nixos/config/nvim/lua/config_plugins/config_lsp.lua

-- 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

-- Use an on_attach function to only map the following keys
-- after the language server attaches to the current buffer
local on_attach = function(client, bufnr)
    -- Enable completion triggered by <c-x><c-o>
    vim.api.nvim_buf_set_option(bufnr, 'omnifunc', 'v:lua.vim.lsp.omnifunc')

    -- 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', 'gd', '<cmd>Trouble lsp_definitions<cr>', bufopts)
    vim.keymap.set('n', 'gR', vim.lsp.buf.references, bufopts)
    vim.keymap.set('n', 'gr', '<cmd>Trouble lsp_references<cr>', bufopts)
    vim.keymap.set('n', 'gI', vim.lsp.buf.implementation, bufopts)
    vim.keymap.set('n', 'gi', '<cmd>Trouble lsp_implementations<cr>', bufopts)
    vim.keymap.set('n', 'K', vim.lsp.buf.hover, bufopts)
    -- vim.keymap.set('n', '<C-k>', vim.lsp.buf.signature_help, bufopts)
    vim.keymap.set('n', '<leader>wa', vim.lsp.buf.add_workspace_folder, bufopts)
    vim.keymap.set('n', '<leader>wr', vim.lsp.buf.remove_workspace_folder, bufopts)
    vim.keymap.set('n', '<leader>wl', function()
        print(vim.inspect(vim.lsp.buf.list_workspace_folders()))
    end, 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)
    -- Keep support for deprecated syntax in vim <= 7
    if vim.version().minor <= 7 then
        vim.keymap.set('n', '<leader>i', function()
            vim.lsp.buf.formatting()
        end, bufopts)
    else
        vim.keymap.set('n', '<leader>i', function()
            vim.lsp.buf.format({ timeout_ms = 10000, async = false })
        end, bufopts)
    end
    -- Enable aerial support
    require("aerial").on_attach(client, bufnr)
end

local lsp_flags = {
    -- This is the default in Nvim 0.7+
    debounce_text_changes = 150,
}

-- Setup nvim-cmp.
local cmp = require 'cmp'

cmp.setup({
    snippet = {
        -- REQUIRED - you must specify a snippet engine
        expand = function(args)
            vim.fn["vsnip#anonymous"](args.body) -- For `vsnip` users.
            -- require('luasnip').lsp_expand(args.body) -- For `luasnip` users.
            -- require('snippy').expand_snippet(args.body) -- For `snippy` users.
            -- vim.fn["UltiSnips#Anon"](args.body) -- For `ultisnips` users.
        end,
    },
    window = {
        completion = cmp.config.window.bordered(),
        documentation = cmp.config.window.bordered(),
    },
    mapping = cmp.mapping.preset.insert({
        ['<C-b>'] = cmp.mapping.scroll_docs(-4),
        ['<C-f>'] = cmp.mapping.scroll_docs(4),
        ['<C-Space>'] = cmp.mapping.complete(),
        ['<C-e>'] = cmp.mapping.abort(),
        ['<CR>'] = cmp.mapping.confirm({ select = true }), -- Accept currently selected item. Set `select` to `false` to only confirm explicitly selected items.
    }),
    sources = cmp.config.sources({
        { name = 'nvim_lsp' },
        { name = 'vsnip' }, -- For vsnip users.
        -- { name = 'luasnip' }, -- For luasnip users.
        -- { name = 'ultisnips' }, -- For ultisnips users.
        -- { name = 'snippy' }, -- For snippy users.
    }, {
        { name = 'buffer' },
    })
})

-- Set configuration for specific filetype.
cmp.setup.filetype('gitcommit', {
    sources = cmp.config.sources({
        { name = 'cmp_git' }, -- You can specify the `cmp_git` source if you were installed it.
    }, {
        { name = 'buffer' },
    })
})

-- Use buffer source for `/` (if you enabled `native_menu`, this won't work anymore).
cmp.setup.cmdline('/', {
    mapping = cmp.mapping.preset.cmdline(),
    sources = {
        { name = 'buffer' }
    }
})

-- Use cmdline & path source for ':' (if you enabled `native_menu`, this won't work anymore).
cmp.setup.cmdline(':', {
    mapping = cmp.mapping.preset.cmdline(),
    sources = cmp.config.sources({
        { name = 'path' }
    }, {
        { name = 'cmdline' }
    })
})

-- Setup lspconfig.
local capabilities = require('cmp_nvim_lsp').default_capabilities(vim.lsp.protocol.make_client_capabilities())

require('lspconfig')['pylsp'].setup {
    on_attach = on_attach,
    flags = lsp_flags,
    capabilities = capabilities,
    settings = {
        pylsp = {
            plugins = {
                pycodestyle = {
                    maxLineLength = 88
                },
                mypy = {
                    report_progress = true,
                },
            },
        },
    },
}

require('lspconfig')['fortls'].setup {
    on_attach = on_attach,
    flags = lsp_flags,
    capabilities = capabilities
}

require('lspconfig')['sumneko_lua'].setup {
    settings = {
        Lua = {
            runtime = {
                -- Tell the language server which version of Lua you're using (most likely LuaJIT in the case of Neovim)
                version = 'LuaJIT',
            },
            diagnostics = {
                -- Get the language server to recognize the `vim` global
                globals = { 'vim' },
            },
            workspace = {
                -- Make the server aware of Neovim runtime files
                library = vim.api.nvim_get_runtime_file("", true),
            },
            -- Do not send telemetry data containing a randomized but unique identifier
            telemetry = {
                enable = false,
            },
        },
    },
    on_attach = on_attach,
    flags = lsp_flags,
    capabilities = capabilities,
}

require('lspconfig')['texlab'].setup {
    on_attach = on_attach,
    flags = lsp_flags,
    capabilities = capabilities,
}