---@class diff
---@field start  integer # The number of bytes at the beginning of the replacement
---@field finish integer # The number of bytes at the end of the replacement
---@field text   string  # What to replace
---@param  uri  string # The uri of file
---@param  text string # The content of file
---@return nil|diff[]
function OnSetText(uri, text) end

function OnSetText(uri, text)
    if text:sub(1, 4) ~= '--##' then
        return nil
    end
    local diffs = {}
    diffs[#diffs+1] = {
        start  = 1,
        finish = 4,
        text   = '',
    }
    for localPos, colonPos, typeName, finish in text:gmatch '()local%s+[%w_]+()%s*%:%s*([%w_]+)()' do
        diffs[#diffs+1] = {
            start  = localPos,
            finish = localPos - 1,
            text   = ('---@type %s\n'):format(typeName),
        }
        diffs[#diffs+1] = {
            start  = colonPos,
            finish = finish - 1,
            text   = '',
        }
    end
    return diffs
end