Neovim/lua/plugins/nvim-lspconfig.lua

--
-- Start config for builtin Neovim language server protocol client
--
-- Source: https://github.com/RRethy/vim-illuminate
-- ..............................................
--
-- Author: Sven Vogel
-- Created: 08.11.2024
-- Edited: 08.11.2024
--
-- ==============================================

local ui = require 'config.ui'
local icons = require 'config.icons'

return {
    {
        'neovim/nvim-lspconfig',
        dependencies = {
            "williamboman/mason.nvim",
            {
                "williamboman/mason-lspconfig.nvim",
                config = function()
                end
            },
        },
        opts = {
            inlay_hints = {
                enabled = true,
            },
            diagnostics = {
                update_in_insert = false,
                underline = true,
                severity_sort = false,
                float = {
                    border = ui.border,
                    source = 'always',
                },
                virtual_text = {
                    spacing = 4,
                    source = "if_many",
                    -- this will set set the prefix to a function that returns the diagnostics icon based on the severity
                    -- this only works on a recent 0.10.0 build. Will be set to "●" when not supported
                    prefix = "icons"
                },
                signs = {
                    text = {
                        [vim.diagnostic.severity.ERROR] = icons.diagnostics.error,
                        [vim.diagnostic.severity.WARN] = icons.diagnostics.warn,
                        [vim.diagnostic.severity.HINT] = icons.diagnostics.hint,
                        [vim.diagnostic.severity.INFO] = icons.diagnostics.info
                    }
                }
            }
        },
        config = function(_, opts)
            require("mason").setup()

            local handlers = {
                -- The first entry (without a key) will be the default handler
                -- and will be called for each installed server that doesn't have
                -- a dedicated handler.
                function(server_name) -- default handler (optional)
                    require("lspconfig")[server_name].setup({
                        on_attach = function(client, bufnr)
                            -- optionally enable inlay hints
                            -- Source: https://www.reddit.com/r/neovim/comments/14em0f8/how_to_use_the_new_lsp_inlay_hints/
                            -- ..............................................

                            if client.server_capabilities.inlayHintProvider and opts.inlay_hints.enabled then
                                vim.lsp.inlay_hint.enable(true, { bufnr })
                            end
                        end
                    })
                end,
            }

            require("mason-lspconfig").setup({ handlers = handlers })

            -- Setup diagnostic signs
            --
            -- Source: https://www.lazyvim.org/plugins/lsp#mason-lspconfignvim
            -- ..............................................

            -- diagnostics signs
            if type(opts.diagnostics.signs) ~= "boolean" then
                for severity, icon in pairs(opts.diagnostics.signs.text) do
                    local name = vim.diagnostic.severity[severity]:lower():gsub("^%l", string.upper)
                    name = "DiagnosticSign" .. name
                    vim.fn.sign_define(name, { text = icon, texthl = name, numhl = "" })
                end
            end

            -- diagnostic sign as prefix for virtual text
            if type(opts.diagnostics.virtual_text) == "table" and opts.diagnostics.virtual_text.prefix == "icons" then
                opts.diagnostics.virtual_text.prefix = vim.fn.has("nvim-0.10.0") == 0 and "●" or function(diagnostic)
                    for d, icon in pairs(icons.diagnostics) do
                        if diagnostic.severity == vim.diagnostic.severity[d:upper()] then
                            return icon
                        end
                    end
                end
            end

            -- Setup diagnostic user interface
            --
            -- Source: https://vonheikemen.github.io/devlog/tools/setup-nvim-lspconfig-plus-nvim-cmp
            -- ..............................................

            vim.lsp.handlers['textDocument/hover'] = vim.lsp.with(
                vim.lsp.handlers.hover,
                {
                    border = ui.border
                })

            vim.lsp.handlers['textDocument/signatureHelp'] = vim.lsp.with(
                vim.lsp.handlers.signature_help,
                {
                    border = ui.border
                })

            vim.diagnostic.config(vim.deepcopy(opts.diagnostics))
        end
    }
}