymap.set("n", "<leader>D", vim.lsp.buf.type_definition, bufopts)
    vim.keymap.set("n", "<leader>rn", vim.lsp.buf.rename, bufopts)
    vim.keymap.set("n", "<leader>ca", vim.lsp.buf.code_action, bufopts)
    vim.keymap.set(
        "n",
        "<leader>i",
        function() vim.lsp.buf.format { bufnr = bufnr, timeout_ms = 2000, async = true } end,
        bufopts
    )

    -- specific client tweaks
    if client.name ~= "null-ls" then client.server_capabilities.documentFormattingProvider = false end
    if client.name == "ruff_lsp" then client.server_capabilities.hoverProvider = false end

    -- Attach navic and navbuddy if applicable
    if client.server_capabilities.documentSymbolProvider then
        require("nvim-navic").attach(client, bufnr)
        require("nvim-navbuddy").attach(client, bufnr)
    end
end

local config = function()
    require("neodev").setup()

    -- Mappings.
    -- See `:help vim.diagnostic.*` for documentation on any of the below functions
    local opts = { noremap = true, silent = true }
    vim.keymap.set("n", "<leader>e", vim.diagnostic.open_float, opts)
    vim.keymap.set("n", "[d", vim.diagnostic.goto_prev, opts)
    vim.keymap.set("n", "]d", vim.diagnostic.goto_next, opts)
    vim.keymap.set("n", "<leader>q", vim.diagnostic.setloclist, opts)

    local signs = { Error = " ", Warn = " ", Hint = " ", Info = " " }
    for type, icon in pairs(signs) do
        local hl = "DiagnosticSign" .. type
        vim.fn.sign_define(hl, { text = icon, texthl = hl, numhl = hl })
    end

    local lsp_flags = { debounce_text_changes = 150 }
    local capabilities = require("cmp_nvim_lsp").default_capabilities()
    local servers = {
        "pyright",
        "ruff_lsp",
        "nil_ls",
        "lua_ls",
        "fortls",
        "yamlls",
        "vimls",
        "bashls",
    }
    for _, name in ipairs(servers) do
        require("lspconfig")[name].setup {
            on_attach = on_attach,
            flags = lsp_flags,
            capabilities = capabilities,
        }
    end

    local builtins = require "null-ls.builtins"
    require("null-ls").setup {
        sources = {
            builtins.code_actions.gitsigns,
            builtins.formatting.alejandra,
            builtins.formatting.autoflake,
            builtins.formatting.beautysh,
            builtins.formatting.black,
            builtins.formatting.fixjson,
            builtins.formatting.isort,
            builtins.formatting.mdformat,
            builtins.formatting.shellharden,
            builtins.formatting.stylua,
            builtins.hover.dictionary,
        },
        on_attach = on_attach,
        flags = lsp_flags,
        capabilities = capabilities,
    }
end

return {
    "neovim/nvim-lspconfig",
    event = { "BufReadPre", "BufNewFile" },
    dependencies = { "cmp-nvim-lsp", "folke/neodev.nvim", "jose-elias-alvarez/null-ls.nvim" },
    config = config,
}