/**
 * CompletionsDropdown — autocomplete popover for journal command input.
 */

import { Component, For, Show, createEffect, onMount, onCleanup } from "solid-js";
import type { CompletionItem } from "./command-parser";
import type { CompletionsState } from "./completions";

export interface CompletionsDropdownProps {
  show: boolean;
  items: CompletionItem[];
  selectedIdx: number;
  onSelect: (item: CompletionItem) => void;
  onHover: (idx: number) => void;
  onClose: () => void;
  state: CompletionsState;
}

export const CompletionsDropdown: Component<CompletionsDropdownProps> = (
  props,
) => {
  let containerRef!: HTMLDivElement;

  // Scroll selected into view
  createEffect(() => {
    const idx = props.selectedIdx;
    if (!props.show || !containerRef) return;
    const el = containerRef.querySelector(`[data-comp-idx="${idx}"]`);
    if (el) el.scrollIntoView({ block: "nearest" });
  });

  // Click outside
  onMount(() => {
    const handler = (e: MouseEvent) => {
      if (containerRef && !containerRef.contains(e.target as Node)) {
        props.onClose();
      }
    };
    document.addEventListener("mousedown", handler);
    onCleanup(() => document.removeEventListener("mousedown", handler));
  });

  return (
    <Show when={props.show}>
      <Show
        when={props.state.status === "loaded" || props.state.status === "empty"}
        fallback={
          <Show
            when={props.state.status === "loading"}
            fallback={
              <div
                ref={containerRef}
                class="absolute bottom-full left-0 right-0 bg-white border border-red-200 rounded-t shadow-lg mb-0.5 z-50 px-3 py-2 text-xs text-red-500"
              >
                {(props.state as any).message || "无法加载补全数据"}
              </div>
            }
          >
            <div
              ref={containerRef}
              class="absolute bottom-full left-0 right-0 bg-white border border-gray-200 rounded-t shadow-lg mb-0.5 z-50 px-3 py-2 text-xs text-gray-400 italic"
            >
              正在加载补全数据…
            </div>
          </Show>
        }
      >
        <Show when={props.items.length > 0}>
          <div
            ref={containerRef}
            class="absolute bottom-full left-0 right-0 bg-white border border-gray-200 rounded-t shadow-lg mb-0.5 max-h-40 overflow-y-auto z-50"
          >
            <For each={props.items}>
              {(item, idx) => (
                <div
                  data-comp-idx={idx()}
                  class={`flex items-center gap-2 px-3 py-1.5 cursor-pointer text-sm ${
                    item.kind === "no-results"
                      ? "text-gray-400 italic cursor-default"
                      : idx() === props.selectedIdx
                        ? "bg-blue-50 text-blue-700"
                        : "hover:bg-gray-100 text-gray-700"
                  }`}
                  onClick={() => props.onSelect(item)}
                  onMouseEnter={() =>
                    item.kind !== "no-results" && props.onHover(idx())
                  }
                >
                  <Show
                    when={item.kind !== "no-results"}
                    fallback={
                      <span class="text-xs text-gray-300 shrink-0">—</span>
                    }
                  >
                    <span
                      class={`text-xs px-1 rounded shrink-0 ${
                        item.kind === "command"
                          ? "bg-purple-100 text-purple-700"
                          : "bg-gray-100 text-gray-500"
                      }`}
                    >
                      {item.kind === "command" ? "cmd" : "val"}
                    </span>
                  </Show>
                  <span class="font-mono truncate flex-1">{item.label}</span>
                </div>
              )}
            </For>
          </div>
        </Show>
      </Show>
    </Show>
  );
};