--use {'kevinhwang91/nvim-ufo', requires = 'kevinhwang91/promise-async'}

vim.o.foldcolumn = '0' -- '0' is not bad
vim.o.foldlevel = 99 -- Using ufo provider need a large value, feel free to decrease the value
vim.o.foldlevelstart = 99
vim.o.foldenable = true

-- Using ufo provider need remap `zR` and `zM`. If Neovim is 0.6.1, remap yourself
-- vim.keymap.set('n', 'zR', require('ufo').openAllFolds)
-- vim.keymap.set('n', 'zM', require('ufo').closeAllFolds)

---- Option 1: coc.nvim as LSP client
--use {'neoclide/coc.nvim', branch = 'master', run = 'yarn install --frozen-lockfile'}
--require('ufo').setup()
----

-- Option 2: nvim lsp as LSP client
-- Tell the server the capability of foldingRange,
-- Neovim hasn't added foldingRange to default capabilities, users must add it manually
local capabilities = vim.lsp.protocol.make_client_capabilities()
capabilities.textDocument.foldingRange = {
    dynamicRegistration = false,
    lineFoldingOnly = true
}
local language_servers = require("lspconfig").util.available_servers() -- or list servers manually like {'gopls', 'clangd'}
for _, ls in ipairs(language_servers) do
    require('lspconfig')[ls].setup({
        capabilities = capabilities
        -- you can add other fields for setting up lsp server in this table
    })
end

local handler = function(virtText, lnum, endLnum, width, truncate)
    local newVirtText = {}
    local suffix = ('   %d lines '):format(endLnum - lnum)
    local sufWidth = vim.fn.strdisplaywidth(suffix)
    local targetWidth = width - sufWidth
    local curWidth = 0
    for _, chunk in ipairs(virtText) do
        local chunkText = chunk[1]
        local chunkWidth = vim.fn.strdisplaywidth(chunkText)
        if targetWidth > curWidth + chunkWidth then
            table.insert(newVirtText, chunk)
        else
            chunkText = truncate(chunkText, targetWidth - curWidth)
            local hlGroup = chunk[2]
            table.insert(newVirtText, {chunkText, hlGroup})
            chunkWidth = vim.fn.strdisplaywidth(chunkText)
            -- str width returned from truncate() may less than 2nd argument, need padding
            if curWidth + chunkWidth < targetWidth then
                suffix = suffix .. (' '):rep(targetWidth - curWidth - chunkWidth)
            end
            break
        end
        curWidth = curWidth + chunkWidth
    end
    table.insert(newVirtText, {suffix, 'MoreMsg'})
    return newVirtText
end

-- global handler
-- `handler` is the 2nd parameter of `setFoldVirtTextHandler`,
-- check out `./lua/ufo.lua` and search `setFoldVirtTextHandler` for detail.
require('ufo').setup({
    fold_virt_text_handler = handler
})
