module Isomorfeus
  class TopLevel
    class << self
      if on_browser?
        def mount!
          Isomorfeus.init
          Isomorfeus::TopLevel.on_ready do
            root_element = `document.querySelector('div[data-iso-root]')`
            Isomorfeus.raise_error(message: "Isomorfeus root element not found!") unless root_element
            component_name = root_element.JS.getAttribute('data-iso-root')
            Isomorfeus.env = root_element.JS.getAttribute('data-iso-env')
            user_sid = root_element.JS.getAttribute('data-iso-usid')
            Isomorfeus.current_user_sid =`JSON.parse(user_sid)` if user_sid
            component = nil
            begin
              component = component_name.constantize
            rescue Exception => e
              `console.warn("Deferring mount: " + #{e.message})`
              @timeout_start = Time.now unless @timeout_start
              if (Time.now - @timeout_start) < 10
                `setTimeout(Opal.Isomorfeus.TopLevel['$mount!'], 100)`
              else
                `console.error("Unable to mount '" + #{component_name} + "'!")`
              end
            end
            if component
              props_json = root_element.JS.getAttribute('data-iso-props')
              props = `Opal.Hash.$new(JSON.parse(props_json))`
              raw_hydrated = root_element.JS.getAttribute('data-iso-hydrated')
              hydrated = (raw_hydrated && raw_hydrated == "true")
              %x{
                if (global.ServerSideRenderingStateJSON) {
                var state = global.ServerSideRenderingStateJSON;
                  var keys = Object.keys(state);
                  for(var i=0; i < keys.length; i++) {
                    if (Object.keys(state[keys[i]]).length > 0) {
                      global.Opal.Isomorfeus.store.native.dispatch({ type: keys[i].toUpperCase(), set_state: state[keys[i]] });
                    }
                  }
                }
              }
              Isomorfeus.execute_init_after_store_classes
              begin
                result = Isomorfeus::TopLevel.mount_component(component, props, root_element, hydrated)
                @tried_another_time = false
                result
              rescue Exception => e
                if  !@tried_another_time
                  @tried_another_time = true
                  `console.warn("Deferring mount: " + #{e.message})`
                  `console.error(#{e.backtrace.join("\n")})`
                  `setTimeout(Opal.Isomorfeus.TopLevel['$mount!'], 250)`
                else
                  `console.error("Unable to mount '" + #{component_name} + "'! Error: " + #{e.message} + "!")`
                  `console.error(#{e.backtrace.join("\n")})`
                end
              end
            end
          end
        end

        def on_ready(&block)
          %x{
            function run() { block.$call() };
            function ready_fun(fn) {
              if (document.readyState === "complete" || document.readyState === "interactive") {
                setTimeout(fn, 1);
              } else {
                document.addEventListener("DOMContentLoaded", fn);
              }
            }
            ready_fun(run);
          }
        end

        def on_ready_mount(component, props = nil, element_query = nil)
          # init in case it hasn't been run yet
          Isomorfeus.init
          on_ready do
            Isomorfeus::TopLevel.mount_component(component, props, element_query)
          end
        end

        def mount_component(component, props, element_or_query, hydrated = false)
          if `(typeof element_or_query === 'string')` || (`(typeof element_or_query.$class === 'function')` && element_or_query.class == String)
            element = `document.body.querySelector(element_or_query)`
          elsif `(typeof element_or_query.$is_a === 'function')` && element_or_query.is_a?(Browser::Element)
            element = element_or_query.to_n
          else
            element = element_or_query
          end

          top = Preact.create_element(component, props)
          hydrated ? Preact.hydrate(top, element) : Preact.render(top, element)
          Isomorfeus.top_component = top
        end
      end
    end
  end
end