nixos/lua/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)

-- 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.declaration, bufopts)
    vim.keymap.set('n', 'gd', vim.lsp.buf.definition, bufopts)
    vim.keymap.set('n', 'K', vim.lsp.buf.hover, bufopts)
    vim.keymap.set('n', 'gi', vim.lsp.buf.implementation, 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)
    vim.keymap.set('n', 'gr', vim.lsp.buf.references, bufopts)
    vim.keymap.set('n', '<leader>i', vim.lsp.buf.formatting, bufopts)
    -- 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())

local function file_exists(name)
    local f=io.open(name,"r")
    if f~=nil then io.close(f) return true else return false end
end

local pyright_file = os.getenv( "HOME" ).."/.pyenv/versions/neovim3/bin/pyright-langserver"
local pylsp_file = os.getenv( "HOME" ).."/.pyenv/versions/neovim3/bin/pylsp"

if file_exists(pyright_file) then
    require('lspconfig')['pyright'].setup{
        cmd = {pyright_file, "--stdio"},
        on_attach = on_attach,
        flags = lsp_flags,
        capabilities = capabilities,
    }
elseif file_exists(pylsp_file) then
    require('lspconfig')['pylsp'].setup{
        cmd = {pylsp_file},
        on_attach = on_attach,
        flags = lsp_flags,
        settings = {
            pylsp = {
                plugins = {
                    pycodestyle = {maxLineLength = 88},
                    flake8 = {maxLineLength = 88}
                }
            }
        },
        capabilities = capabilities
    }
end

require('lspconfig')['fortls'].setup{
    cmd = {os.getenv( "HOME" ).."/.pyenv/versions/neovim3/bin/fortls"},
    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,
            },
        },
    },
}