/**
 * SessionDropdown — session switcher for the journal header (GM only)
 */
import { Component, createSignal, For, Show } from "solid-js";
import {
  sessions,
  setSessionId,
  hydrateFromServer,
  useJournalStream,
} from "../stores/journalStream";

interface SessionDropdownProps {
  onCreate: () => void;
}

export const SessionDropdown: Component<SessionDropdownProps> = (props) => {
  const stream = useJournalStream();
  const manifest = sessions;
  const [dropdownOpen, setDropdownOpen] = createSignal(false);
  let dropdownRef!: HTMLDivElement;

  const handleSessionSelect = (id: string) => {
    if (id === stream.sessionId) {
      setDropdownOpen(false);
      return;
    }
    setDropdownOpen(false);
    setSessionId(id);
    hydrateFromServer(id).catch(() => {});
  };

  // Close dropdown on outside click
  if (typeof document !== "undefined") {
    document.addEventListener("click", (e) => {
      if (dropdownRef && !dropdownRef.contains(e.target as Node)) {
        setDropdownOpen(false);
      }
    });
  }

  return (
    <div ref={dropdownRef} class="relative">
      <button
        onClick={() => setDropdownOpen((v) => !v)}
        class="text-[10px] text-gray-400 hover:text-gray-600 truncate leading-tight cursor-pointer text-left"
      >
        {stream.sessionName || stream.sessionId}{" "}
        <span class="text-gray-300">▾</span>
      </button>
      <Show when={dropdownOpen()}>
        <div
          class="absolute top-full left-0 mt-1 w-48 bg-white border border-gray-200 rounded shadow-lg z-50 py-1 max-h-48 overflow-y-auto"
          onClick={(e) => e.stopPropagation()}
        >
          <For each={Object.entries(manifest().sessions)}>
            {([id, meta]) => (
              <button
                onClick={(e) => {
                  e.stopPropagation();
                  handleSessionSelect(id);
                }}
                class={`w-full text-left px-3 py-1 text-xs hover:bg-gray-100 flex items-center gap-1 ${
                  id === stream.sessionId
                    ? "bg-blue-50 text-blue-700"
                    : "text-gray-700"
                }`}
              >
                <span class="truncate flex-1">{meta.name || id}</span>
                <Show when={id === stream.sessionId}>
                  <span class="text-blue-500 shrink-0">✓</span>
                </Show>
              </button>
            )}
          </For>
          <div class="border-t border-gray-100 my-0.5" />
          <button
            onClick={(e) => {
              e.stopPropagation();
              e.preventDefault();
              setDropdownOpen(false);
              props.onCreate();
            }}
            class="w-full text-left px-3 py-1 text-xs text-blue-600 hover:bg-gray-100"
          >
            + 新建会话
          </button>
        </div>
      </Show>
    </div>
  );
};